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Ariyama, Hiroyuki, Mori, Keisuke (2023): Two Distinctive Amphipods (Crustacea) Collected from the Ariake Sea, Western Japan, with the Description of a New Species. Species Diversity 28 (1): 31-44, DOI: 10.12782/specdiv.28.31, URL: http://dx.doi.org/10.12782/specdiv.28.31

Ariyama, Hiroyuki, Kawabe, Katsutoshi (2022): Two New Species of Aoridae from Chichijima Island, the Ogasawara Islands in Japan (Crustacea: Amphipoda). Species Diversity 27 (1): 113-128, DOI: 10.12782/specdiv.27.113, URL: http://dx.doi.org/10.12782/specdiv.27.113

Metarhachotropis parva sp. nov. [Japanese name: Kawari-ryūgūyokoebi, new] (Figs 1–4) Type material. Holotype: male, 2.1 mm (OMNH-Ar-12515), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08'25"N 139°33'42"E –35°08'19"N 139°33'41"E, 95–96 m depth, gravel and sand bottom, using dredge, 5 November 2015, coll. H. Kohtsuka. Paratype: male, 2.0 mm (OMNH-Ar-12516), same data as holotype. Type locality. Sagami Bay, west of Jōgashima Island in Miura City, Kanagawa Prefecture, Japan. Etymology. From the Latin parvus, - a, - um (= small), referring to the body size. Description of male. Based on holotype (OMNH-Ar-12515, 2.1 mm) and paratype (OMNH-Ar-12516, 2.0 mm) only for mouthparts. Head (Figs 1, 2) large, rostrum developed. Eyes situated subventrally, ca. 1/3 length of head, composed of many dispersed ommatidia. Antenna 1 short, about 0.3 times of BL, weakly setose; peduncular articles 1–3 with length ratio of 1:1.05:0.45, article 1 stout, ventral margin lacking robust setae; accessory flagellum short, 1-articulate, tip with 2 setae; primary flagellum with 4 articles, articles 2, 3 each with aesthetasc. Antenna 2 also short, weakly setose; peduncular articles 3–5 with length ratio of 1:2.1:2.25; flagellum with 4 articles. Upper lip with ventral margin rounded, bare. Mandibles, incisors with 2 cusps, laciniae mobilis 2-toothed, wide in left and narrow in right, 3 accessory blades present, minute; molar columnar, poorly triturative; palp stout, article length ratio 1:4.25:5.0, articles 1, 2 lacking setae, article 3 with 2–3 short setae on tip. Lower lip wide, bare; mandibular processes large, inner lobes short. Maxilla 1 with inner plate lacking seta; outer plate with 4 robust setae apically; tip of palp article 2 with 4 short setae. Maxilla 2, inner plate wider and shorter than outer plate, both plates with several short setae distally. Maxilliped stout; inner and outer plates bearing 5 and 2 short setae, respectively; palp developed, medial margin of article 2 and distal margin of article 3 with 2 and 5 short setae, respectively. Pereon (Fig. 3). Gnathopod 1 large, poorly setose; coxa strongly projected anteroventrally; basis widened distally; merus short; carpus narrow, lobate posteriorly; propodus stout, palm oblique, smooth; dactylus curved posteriorly. Gnathopod 2 also large, poorly setose; coxa pentagonal, basis–dactylus similar to gnathopod 1. Pereopods 3, 4 slender, weakly setose; coxae subtriangular, gill on pereopod 4 wider than that on pereopod 3; dactyli almost linear. Pereopod 5 about 1.2 times as long as pereopod 4, weakly setose; coxa bilobed, posterior lobe deeper; basis relatively wide, subrectagular; propodus long; dactylus almost straight. Pereopod 6 about 1.05 times as long as pereopod 5, weakly setose; coxa bilobed, posterior lobe deeper; basis wide, subrectangular; propodus long; dactylus linear. Pereopod 7 ca. 1.15 times length of pereopod 6, weakly setose; coxa oval; basis expanded, posterodistal corner roundly projected; propodus long; dactylus straight. Pleon (Fig. 4). Epimeral plates, posteroventral corners of plates 1, 2 angular, that of plate 3 rounded, ventral margins without setae. Pleopods, pleopod 3 shortest; peduncles projected posterodistally, without setae; both rami short, outer rami longer than inner rami, outer and inner rami with 4 and 3 articles, respectively. Uropods relatively slender, outer rami shorter than inner rami, tips of both rami with minute embedded seta; length ratio of uropods 1–3 1:0.9:0.65. Telson elongate, cleft 38% of telson length; lateral margins each with long sensory seta and short seta. Female. Unknown. Coloration in preservative (10 months after fixation). Eyes light brown. Body and appendages generally white. Remarks. The uropods 1 and 2 with rami each bearing only minute embedded seta on the tip are also distinctive in the family Eusuridae sensu stricto. But discussion on the relationship with the senticaudate character is beyond the scope of this paper. Habitat. Gravel and sand bottom, 95–96 m depth. Distribution. Japan: Sagami Bay (present study)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Metarhachotropis parva, a new genus and species of Eusiridae (Crustacea: Amphipoda) from Sagami Bay, central Japan, pp. 95-100 in Zootaxa 5188 (1) on pages 96-99, DOI: 10.11646/zootaxa.5188.1.6, http://zenodo.org/record/7087440

Genus Metarhachotropis, new [Japanese name: Kawari-ryūgūyokoebi-zoku, new] Type species. Metarhachotropis parva sp. nov. by monotypy. Diagnosis. Body weakly compressed laterally, smooth. Head massive, rostrum large, eyes present. Antennae subequal, without calceoli, accessory flagellum 1-articulate, flagella short. Mandible, molar poorly triturative. Maxillae reduced, palp of maxilla 1 ordinary, maxilla 2 inner plate broader than outer plate. Coxae very short, coxa 1 strongly produced anteriorly, coxa 4 lacking posterior excavation, coxae 5, 6 bilobed. Gnathopods alike, large, subchelate, not eusirid form; carpi narrow, with posterior lobe; propodi ovate, much longer than carpi, palms oblique. Pereopods slender; pereopods 3, 4 similar, bases narrow; pereopods 5–7 progressively longer, bases expanded. Pleonal epimeron 3 rounded. Uropods biramous, outer rami shorter than inner rami. Telson elongate, cleft. Etymology. From the Greek meta (= beyond) and Rhachotropis (related genus). Remarks. Metarhachotropis gen. nov. is characterized by the massive head with large rostrum. Despite the unique body shape, the keys to families in Barnard & Karaman (1991) lead the present specimens to Eusiridae sensu lato owing to (1) head massive but not downturned; (2) accessory flagellum 1-articulate; (3) mandibular palp present, molar well developed; (4) coxae 1–3 almost same length; (5) urosomites separate; (6) uropod 3 biramous, peduncle short, inner ramus not reduced; and (7) telson flat, elongate and cleft. Within the genera of the family, only Eusirella Chevreux, 1908 and Rhachotropis Smith, 1883 [both included in Eusiridae sensu stricto (Lowry & Myers 2017)] resembles this new genus in the very short coxae and the strongly produced coxa 1. However, Metarhachotropis can be distinguished from Eusirella by the large rostrum (small in Eusirella) and the ordinary length of the maxilla 1 palp (short in Eusirella), and from Rhachotropis by the smooth body (carinate or toothed in Rhachotropis). Included taxa. Metarhachotropis parva sp. nov., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Metarhachotropis parva, a new genus and species of Eusiridae (Crustacea: Amphipoda) from Sagami Bay, central Japan, pp. 95-100 in Zootaxa 5188 (1) on page 96, DOI: 10.11646/zootaxa.5188.1.6, http://zenodo.org/record/7087440, {"references":["Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Chevreux, E. (1908) Diagnoses d'Amphipodes nouveaux provenant des Campagnes de la Princesse-Alice dans 1 ' Atlantique Nord. Bulletin de l'Institut Oceanographique, 121, 1 - 15.","Smith, S. I. (1883) List of the Crustacea dredged on the coast of Labrador by the Expedition under the direction of W. A. Stearns, in 1882. Proceedings of the United States National Museum, 6 (374), 218 - 222. https: // doi. org / 10.5479 / si. 00963801.374.218","Lowry, J. K. & Myers, A. A. (2017) A phylogeny and classification of the Amphipoda with the establishment of the new order Ingolfiellida (Crustacea: Peracarida). Zootaxa, 4265 (1), 1 - 89. https: // doi. org / 10.11646 / zootaxa. 4265.1"]}

Eusiridae Stebbing, 1888 [Japanese name: Tenrōyokoebi-ka], Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Metarhachotropis parva, a new genus and species of Eusiridae (Crustacea: Amphipoda) from Sagami Bay, central Japan, pp. 95-100 in Zootaxa 5188 (1) on page 96, DOI: 10.11646/zootaxa.5188.1.6, http://zenodo.org/record/7087440, {"references":["Stebbing, T. R. R. (1888) Report on the Amphipoda collected by H. M. S. Challenger during the years 1873 - 76. Report on the Scientific Results of the Voyage of H. M. S. Challenger during the Years 1873 - 76, Zoology, 29, 1 - 1737., 210 pls. https: // doi. org / 10.5962 / bhl. title. 6513"]}

Aoridae Stebbing, 1899 [Japanese name: Yumbosokoebi-ka], Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on page 394, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795, {"references":["Stebbing, T. R. R. (1899) Revision of Amphipoda (continued). Annals and Magazine of Natural History, Series 7, 4, 205 - 211. https: // doi. org / 10.1080 / 00222939908678185"]}

Grandidierella Coutière, 1904 [Japanese name: Dorosokoebi-zoku] Grandidierella Coutière, 1904: 166.—J.L. Barnard & Karaman, 1991: 194.— Myers & Lowry, 2003: 465. Neomicrodeutopus Schellenberg, 1925: 168. Grandidierella (Bigrandidierella) Karaman, 1985: 37. Propejanice Myers & Desiderato, 2019: 288. Type species. Grandidierella mahafalensis Coutière, 1904, fixed by monotypy. Diagnostic description. See Ariyama & Kawabe (2022). Grandidierella gracilis sp. nov. [Japanese name: Hosonaga-dorosokoebi, new] (Figs 9–13) Type material. Holotype: male, 3.9 mm (OMNH-Ar-12442), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08′15″N 139°34′44″E –35°08′58″N 139°34′45″E, 87–89 m depth, sand bottom, 31 October 2013. Paratypes: ovigerous female, 6.4 mm (OMNH-Ar-12443), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08′06″N 139°34′03″E –35°08′23″N 139°33′46″E, 95–97 m depth, 16 April 2014; male, 2.6 mm (OMNH-Ar-12444), west of Miura City, Kanagawa Prefecture, 35°09′09″N 139°34′50″E –35°08′57″N 139°34′00″E, 76–80 m depth, 27 April 2016; male, 4.0 mm and ovigerous female, 4.9 mm (OMNH-Ar-12445, 12446), off Shimoda City, Shizuoka Prefecture, 34°38′18″N 138°56′30″E –34°38′13″N 138°56′18″E, 42–47 m depth, gravel bottom, 27 November 2014. Type locality. Sagami Bay, west of Jōgashima Island in Miura City, Kanagawa Prefecture, Japan. Etymology. The Latin gracilis, - is, - e (= slender) refers to the body shape. Description of male. Based on holotype (OMNH-Ar-12442, 3.9 mm) and paratype (OMNH-Ar-12445, 4.0 mm) only for lower lip, coxa 1, and pereopods 6, 7. Body (Fig. 9) slender; eyes medium-sized, about 0.3 times length of head. Head (Fig. 10). Antenna 1 slender, ca. 0.4 times as long as body; length ratio of peduncular articles 1–3 1:1.4:0.6, article 1 with 3 ventromedial robust setae; accessory flagellum short, minutely biarticulate, tip with 5 setae; primary flagellum with 16 articles, terminal article minute, articles 3, 5, 7–14 each with aesthetasc. Antenna 2 also slender, length about 3/4 length of antenna 1; length ratio of peduncular articles 3–5 1:1.85:1.9, article 3 with 2 lateral and 2 ventral robust setae; flagellum short, consisting of 6 normal and 1 minute articles, article 3 with 2 robust and 1 thick setae, articles 4–6 each bearing 2 robust setae. Upper lip rounded ventrally, bearing many thin setae. Mandibles, incisor with 4 cusps, lacinia mobilis with 3 and 4 cusps in left and right, respectively, accessory setae 9 in left and 7 in right; palp stout, article 3 rectolinear, article length ratio 1:0.95–1.0:1.05–1.1, articles 1, 2 with 2 and 3 setae, respectively, article 3 bearing many long thick setae distally and subdistally. Lower lip with short mandibular process, mediodistal corner of outer lobe setose, distal parts of outer and inner lobes covered with thin setae. Maxilla 1, outer plate with 10 distal robust setae, palp article 2 bearing 6 robust and 4 slender setae apically. Maxilla 2, inner plate bearing distal and medial setae, outer plate setose on distal margin. Maxilliped, distal part of inner plate setose, mediodistal corner with curved robust seta and plumose seta; outer plate bearing 9 long-to-short robust setae mediodistally; palp article 2 long, articles 2, 3 weakly setose, article 4 with nail apically. Pereon (Fig. 11). Ventral surface lacking process. Gnathopod 1 not so large, carpochelate; coxa trapezoidal; basis wide, clavate; ischium short, posterodistal corner not projected; merus posterodistal corner lacking projection, distal margin setose; carpus rectangular, length except posterodistal tooth about 1.6 times width, posterodistal corner with acute tooth, medial surface without tooth, anterior margin bearing 37 stridulating ridges and 2 short robust setae medially, posterior margin setose; propodus ovoid, about 0.7 times as long as carpus, posterior margin lacking robust setae, weakly setose; dactylus slightly curved posteriorly, posterior margin with 7 denticles. Gnathopod 2 subchelate; coxa trapezoidal; basis very long, slender, anterior and posterior margins each with a few setae; merus posterodistal corner setose; carpus trapezoidal, posterior margin and posteromedial surface heavily setose; propodus ca. 1.15 times as long as carpus, posterodistal corner and posterior margin with 3 and 1 short robust setae, respectively; dactylus short, slightly curved posteriorly, posterior margin with 4 denticles. Pereopods 3, 4 slender, pereopod 3 longer than gnathopod 2 and pereopod 4, weakly setose; coxae trapezoidal; bases elongate; meri slightly wide, straight; propodi longer than carpi; dactyli narrow. Pereopod 5 shorter than pereopod 4; coxa bilobed; basis rectangular, posteroproximal corner triangularly projected, anterior and posterior margins with several simple setae; merus with thick seta each on anterodistal and posterodistal corners; carpus bearing anterodistal thick seta and 3 posterior robust setae; propodus with 3 anterior robust setae and 1 posterior and 2 posterodistal thick setae; dactylus short, slightly curved, with plumose seta. Pereopod 6 long; coxa short, bilobed; basis rectangular, posteroproximal corner roundly projected, anterior margin with 5 short robust and 3 simple setae, posterior margin bearing 9 plumose, 2 robust and 5 simple setae; merus with 1 anterodistal, 2 posterior and 1 posterodistal thick setae; carpus with 3 lateral robust setae, posterodistal corner bearing 1 robust and 1 thick setae; propodus with 4 anterior robust setae, posterodistal corner setose; dactylus slightly curved, with plumose seta. Pereopod 7 about 1.2 times as long as pereopod 6; coxa short, not bilobed; basis rectangular, posteroproximal corner slightly projected, anterior margin with 3 short robust setae, anterodistal corner bearing thick seta, posterior margin with 9 plumose setae; merus anterior margin with robust seta, posterodistal corner with thick seta; carpus with 3 lateral and 1 medial robust setae, mediodistal margin and posterodistal corner each with thick seta; propodus with 4 anterior robust setae and 2 posterior thick setae, posterodistal corner setose; dactylus slightly curved, bearing plumose seta. Pleon (Figs 9, 12). Epimeral plates 1–3 rounded posteroventrally, each with short seta, ventral margins bare. Pleopods, peduncles of pleopods 1–3 bearing 2, 2, 4 plumose setae, respectively; outer rami shorter than inner rami, outer rami with 10, 9, 9 articles and inner rami with 9, 9, 8 articles in pleopods 1–3, respectively. Uropod 1 long; dorsal surface of peduncle bearing 2 lateral and 5 medial robust setae, ventrodistal end with short inter-ramal process (18% length of peduncle); both rami shorter than peduncle, outer ramus slightly longer than inner ramus, former with 3 dorsolateral, 2 dorsomedial and 4 terminal robust setae, latter bearing 1 ventrolateral, 1 dorsolateral, 4 dorsomedial and 4 terminal robust setae. Uropod 2 about 0.6 times as long as uropod 1; peduncle dorsal surface with 1 laterodistal and 1 mediodistal robust setae; outer ramus shorter and inner ramus longer than peduncle, outer ramus 3/4 length of inner ramus, former with 1 dorsolateral, 1 dorsomedial and 4 terminal robust setae, latter bearing 2 dorsolateral, 3 dorsomedial and 5 terminal robust setae. Uropod 3 ca. 0.55 times length of uropod 2; peduncle slightly longer than wide, swollen medially, dorsal and ventral surfaces each with seta; single ramus about 2.6 times as long as peduncle, with 2 lateral, 2 dorsal and 2 medial setae, tip bearing tiny second article and 4 setae. Telson fleshy, laterodistal corners each with 2 simple and 1 sensory setae, lateral margins each bearing 2 sensory setae. Description of female. Based on paratype, ovigerous female (OMNH-Ar-12443, 6.4 mm). Generally similar to male holotype except for gnathopods and oostegites. Gnathopod 1 (Fig. 12 F-G1) subchelate; coxa roundish trapezoidal; basis almost straight; ischium and merus short, both lacking projection; carpus wide, posterior margin heavily setose; propodus about 0.9 times as long as carpus, palm almost transverse, posterior margin with 2 robust setae; dactylus slightly curved posteriorly, posterior margin with 4 denticles. Gnathopod 2 (Fig. 12 F-RG2) almost same as that of male, but basis wider, propodus with 3 posterodistal and 2 posterior robust setae. Variation. Paratype, male (OMNH-Ar-12445, 4.0 mm). Gnathopod 1 (Fig. 12 M-G1) almost same as that of holotype, but carpus posteromedial surface with small tooth, anterior margin bearing 4 small robust setae and 45 stridulating ridges. Paratype, juvenile male (OMNH-Ar-12444, 2.6 mm). Gnathopod 1 (Fig. 12 JM-RG1), carpus short like female, posterodistal tooth very small; propodus posterior margin with long robust seta. Coloration in life (Fig. 13). Based on paratype, ovigerous female (OMNH-Ar-12443, 6.4 mm). Eyes brown, whole body yellowish light brown. Remarks. Grandidierella gracilis sp. nov. has stridulating ridges on the carpus of the male gnathopod 1.This character is shared with eight species of Grandidierella: G. chaohuensis Hou & Li, 2002; G. japonica Stephensen, 1938; G. japonica sensu Myers, 1981 (probably different species); G. japonicoides Ariyama, 2020; G. lagamarensis (Myers & Desiderato, 2019); G. perlata Schellenberg, 1938; G. taihuensis Morino & Dai, 1990; and G. vietnamica Dang, 1968. Among these species, G. japonica sensu Myers, 1981, G. japonicoides, G. lagamarensis, and G. perlata resemble G. gracilis in the teeth arrangement on the male gnathopod 1 carpus (Table 1); however, this new species can be distinguished from G. japonica sensu Myers, 1981 by the poorly setose antennae, from G. japonicoides by the sparsely setose posterior margins of the pereopods 6, 7 bases, and from G. lagamarensis and G. perlata by the ordinary form of the male gnathopod 2. In addition, the habitat of G. gracilis is quite different from those of the eight species which inhabit freshwater areas, brackish waters or shallow seas (Table 1). Habitat. Sand or gravel bottom, 42–97 m depth. Distribution. Japan: Sagami Bay (present study)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on pages 405-411, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795, {"references":["Coutiere, H. (1904) Sur un type nouveau d'Amphipode, Grandidierella mahafalensis, provenant de Madagascar. Bulletin de la Societe philomathique de Paris, Serie 9, 6, 166 - 174.","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.91 https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Myers, A. A. & Lowry, J. K. (2003) A phylogeny and a new classification of the Corophiidea Leach, 1814 (Amphipoda). Journal of Crustacean Biology, 23, 443 - 485. https: // doi. org / 10.1163 / 20021975 - 99990353","Schellenberg, A. (1925) Crustacea VIII: Amphipoda. In: Michaelsen, W. (Ed.), Beitrage zur Kenntnis der Meeresfauna Westafrikas. Vol. 3. Fredrichsen, Hamburg, pp. 113 - 204.","Karaman, G. S. (1985) Two new taxa of suborder Gammaridea from Asia, with remarks to some Sri Lanka's species (contribu- tion to the knowledge of the Amphipoda 142). Poljoprivreda i sumarstvo, 31, 15 - 40.","Myers, A. A. & Desiderato, A. (2019) A new genus and species of Aoridae (Amphipoda, Senticaudata), Propejanice lagamarensis gen. nov. sp. nov. from Brazil. Zootaxa, 4629 (2), 287 - 293. https: // doi. org / 10.11646 / zootaxa. 4629.2.11","Ariyama, H. & Kawabe, K. (2022) Two new species of Aoridae from Chichijima Island, the Ogasawara Islands in Japan (Crustacea: Amphipoda). Species Diversity, 27, 113 - 128. https: // doi. org / 10.12782 / specdiv. 27.113","Hou, Z. & Li, S. (2002) A new species of the genus Grandidierella from lake Chaohu, China (Crustacea: Amphipoda: Aoridae). Acta Zootaxonomica Sinica, 27, 225 - 234.","Stephensen, K. (1938) Grandidierella japonica n. sp., a new amphipod with stridulating (?) organs from brackish water in Japan. Annotationes Zoologicae Japonenses, 17, 179 - 184.","Myers, A. A. (1981) Taxonomic studies on the genus Grandidierella Coutiere (Crustacea, Amphipoda). III. Fijian, Australian and Saudi Arabian species. Bulletin du Museum National d'Histoire Naturelle, Paris, 4 e Serie, 3, Section A, nº 1, 213 - 226.","Ariyama, H (2020) Six species of Grandidierella collected from the Ryukyu Archipelago in Japan, with descriptions of four new species (Crustacea: Amphipoda: Aoridae). Zootaxa, 4810 (1), 1 - 44. https: // doi. org / 10.11646 / zootaxa. 4810.1.1","Schellenberg, A. (1938) Litorale Amphipoden des tropischen Pazifik snach Sammlungen von Prof. Bock (Stockholm), Prof. Dahl (Berlin) und Prof. Pietschmann (Wein). Kungliga Svenska Vetenskapsakademiens Handlingar Series, 316 (6), 1 - 105.","Morino, H. & Dai, A. Y. (1990) Three amphipod species (Crustacea) from East China. Publications of Itako Hydrobiological Station, 4, 7 - 27.","Dang, D. N. (1968) Nouveaux amphipodes des eaux douces et saumatres du Nord Viet Nam. Zoologicheskii Zhurnal, 47, 212 - 222. [in Russian with French abstract]"]}

Aoroides sagamiensis sp. nov. [Japanese name: Sagami-burabura-sokoebi, new] (Figs 5–8) Type material. Holotype: male, 3.1 mm (OMNH-Ar-12435), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08′22″N 139°34′38″E –35°08′17″N 139°34′28″E, 87–90 m depth, gravel and sand bottom, 25 March 2015. Paratypes: female, 3.7 mm (OMNH-Ar-12436), same data as holotype; male, 3.1 mm and female, 4.5 mm (OMNH-Ar-12437, 12438), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08′06″N 139°34′03″E –35°08′23″N 139°33′46″E, 95–97 m depth, 16 April 2014; male, 2.3 mm and female, 3.0 mm (OMNH-Ar-12439, 12440), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°08′15″N 139°34′44″E – 35°08′58″N 139°34′45″E, 87–89 m depth, sand bottom, 31 October 2013; female, 3.0 mm (OMNH-Ar-12441), west of Jôgashima Island in Miura City, Kanagawa Prefecture, 35°08′25″N 139°34′25″E –35°08′07″N 139°33′32″E, 100–103 m depth, 20 January 2015. Type locality. Sagami Bay, west of Jōgashima Island in Miura City, Kanagawa Prefecture, Japan. Etymology. The Latin sagamiensis, - is, - e refers to the type locality. Description of male. Based on holotype (OMNH-Ar-12435, 3.1 mm) and paratype (OMNH-Ar-12437, 3.1 mm) only for pereopods 5, 7. Head (Figs 5, 6). Eyes medium-sized, about quarter of head length. Antenna 1 very long, ca. 0.95 times of BL, slender, poorly setose; peduncular articles 1–3 with length ratio of 1:1.75:0.55, article 1 with 4 robust setae ventrally; accessory flagellum vestigial, tip bearing 2 setae; primary flagellum with 14 articles, last article minute, articles 10, 11 each with aesthetasc. Antenna 2 about 0.6 times as long as antenna 1, slender, weakly setose; peduncular articles 3–5 with length ratio of 1:3.5:3.3; flagellum with 3 articles, with 4, 2, 2 long robust setae, respectively. Upper lip with ventral margin rounded, bearing short thin setae. Mandibles, incisor with 5 and 7 cusps in left and right, respectively, lacinia mobilis 4-toothed in left and 3-toothed in right, accessory blades bifid, 3 in left and 2 in right; palp rod-shaped, article length ratio 1:1.9–2.0:2.8, articles 1, 2 bare, article 3 with 2 long setae on tip. Lower lip with acute-tipped mandibular process, distal margin of outer lobe with 3 thick setae; distal margin of inner lobe bearing short thin setae. Maxilla 1 with small inner plate bearing long plumose seta; outer plate with 10 robust setae apically; tip of palp article 2 with 6 distal robust setae. Maxilla 2, outer plate setose mediodistally, inner plate with mediofacial row of setae and distal setae. Maxilliped with inner plate bearing 2 quadrate and 1 short robust setae and several thick setae; outer plate broad, barely not reaching apex of palp article 2, distomedial margin with 10 long-to-short robust setae; palp weakly setose, dorsodistal end of article 3 projected, article 4 bearing nail on tip. Pereon (Fig. 7). Sternal process absent. Gnathopod 1 large, merochelate; coxa roundish trapezoidal, anteroventral corner roundly projected, with robust seta; basis stout, anterior margin with a few short simple setae, lateral margin bearing several long and short simple setae; ischium with simple seta posterodistally; merus long, abruptly narrowed distally, distal 2/3 bearing dense plumose setae; carpus bullet-shaped, anterior margin with simple seta near distal corner, posterior margin with dense plumose setae; propodus straight, almost same length as carpus, anterior margin with a few simple setae, posterior margin and medial surface bearing many simple setae; dactylus slightly curved, posterior margin with 4 small denticles. Gnathopod 2 smaller than gnathopod 1, subchelate; coxa oval, ventral margin with 4 short setae; basis almost straight, anterior margin with several short setae, posterior margin bearing 3 robust setae; meus short, setose distally; carpus longish triangular, posterior margin heavily setose; propodus slightly longer than carpus, palm oblique, defined by robust seta, anterodistal corner, posterior and distal margins setose; dactylus short, slightly curved, posterior margin with 4 denticles. Pereopods 3, 4 slender, pereopod 3 slightly longer than gnathopod 2, pereopod 4 almost same length as gnathopod 2; coxae roundish trapezoidal; bases narrow, anterior and posterior margins each with a few setae; meri and carpi lacking robust setae on posterior margins; propodi and dactyli narrow. Pereopod 5, coxa bilobed; basis wide, posteroproximal corner rounded, anterior margin with a few short setae (1 robust); carpus with thick seta at posterodistal corner; propodus anterior margin bearing 3 robust setae, posterodistal corner weakly setose. Pereopod 6 longer than pereopod 5; coxa bilobed; basis wide, posteroproximal corner rounded, anterior margin bare, posterior margin with a few short setae; merus with thick seta each on posterodistal corner, posterior margin and posterodistal corner; carpus with 1 posterolateral and 3 (1 lost) posterodistal robust setae; propodus anterior margin with 4 robust setae, posterodistal corner setose. Pereopod 7 probably longer than pereopod 6; coxa semicircular; basis wide, posteroproximal corner slightly projected, anterior margin with a few short setae (1 robust), posterior margin bearing several short setae, posterodistal corner with thick seta; merus with 1, 3, 2 thick setae on anterodistal corner, posterior margin and posterodistal corner, respectively; carpus–dactylus lost. Pleon (Figs 5, 8). Epimeral plates 1–3 each with minute projection and short seta on posteroventral corner, ventral margins bare. Pleopods, pleopod 2>1> 3 in length; peduncles with 3, 4, 1 plumose setae in pleopods 1–3, respectively; outer rami shorter than inner rami, both rami with 6 articles in pleopods 1, 2, and with 5 articles in pleopod 3. Uropod 1, peduncle with 3 dorsolateral and 2 dorsomedial robust setae, inter-ramal process medium, 34% length of peduncle; outer and inner rami ca. 0.85 and 0.9 times as long as peduncle, respectively, outer ramus with 1 dorsolateral and 4 terminal robust setae, inner ramus bearing 2 dorsolateral and 4 terminal robust setae. Uropod 2 about 0.7 times length of uropod 1, peduncle with 2 dorsolateral and 1 dorsomedial robust setae, inter-ramal process vestigial; outer ramus almost same length as peduncle, inner ramus ca. 1.15 times of peduncle, outer ramus with 1 dorsal and 4 terminal robust setae, inner ramus bearing 3 dorsal and 4 terminal robust setae. Uropod 3 short, about half length of uropod 2, peduncle with 2 laterodistal robust setae, inter-ramal process vestigial; outer and inner rami ca. 1.05 and 1.15 times of peduncle, respectively, outer ramus without marginal robust seta, tip with tiny second article and 1 robust and 3 long setae, inner ramus with 1 marginal and 1 terminal robust setae and long apical seta. Telson roundish pentagonal, distal margin with pair of 1 long, 1 short and 1 sensory setae. Description of female. Based on paratype (OMNH-Ar-12438, 4.5 mm). Generally similar to male holotype except for gnathopods and oostegites. Gnathopod 1 (Fig. 8 F-G1) subchelate; coxa roundish trapezoidal, anteroventral corner not projected; basis slightly stout, poorly setose; ischium setose posterodistally; merus short, posterodistal margin setose; carpus longish triangular, posterior margin setose; propodus slightly longer than carpus, posterior margin and medial surface setose, palm oblique, defined by long robust seta; dactylus weakly curved, posterior margin with 5 denticles. Gnathopod 2 (Fig. 8 F-G2) subchelate; coxa large, roundish trapezoidal; basis narrow, straight, anterior and posterior margins with several short setae; meus short, setose distally; carpus longish triangular, posterior margin heavily setose; propodus long, ca. 1.2 times length of carpus, palm oblique, defined by robust seta, anterodistal corner and distal margin setose; dactylus short, slightly curved, posterior margin with 3 denticles. Variation. Paratype, male (OMNH-Ar-12437, 3.1 mm). Gnathopod 1 (Fig. 8 M-RG1) larger than that of holotype (Fig. 7 RG1) in spite of same body length; coxa long, acutely projected anteriorly; basis, carpus and propodus more slender and merus shorter than those of holotype. Paratype, small male (OMNH-Ar-12439, 2.3 mm). Gnathopod 1 almost same as that of holotype. Paratype, female (OMNH-Ar-12438, 4.5 mm). Uropod 3, outer ramus with 1 marginal and 1 terminal robust setae, inner ramus with 2 marginal and 1 terminal robust setae. Coloration in life. Unknown. Remarks. Aoroides sagamiensis sp. nov. has a distinctive male gnathopod 1 with poorly setose basis and heavily setose merus. Only Aoroides rubellus Ariyama, 2004 from Japan shares such a gnathopod 1 in the genus. However, this new species can be distinguished from A. rubellus in the fewer robust setae on the uropods 1–3. Habitat. Gravel and sand bottom, 87–103 m depth. Distribution. Japan: Sagami Bay (present study)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on pages 400-405, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795

Aoroides Walker, 1898 [Japanese name: Yumbo-sokoebi-zoku] Aoroides Walker, 1898: 284. — Myers, 1988: 187;—J.L. Barnard and Karaman, 1991: 171;— Myers and Lowry, 2003: 465. Type species. Aoroides columbiae Walker, 1898, fixed by monotypy. Diagnostic description. See Ariyama & Kawabe (2022)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on page 400, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795, {"references":["Walker, A. O. (1898) Crustacea collected by W. A. Herdman, F. R. S., in Puget Sound, Pacific coast of North America, September, 1897. Proceedings and Transactions of the Liverpool Biological Society, 12, 268 - 287, pls. 15 + 16.","Myers, A. A. (1988) A cladistic and biogeographic analysis of the Aorinae subfamily nov. Crustaceana, Supplement 13, 167 - 192.","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.91 https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Myers, A. A. & Lowry, J. K. (2003) A phylogeny and a new classification of the Corophiidea Leach, 1814 (Amphipoda). Journal of Crustacean Biology, 23, 443 - 485. https: // doi. org / 10.1163 / 20021975 - 99990353","Ariyama, H. & Kawabe, K. (2022) Two new species of Aoridae from Chichijima Island, the Ogasawara Islands in Japan (Crustacea: Amphipoda). Species Diversity, 27, 113 - 128. https: // doi. org / 10.12782 / specdiv. 27.113"]}

Aora Krøyer, 1845 [Japanese name: Himeyumbo-sokoebi-zoku] Aora Krøyer, 1845: 335.— Myers & Moore, 1983: 167 (key).— Myers, 1988: 187.—J.L. Barnard & Karaman, 1991: 161.— Myers & Lowry, 2003: 465. Type species. Aora typica Krøyer, 1845, fixed by monotypy. Diagnostic description [emended from J.L. Barnard & Karaman (1991)]. Body laterally compressed, smooth. Head, rostrum short, ocular lobes short, anterodistal corner slightly or not projected; eyes small to large. Urosomites free. Antenna 1 very long, slender; peduncular article 3 usually shorter than article 1; accessory flagellum 2- to 6- articulate. Antenna 2 shorter than antenna 1, flagellum short, with 4–9 articles. Mandible, palp strong, slender, with 3 articles, article 3 longest, parallel-sided or semi-falciform, well setose; left molar traversed with parallel channels. Maxilla 1, inner plate triangular or conical, with apical seta; outer plate with 9–10 apical robust setae; palp biarticulate, with several robust setae distally. Maxilla 2 broad, inner plate with mediofacial row of setae. Maxilliped, inner plate with several robust setae distally; outer plate with several marginal robust setae; palp consisting of 4 articles, article 4 bearing robust seta (nail) on tip. Coxae, male coxa 1 dilated, produced forward, male coxae 2–7 and all coxae in female ordinary to short, weakly overlapping; gills present on coxae 2–6; oostegites of female broad, present on coxae 2–5. Male gnathopod 1 greatly enlarged, merochelate; merus produced into long distal tooth; carpus long, linear, propodus usually shorter than carpus. Female gnathopod 1 smaller than that of male, subchelate; carpus shorter than propodus, palm oblique. Gnathopod 2 of both sexes smaller than gnathopod 1, subchelate; propodus shorter than or as long as carpus in male, length variable in female, palm oblique. Pereopods 3, 4 similar to each other; bases slender. Pereopods 5–7 similar to each other, progressively longer; bases broad. Epimeral plates 1–3 usually each with notch on ventroposterior corner. Uropods biramous; uropod 1 peduncle shorter than or same length as rami, distal end of peduncle with long inter-ramal process, both rami subequal in length; uropod 2 shorter than uropod l, peduncle shorter than rami, distal end of peduncle with short or vestigial inter-ramal process, outer ramus slightly shorter than inner ramus; uropod 3 shortest, peduncle slightly elongate, shorter than rami, both rami subequal in length, outer ramus often with tiny second article. Telson entire, fleshy, usually with pair of hooked cusps. Remarks. This genus contains twenty species to date (Horton et. al. 2022). But Aora inermis Appadoo & Myers, 2004 from Mauritius should be included in another genus (possibly Tethylembos), because this species has an acute anterodistal corner of the head, the non-merochelate (subchelate) male gnathopod 1, and the uropod 2 with a long inter-ramal process. The Aora species share the merochelate gnathopod 1 and the smaller subchelate gnathopod 2 both in male with the Aoroides species; however, the former can be distinguished from the latter by the 2–6 articulated accessory flagellum (rudimentary or absent in Aoroides) and the parallel-sided or semi-falciform article 3 of the maxillipedal palp (rod-shaped in Aoroides)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on page 394, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795, {"references":["Kroyer, H. (1845) Karcinologiske Bidrag. Naturhistorisk Tidsskrift, Series 2, 1, 283 - 345, 403, 453 - 638, pls 2, 3, 6, 7.","Myers, A. A. & Moore, P. G. (1983) The New Zealand and south-east Australian species of Aora Kroyer (Amphipoda, Gammaridea). Records of the Australian Museum, 35, 167 - 180. https: // doi. org / 10.3853 / j. 0067 - 1975.35.1983.316","Myers, A. A. (1988) A cladistic and biogeographic analysis of the Aorinae subfamily nov. Crustaceana, Supplement 13, 167 - 192.","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.91 https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Myers, A. A. & Lowry, J. K. (2003) A phylogeny and a new classification of the Corophiidea Leach, 1814 (Amphipoda). Journal of Crustacean Biology, 23, 443 - 485. https: // doi. org / 10.1163 / 20021975 - 99990353","Appadoo, C. & Myers, A. A. (2004) Corophiidea (Crustacea: Amphipoda) from Mauritius. Records of the Australian Museum, 56, 331 - 362. https: // doi. org / 10.3853 / j. 0067 - 1975.56.2004.1435"]}

Aora biarticulata sp. nov. [Japanese name: Nisetsu-himeyumbo-sokoebi, new] (Figs 1–4) Type material. Holotype: male, 6.3 mm (OMNH-Ar-12429), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°07′10″N 139°34′11″E –35°06′46″N 139°34′10″E, 238–282 m depth, 25 June 2015. Paratypes: 3 males, 5.1, 4.7, 3.6 mm (OMNH-Ar-12430–12432), female with juveniles, 6.2 mm (OMNH-Ar-12433) and female, 5.2 mm (OMNH-Ar-12434), west of Jōgashima Island in Miura City, Kanagawa Prefecture, 35°06′57″N 139°33′44″E –35°06′43″N 139°34′03E″, 230–398 m depth, 10 December 2015. Type locality. Sagami Bay, west of Jōgashima Island in Miura City, Kanagawa Prefecture, Japan. Etymology. The Latin biarticulatus, - a, - um (= 2-articulated) refers to the number of the accessory flagellum articles. Description of male. Based on holotype (OMNH-Ar-12429, 6.3 mm). Head (Figs 1, 2). Eyes medium (diameter: ca. 0.3 times of head length). Antenna 1 long, ca. 0.7 times of BL, slender; peduncular articles 1–3 with length ratio of 1:1.5:0.35, article 1 stout, ventral margin lacking robust setae; accessory flagellum short, 2-articulate, second article minute, with 4 setae on tip; primary flagellum with 22 articles, last article minute. Antenna 2 far shorter than antenna 1 (about 0.55 times), slender, weakly setose; peduncular articles 3–5 with length ratio of 1:3.1:3.55; flagellum with 6 articles, last article minute, articles 3–5 each with 2 robust setae distally. Upper lip with ventral margin rounded, bearing many short thin setae. Mandibles, left one with incisor bearing 5 cusps, 4-toothed lacinia mobilis, 4 accessory blades and 2 plumose setae, right one with incisor bearing 7 cusps, 6-toothed lacinia mobilis, 3 accessory blades and 1 plumose seta; palp stout, article 3 semi-falciform, article length ratio of right one 1:3.2:4.4, article 1 bare, article 2 with 5–6 setae, article 3 heavily setose. Lower lip with acute-tipped mandibular process, distal margin of outer lobe with several thick setae, dorsal surfaces of inner and outer lobes and ventral surface of outer lobe covered with short thin setae. Maxilla 1 with small inner plate bearing single long seta; outer plate with 10 robust setae apically; tip of palp article 2 with 7 distal robust setae. Maxilla 2, outer plate setose mediodistally, inner plate with many distal setae and mediofacial row of setae. Maxilliped with inner plate bearing 3 short robust setae and several plumose setae; outer plate broad, not reaching apex of palp article 2, distomedial margin with 11 robust setae; palp weakly setose, dorsodistal end of article 3 projected triangularly. Pereon (Fig. 3). Sternal process absent. Gnathopod 1 very large; coxa trapezoidal, anteroventral corner rounded, ventral margin bearing 3 short setae; basis stout, anterior margin and lateral surface bare, posterodistal corner with 2 short setae; ischium bearing 2 short setae on posterodistal corner; merus long, lanceolate, weakly setose; carpus roundish rectangular, anterior margin without setae, posterior margin and medial surface weakly setose; propodus almost straight, notched posterodistally, ca. 0.65 times as long as carpus, anterior margin with a few setae, posterior margin and medial surface weakly setose; dactylus slightly curved, posterior margin with 5 small denticles. Gnathopod 2 small, carpus–dactylus strongly twisted (counter clockwise in left, Fig. 1); coxa roundish rectangular, ventral margin with 5 short setae; basis slightly curved anteriorly, anterior margin with several short setae, posterior margin bearing single long and several short setae; meus short, setose posterodistally; carpus longish triangular, posterior margin heavily setose; propodus ca. 0.9 times as long as carpus, palm oblique, defined by robust seta, anteromedial surface and posterior margin heavily setose; dactylus short, curved, posterior margin with 5 denticles. Pereopods 3, 4 slender, slightly longer than gnathopod 2; coxae roundish rectangular; bases narrow, anterior margins with a few setae, posterior margins bearing 1 long and 4–6 short setae; meri and carpi without robust setae on posterior margins; propodi and dactyli narrow. Pereopod 5 almost same length as pereopod 4; coxa bilobed; basis wide, posteroproximal corner rounded, anterior margin with a few short robust setae, posterodistal corner bearing thick seta; carpus with 1 lateral and 3 distal robust setae; propodus anterior margin bearing 4 robust setae, posterodistal corner setose. Pereopod 6 about 1.5 times as long as pereopod 5; coxa bilobed; basis wide, posteroproximal corner rounded, anterior margin with a few short robust setae, posterodistal corner bearing thick seta; merus with 3 long thick setae on posterior margin; carpus bearing 1 lateral and 2 posterodistal robust setae; propodus anterior margin with several robust setae, posterodistal corner weakly setose. Pereopod 7 ca. 1.3 times length of pereopod 6; coxa oval; basis wide, posteroproximal corner roundly projected, anterior margin with a few short robust setae, posterodistal corner bearing thick seta; merus with 5 thick setae on posterior margin; carpus bearing a few thick setae each on anterior and posterior margins; propodus elongate, anterodistal corner with 2 short robust setae, posterodistal corner weakly setose. Pleon (Figs 1, 4). Epimeral plates 1–3 each with minute projection and short seta on posteroventral corner, ventral margins bare. Pleopods, pleopod 3 shortest; peduncles with 9, 3, 3 plumose setae in pleopods 1–3, respectively; outer rami shorter than inner rami, outer ramus of pleopod 3 with 8 articles, other outer rami and inner rami bearing 9 articles. Uropod 1, peduncle with 1 basofacial, 3 dorsolateral and 2 dorsomedial robust setae, inter-ramal process long, 62% length of peduncle; both rami ca. 1.35 times as long as peduncle, outer ramus with 3 dorsolateral and 4 terminal robust setae, inner ramus bearing 2 ventrolateral, 1 dorsolateral, 6 dorsomedial and 4 terminal robust setae. Uropod 2 about 3/4 length of uropod 1, peduncle with 2 dorsolateral and 1 dorsomedial robust setae, inter-ramal process short, 12% length of peduncle; outer and inner rami ca. 1.2 and 1.4 times of peduncle, respectively, outer ramus with 4 dorsal and 4 terminal robust setae, inner ramus bearing 5 dorsal and 4 terminal robust setae. Uropod 3 about 0.6 times length of uropod 2, peduncle with 2 laterodistal and 1 mediodistal robust setae, inter-ramal process minute; outer and inner rami ca. 1.45 and 1.25 times of peduncle, respectively, outer ramus with marginal robust seta in middle, tip with tiny second article bearing 2 long setae, 2 robust setae and 1 short seta, inner ramus with 3 marginal and 1 terminal robust setae and long apical seta. Telson roundish pentagonal, distal margin with pair of 2 long and 1 short setae, lateral margins each with 2 sensory setae. Description of female. Based on paratype (OMNH-Ar-12433, 6.2 mm). Generally similar to male holotype except for gnathopods and oostegites. Gnathopod 1 (Fig. 4 F-G1) subchelate; coxa roundish trapezoidal; basis stout, poorly setose; ischium with posterodistal setae; merus short, posterodistal margin setose; carpus longish triangular, posterior margins setose; propodus about 1.2 times length of carpus, posterior margin and medial surface setose, palm oblique, defined by long robust seta; dactylus weakly curved, posterior margin with 7 denticles. Gnathopod 2 (Fig. 4 F-G2), carpus–dactylus strongly twisted like male holotype; coxa large, roundish square; basis relatively narrow, anterior margin with several short setae, posterior margin bearing 1 long and a few short setae; meus short, weakly setose posterodistally; carpus longish triangular, posterior margin setose; propodus long, ca. 1.05 times length of carpus, palm oblique, defined by robust seta, posterior margin weakly setose; dactylus short, distal 1/3 narrowed, posterior margin with 2 denticles. Variation. Paratype, small male (OMNH-Ar-12430, 5.1 mm). Gnathopod 1 (Fig. 4 SM-G1), carpus wider than that of holotype (Fig. 3G 1); propodus ca. 0.85 times as long as carpus, palm oblique, defined by long robust seta; dactylus posterior margin with 6 denticles. Paratype, juvenile male (OMNH-Ar-12432, 3.6 mm). Gnathopod 1 (Fig. 4 JM-G1), merus short, with distal tip reaching half-length of carpus; propodus ca. 1.1 times length of carpus, palm oblique, defined by long robust seta; dactylus posterior margin with 4 denticles. Coloration in life. Unknown. Remarks. Aora biarticulata sp. nov. is characterized by (1) accessory flagellum with 2 articles, (2) weakly setose male gnathopod 1 with rounded coxa, and (3) male gnathopod 2 with setose carpus and propodus (setose only on posterior margin of carpus and both anterior and posterior margins of propodus). There is no other Aora species possessing all these characters. Especially in the accessory flagellum, the number of articles varies from 3 to 6 in the Aora species except for this new species (unknown in Aora adpressa Myers & Moore, 1983, A. anomala Schellenberg, 1926, and A. gibbula K.H. Barnard, 1932), whereas A. biarticulata has a 2-articulated accessory flagellum. Although Aora adpressa has the above characters (2) and (3), A. adpressa can be distinguished from A. biarticulata by the male pereon segments 2–4 each bearing strong sternal process, the male gnathopod 1 with shorter propodus, and the male gnathopod 2 with longer carpus. Habitat. Bottom sediment unknown, 230–398 m depth. Distribution. Japan: Sagami Bay (present study)., Published as part of Ariyama, Hiroyuki & Kohtsuka, Hisanori, 2022, Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda), pp. 393-413 in Zootaxa 5159 (3) on pages 395-400, DOI: 10.11646/zootaxa.5159.3.5, http://zenodo.org/record/6781795, {"references":["Myers, A. A. & Moore, P. G. (1983) The New Zealand and south-east Australian species of Aora Kroyer (Amphipoda, Gammaridea). Records of the Australian Museum, 35, 167 - 180. https: // doi. org / 10.3853 / j. 0067 - 1975.35.1983.316","Schellenberg, A. (1926) Die Gammariden der Deutschen Sudpolar-Expedition 1901 - 1903. Deutsche Sudpolar Expedition, 18 (Zoologie 10), 235 - 414.","Barnard, K. H. (1932) Amphipoda. Discovery Reports, 5, 1 - 326, 1 pl. https: // doi. org / 10.5962 / bhl. part. 27664"]}

Genus Antarctodius Berge, Vader & Coleman, 1999 [Japanese name: Mukashi-subeyokoebi-zoku] Antarctodius Berge, Vader & Coleman, 1999: 244; Labay, 2010: 35. Type species. Odius antarcticus Watling & Holman, 1981. Diagnosis [emended from Ariyama (2011)]. Body, anterodorsal margin of pereonite 1 not produced; dorsal projections of pereonites absent, those of pleonites present or absent; posterolateral margin of pleonite 3 with or without projection. Eyes variable. Antenna 1, peduncle with article 2 shorter than article 1; accessory flagellum absent or present. Upper lip, tip incised asymmetrically. Mandible conical; incisor narrow; lacinia mobilis present on left side; palp somewhat distal to molar. Lower lip with outer lobes long, strongly notched inside. Maxilla 1 with inner plate bearing 3 apical plumose setae; outer plate relatively short, styliform, with many robust setae on tip; palp 2-articulated, wide, exceeding outer plate, with several apical setae. Maxilla 2, inner plate almost same length as outer plate, mediodistal margins of both plates strongly setose. Maxilliped, inner plate narrow; outer plate medium, reaching distal end of palp article 2; palp 4-articulated, article 2 not expanded medially, article 4 short or long. Coxa 1 a little shorter than coxa 2; coxae 2–4 progressively wider, equally long. Gills present on gnathopod 2–pereopod 7(?). Oostegites of female present on gnathopod 2–pereopod 5. Gnathopod 1, propodus not projected posterodistally, posterodistal corner with long robust seta; dactylus small, triangular, with several plumose setae. Gnathopod 2, propodus narrow, palm weakly transverse, distal margin serrated; dactylus with accessory spine. Pereopods 3–7, meri projected distally. Uropods, inner ramus of uropod 3 slightly wide; peduncles of uropods 1, 2 and both rami bearing many robust setae. Telson cleft or entire. Species included. Antarctodius antarcticus (Watling & Holman, 1981); A. japonicus Ariyama, 2011; A. noncarinatus Labay, 2010; and A. rauscherti Coleman & Kauffeldt, 2001. Remarks. The diagnosis of the genus is emended mainly because the presence of the accessory flagellum and the gill on the coxa 7 is confirmed in the present study. However, in the papers dealing with the other Antarctodius species, the accessory flagellum is stated to be absent and the gill is not mentioned (Watling & Holman 1981, Coleman & Kauffeldt 2001, Labay 2010). A closer examination of them is needed. Distribution. Antarctic Ocean, Okhotsk Sea and Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 512-513, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Berge, J., Vader, W. & Coleman, O. (1999) A cladistic analysis of the amphipod families Ochlesidae and Odiidae, with description of a new species and genus. In: Schram, F. R. & von Vaupel Klein, J. C. (Eds.), Crustaceans and the Biodiversity Crisis. Brill, Leiden, pp. 239 - 265.","Labay, V. S. (2010) A new species and subspecies of Ochlesidae Stebbing, 1910 (Amphipoda: Gammaridea) from the Okhotsk Sea. Zootaxa, 2354 (1), 35 - 44. https: // doi. org / 10.11646 / zootaxa. 2354.1.3","Watling, L. & Holman, H. (1981) Additional acanthonotozomatid, paramphithoid, and stegocephalid Amphipoda from the Southern Ocean. Proceeding of the Biological Society of Washington, 94, 181 - 227.","Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39.","Coleman, C. O. & Kauffeldt, J. (2001) Antarctodius rauscherti, a new species (Crustacea: Amphipoda: Ochlesidae) from the Antarctic Ocean. Proceedings of the Biological Society of Washington, 114, 427 - 434."]}

Metodius cyanomaculatus sp. nov. [Japanese name: Rurihoshi-subeyokoebi, new] (Figs 2–6) Type material. Holotype: ovigerous female, 5.0 mm (OMNH-Ar-12230), Nodahama Beach, Izu-ōshima Island (Ōshima Town), Tokyo Prefecture, 34°47′49′′N, 139°21′31′′E, 12 m depth, using SCUBA, 24 March 2015, coll. O. Hoshino. Paratypes: male, 3.5 mm (OMNH-Ar-12231), same locality, 10 m depth, using SCUBA, 4 April 2015, coll. O. Hoshino; male, 2.8 mm (OMNH-Ar-12232), same locality, 10 m depth, using SCUBA, sandy bottom, 23 December 2015, coll. O. Hoshino. Type locality. Nodahama Beach, Izu-ōshima Island, Tokyo Prefecture in Japan. Etymology. From the Greek cyano (= dark blue) + the Latin maculatus (= maculate), referring to the body coloration. Description of female. Based on holotype, ovigerous female, 5.0 mm (OMNH-Ar-12230). Body (Fig. 2), pereonites and pleonites lacking dorsal projection. Head (Figs 2, 3). Lateral cephalic lobe acutely projected anteroventrally. Eyes large, 8.3% length of body. Antenna 1 stout; length ratio of peduncular articles 1–3 1:0.65:0.3; accessory flagellum slender, tip with 1 plumose and 2 simple setae; primary flagellum with 7 articles, article 1 elongate, each article with several aesthetascs. Antenna 2 also stout, almost same length as antenna 1, with ratio of lengths of peduncular articles 3–5 1:1.7:1.5; flagellum with 5 articles, article 1 long. Mandible, incisor wide, distal margin with 9–10 denticles; left lacinia mobilis bearing 10 denticles; accessory blades 13 in number; palp long, length ratio of palp articles 1–3 1:3.55:2.65, article 3 with numerous fine setae on anterior margin and lateral surface and 3 thick setae on tip. Maxilla 1, inner plate ovoid, with 3 setae on tip; medial margin of outer plate bearing 4 large and ca. 20 small robust setae, dorsal surface covered with many fine setae, palp very short. Maxilliped, inner plate slightly projected mediodistally, bearing 8 plumose setae; outer plate rounded, mediodistal margin minutely serrated, distal margin with several thick setae; laterodistal corners of palp articles 1, 2 each bearing a few robust setae, article 3 setose mediodistally, article 4 slender, about half length of article 3. Pereon (Fig. 4). Gnathopod 1 small; coxa narrow; basis slightly widened proximally, anterior and posterior margins without plumose setae; posterodistal projection of propodus with 1 robust, 1 plumose and several short setae; dactylus slightly exceeding tip of robust setae on propodus, bearing small robust seta and several short setae. Gnathopod 2 far larger than gnathopod 1; coxa with blunt projection and plumose seta on posterior margin, inner surface with tiny process; basis without plumose setae on anterior and posterior margins, posterodistal corner weakly projected, bearing robust seta; ischium also projected posterodistally; merus with 3 and 3 robust setae on posterior margin and at posterodistal corner, respectively; carpus projected posterodistally, tip with 4 robust setae medially; propodus long and wide, ca. 0.9 times length of coxa, anterodistal corner projected and excavated, palm slightly rounded, with many serrations, posterodistal corner and posterior margin with 9 and 2 robust setae, respectively; dactylus slender, tip narrowed, slightly exceeding posterodistal corner of propodus. Pereopod 3 longer than gnathopod 2; coxa with blunt projection and plumose seta posteriorly, inner surface with small triangular process; basis with 14 plumose setae on anterior margin and 5 small robust setae on posterior margin, posterodistal corner bearing 6 robust setae; ischium with 2 small robust setae on posterior margin; merus bearing 2 anterior, 3 anterodistal, 4 posterolateral, 5 posteromedial and 2 posterodistal robust setae; carpus with 4 anterodistal, 2 posterolateral, 4 posteromedial and 5 posterodistal robust setae; propodus with 6 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 4 longer than pereopod 3; coxa wide, inner surface with large triangular process; basis with 4 plumose and many short setae on anterior margin and 7 robust setae on posterolateral margin, posterodistal corner bearing 6 robust setae; ischium with 3 posterolateral and 2 posteromedial robust setae; merus with 1 anterior, 3 anterodistal, 2 posterolateral, 7 posteromedial and 2 posterodistal robust setae; carpus with 3 anterodistal, 4 posterolateral, 4 posteromedial and 5 posterodistal robust setae; propodus with 1 single and 5 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 5 slightly longer than pereopod 4; coxa lobate, anteroventral margin with 6 plumose setae on inner surface; basis produced posterodistally, posterior margin weakly convex, anteroproximal margin with 1 plumose and 1 robust setae, anterolateral surface and anterodistal corner bearing 9 and 2 robust setae, respectively; ischium with 4 robust setae on anterior margin; merus with 6 anterolateral, 2 anteromedial, 2 anterodistal, 1 posterior and 1 posterodistal robust setae; carpus with 4 anterolateral, 3 anteromedial and 3 anterodistal robust setae; propodus with 1 single and 6 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 6 slightly longer than pereopod 5; coxa lobate, anterior margin with 10 plumose setae; basis produced posterodistally, posterior margin weakly convex, anterolateral surface with many robust setae, anterodistal corner bearing 3 robust setae; ischium with 4 anterior robust setae; merus with 5 anterolateral, 2 anteromedial, 2 anterodistal and 2 posterior robust setae; carpus with 2 anterolateral, 4 anteromedial and 4 anterodistal robust setae; propodus with 7 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 7 a little longer than pereopod 6; coxa small, unlobed, anterior margin with ca. 20 plumose setae; basis wide, produced posterodistally, posterior margin strongly convex, anterior part with 8 marginal, 5 lateral and 2 distal robust setae, inner surface bearing many plumose setae; ischium with 3 anterior and 1 medial robust setae; merus bearing 3 anterior, 4 anteromedial, 2 anterodistal, 2 posterior and 1 posterodistal robust setae; carpus with 3 anterolateral, 3 anteromedial and 4 anterodistal robust setae; propodus with 1 single and 6 couples of robust setae anteriorly; dactylus with plumose seta. Pleon (Fig. 5). Pleopods, pleopod 3 shortest; peduncles each with many plumose setae laterally and 2 coupling hooks mediodistally, peduncle of pleopod 3 also bearing 4 robust and 5 simple setae mediodistally; outer rami longer than inner, outer and inner rami with 17, 18, 16 and 15, 16, 15 articles, respectively. Uropod 1 long; peduncle bearing 15 lateral, 1 laterodistal, 4 medial and 1 mediodistal robust setae; outer ramus with 12 lateral, 7 medial and 4 terminal robust setae, inner ramus with 6 lateral, 8 medial and 4 terminal robust setae. Uropod 2 short, ca. 0.7 times length of uropod 1; peduncle bearing 7 lateral, 1 laterodistal and 1 mediodistal robust setae; outer ramus ca. 3/4 times length of inner ramus, with 6 lateral, 2 medial and 3 terminal robust setae, inner ramus with 5 lateral, 5 medial and 3 terminal robust setae. Uropod 3 almost same length as uropod 2; peduncle with laterodistal robust seta; outer ramus ca. 0.6 times length of inner ramus, with 5 lateral and 3 medial robust setae and terminal short seta, inner ramus with 6 lateral and 7 medial robust setae and terminal short seta. Telson long triangular, tip minutely incised, with short seta. Description of male [based on paratype, 3.5 mm (OMNH-Ar-12231)]. Eyes larger than those of female. Antenna 1 (Fig. 5 M-A1), primary flagellum stouter than that of female, with 8 articles, each bearing numerous aesthetascs. Gnathopod 2 (Fig. 5 M-G2) subequal to that of female except for oostegite, but propodus more slender. Pereopod 7 (Fig. 5 M-P7), coxa anterior margin with 8 plumose setae; basis more slender than that of female, with 7 anterior, 5 anterolateral and 2 anterodistal robust setae, inner surface lacking plumose setae. Coloration in life [based on paratype, male, 2.8 mm (OMNH-Ar-12232); Fig. 6]. Head white, eyes red. Body and coxae brown, with ca. 15 bright blue spots and several white spots, dorsal margin of body framed in red. Antennae white and partly bright red. Pereopods 5–7 except coxae white. Habitat. Found on sandy bottom, 10–12 m depth. Distribution. Only Izu-ōshima Island in Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 488-493, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379

Metodius leucomaculatus sp. nov. [Japanese name: Shirahoshi-subeyokoebi, new] (Figs 7–11) Type material. Holotype: ovigerous female, 7.1 mm (OMNH-Ar-12233), off Jōgashima Island, Miura City, Kanagawa Prefecture, 35°08′25′′N, 139°32′30′′E, 147–250 m depth, using dredge, 12 February 2015, coll. H. Kohtsuka. Paratypes: ovigerous female, 8.6 mm (OMNH-Ar-12234), same locality, 35°08′18′′N, 139°34′41′′E, 86.8–87.7 m depth, sandy bottom, using dredge, 29 July 2014, coll. H. Kohtsuka; ovigerous female, 6.8 mm (OMNH-Ar-12235), same locality, 35°08′16′′N, 139°33′28′′E, 100–103 m depth, using dredge, 20 January 2015, coll. H. Kohtsuka; male, 7.0 mm (OMNH-Ar-12236), same locality, 35°08′22′′N, 139°33′41′′E, 95.2–95.9 m depth, gravel and sand bottom, using dredge, 5 November 2015, coll. H. Kohtsuka. Type locality. Off Jōgashima Island, Miura City, Kanagawa Prefecture in Japan. Etymology. From the Greek leuco (= white) + the Latin maculatus (= maculate), referring to the body coloration. Description of female. Based on holotype, ovigerous female, 7.1 mm (OMNH-Ar-12233). Body (Fig. 7), pereonites 6, 7 with small and medium dorsal projections, respectively; pleonites 1–3 each with dorsal projection. Head (Figs 7, 8). Lateral cephalic lobe projected anteroventrally. Eyes large, 9.9% length of body. Antenna 1 somewhat slender; length ratio of peduncular articles 1–3 1:0.55:0.25; accessory flagellum minute, tip with 1 thick and 1 simple setae; primary flagellum with 8 articles, article 1 elongate, each article with several aesthetascs. Antenna 2 slender, almost same length as antenna 1, with ratio of lengths of peduncular articles 3–5 1:1.85:1.4; flagellum with 10 articles, article 1 long. Mandible, incisor wide, distal margin with 9–11 denticles; left lacinia mobilis bearing 10 denticles; accessory blades 14 in number; palp long, length ratio of palp articles 1–3 in right 1:4.1:4.0, with numerous fine setae on anterior margin and lateral surface and 3 thick setae on tip. Maxilla 1, inner plate oval, with single seta on tip; medial margin of outer plate bearing 6 large and ca. 30 small robust setae and many simple setae, dorsal and ventral surfaces covered with fine setae, palp very short. Maxilliped, inner plate slightly projected mediodistally, with many plumose setae distally and medially; outer plate rounded, mediodistal margin distinctly serrated, distal margin setose; laterodistal corners of palp articles 1, 2 each bearing single robust seta, article 3 setose mediodistally, article 4 slender, ca. 0.6 times length of article 3. Pereon (Fig. 9). Gnathopod 1 small; coxa narrow; basis slightly narrowed distally, anterior margin with single plumose seta proximally, posterior margin lacking plumose seta; posterodistal projection of propodus with 1 robust, 1 plumose and several short setae; dactylus far exceeding tip of robust setae on propodus, bearing small robust seta, plumose seta and several short setae. Gnathopod 2 greatly larger than gnathopod 1; coxa with blunt projection on posterior margin, inner surface with tiny process; basis without plumose setae on anterior and posterior margins, posterodistal corner weakly projected, bearing 3 robust setae; ischium slightly projected posterodistally; merus with 2 robust setae at posterodistal corner; carpus projected posterodistally, posterior margin with 5 robust setae; propodus long and wide, almost same length as coxa, anterodistal corner projected and excavated, palm slightly rounded, with numerous denticles, posterodistal corner and posterior margin with single large and 7 small robust setae, respectively; dactylus slender, slightly exceeding posterodistal corner of propodus. Pereopod 3 a little shorter than gnathopod 2; coxa with blunt projection and plumose seta posteriorly, inner surface with small triangular process; basis without plumose setae, but with 9 and 4 robust setae on posterior margin and at posterodistal corner, respectively; ischium with 2 small robust setae on posteromedial surface; merus bearing 1 anterodistal and 1 posterodistal robust setae; carpus with 2 anterodistal and 4 posterodistal robust setae, posterior margin with 1 single and 3 couples of robust setae; propodus with 8 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 4 almost same length as pereopod 3; coxa wide, inner surface with large triangular process; basis without plumose setae, but with 10 and 4 robust setae on posterior margin and at posterodistal corner, respectively; ischium with posteromedial robust seta; merus with 1 anterodistal, 2 posterolateral, 2 posteromedial and 3 posterodistal robust setae; carpus with 3 anterodistal, 4 posterolateral, 5 posteromedial and 3 posterodistal robust setae; propodus with 8 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 5 slightly shorter than pereopod 4; coxa lobate, anteroventral margin with 6 inner and marginal simple setae; basis produced posterodistally, posterior margin distinctly convex distally, anterior part with 8 lateral, 3 medial and 2 distal robust setae; ischium with 3 robust setae on anterior margin; merus with 5 anterolateral, 1 anterodistal, 1 posterior and 1 posterodistal robust setae; carpus with 5 anterolateral, 5 anteromedial and 2 anterodistal robust setae; propodus with 1 single and 7 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 6 slightly longer than pereopod 5; coxa lobate, anterior margin with many plumose setae and strange-shaped thick seta; basis produced posterodistally, posterior margin distinctly convex distally, anterolateral surface with several proximal simple setae and 5 robust setae, anterior margin bearing 10 robust setae, anterodistal corner with 2 robust setae; ischium with 3 anterior robust setae; merus bearing 5 anterior, 1 anteromedial, 2 anterodistal, 2 posterior and 1 posterodistal robust setae; carpus with 6 couples of robust setae anteriorly; propodus with 8 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 7 a little shorter than pereopod 6; coxa small, unlobed, anterior margin with 13 plumose setae; basis wide, produced posterodistally, distal end of posterior margin strongly convex, anterior part with 12 marginal, 3 lateral and 2 distal robust setae, inner surface bearing many plumose setae; ischium with 3 anterior and 1 anteromedial robust setae; merus bearing 5 anterior, 2 anteromedial, 2 anterodistal and 1 posterior robust setae; carpus with 5 couples of robust setae anteriorly; propodus bearing 8 couples of robust setae anteriorly; dactylus with plumose seta. Pleon (Fig. 10). Pleopods, pleopod 3 shortest; peduncles each with many plumose setae laterally and 2 coupling hooks mediodistally, peduncle of pleopod 3 also bearing 5 robust and 3 simple setae medially and 6 plumose setae posteriorly; outer rami longer than inner, outer and inner rami with 18, 20, 19 and 18, 16, 17 articles, respectively. Uropod 1 long; peduncle bearing 5 lateral, 1 laterodistal, 10 medial and 1 mediodistal robust setae [lost in part; with 11 lateral, 1 laterodistal, 10 medial and 1 mediodistal robust setae in paratype, ovigerous female, 6.8 mm (OMNH-Ar-12235)]; outer ramus with 8 lateral, 8 medial and 3 terminal robust setae, inner ramus with 6 lateral, 9 medial and 3 terminal robust setae. Uropod 2 short, ca. 3/4 times length of uropod 1; peduncle bearing 7 lateral and 1 laterodistal robust setae; outer ramus ca. 0.8 times length of inner ramus, with 7 lateral, 2 medial and 3 terminal robust setae, inner ramus with 6 lateral, 8 medial and 3 terminal robust setae. Uropod 3 almost same length as uropod 2; peduncle with 2 lateral and 1 laterodistal robust setae; outer ramus ca. 0.6 times length of inner ramus, with 5 lateral and 3 medial robust setae, inner ramus with 6 lateral and 8 medial robust setae and terminal short seta. Telson long triangular, tip acutely projected, not incised. Description of male [based on paratype, 7.0 mm (OMNH-Ar-12236)]. Eyes larger than those of female. Antenna 1 (Fig. 10 M-RA1), peduncular article 3 shorter than that of female; primary flagellum with 10 articles, each bearing many aesthetascs. Gnathopod 2 (Fig. 10 M-RG2) subequal to that of female except for oostegite. Pereopod 7 (Fig. 10 M-RP7), coxa anterior margin with 10 plumose setae; basis shorter than that of female, with 9 anterior, 4 anterolateral and 2 anterodistal robust setae, inner surface bearing only 2 plumose setae. Coloration in life [based on holotype, ovigerous female, 7.1 mm (OMNH-Ar-12233); Fig. 11]. Eyes red. Body and coxae dark olive green, with ca. 20 white spots, middorsal margin of each pereonites and pleonites red surrounded by white, middle part of pereonite 4 and dorsal part of coxa 4 yellowish white (probably due to reflection of light). Gnathopod 2 white. Pereopods 3–7 except coxae and urosomite light olive green. Remarks. Metodius leucomaculatus sp. nov. differs from M. cyanomaculatus sp. nov. in the larger size, the dorsal projections on the pereonite 7 and pleonites, the distinct serration on the maxilliped outer plate, the longer dactylus of the gnathopod 1, the more slender bases of the pereopods, and the coloration. Habitat. Found on gravel and sand bottom, 86–250 m depth. Distribution. Only off Jōgashima Island, Miura City in Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 493-499, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379

Postodius sanguineus sp. nov. [Japanese name: Chigoke-subeyokoebi, new] (Figs 17–22) Type material. Holotype: ovigerous female, 3.4 mm (OMNH-Ar-12241), Mihonoseki, Matsue City, Shimane Prefecture, 35°33′25′′N, 133°16′55′′E, 0.1–0.5 m depth, on a bryozoan Watersipora sp., 30 May 2020, coll. S. Morihisa. Paratypes: ovigerous female, 2.9 mm (OMNH-Ar-12242); male, 2.0 mm (OMNH-Ar-12243); male, 1.7 mm (OMNH-Ar-12244), same data as holotype. Type locality. Mihonoseki, Matsue City, Shimane Prefecture in Japan. Etymology. From the Latin sanguineus (= blood-red), referring to the body coloration. Description of female. Based on holotype, ovigerous female, 3.4 mm (OMNH-Ar-12241). Body (Fig. 17), pleonites 1 and 2 each with indistinct posterodorsal projection, pleonite 3 with blunt projection at mid-length. Head (Figs 17, 18). Lateral cephalic lobe projected anteroventrally. Eyes 7.3% length of body. Antenna 1 stout; length ratio of peduncular articles 1–3 1:0.7:0.45; accessory flagellum minute, tip with 2 setae; primary flagellum with 6 articles, article 1 elongate, each article with several aesthetascs. Antenna 2 also stout, shorter than antenna 1, with ratio of lengths of peduncular articles 3–5 1:1.5:1.2; flagellum with 6 articles, article 1 long. Mandible, incisor narrow, dorsal margin with 13–14 denticles; left lacinia mobilis slender, bearing 12 denticles; accessory blades slender, 14–15 in number; anterior margin distal to palp slightly expanded; palp long, length ratio of palp articles 1–3 in left 1:2.35:2.6, article 3 with numerous fine setae on anterior margin and lateral surface and 3 thick setae on tip. Maxilla 1, inner plate longish pear-shaped, with single seta on tip; medial margin of outer plate bearing 8 robust setae and many fine setae, palp with 1 long and 2 minute setae on tip. Maxilliped, inner plate distal margin bearing 2 minute robust setae; outer plate long, exceeding distal end of palp article 4; palp short, articles 2 and 3 setose mediodistally, article 4 short, ca. 0.15 times length of article 3. Pereon (Fig. 19). Gnathopod 1 small; coxa narrowed distally; basis widened proximally, anterior margin with single simple seta, posterior margin bare; posterodistal projection of propodus with 1 robust, 1 plumose and 2 short setae; dactylus bearing 3 needle-shaped and 2 plumose setae. Gnathopod 2 larger than gnathopod 1; coxa with blunt projection on posterior margin, process on inner surface indistinct; basis with single anterior and 2+2 posterior plumose setae; ischium with robust seta at posterodistal corner; merus projected posterodistally, with 4 and 5 robust setae on posterior margin and at posterodistal corner, respectively; carpus produced posterodistally, with 7 robust setae; propodus wide, ca. 0.45 times length of coxa, palm almost straight, with many serrations, posterodistal corner and medial surface with 3 and 4 robust setae, respectively; dactylus stout, with nail, tip not reaching posterodistal corner of propodus. Pereopod 3 far longer than gnathopod 2; coxa with blunt projection posteriorly, inner surface with small triangular process; basis with 4 anterior and 6 posterior plumose setae, posterodistal corner bearing 2 plumose, 1 robust and 3 short setae; ischium with 3 robust setae on posterior margin; merus bearing 4 anterior, 1 anterodistal, 2 posterior, 3 posterolateral, 1 posteromedial and 1 posterodistal robust setae; carpus with 1 posterolateral, 1 posteromedial and 3 posterodistal robust setae; propodus with 4 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 4 slightly longer than pereopod 3; coxa wide, inner surface with very large triangular process; basis with 13 anterior and 6 posterior plumose setae, posterodistal corner bearing 3 plumose, 3 robust and 1 short setae; ischium with 3 posterior robust setae; merus with 3 anterior, 1 anterodistal, 3 posterior and 3 posteromedial robust setae; carpus with 1 posterior and 3 posterodistal robust setae; propodus with 1 single and 4 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 5 shorter than pereopod 4; coxa lobate, anteroventral margin with 3 inner and 1 marginal plumose setae; basis produced posterodistally, posterior margin smooth, anterior margin with 6 plumose setae, anterodistal corner bearing robust seta; ischium with 4 robust setae on anterior margin; merus with 6 anterior, 2 anterolateral, 1 anteromedial, 3 posterior and 1 posterodistal robust setae; carpus with 1 anterolateral, 1 anteromedial and 5 anterodistal robust setae; propodus with 4 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 6 slightly longer than pereopod 5; coxa lobate, anterior margin with 6 plumose setae; basis produced posterodistally, posterior margin weakly convex, anterior margin with 2+1 plumose setae and 4 robust setae, anterodistal corner bearing 2 robust setae; ischium with 4 anterior robust setae; merus with 5 anterior, 2 anteromedial, 4 posterior and 1 posterodistal robust setae; carpus with 1 anterior, 2 anteromedial and 4 anterodistal robust setae; propodus with 2 single and 2 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 7 a little shorter than pereopod 6; coxa small, unlobed, anterior margin with 10 plumose setae; basis wide, produced posterodistally, posterior margin moderately convex, anterior margin with single plumose seta and 5 short robust setae, anteromedial surface with several short robust setae, anterodistal corner bearing 2 robust setae; ischium with 3 anterior robust setae; merus with 3 anterior, 2 anteromedial, 2 anterodistal and 4 posterior robust setae; carpus with 1 anterolateral, 3 anteromedial and 4 anterodistal robust setae; propodus with 2 single and 2 couples of robust setae anteriorly; dactylus with plumose seta. Pleon (Fig. 20). Pleopods, pleopod 3 shortest; peduncles each with many plumose setae laterally and 2 coupling hooks mediodistally; outer rami longer than inner, outer rami with 13, 13, 12 articles, respectively, inner rami with 11 articles. Uropod 1 long; peduncle bearing 10 lateral, 1 laterodistal and 4 medial robust setae; outer ramus with 7 lateral, 2 medial and 3 terminal robust setae, inner ramus with 3 lateral, 5 medial and 3 terminal robust setae. Uropod 2 short, ca. 0.7 times length of uropod 1; peduncle bearing 5 lateral, 1 laterodistal and 1 medial robust setae; outer ramus ca. 3/4 times length of inner ramus, with 4 lateral and 3 terminal robust setae, inner ramus with 3 lateral, 3 medial and 3 terminal robust setae. Uropod 3 shorter than uropod 2; peduncle with 1 lateral and 1 laterodistal robust setae; outer ramus ca. 0.6 times length of inner ramus, with 3 lateral robust setae and terminal short seta, inner ramus with 5 lateral and 4 medial robust setae and terminal short seta. Telson long-triangular, tip with 2 minute excavations. Description of male [based on paratype, 2.0 mm (OMNH-Ar-12243)]. Eyes larger than those of female. Antenna 1 (Fig. 20 M-A1) stouter than that of female; accessory flagellum longer; primary flagellum with 5 articles, article 1 very long, each articles bearing many aesthetascs. Gnathopod 2 (Fig. 20 M-G2) subequal to that of female except for oostegite, but coxa inner surface with small triangular process, basis lacking plumose setae and propodus more slender. Pereopod 3, basis without plumose setae. Pereopod 7 (Fig. 20 M-RP7), coxa with single plumose seta on anterior margin; basis roundish, anterior margin without plumose seta. Uropod 1, peduncle with 5 lateral, 1 laterodistal and 2 medial robust setae. Coloration in life [based on holotype, ovigerous female, 3.4 mm (OMNH-Ar-12241) and paratype, male, 1.7 mm (OMNH-Ar-12244)]. Female (Fig. 21). Eyes dark red. Body and coxae light blood-red, with ambiguous white spots, dorsal margin white and light blood-red. Antennae white and partly red. Pereopods 3–7 except coxae and urosome light orange. Male (Fig. 22). Eyes dark red. Body and coxae dark blood-red, with ambiguous white spots, dorsal margin white and dark blood-red. Antennae dark blood-red and partly dark red. Pereopods 3–7 except coxae and urosome light to pale orange. Remarks. Postodius sanguineus sp. nov. is characterized by the wider propodus of the gnathopod 2 in both sexes. The plumose setae on the bases posterior margins of the female gnathopod 2 and pereopods 3, 4 are probably unique in the genus, whereas Ariyama (2011) did not describe the female setation. In addition, the body coloration of P. sanguineus is distinctive in the genus. Habitat. Found on a bryozoan Watersipora sp., 0.1–0.5 m depth. Distribution. Only Mihonoseki, Matsue City in Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 506-512, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39."]}

Metodius gen. nov. [Japanese name: Kawari-subeyokoebi-zoku, new] Type species. Metodius cyanomaculatus sp. nov. Diagnosis. Body, anterodorsal corner of pereonite 1 slightly produced; dorsal projections of pereonites 1–5 absent, those of pereonite 6, 7 and pleonites absent or present; posterolateral margin of pleonite 3 with acute, upwardly directed projection at midpoint. Eyes longish reniform. Antenna 1, peduncular article 2 shorter than article 1; accessory flagellum 1-articulated; primary flagellum with many aesthetascs in male. Upper lip, tip incised asymmetrically. Mandible slender; incisor wide, fan-shaped; lacinia mobilis present on left side, also fan-shaped; accessory blades developed; molar pear-shaped; palp long, slightly distal to molar. Lower lip, outer lobes not notched inside, tips projected. Maxilla 1 short; inner plate small, bearing 1–3 apical setae; outer plate acutely projected apically, with many robust setae on mediodistal margin; palp 1-articulated, short, tip rounded, without setae. Maxilla 2, inner plate shorter than outer plate, mediodistal margins of both plates strongly setose. Maxilliped, inner plate setose; outer plate short, not reaching distal end of palp article 2; palp 4-articulated, article 2 medial margin slightly expanded, article 4 long triangular. Coxa 1 relatively small, coxae 2–4 progressively wider and longer; inner surfaces of coxae 2–4 each with “holder structure” (its triangular process holding anterior coxa together with coxal plate). Gills present on gnathopod 2–pereopod 6. Oostegites of female present on gnathopod 2–pereopod 5. Gnathopod 1, propodus projected posterodistally, projection with short robust seta; dactylus small. Gnathopod 2, propodus large, ca. 0.9–1.0 times of coxal length, palm weakly oblique, defined by small projection, margin minutely serrated. Pereopods 3, 4 slender, 5–7 stout; meri projected distally, projections not reaching distal end of carpi, dactyli each with nail. Uropods, inner ramus of uropod 3 relatively wide; peduncles of uropods 1, 2 and both rami bearing many robust setae. Telson minutely cleft or entire, lateral margins each with pair of penicillate setae. Etymology. From the Greek met (= beyond) and Odius (type genus of the family). Species included. Metodius cyanomaculatus sp. nov. and M. leucomaculatus sp. nov. Remarks. Metodius gen. nov. differs from the other odiid genera in the short maxilla 1 palp with rounded bare tip and the large gnathopod 2 propodus almost the same length as the coxa 2. Distribution. Japan only., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on page 487, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379

Postodius albifacies sp. nov. [Japanese name: Shirogao-subeyokoebi, new] (Figs 12–16) Type material. Holotype: female with juveniles, 4.1 mm (OMNH-Ar-12237), Ōsezaki, Numazu City, Shizuoka Prefecture, 35°01′36′′N, 138°47′05′′E, 20 m depth, rocky reef with soft corals, using SCUBA, 9 April 2015, coll. Y. Kawahara. Paratypes: ovigerous female, 3.8 mm (OMNH-Ar-12238); ovigerous female, 2.7 mm (OMNH-Ar-12239); male, 2.4 mm (OMNH-Ar-12240), same data as holotype. Type locality. Ōsezaki, Numazu City, Shizuoka Prefecture in Japan. Etymology. From the Latin albi (= white) + facies (= face), referring to the head coloration. Description of female. Based on holotype, female with juveniles, 4.1 mm (OMNH-Ar-12237). Body (Fig. 12), pereonite 7 and pleonites 1–3 each with small dorsal projection. Head (Figs 12, 13). Lateral cephalic lobe projected anteroventrally. Eyes 6.8% length of body. Antenna 1 stout; length ratio of peduncular articles 1–3 1:0.65:0.4; accessory flagellum minute, tip with 3 setae; primary flagellum with 5 articles, article 1 elongate, each article with several aesthetascs. Antenna 2 also stout, slightly shorter than antenna 1, with ratio of lengths of peduncular articles 3–5 1:2.2:1.65; flagellum with 5 articles, article 1 long. Mandible, incisor narrow, dorsal margin with 13–14 denticles; left lacinia mobilis slender, bearing 5 denticles; accessory blades slender, 11 in number; anterior margin distal to palp expanded; palp long, length ratio of palp articles 1–3 1:4.75:3.9, article 3 with numerous fine setae on lateral surface and 3 thick setae on tip. Maxilla 1, inner plate pearshaped, with 2 setae on tip; medial margin of outer plate bearing 7 large and ca. 20 small robust setae and many slender setae, palp with long apical seta and many short marginal setae. Maxilliped, inner plate distal margin bearing 3 robust setae; outer plate long, exceeding distal end of palp article 4; palp short, articles 2, 3 setose mediodistally, article 4 short, about 0.15 times length of article 3. Pereon (Fig. 14). Gnathopod 1 small; coxa narrowed distally; basis slightly widened proximally, anterior margin with single plumose seta and many short setae, posterior margin bearing a few short setae; posterodistal projection of propodus with 1 robust, 2 plumose and several short setae; dactylus bearing 2 needle-shaped and 3 plumose setae. Gnathopod 2 larger than gnathopod 1; coxa with blunt projection on posterior margin, inner surface with tiny process; basis with 3 plumose and many short setae on anterior margin, posterior margin bare, posterodistal corner bearing 1 robust and 2 slender setae; ischium with long robust seta at posterodistal corner; merus slightly projected posterodistally, with 5 and 2 robust setae on posterior margin and at posterodistal corner, respectively; carpus produced posterodistally, with 10 robust setae; propodus wide, ca. 0.45 times length of coxa, anterodistal corner slightly projected, palm straight, with many serrations, posterodistal corner with 2 robust setae; dactylus stout, with nail, tip not reaching posterodistal corner of propodus. Pereopod 3 far longer than gnathopod 2; coxa with blunt projection posteriorly, inner surface with small triangular process; basis with 17 plumose setae on anterior margin and 6 small robust setae on posterior margin, posterodistal corner bearing 6 robust setae; ischium with 2 small robust setae on posterior margin, posterodistal corner bearing 2 robust setae; merus with 6 anterior, 2 anterodistal, 4 posterior, 4 posterolateral, 2 posteromedial and 1 posterodistal robust setae; carpus with 3 posterolateral, 3 posteromedial and 6 posterodistal robust setae; propodus with 5 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 4 longer than pereopod 3; coxa wide, inner surface with very large triangular process; basis with>20 plumose and many short setae on anterior margin and 7 robust setae on posterolateral margin, posterodistal corner bearing 6 robust setae; ischium with 11 posterior, 5 posterolateral and 2 posteromedial robust setae; merus with 5 anterior, 1 anterodistal, 3 posterior, 8 posterolateral, 10 posteromedial and 3 posterodistal robust setae; carpus with 1 anterodistal, 1 posterior, 2 posterolateral, 5 posteromedial and 6 posterodistal robust setae; propodus with 1 single and 5 couples of robust setae posteriorly; dactylus with plumose seta. Pereopod 5 almost same length as pereopod 4; coxa lobate, anteroventral margin with>10 plumose setae on inner surface; basis produced posterodistally, posterior margin smooth, anterior margin with ca. 15 plumose and 8 robust setae, anterodistal corner bearing 3 robust setae; ischium with 10 robust setae on anterior margin; merus with 8 anterior, 9 anteromedial, 2 anterodistal, 7 posterior and 1 posterodistal robust setae; carpus with 2 anterior, 6 anteromedial and 5 anterodistal robust setae; propodus with 1 single and 4 couples of robust setae posteriorly. Pereopod 6 slightly shorter than pereopod 5; coxa lobate, anterior margin with>20 plumose setae; basis produced posterodistally, posterior margin smooth, anterior margin with 6 plumose setae and ca. 10 short robust setae, anterolateral surface with several short robust setae, anterodistal corner bearing 2 robust setae; ischium with 7 anterior robust setae; merus with 6 anterior, 8 anteromedial, 2 anterodistal, 7 posterior and 1 posterodistal robust setae; carpus with 1 anterior, 1 anterolateral, 4 anteromedial and 5 anterodistal robust setae; propodus with 1 single and 5 couples of robust setae anteriorly; dactylus with plumose seta. Pereopod 7 a little longer than pereopod 6; coxa small, unlobed, anterior margin with ca. 15 plumose setae; basis wide, produced posterodistally, posterior margin weakly convex, anterior margin with 11 plumose setae and 8 short robust setae, anterolateral surface with several short robust setae, anterodistal corner bearing 3 robust setae, inner surface with many plumose setae; ischium with 5 anterior and 7 anteromedial robust setae; merus with 5 anterior, 9 anteromedial, 3 anterodistal, 8 posterior and 1 posterodistal robust setae; carpus with 1 anterior, 3 anteromedial and 6 anterodistal robust setae; propodus bearing 1 single and 4 couples of robust setae anteriorly; dactylus with plumose seta. Pleon (Fig. 15). Pleopods, pleopod 3 shortest; peduncles each with many plumose setae laterally and several plumose setae and 2 coupling hooks medially; outer rami longer than inner, outer and inner rami with 18, 18, 16 and 17, 16, 14 articles, respectively. Uropod 1 long; peduncle bearing 29 lateral, 1 laterodistal and 9 medial robust setae; outer ramus with 13 lateral, 6 medial and 3 terminal robust setae, inner ramus with 7 lateral, 9 medial and 3 terminal robust setae. Uropod 2 short, ca. 3/4 times length of uropod 1; peduncle bearing 10 lateral, 1 laterodistal and 2 medial robust setae; outer ramus ca. 3/4 times length of inner ramus, with 8 lateral, 1 medial and 3 terminal robust setae, inner ramus with 6 lateral, 6 medial and 3 terminal robust setae. Uropod 3 slightly shorter than uropod 2; peduncle with 1 lateral and 1 laterodistal robust setae; outer ramus ca. 0.6 times length of inner ramus, with 5 lateral and 1 medial robust setae and terminal short seta, inner ramus with 8 lateral and 7 medial robust setae and terminal short seta. Telson roundish long-triangular, tip with minute excavation. Description of male [based on paratype, 2.4 mm (OMNH-Ar-12240)]. Antenna 1 (Fig. 15 M-A1), accessory flagellum longer than that of female; primary flagellum with 6 articles, article 1 very long, each articles bearing many aesthetascs. Gnathopod 2 (Fig. 15 M-G2) subequal to that of female except for oostegite, but basis without plumose setae and propodus more slender. Pereopod 3, basis with 3 plumose setae on anterior margin. Pereopod 7 (Fig. 15 M-P7), coxa anterior margin with 4 plumose setae; basis anterior margin with single plumose seta and 6 robust setae, inner surface lacking plumose setae. Uropod 1, peduncle with 12 lateral, 1 laterodistal and 4 medial robust setae. Coloration in life (based on female, size unknown; Fig. 16). Head white, eyes light red. Body and coxae light orange, with 11 violet curved lines, middle dorsal margin of each pereonites and pleonites red. Antennae white and partly red. Pereopods 3–7 also light orange. Remarks. Postodius albifacies sp. nov. can be distinguished from the other Postodius species by the coloration and the combination of the shapes of gnathopod 2 and pereopods 3, 7 (see the above key). The uropod 1 peduncle with many lateral and medial robust setae is probably distinctive, although those in the females of four species are not shown in Ariyama (2011). Habitat. Found on rocky reef with soft corals, 20 m depth. Distribution. Only Ōsezaki, Numazu City in Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 500-502, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39."]}

Genus Postodius Hirayama, 1983 [Japanese name: Hime-subeyokoebi-zoku] Postodius Hirayama, 1983: 97.— Barnard & Karaman, 1991: 400.— Coleman & Barnard, 1991: 263.— Moore, 1992: 913.— Berge, Vader & Coleman, 1999: 246 (in part).— Ariyama, 2011: 3. Type species. Postodius imperfectus Hirayama, 1983. Diagnosis [emended from Ariyama (2011)]. Body, anterodorsal corner of pereonite 1 strongly produced; dorsal projections of pereonites 1–6 absent, on pleonites present, but small; posterolateral margin of pleonite 3 with acute, upwardly directed projection at midpoint. Eyes reniform. Antenna 1, peduncular article 2 shorter than article 1; accessory flagellum 1-articulated; primary flagellum with many aesthetascs in male. Upper lip, tip incised asymmetrically. Mandible slender; incisor narrow; lacinia mobilis present on left side, slender; accessory blades weak; palp long, at same level as molar. Lower lip, outer lobes long, weakly notched inside. Maxilla 1, inner plate small, bearing 1–2 apical setae; outer plate styliform, with several robust setae on tip; palp 1-articulated, slender, tip with long apical seta. Maxilla 2, inner plate shorter than outer plate, mediodistal margins of both plates strongly setose. Maxilliped, inner plate slender, with 2–3 robust setae on tip; outer plate long, exceeding distal end of palp article 2; palp 4-articulated, article 2 medial margin weakly expanded, article 4 vestigial. Coxae 1–4 progressively wider, equally long; inner surfaces of coxae 2–4 each with “holder structure”. Gills present on gnathopod 2–pereopod 6. Oostegites of female present on gnathopod 2–pereopod 5. Gnathopod 1, propodus projected posterodistally, projection with short robust seta; dactylus small, triangular. Gnathopod 2, propodus not large, ca. 0.35–0.6 times of coxal length, palm transverse, distal margin serrated, with 2–3 robust setae on posterodistal corner. Pereopods 3–7 stout, meri projected distally, projections of pereopods 5–7 exceeding distal end of carpi, dactyli each with nail. Uropods, inner ramus of uropod 3 relatively wide; peduncles of uropods 1, 2 and both rami bearing many robust setae. Telson minutely cleft, lateral margins each with pair of penicillate setae. Species included. Postodius albifacies sp. nov.; P. igneus Ariyama, 2011; P. imperfectus Hirayama, 1983; P. ornatus Ariyama, 2011; P. sanguineus sp. nov.; and P. striatus Ariyama, 2011. Distribution. Japan only., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 499-500, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Hirayama, A. (1983) Taxonomic studies on the shallow water gammaridean Amphipoda of west Kyushu, Japan. I. Acanthonotozomatidae, Ampeliscidae, Ampithoidae, Amphilochidae, Anamixidae, Argissidae, Atylidae and Colomastigidae. Publications of the Seto Marine Biological Laboratory, 28, 75 - 150. https: // doi. org / 10.5134 / 176060","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Coleman, C. O. & Barnard, J. L. (1991) Revision of Iphimediidae and similar families (Amphipoda: Gammaridea). Proceedings of the Biological Society of Washington, 104, 253 - 268.","Moore, P. G. (1992) A study on amphipods from the superfamily Stegocephaloidea Dana, 1852 from the northeastern Pacific region: systematics and distributional ecology. Journal of Natural History, 26, 905 - 936. https: // doi. org / 10.1080 / 00222939200770551","Berge, J., Vader, W. & Coleman, O. (1999) A cladistic analysis of the amphipod families Ochlesidae and Odiidae, with description of a new species and genus. In: Schram, F. R. & von Vaupel Klein, J. C. (Eds.), Crustaceans and the Biodiversity Crisis. Brill, Leiden, pp. 239 - 265.","Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39."]}

Family Odiidae Coleman & Barnard, 1991 [Japanese name: Subeyokoebi-ka] Odiidae Coleman & Barnard, 1991: 262.— Moore, 1992: 913.— Ariyama, 2011: 2.— Lowry & Myers, 2017: 55. Iphimediidae: Barnard & Karaman, 1991: 378 (in part). Ochlesidae: Berge, Vader & Coleman, 1999: 242 (in part).— Labay, 2010: 35 (in part).— Labay, 2019: 503 (in part). Type genus. Odius Liljeborg, 1865. Diagnosis [emended from Ariyama (2011)]. Body compressed laterally. Rostrum well developed. Pereonites dorsally flush, usually raised into thin keels. Pleonites often with dorsal projections. Antennae short, accessory flagellum present or absent. Mouth parts conically developed. Upper lip narrow, tip asymmetrically incised. Mandible styliform; incisor toothed, accessory blades strong or absent, molar triturative; palp 3-articulated, article 1 shorter than half length of article 3. Lower lip without inner lobes, outer lobes thin. Maxilla 1 with small inner plate bearing 1–3 apical setae; outer plate conical; palp 1- or 2-articulated. Maxilla 2 with inner plate lacking facial row of setae. Maxilliped, palp 3- or 4-articulated. Gnathopod 1 weak, chelate, carpus and propodus elongate. Gnathopod 2 subchelate, merus and carpus produced posterodistally. Coxa 4 with large acute posterior projection. Pereopods 5–7 with bases expanded posteriorly. Urosomites free. Uropods biramous, both rami of uropod 1 subequal in length, outer rami shorter than inner in uropods 2, 3. Telson entire or incised. Genera included. Antarctodius Berge, Vader & Coleman, 1999; Cryptodius Moore, 1992; Gordonodius Ariyama, 2011; Metodius gen. nov.; Odius Liljeborg, 1865; and Postodius Hirayama, 1983. Key to the genera in the world. As the presence of accessory flagellum was revealed recently in two Cryptodius species (Kim & Hong 2014, Labay 2019) and is confirmed in Antarctodius japonicus as stated below, Ariyama’s (2011) key is revised herein. 1. Maxilla 1 palp powerful, 2-articulated.................................. Antarctodius Berge, Vader & Coleman, 1999 – Maxilla 1 palp reduced, uniarticulated.................................................................... 2 2. Maxilla 1 palp short, rounded, tip bare...................................................... Metodius gen. nov. – Maxilla 1 palp slender, tip with 1–2 setae.................................................................. 3 3. Maxillipedal palp 3-articulated.................................................... Gordonodius Ariyama, 2011 – Maxillipedal palp 4-articulated.......................................................................... 4 4. Fourth article of maxillipedal palp vestigial............................................ Postodius Hirayama, 1983 – Fourth article of maxillipedal palp not vestigial, triangular.................................................... 5 5. Pereopod 7 basis with projection on posterior margin, telson incised........................... Odius Liljeborg, 1865 – Pereopod 7 basis smooth in posterior margin, telson entire or slightly incised.................. Cryptodius Moore, 1992, Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 486-487, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Coleman, C. O. & Barnard, J. L. (1991) Revision of Iphimediidae and similar families (Amphipoda: Gammaridea). Proceedings of the Biological Society of Washington, 104, 253 - 268.","Moore, P. G. (1992) A study on amphipods from the superfamily Stegocephaloidea Dana, 1852 from the northeastern Pacific region: systematics and distributional ecology. Journal of Natural History, 26, 905 - 936. https: // doi. org / 10.1080 / 00222939200770551","Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39.","Lowry, J. K. & Myers, A. A. (2017) A phylogeny and classification of the Amphipoda with the establishment of the new order Ingolfiellida (Crustacea: Peracarida). Zootaxa, 4265 (1), 1 - 89. https: // doi. org / 10.11646 / zootaxa. 4265.1.1","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Berge, J., Vader, W. & Coleman, O. (1999) A cladistic analysis of the amphipod families Ochlesidae and Odiidae, with description of a new species and genus. In: Schram, F. R. & von Vaupel Klein, J. C. (Eds.), Crustaceans and the Biodiversity Crisis. Brill, Leiden, pp. 239 - 265.","Labay, V. S. (2010) A new species and subspecies of Ochlesidae Stebbing, 1910 (Amphipoda: Gammaridea) from the Okhotsk Sea. Zootaxa, 2354 (1), 35 - 44. https: // doi. org / 10.11646 / zootaxa. 2354.1.3","Labay, V. S. (2019) Review of amphipods of the genus Cryptodius Moore, 1992 (Amphipoda: Ochlesidae) from the coastal waters of Sakhalin Island (Far East of Russia). Zootaxa, 4603 (3), 501 - 519. https: // doi. org / 10.11646 / zootaxa. 4603.3.4","Liljeborg, W. (1865) On the Lysianassa magellanica H. Milne Edwards, and on the Crustacea of the suborder Amphipoda and subfamily Lysianassina found an [sic] the coast of Sweden and Norway. Nova Acta Regiae Societatis Scientiarum Upsaliensis, Series 3, 6 (1), 1 - 38, pls. 1 - 5.","Hirayama, A. (1983) Taxonomic studies on the shallow water gammaridean Amphipoda of west Kyushu, Japan. I. Acanthonotozomatidae, Ampeliscidae, Ampithoidae, Amphilochidae, Anamixidae, Argissidae, Atylidae and Colomastigidae. Publications of the Seto Marine Biological Laboratory, 28, 75 - 150. https: // doi. org / 10.5134 / 176060","Kim, Y. H. & Hong, S. S. (2014) First recorded family Odiidae (Crustacea, Amphipoda, Gammaridea) from the Korean coast, with description of newly recorded species. Animal Systematics, Evolution and Diversity, 30, 137 - 143. https: // doi. org / 10.5635 / ASED. 2014.30.2.137"]}

Antarctodius japonicus Ariyama, 2011 [Japanese name: Mukashi-subeyokoebi] (Figs 23, 24) Antarctodius japonicus Ariyama, 2011: 34, figs 22–25. Material examined. Female, 3.2 mm (OMNH-Ar-12245), off Jōgashima Island, Miura City, Kanagawa Prefecture, 35°07′14′′N, 139°34′24′′E, 91-95 m depth, sandy bottom, using dredge, 17 June 2013, coll. H. Kohtsuka. Material for comparison. Holotype: male, 2.9 mm (1.7 mm in a straight line) (NSMT-Cr-21285), midway between Kuchinotsu and Ohyano, Ariake Sound, 32°34′N, 130°15′E, 47 m depth, sandy gravel bottom, using Smith-McIntyre grab, 5 June 1997, coll. M. Azuma. Description of female. Based on female, 3.2 mm (OMNH-Ar-12245). Body (Fig. 23), pleonites 1–3 each lacking dorsal projection, pleonite 3 with small projection posteroventrally. Head (Figs 23, 24). Lateral cephalic lobe projected anteroventrally. Eyes 9.3% length of body. Antenna 1 stout; length ratio of peduncular articles 1–3 1:0.8:0.35; accessory flagellum present, minute, tip with 1 seta; primary flagellum with 6 articles, article 1 not elongate, each article with a few aesthetascs. Maxilla 1 small; inner plate longish pear-shaped, with 3 plumose setae on tip; medial margin of outer plate bearing 8 robust setae and many thick and fine setae, palp 2-articulated, tip heavily setose. Maxilliped, inner plate distal margin bearing 3 robust setae; outer plate truncate, slightly exceeding distal end of palp article 2, laterodistal corner with 7 robust setae; palp articles 2 and 3 setose mediodistally, article 4 long triangular, about 0.7 times length of article 3. Pereon and pleon (Fig. 24). Gnathopod 1 slender; coxa narrow; basis slightly widened proximally, anterior margin with several short setae, posterior margin bearing 6 long setae; posterodistal corner of propodus with long robust seta and 3 short setae; dactylus complexly trifurcated, exceeding tip of robust seta of propodus, bearing 2 plumose and 1 short setae. Gnathopod 2 larger than gnathopod 1; coxa almost straight, inner surface with tiny process; basis with single short seta on anterior margin; merus truncate distally, posterodistal corner with 2 robust setae; carpus produced posterodistally, with 2 anterodistal, 2 lateral, 3 posterior and 8 posterodistal robust setae; propodus short, with 2 anterior, 2 anterodistal, 5 lateral and 5 medial robust setae, palm slightly curved, with many serrations; dactylus short, posterior margin with small spine. Pereopod 7, coxa small, unlobed, anterodistal margin with 3 short setae, gill present; basis wide, produced posterodistally, posterior margin slightly concave, anterior margin with 8 plumose and 12 robust setae, anterolateral surface and anterodistal corner bearing 5 and 1 robust setae, respectively, inner surface with many plumose (?) setae; ischium with 1 anterior and 1 anterodistal robust setae; merus with 2 anterior, 7 anteromedial, 2 anterodistal, 4 posterior and 1 posterodistal robust setae; carpus–dactylus lost. Telson deeply cleft, both tips each with minute seta. Description of male [based on holotype, male, 2.9 mm (1.7 mm in a straight line) (NSMT-Cr-21285)]. Antenna 1 with large accessary flagellum, tip with 2 setae (Fig. 24 M-AF). Pereopod 7, coxa with damaged fragment of gill. Both overlooked in Ariyama (2011). Coloration in life. Unknown. Remarks. Ariyama (2011) described this species based on a single male specimen. The present female specimen, however, can be identified as Antarctodius japonicus, because most characters including important ones are shared with the holotype (ex. maxilla 1, maxilliped, gnathopods and telson), although there are some trifle differences. Habitat. Found on sandy gravel bottom and sandy bottom, 47–95 m depth. Distribution. Ariake Sound in Kyūshū (Ariyama 2011) and off Jōgashima Island, Miura City (present study), both in Japan., Published as part of Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, pp. 485-516 in Zootaxa 5067 (4) on pages 513-515, DOI: 10.11646/zootaxa.5067.4.2, http://zenodo.org/record/5683379, {"references":["Ariyama, H. (2011) Six species of the family Odiidae (Crustacea: Amphipoda) from Japan, with descriptions of a new genus and four new species. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 1 - 39."]}

Ariyama, Hiroyuki, Kodama, Masafumi, Tomikawa, Ko (2020): Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae). Zootaxa 4885 (3): 336-352, DOI: https://doi.org/10.11646/zootaxa.4885.3.2

Maera denticoxa sp. nov. [Japanese name: Kita-sunnariyokoebi, new] (Figs 2���7) Maera danae.��� Tomikawa et al., 2010: table 1, figs 1���3. [not Maera danae (Stimpson, 1853)] Type material. Holotype: male, 14.7 mm (OMNH-Ar-11724), Nagane, Otsuchi Bay in Iwate Prefecture, 39��21'45"N, 141��57'35"E (Fig. 1B), 3���4 m depth, under stones, by SCUBA, 18 February 2019, coll. M. Kodama. Paratypes: female, 15.6 mm (OMNH-Ar-11725), same locality, 7���8 m depth, under stones, by SCUBA, 11 July 2018, coll. M. Kodama; female, 15.5 mm (OMNH-Ar-11734, not dissected), same locality, 7���8 m depth, on coarse sand under stones, by SCUBA, 19 May 2020, coll. M. Kodama; ovigerous female, 13.2 mm (OMNH-Ar-11726), Nagoshi, Otsuchi Bay in Iwate Prefecture, 39��21'04"N, 141��56'50"E (Fig. 1B), 4.3 m depth, by SCUBA and airlift, 14 November 2018, coll. N. Ohtsuchi; male, 16.2 mm and female, 16.3 mm (OMNH-Ar-11727, 11728), Daikoku Island, Akkeshi Town, Hokkaido, 42��57'47"N, 144��52'19"E (Fig. 1A), intertidal, using hand net, fixed by 99% Ethanol, 24 June 2005, coll. K. Tomikawa. Type locality. Nagane, Otsuchi Bay in Iwate Prefecture, Japan. Etymology. From the Latin dentatus, -a, -um (= dentate) + coxa, referring to the shapes of coxae 1���6. Diagnosis. Eyes present. Mandible, palp article 1 with acute distal tooth. Coxae 1���6, posteroventral margins each with 1���7 notches; coxa 1 anteroventral corner acutely produced. Gnathopod 2 in both sexes, palm strongly oblique, defined by small tooth. Pereopods dactyli simple; bases of pereopods 5���7 rectangular, posterodistal corners square. Pleonal e pimera 1���3 acutely projected posteroventrally. Uropod 3, outer ramus longer than inner ramus, rami about 3 times as long as peduncle. Telson longer than wide, distal ends pointed, lateral margins each with 7���8 robust setae. Description. Based on holotype, male, 14.7 mm (OMNH-Ar-11724). Head (Figs 2���3). Eyes oval, about 0.2 times length of head. Antenna 1 weakly setose; peduncular articles 1���3 with length ratio of 1: 1.1: 0.3, article 1 with 8 posteromedial robust setae; accessory flagellum with 7 articles; primary flagellum with 29 articles, terminal article minute. Antenna 2 about 0.55 times length of antenna 1, setose; peduncular articles 3���5 with length ratio of 1:3.15:2.3; flagellum with 10 articles, terminal article minute. Upper lip, ventral margin rounded, weakly setose. Mandible, incisor bearing 5 and 4 cusps in left and right, respectively, each lacinia mobilis 4-dentate, with 12���14 accessory setae; palp article 1 with acute distal tooth, articles 1 ��� 3 length ratio (excluding distal tooth of article 1) 1: 3.6���3.7: 2.2���2.4, articles 2 ��� 3 setose. Lower lip with inner lobes, distal margins of inner and outer lobes weakly setose, mandibular processes small. Maxilla 1, inner plate with 3 long and 3 short apical setae, medial margin bearing a few feeble setae, outer plate with 11 apical robust setae and medial feeble setae, palp article 1 with a few laterodistal and lateral setae, article 2 bearing many apical setae. Maxilla 2, outer plate larger than inner plate; both plates bearing many apical setae, medial margin of inner plate with 2 setae. Maxilliped, inner plate truncate, distal margin with many thick setae, distomedial corner with 4 robust setae ventrally; outer plate with 27 long-to-short robust setae on distomedial margin; palp 4-articulate, article 2 setose medioventrally, article 3 with many distolateral setae, article 4 with large apical robust seta. Pereon (Fig. 4). Gnathopod 1, coxa anteroventral corner acutely produced, ventral margin with 5 small notches posteriorly; basis setose on anteroproximal and posterior margins; carpus swollen posterodistally, posterior margin and medial surface heavily setose; propodus about 80% as long as carpus, anterior and posterior margins setose, palm defined by 3 short robust setae; dactylus slender, slightly curved posteriorly. Gnathopod 2, coxa subquadrate, posteroventral margin with 7 small notches; basis narrow, anteroproximal and posterior margins and anterodistal corner with several setae; merus with acute posterodistal spine; carpus lobate posterodistally, posterior margin heavily setose; propodus slender, length about 1.9 times width, anteromedial surface and posterior margin setose; palm strongly oblique, defined by small triangular tooth with robust seta, palmar margin with 6 minute teeth, bearing 9 lateral and 12 medial robust setae; dactylus strongly curved, anterior margin with 17 setae. Pereopods 3���4, shapes subequal, pereopod 3 about 1.2 times as long as pereopod 4; coxa trapezoidal, posteroventral margins with 4 and 2 small notches, respectively, gill large, shorter than basis length; basis rectilinear, anterior and posterior margins each with a few long proximal setae and many small robust setae; propodus lined with bundle of robust setae posteriorly; dactylus short, about 0.4 times length of propodus, simple. Pereopods 5���7, shapes subsimilar, about 1.1, 1.5, 1.6 times lengths of pereopod 4, respectively; coxae 5���6, posteroventral corner with single small notch, coxa 7 lacking notch, coxae 6���7 anteroventral margin bearing 3 robust setae; basis rectangular, lengths about 2.0, 1.95, 1.8 times widths respectively, posteroproximal corner roundly projected, anterior margin with many short robust setae, posterior margin serrate, posterodistal corner square; carpus and merus lined with bundle of robust setae; dactylus short, 0.3���0.4 times length of propodus, simple. Pleon (Fig. 5). Epimera 1���3 acutely projected posteroventrally, each with lateral ridge, ventral margins of epimera 1���3 with 7, 7, 5 robust setae, respectively. Pleopods 1���3 slender, pleopods 2 ��� 3 shorter than pleopod 1; peduncles with 6 (4 lost), 8 (1 lost), 7 coupling hooks respectively; both rami each with 12���14 articles. Uropod 1, peduncle with large basofacial and distolateral robust setae and 17 dorsolateral and 17 dorsomedial robust setae; outer ramus subequal length of inner ramus, about 0.7 times as long as peduncle, with 4 dorsolateral, 6 dorsomedial and 4 terminal robust setae; inner ramus with 6 dorsolateral, 12 dorsomedial, 1 ventrolateral and 5 terminal robust setae. Uropod 2 short, about 0.55 times length of uropod 1; peduncle laterodistal corner triangularly projected, dorsolateral margin, dorsomedial margin and distomedial corner with 11, 6 and 3 robust setae, respectively; outer ramus about 0.9 times length of inner ramus, almost same length as peduncle, with 8 dorsolateral, 5 dorsomedial and 5 terminal robust setae; inner ramus with 5 dorsolateral, 14 dorsomedial, 1 ventrolateral and 5 terminal robust setae. Uropod 3 long, about 195% as long as uropod 2; peduncle, lateral and medial surfaces with 1 and 8 robust setae, respectively, laterodistal corner bearing 8 robust setae; both rami rectilinear, outer ramus about 1.1 times length of inner ramus, about 3.1 times length of peduncle, with vestigial second article; lateral and medial margins of both rami lined with many robust setae, distal margins bearing several robust setae and a few slender setae, longest seta about 0.2 times length of outer ramus. Telson about 1.15 times longer than wide, each lateral margin with 7 ��� 8 robust setae, tips acutely projected, dorsal surfaces of each lobe with a robust seta and 3 sensory setae. Description of female (paratype, 15.6 mm, OMNH-Ar-11725). Gnathopod 2 (Fig. 5 F-G2) almost same as male, holotype, 14.7 mm (OMNH-Ar-11724) except for oostegite. Variation. Notches on posteroventral margins of coxae 1 ��� 6 present in all specimens. Their numbers vary from 1 to 7 (Table 1). Coloration in life (Fig. 6). Eyes dark brown, other parts pale pink. Remarks. Maera denticoxa sp. nov. has small notches on the coxae 1 ��� 6. Only three species having such notches were recorded in the genus (Ariyama 2020): Maera loveni (Bruzelius, 1859) [Japanese specimens], M. pachytelson Karaman & Ruffo, 1971, and M. sagamiensis Ariyama, 2020. However, the notches are present on the coxa 2, the coxae 1���2 and the coxae 1���3 in these species, respectively. These three species also differ from the new species in the shape of the gnathopod 2 palm, the shape of the telson, and the number of the coupling hooks, respectively. Habitat. On coarse sand bottom under stones (Fig. 7), intertidal to 8 m depth (present study). Distribution. Coast of Daikoku Island in Hokkaido and Otsuchi Bay in Iwate Prefecture, Japan (present study)., Published as part of Ariyama, Hiroyuki, Kodama, Masafumi & Tomikawa, Ko, 2020, Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 336-352 in Zootaxa 4885 (3) on pages 338-344, DOI: 10.11646/zootaxa.4885.3.2, http://zenodo.org/record/4296670, {"references":["Tomikawa, K., Kobayashi, N. & Mawatari, S. F. (2010) Phylogenetic relationships of superfamily Gammaroidea (Amphipoda) and its allies from Japan. Crustacean Research, 39, 1 - 10. https: // doi. org / 10.18353 / crustacea. 39.0 _ 1","Stimpson, W. (1853) Synopsis of the marine Invertebrata of Grand Manan: or the region about the mouth of the Bay of Fundy, New Brunswick. Smithsonian Contributions to Knowledge, 6, 5 - 66, 3 pls. https: // doi. org / 10.5962 / bhl. title. 30062","Ariyama, H. (2020) Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae). Zootaxa, 4743 (4), 451 - 479. https: // doi. org / 10.11646 / zootaxa. 4743.4.1","Bruzelius, R. M. (1859) Bidrag till kannedomen om skandinaviens Amphipoda Gammaridea. Kongliga Svenska Vetenskaps- Akademiens Handlingar, New Series, 3 (1), 1 - 104, 4 pls. https: // doi. org / 10.5962 / bhl. part. 28297","Karaman, G. & Ruffo, S. (1971) Contributo alla conoscenza della specie Mediterranee del genere Maera. Memorie del Museo Civico di Storia Naturale, Verona, 19, 113 - 176."]}

Maeridae Krapp-Schickel, 2008 [Japanese name: Sunnariyokoebi-ka], Published as part of Ariyama, Hiroyuki, Kodama, Masafumi & Tomikawa, Ko, 2020, Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 336-352 in Zootaxa 4885 (3) on page 338, DOI: 10.11646/zootaxa.4885.3.2, http://zenodo.org/record/4296670, {"references":["Krapp-Schickel, T. (2008) What has happened with the Maera - clade (Crustacea, Amphipoda) during the last decades? Bollettino del Museo Civico di Storia Naturale di Verona, 32, 3 - 32."]}

Quadrimaera Krapp-Schickel & Ruffo, 2000 [Japanese name: Kaku-sunnariyokoebi-zoku] Synonym, diagnosis and included species. See Ariyama (2019). However, on the mandibular palp in the diagnosis, “article 1 lacking distal tooth” is modified to “article 1 usually lacking distal tooth” (see Remarks of Quadrimaera angulata sp. nov.). In addition, the following four species are added to the included species: Quadrimaera anhi Dang & Le, 2011; Q. miramirandella Alves, Neves & Johnsson, 2018; Q. vietnamica Dang & Le, 2011; and Q. yemanjae Alves, Neves & Johnsson, 2018., Published as part of Ariyama, Hiroyuki, Kodama, Masafumi & Tomikawa, Ko, 2020, Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 336-352 in Zootaxa 4885 (3) on page 344, DOI: 10.11646/zootaxa.4885.3.2, http://zenodo.org/record/4296670, {"references":["Krapp-Schickel, T. & Ruffo, S. (2000) The Maera quadrimana - complex (Crustacea Amphipoda, Melitidae) demands a new concept: Quadrimaera n. gen. (with description of three new species from Western Atlantic). Bollettino del Museo Civico di Storia Naturale di Verona, 24, 193 - 214.","Ariyama, H. (2019) Species of the Maera - clade collected from Japan. Part 2: genera Austromaera Lowry & Springthorpe, 2005 and Quadrimaera Krapp-Schickel & Ruffo, 2000 (Crustacea: Amphipoda: Maeridae). Zootaxa, 4554 (2), 460 - 496. https: // doi. org / 10.11646 / zootaxa. 4554.2.6","Dang, N. T. & Le, H. A. (2011) Crustaceans family Melitidae (Amphipoda- Gammaridea) from Vietnam sea. Vietnam Journal of Biology, 33 (2), 1 - 18. [in Vietnamese with English abstract and descriptions of new species] https: // doi. org / 10.15625 / 0866 - 7160 / v 33 n 2.740","Alves, J., Neves, E. & Johnsson, R. (2018) A review of Quadrimaera Krapp-Schickel & Ruffo, 2000 (Amphipoda: Senticaudata) from Brazil. Zootaxa, 4532 (4), 567 - 593. https: // doi. org / 10.11646 / zootaxa. 4532.4.8"]}

Key to adult males of Japanese species of the Maera -clade (revised). Quadrimaera angulata sp. nov. is not included because the male is unknown. 1. Gnathopod 2, anterior margin of dactylus bearing many setae.................................................. 2 - Gnathopod 2, anterior margin of dactylus with single seta..................................................... 4 2. Body very large (maximum BL:> 50 mm), gnathopod 2 palm defined by tooth bearing strong robust seta............................................................................................ Maera loveni (Bruzelius, 1859) - Body small (maximum BL: about 10–16mm), gnathopod 2 palm defined by tooth bearing small robust seta.............. 3 3. Small notches present on coxae 1–6.................................................... Maera denticoxa sp. nov. - Small notches present on coxae 1–3............................................ Maera sagamiensis Ariyama, 2020 4. Pereopods 3–7 dactyli bifid............................................................................. 5 - Pereopods 3–7 dactyli simple............................................................................ 8 5. Gnathopod 2 palm with 2 excavations in middle.............................. Quadrimaera quqdrimana (Dana, 1853) - Gnathopod 2 palm with single excavation in middle.......................................................... 6 6. Excavation on gnathopod 2 palm quadrate................................... Quadrimaera gotoensis Ariyama, 2019 - Excavation on gnathopod 2 palm rounded.................................................................. 7 7. Pereopod 6, posterior margin of basis heavily setose............................ Quadrimaera setibasis Ariyama, 2019 - Pereopod 6, posterior margin of basis not setose........................... Quadrimaera pacifica (Schellenberg, 1938) 8. Uropod 3, tips of both rami pointed......................................... Austromaera ariakensis Ariyama, 2019 - Uropod 3, tips of both rami truncate...................................................................... 9 9. Gnathopod 2 basis wide; uropod 3 rami long, about 3 times length of peduncle........ Meximaera mooreana (Myers, 1989) - Gnathopod 2 basis ordinary; uropod 3 rami relatively short, 1 – 2 times length of peduncle........................... 10 10. Gnathopod 2 palm transverse, without robust setae; mandibular palp article 1 with distal tooth....................... 11 - Gnathopod 2 palm slightly or moderately oblique, with many robust setae; mandibular palp article 1 lacking distal tooth.. 12 11. Uropod 3 longer than uropod 2, basis of pereopod 5 subovate.................... Maeropsis okinawensis Ariyama, 2018 - Uropod 3 shorter than uropod 2, basis of pereopod 5 subrectangular.............. Maeropsis serratipalma (Nagata, 1965) 12. Palm of gnathopod 2 moderately oblique (angle of palmar corner: 115–130°)..................................... 13 - Palm of gnathopod 2 slightly oblique (angle of palmar corner: 90–105°)......................................... 14 13. Coxa 1 anteroventral corner produced acutely, distal robust setae of telson short (ca. 20% of telson length).................................................................................... Orientomaera obliquua Ariyama, 2018 - Coxa 1 anteroventral corner rounded, distal robust setae of telson long (ca. 45% of telson length)......................................................................................... Orientomaera rotundicoxa Ariyama, 2018 14. Palm of gnathopod 2 with two distinct teeth.................................... Orientomaera incisa Ariyama, 2020 - Palm of gnathopod 2 with several blunt teeth.............................................................. 15 15. Posterior margin of pereopod 6 basis almost straight, body color bluish pale pink................................................................................................... Orientomaera brevispina (Kim & Kim, 1991) - Posterior margin of pereopod 6 basis convex, body color light crimson............ Orientomaera decipiens Ariyama, 2018, Published as part of Ariyama, Hiroyuki, Kodama, Masafumi & Tomikawa, Ko, 2020, Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 336-352 in Zootaxa 4885 (3) on page 350, DOI: 10.11646/zootaxa.4885.3.2, http://zenodo.org/record/4296670, {"references":["Bruzelius, R. M. (1859) Bidrag till kannedomen om skandinaviens Amphipoda Gammaridea. Kongliga Svenska Vetenskaps- Akademiens Handlingar, New Series, 3 (1), 1 - 104, 4 pls. https: // doi. org / 10.5962 / bhl. part. 28297","Ariyama, H. (2020) Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae). Zootaxa, 4743 (4), 451 - 479. https: // doi. org / 10.11646 / zootaxa. 4743.4.1","Dana, J. D. (1853) Crustacea. Part II. United States Exploring Expedition, 14, 689 - 1618. https: // doi. org / 10.5962 / bhl. title. 61409","Ariyama, H. (2019) Species of the Maera - clade collected from Japan. Part 2: genera Austromaera Lowry & Springthorpe, 2005 and Quadrimaera Krapp-Schickel & Ruffo, 2000 (Crustacea: Amphipoda: Maeridae). Zootaxa, 4554 (2), 460 - 496. https: // doi. org / 10.11646 / zootaxa. 4554.2.6","Schellenberg, A. (1938) Litorale Amphipoden des tropischen Pazifiks nach Sammlungen von Prof. Bock (Stockholm), Prof. Dahl (Berlin) und Prof. Pietschmann (Wein). Kungliga Svenska Vetenskapsakademiens Handlingar, Series 3, 16 (6), 1 - 105.","Myers, A. A. (1989) Amphipoda from the South Pacific: the Society Islands. Records of the Australian Museum, 41, 63 - 82. https: // doi. org / 10.3853 / j. 0067 - 1975.41.1989.136","Ariyama, H. (2018) Species of the Maera - clade collected from Japan. Part 1: genera Maeropsis Chevreux, 1919 and Orientomaera gen. nov. (Crustacea: Amphipoda: Maeridae). Zootaxa, 4433 (2), 201 - 244. https: // doi. org / 10.11646 / zootaxa. 4433.2.1","Nagata, K. (1965) Studies on marine gammaridean Amphipoda of the Seto Inland Sea. III. Publications of the Seto Marine Biological Laboratory, 13, 291 - 326. https: // doi. org / 10.5134 / 175410","Kim, W. & Kim, C. B. (1991) The marine amphipod crustaceans of Ulreung Island, Korea. Part III. The Korean Journal of Zoology, 34, 323 - 337."]}

Quadrimaera angulata sp. nov. [Japanese name: Maru-sunnariyokoebi, new] (Figs 8���11) Type material. Holotype: female, 10.1 mm (OMNH-Ar-11729), north of Tanegashima Island in Kagoshima Prefecture, 30��54.07'N, 131��02.32'E ��� 30��54.65'N, 131��01.97'E (Fig. 1C), 140���152 m depth, using beam trawl, 29 May 2006, coll. K. Tomikawa. Paratypes: females, 9.2 and 6.6 mm (OMNH-Ar-11730, 11731), same data as holotype. Type locality. North of Tanegashima Island in Kagoshima Prefecture, Japan. Etymology. From the Latin angulatus, -a, -um (=angular, angulate), referring to the shape of the pereopod 7 basis. Diagnosis. Mandible, palp article 1 with distal tooth. Gnathopod 1, coxa anteroventral corner pointed. Female gnathopod 2, anterior margin of basis without robust setae, anterodistal corners of basis and ischium lobate on lateral and medial surfaces, propodus subrectangular, palm slightly oblique and rounded, defined by small tooth, palmar margin with small rounded excavation in middle, posterior excavation absent. Pereopods 5���7, bases subovate, posterodistal corners roundly lobate in pereopods 5���6 and angular in pereopod 7, posterior margins not setose. Uropod 3, outer ramus longer than inner ramus, about 1.7 times length of peduncle. Telson longer than wide, tips of both lobes incised, each with 2 robust setae, longest robust seta about 0.8 times as long as telson. Description. Based on holotype, female, 10.1 mm (OMNH-Ar-11729) and paratype, female, 9.2 mm (OMNHAr-11730) for lower lip. Head (Figs 8���9). Anteroventral corner produced acutely, eyes subrounded, about 0.2 times as long as head. Antenna 1 slender, poorly setose; peduncular articles 1���3 with length ratio of 1: 1.15: 0.25, article 1 with 4 robust setae posteriorly; accessory flagellum long, with>12 articles, tip lost; primary flagellum with>28 articles, tip lost. Antenna 2 about 35% length of body, poorly setose; peduncular articles 3���5 with length ratio of 1: 2.9: 2.65; flagellum with 8 articles, terminal article minute. Upper lip, ventral margin rounded, with short setae. Mandible, incisor bearing 5 cusps and 8 accessory setae, left lacinia mobilis 4-dentate, right lacinia mobilis 5-dentate; palp article 1 with distal tooth, articles 1���3 length ratio (excluding distal tooth of article 1) 1: 2.05: 1.7 in left and 1: 2.25: 1.75 in right, articles 2 ��� 3 setose. Lower lip with inner lobes, distal margins weakly setose, distal parts of outer lobes each with bundle of setae and dense fine setae, mandibular processes small. Maxilla 1, inner plate bullet-shaped, apically with long plumose seta and several short setae, medial margin bare; distal margin of outer plate with 7 robust setae; palp article 2 with many apical setae. Maxilla 2, outer plate larger than inner plate; medial margin of inner plate with several distal setae and several feeble setae. Maxilliped, distomedial corner of inner plate with 3 distal and 2 ventral robust setae; outer plate with 19 long-to-short robust setae on distomedial margin; palp with 4 articles, article 4 with large apical robust seta. Pereon (Fig. 10). Gnathopod 1, coxa anteroventral corner pointed; basis with many long setae on posterior margin and medial surface; carpus with shallow excavation on anterior margin; propodus about 85% length of carpus, palm defined by 5 short robust setae. Gnathopod 2, coxa subquadrate; basis relatively narrow, anterodistal corners on lateral and medial surfaces lobate, anterior margin with several minute setae, posterior margin bearing several long setae; ischium, anterodistal corners on lateral and medial surfaces lobate; merus with acute posterodistal spine; propodus subrectangular, slightly widened distally, length about 1.35 times width; palm slightly oblique, rounded, defined by small tooth with small robust seta, margin with small rounded excavation in middle, posterior excavation absent, anterior lobe with 5 lateral and 4 medial robust setae, posterior lobe bearing 8 lateral and 8 medial robust setae; dactylus, inner margin slightly curved. Pereopods 3���4 subequal in shape, pereopod 3 about 1.1 times length of pereopod 4; coxa subrectangular; basis with posterior margin bearing several long setae. Pereopod 5 about 1.2 times length of pereopod 4; coxa with posterior lobe bearing robust seta; basis oblong, length about 2.0 times width, posterodistal lobe rounded, anterior margin with 6 short robust setae; merus swollen in middle. Pereopod 6 about 135% length of pereopod 5; coxa with 2 and 1 ventral robust setae on anterior and posterior lobes, respectively; basis subovate, length about 1.65 times width, posterodistal lobe rounded, anterior margin with 6 short robust setae, posterior margin minutely serrate. Pereopod 7 about 0.9 times length of pereopod 6; coxa subtrapezoidal, anteroventral corner with robust seta; basis subovate, length about 1.5 times width, posterodistal lobe angular, anterior margin with 6 short robust setae, posterior margin minutely serrate. Pleon (Fig. 11). Epimera 1���3 slightly projected posteroventrally; epimera 1���2 each with oblique lateral ridge, ventral margins of epimera 1���3 with 2, 3, 5 robust setae, respectively. Pleopods 1���3, inner rami each with 10 articles and outer rami with 14, 13, 12 articles respectively; pleopod 3 shortest, peduncle bearing 3 robust setae distally. Uropod 1, peduncle with 1 basofacial, 11 dorsolateral, 10 dorsomedial and 1 distolateral robust setae; outer ramus about 85% length of inner ramus, about 75% length of peduncle, with 4 lateral, 6 medial and 5 (1 lost) terminal robust setae; inner ramus with 8 lateral, 9 medial and 5 terminal robust setae. Uropod 2 about 0.7 times length of uropod 1; peduncle bearing 5 dorsolateral and 3 dorsomedial robust setae; outer ramus about 85% length of inner ramus, about 115% length of peduncle, with 8 lateral, 3 medial and 5 (1 lost) terminal robust setae; inner ramus with 5 lateral, 8 medial and 5 terminal robust setae. Uropod 3 about 0.9 times length of uropod 2; distolateral and distomedial corners of peduncle with 2 and 3 robust setae, respectively; outer ramus about 1.1 times length of inner ramus, about 1.7 times length of peduncle; outer ramus with single and 3 groups of robust setae laterally and 5 robust setae medially, distal margin with minute second article and 10 setae; inner ramus with 1+1+2 robust setae laterally and 4 robust setae medially, distal margin with 7 setae. Telson longer than wide, each lateral margin with 2 sensory setae subdistally; distal margins of lobes each with 2 processes, 1 sensory seta and 2 long robust setae, longest robust seta about 0.8 times length of telson. Coloration in life. Unknown. Remarks. This new species has a distal tooth on the mandibular palp article 1, although Ariyama (2019) diagnosed the lack of the tooth in the genus Quadrimaera. As a result of reexamining all literature on the genus, the following five species are revealed to possess the distal tooth: Q. frater Myers, 2014 from the Chagos Archipelago; Q. kaiulani (Barnard, 1970) from Hawaii; Q. massavensis (Kossmann, 1880) from the Red Sea (Krapp-Schickel & Ruffo 2006); Q. micheli Appadoo, Myers & Fagoonee, 2002 sensu Hughes (2015) from Cocos Islands (another species different from the true Q. micheli); and Q. vietnamica Dang & Le, 2011 from Vietnam. Quadrimaera angulata sp. nov. and these species resemble one another and share some characters (e.g. slightly oblique and rounded palm of the gnathopod 2 and incised lobes of the telson). However, this new species can be distinguished from the other five species by the shape of the pereopod 7 basis and the longer rami of the uropod 3 (Table 2). Habitat. Bottom material unknown, 140���152 m depth. The examined specimens were collected together with Quadrimaera quadrimana (Dana, 1853) [two males, 5.4 and 4.8 mm (OMNH-Ar-11732, 11733)]. Distribution. North of Tanegashima Island in Kagoshima Prefecture, Japan (present study)., Published as part of Ariyama, Hiroyuki, Kodama, Masafumi & Tomikawa, Ko, 2020, Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel & Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 336-352 in Zootaxa 4885 (3) on pages 345-350, DOI: 10.11646/zootaxa.4885.3.2, http://zenodo.org/record/4296670, {"references":["Ariyama, H. (2019) Species of the Maera - clade collected from Japan. Part 2: genera Austromaera Lowry & Springthorpe, 2005 and Quadrimaera Krapp-Schickel & Ruffo, 2000 (Crustacea: Amphipoda: Maeridae). Zootaxa, 4554 (2), 460 - 496. https: // doi. org / 10.11646 / zootaxa. 4554.2.6","Myers, A. A. (2014) Amphipoda (Crustacea) from the Chagos Archipelago. Zootaxa, 3754 (1), 1 - 31. https: // doi. org / 10.11646 / zootaxa. 3754.1.1","Barnard, J. L. (1970) Sublittoral Gammaridea (Amphipoda) of the Hawaiian Islands. Smithsonian Contributions to Zoology, 34, 1 - 286. https: // doi. org / 10.5479 / si. 00810282.34","Kossmann, R. (1880) Malacostraca (2. Theil: Anomura). In: Kossmann, R. (Ed.), Zoologische Ergebnisse einer im Auftrage der Koniglichen Akademie der Wissenschaften zu Berlin ausgefuhrten Reise in die Kustengebiete des Rothen Meeres. Halfte II. Lieferung I. Verlag von Wilhelm Engelmann, Leipzig, pp. 67 - 140, pls. 4 - 15.","Krapp-Schickel, T. & Ruffo, S. (2006) New or poorly known Quadrimaera species from the Red Sea and Indian Ocean (Amphipoda, Melitidae). Bollettino del Museo Civico di Storia Naturale di Verona, 30, 57 - 70.","Appadoo, C., Myers, A. A. & Fagoonee, I. (2002) The genera Quadrimaera and Maera (Amphipoda: Gammaridea: Melitidae) from Mauritius. Journal of Natural History, 36, 641 - 673. https: // doi. org / 10.1080 / 00222930010025518","Hughes, L. (2015) Maeridae from the Indo-Pacific: Elasmopus, Leeuwinella gen. nov., Maeropsis, Pseudelasmopus and Quadrimaera (Amphipoda: Crustacea). Zootaxa, 4059 (2), 201 - 256. https: // doi. org / 10.11646 / zootaxa. 4059.2.1","Dang, N. T. & Le, H. A. (2011) Crustaceans family Melitidae (Amphipoda- Gammaridea) from Vietnam sea. Vietnam Journal of Biology, 33 (2), 1 - 18. [in Vietnamese with English abstract and descriptions of new species] https: // doi. org / 10.15625 / 0866 - 7160 / v 33 n 2.740","Dana, J. D. (1853) Crustacea. Part II. United States Exploring Expedition, 14, 689 - 1618. https: // doi. org / 10.5962 / bhl. title. 61409"]}

Grandidierella Coutière, 1904 [Japanese name: Dorosokoebi-zoku] Grandidierella Coutière, 1904: 166.—J.L. Barnard & Karaman, 1991: 194.— Myers & Lowry, 2003: 465. Neomicrodeutopus Schellenberg, 1925: 168. (Bigrandidierella) Karaman, 1985: 37. Propejanice Myers & Desiderato, 2019: 288. Type species. Grandidierella mahafalensis Coutière, 1904, monotypy. Diagnosis [emended from Ariyama & Taru (2017)]. Body subcylindrical, slightly depressed laterally, smooth. Head, rostrum short, ocular lobes short; eyes small to medium. Urosomites free. Antenna 1 elongate, slender, peduncular article 3 much shorter than article 1, accessory flagellum 1–2 articulate; antenna 2 stouter than antenna 1, flagellum shorter than peduncular article 5. Mandible, palp with 3 articles, article 3 clavate or rectolinear. Maxilla 1 with vestigial inner plate; outer plate with ca. 10 robust setae; palp biarticulate, with several robust setae at tip. Maxilla 2, inner plate usually with mediofacial row of setae. Maxilliped, inner plate with several robust setae distally; outer plate not reaching apex of palp article 2, with many marginal robust setae; palp consisting of 4 articles, article 4 with short robust seta (nail). Coxae small, relatively shallow, slightly or not overlapping; gills present on coxae 2–6; oostegites of female broad, present on coxae 2–5. Male gnathopod 1 greatly enlarged, carpochelate; carpus dilated, propodus short, dactylus stout. Female gnathopod 1 smaller than that of male, subchelate, palm oblique. Gnathopod 2 of both sexes smaller than gnathopod 1, subchelate; carpus longer than or almost same length as propodus, palm transverse. Pereopods 3 and 4 similar to each other, slender; bases elongate. Pereopods 5–7 similar to each other, pereopod 5 much shorter than pereopods 6 and 7; basis of pereopod 7 heavily setose posteriorly. Uropods 1 and 2 biramous, spinous, uropod 1 longer than uropod 2, peduncles longer than both rami; uropod 3 uniramous, peduncle usually shorter than single ramus, dilated medially. Telson entire, short, fleshy, with pair of hooked apical cusps. Remarks. Recently, Myers & Desiderato (2019) established a new genus, Propejanice Myers & Desiderato, 2019, having a carpochelate male gnathopod 1 and a setose male gnathopod 2 with a divergent merus. Although they stated Propejanice is close to the genus Janice Griffiths, 1973, this genus should be synonymized with the genus Grandidierella, because three Grandidierella species (G. exilis Myers, 1981; G. gilesi Chilton, 1921; and G. melakaensis Azman & Othman, 2012) have such a gnathopod 2. Following this synonymization, Propejanice lagamarensis Myers & Desiderato, 2019 is changed to Grandidierella lagamarensis (Myers & Desiderato, 2019) comb. nov., Published as part of Ariyama, Hiroyuki, 2020, Six species of Grandidierella collected from the Ryukyu Archipelago in Japan with descriptions of four new species (Crustacea: Amphipoda: Aoridae), pp. 1-44 in Zootaxa 4810 (1) on page 3, DOI: 10.11646/zootaxa.4810.1.1, http://zenodo.org/record/3936945, {"references":["Coutiere, H. (1904) Sur un type nouveau d'Amphipode, Grandidierella mahafalensis, provenant de Madagascar. Bulletin de la Societe philomathique de Paris, Serie 9, 6, 166 - 174.","Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13 (Part 1 & Part 2), 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.91 https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367","Myers, A. A. & Lowry, J. K. (2003) A phylogeny and a new classification of the Corophiidea Leach, 1814 (Amphipoda). Journal of Crustacean Biology, 23, 443 - 485. https: // doi. org / 10.1163 / 20021975 - 99990353","Schellenberg, A. (1925) Crustacea VIII: Amphipoda. In: Michaelsen, W. (Ed.), Beitrage zur Kenntnis der Meeresfauna Westafrikas. Vol. 3. Fredrichsen, Hamburg, pp. 113 - 204.","Karaman, G. S. (1985) Two new taxa of suborder Gammaridea from Asia, with remarks to some Sri Lanka's species (contribution to the knowledge of the Amphipoda 142). Poljoprivreda i sumarstvo, 31, 15 - 40.","Myers, A. A. & Desiderato, A. (2019) A new genus and species of Aoridae (Amphipoda, Senticaudata), Propejanice lagamarensis gen. nov. sp. nov. from Brazil. Zootaxa, 4629 (2), 287 - 293. https: // doi. org / 10.11646 / zootaxa. 4629.2.11","Ariyama, H. & Taru, M. (2017) Three species of Grandidierella (Crustacea: Amphipoda: Aoridae) from coastal areas of the Tohoku and Kanto-Tokai Districts, east Japan, with the description of two new species. Species Diversity, 22, 187 - 200. https: // doi. org / 10.12782 / specdiv. 22.187","Griffiths, C. L. (1973) The Amphipoda of Southern Africa. Part 1. The Gammaridea and Caprellidea of southern Mocambique. Annals of the South African Museum, 60, 265 - 306.","Myers, A. A. (1981) Taxonomic studies on the genus Grandidierella Coutiere (Crustacea, Amphipoda). III. Fijian, Australian and Saudi Arabian species. Bulletin du Museum National d'Histoire Naturelle, Paris, 4 e Serie, 3, Section A, Nº 1, 213 - 226.","Chilton, C. (1921) Fauna of the Chilka Lake. Amphipoda. Memoires of the Indian Museum, 5, 519 - 558.","Azman, B. A. R. & Othman, B. H. R. (2012) Two new species of amphipods of the superfamily Aoroidea (Crustacea: Corophiidea) from the Strait of Malacca, Malaysia, with a description of a new genus. Zoological Studies, 51, 232 - 247."]}

Meximaera mooreana (Myers, 1989) [Japanese name: Kawari-sunnariyokoebi, new] (Figs 11���15) Maera species B Barnard, 1970: 159, fig.100.��� Barnard, 1971: 85, figs 31, 38, 40���41. Maera mooreana Myers, 1989: 72, figs 9���10.��� Appadoo, Myers & Fagoonee, 2002: 661, figs 12���13.��� Ren, 2012: 244, fig. 106. Meximaera mooreana.��� Krapp-Schickel, 2008a: 22. Material examined. Male, 4.3 mm (OMNH-Ar-10626), Tagurazaki coast, Wakayama City, Wakayama Prefecture, 34��16��02����N 135��03��39����E (Fig. 1B), uppermost subtidal, under stones, 10 April 2005, coll. H. Ariyama; ovigerous female, 5.5 mm (OMNH-Ar-10627), same locality and habitat, 17 June 2007, coll. H. Ariyama; male, 6.5 mm (OMNH-Ar-10628), same locality and habitat, 30 June 2007, coll. H. Ariyama; male, 5.2 mm (OMNH-Ar-10629) and male, 3.4 mm (OMNH-Ar-10630), same locality and habitat, 9 April 2016, coll. H. Ariyama. Type locality. Moorea in the Society Islands, French Polynesia (Myers 1989). Diagnosis. Eyes situated anteriorly. Mandible, palp article 1 with acute distal tooth. Gnathopod 1, coxa anteroventral corner roundly produced. Gnathopod 2 in male, basis wide, palm moderately oblique, defined by small tooth, palmar margin with rounded excavation. Gnathopod 2 in female, basis slender, propodus rectangular, palm weakly oblique, lacking excavation. Pereopods dactyli simple; bases of pereopods 5���7 subrectangular, narrowed distally, posterodistal corners square. Pleonal e pimera 1���3 each with small tooth posteroventrally. Uropod 3 very long, rami subequal, about 3.4 times length of peduncle. Telson longer than wide, longest distal seta about 0.3 times length of telson. Description. Based on male, 6.5 mm (OMNH-Ar-10628), male, 5.2 mm (OMNH-Ar-10629) for antennae and telson, and ovigerous female, 5.5 mm (OMNH-Ar-10627) for habitus. Head (Figs 11���12). Eyes about 0.15 times as long as head, situated anteriorly. Antenna 1 about 0.55 times body length, poorly setose; peduncle slender, ratio of lengths of articles 1���3 1:1.25:0.5, article 1 with 4 robust setae posteromedially, anterodistal corner with bundle of setae; accessory flagellum with 6 articles, terminal article minute, length about half length of primary flagellum; primary flagellum with 12 articles, terminal article minute. Antenna 2 about 0.6 times length of antenna 1, weakly setose; peduncle slender, ratio of lengths of articles 3���5 1:2.35:1.9; flagellum with 7 articles, terminal article minute. Upper lip, ventral margin rounded, with dense short setae. Mandible, molar developed; each incisor bearing 3 cusps, each lacinia mobilis 4-dentate, number of accessory setae 5 on both sides; palp article 1 with acute distal tooth, articles 1 ��� 3 length ratio (excluding distal tooth of article 1) 1:1.8:1.6, articles 2 ��� 3 setose. Lower lip with inner lobes, distal margins of both lobes setose, mandibular processes small. Maxilla 1, inner plate bullet-shaped, with 3 long and 2 tiny apical setae, medial margin bare; distal margin of outer plate with 8 robust setae; palp 2-articulate, setose apically. Maxilla 2, outer plate larger than inner plate; both plates bearing many apical setae, medial margin of inner plate with 3 feeble setae. Maxilliped, inner plate truncate, distally setose, distomedial corner with 2 robust setae; outer plate with 16 long-to-short robust setae on distomedial margin; palp with 4 articles, article 2 setose medially, article 4 with large apical robust seta. Pereon (Fig. 13). Gnathopod 1, coxa lozenge-shaped, anteroventral corner produced roundly; basis with posterior margin bearing many long setae; carpus about 1.3 time as long as propodus, broadened distally, posterior margin and medial surface heavily setose; propodus palm defined by 2 short robust setae; dactylus slender, curved posteriorly, anterior margin with single seta. Gnathopod 2, coxa subtrapezoidal, produced posteroproximally; basis wide, about 1.9 times as long as width, poorly setose; merus with acute posterodistal spine; propodus about 2.4 times length of carpus, rectangular, length 1.8 times width; palm moderately oblique, defined by small triangular tooth, palmar margin with rounded excavation in middle and 7 lateral and 7 medial robust setae, posterior margin proximal to tooth also bearing single medial robust seta; dactylus stout, curved distally. Pereopods 3���4, shapes subequal, pereopod 3 about 1.1 times length of pereopod 4; coxae subquadrate, gills on coxae 3���4 small and large, respectively; bases rectilinear, poorly setose. Pereopods 5���7, shapes subsimilar, lengths about 1.15, 1.5, 1.55 times of pereopod 4, respectively; coxae 5���7 bearing 1, 3, 2 robust setae, respectively; bases subrectangular, narrowed distally, lengths about 2.55, 2.2, 1.9 times widths respectively, posteroproximal corners roundly projected, anterior margins with several short robust setae, posterior margins minutely serrate, posterodistal corners square; dactyli straight. Pleon (Fig. 14). Epimera 1���3 each with small tooth on posteroventral corner; ventral margins of epimera 2���3 with 4 and 5 robust setae, respectively. Pleopods 1���3, pleopod 3 shortest; peduncles each with 2 coupling hooks, peduncle of uropod 3 bearing distal robust seta; each inner and outer ramus with 6 and 8 articles, respectively. Uropod 1, peduncle with 4 ventrolateral, 9 dorsolateral, 6 dorsomedial and 1 large distolateral robust setae; outer ramus slightly longer than inner ramus, about 0.7 times length of peduncle, with 4 lateral, 2 medial and 3 terminal robust setae; inner ramus with 4 lateral, 4 medial and 5 terminal robust setae. Uropod 2 about 0.6 times length of uropod 1; peduncle bearing 1 dorsolateral and 4 dorsomedial robust setae; rami subequal, outer ramus almost same length as peduncle, with 3 lateral, 2 medial and 4 terminal robust setae; inner ramus with 3 lateral, 4 medial and 4 terminal robust setae. Uropod 3 very long, about 2.25 times length of uropod 2, rectilinear; distolateral corner and medial margin of peduncle with 1 and 3 robust setae, respectively; rami subequal, about 3.4 times length of peduncle; outer ramus with minute second article, lateral margin of outer ramus setose, medial margin of outer ramus and lateral margin of inner ramus bearing many short robust setae, medial margin of inner ramus with 8 robust setae, distal margins of both rami with several short setae laterally, longest seta about 0.1 times length of outer ramus. Telson about 1.25 times longer than wide, lateral margins bare, dorsal surfaces of each lobe with 2 sensory setae distally, distal margins of lobes each with 2 processes (inner processes smaller than outer), bearing 2 robust setae and sensory seta, longest robust seta about 0.3 times length of telson. Description of female. Ovigerous female, 5.5 mm (OMNH-Ar-10627). Gnathopod 2 (Fig. 14 F-G2), basis slen- der, about 3.8 times as long as width, posterior margin with 4 long setae in middle; propodus about 1.7 times length of carpus, rectangular, length twice width; palm weakly oblique, lacking excavation, defining tooth indistinct, palmar margin with 7 small lateral robust setae and 7 (6 small and 1 large) medial robust setae. Variation. Small male, 3.4 mm (OMNH-Ar-10630). Gnathopod 2 (Fig. 14 SM-G2), propodus narrower, length twice width; palmar excavation indistinct, palmar margin with 4 small lateral robust setae and 6 (5 small and 1 large) medial robust setae. Coloration in life (Fig. 15). Eyes dark brown, article 1 of antenna 2 and mouth parts pale orange, other parts white. Remarks. Morphological characters of the present specimens closely resemble those in the literature (Barnard 1970, Myers 1989, Appadoo et al. 2002, Ren 2012). However, one character is different from Myers (1989) and Appadoo et al. (2002): the mandibular palp article 1 is acutely projected in the specimens, whereas that is not projected in the two papers [Ren���s (2012) figure indicates a presence of the projection]. Because presence or absence of the projection is one of the important characters dividing genera of the Maera -clade (Krapp-Schickel 2008a), closer examination is needed in all of the Meximaera species. Habitat. Among coral and algae (Myers 1989), among algae (Appadoo et al. 2002), coral reef (Ren 2012), under stones (present study); intertidal and shallow-subtidal (Appadoo et al. 2002). Distribution. Pacific Ocean: Society Islands (Myers 1989), Hawaii (Barnard 1970, 1971). China: Hainan Island (Ren 2012). Japan: Wakayama Prefecture (present study). Indian Ocean: Mauritius (Appadoo et al. 2002)., Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on pages 465-470, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Myers, A. A. (1989) Amphipoda from the South Pacific: the Society Islands. Records of the Australian Museum, 41, 63 - 82. https: // doi. org / 10.3853 / j. 0067 - 1975.41.1989.136","Barnard, J. L. (1970) Sublittoral Gammaridea (Amphipoda) of the Hawaiian Islands. Smithsonian Contributions to Zoology, 34, 1 - 286. https: // doi. org / 10.5479 / si. 00810282.34","Barnard, J. L. (1971) Keys to the Hawaiian marine Gammaridea, 0 - 30 meters. Smithsonian Contributions to Zoology, 58, 1 - 135. https: // doi. org / 10.5479 / si. 00810282.58","Appadoo, C., Myers, A. A. & Fagoonee, I. (2002) The genera Quadrimaera and Maera (Amphipoda: Gammaridea: Melitidae) from Mauritius. Journal of Natural History, 36, 641 - 673. https: // doi. org / 10.1080 / 00222930010025518","Ren, X. (2012) Fauna Sinica, Invertebrata. Vol. 43. Crustacea: Amphipoda: Gammaridea (II). Science Press, Beijing, 651 pp. [in Chinese with English abstract and descriptions of new species]","Krapp-Schickel, T. (2008 a) What has happened with the Maera - clade (Crustacea, Amphipoda) during the last decades? Bollettino del Museo Civico di Storia Naturale di Verona, 32, 3 - 32."]}

Maera loveni (Bruzelius, 1859) [Japanese name: Ō- sunnariyokoebi, new] (Figs 2���5) Gammarus loveni Bruzelius, 1859: 59, pl. 2, fig. 9. Moera loveni.��� Bate, 1862: 193, pl. 35, fig. 1.��� Oldevig, 1917: 36. Maera loveni.��� Norman, 1868: 416, pl. 21, figs 11���12.��� Sars, 1895: 519, pl. 182, fig. 2.��� Stebbing, 1906: 438.��� Stephensen, 1927: 114.��� Shoemaker, 1930: 116.��� Stephensen, 1940a: 311.��� Stephensen, 1940b: 55.��� Gurjanova, 1951: 757, fig. 526.���Krapp-Schickel & Jarret, 2000: 34, fig. 4. Moera lovenii.��� Stephensen, 1913: 194. not Maera loveni.��� Barnard, 1962: 103, fig. 19 (= Maera nelsonae Krapp-Schickel & Jarrett, 2000). Material examined. Male, 58.3 mm (OMNH-Ar-10623) and female, 51.7 mm (OMNH-Ar-10624), Sea of Japan, north of Masuda City, Yamaguchi Prefecture, 35��50��26����N 131��46��31����E (Fig. 1C), 300 m depth, using trawl, 28 August 2011, coll. Y. Kogure. Type locality. Bohusl��n in Sweden, 73���100 m depth. Diagnosis. Eyes present. Mandible, palp article 1 with acute distal tooth. Gnathopod 1, coxa anteroventral corner roundly produced. Gnathopod 2 in both sexes, palm slightly oblique, defined by blunt tooth bearing strong robust seta. Pereopods, dactyli simple; bases of pereopods 5���7 rectangular, posterodistal corners square. Pleonal e pimera 1���3 each with small tooth. Uropod 3 rami subequal, twice as long as peduncle. Telson longer than wide, distal margins each with small notch bearing short seta. Description. Based on male, 58.3 mm (OMNH-Ar-10623). Head (Figs 2���3). Eyes, pigments faded. Antenna 1 about 0.6 times as long as body, weakly setose; peduncle with ratio of lengths of articles 1���3 1:1.15:0.35, article 1 with 4 small posteromedial robust setae; accessory flagellum with 10 articles, terminal article minute, length about 0.2 times primary flagellum; primary flagellum with 42 articles, terminal article short. Antenna 2 about half length of antenna 1, heavily setose posteriorly, with ratio of lengths of peduncular articles 3���5 1:2.7:2.1; flagellum with 15 articles, terminal article minute. Upper lip, ventral margin rounded, weakly setose. Mandible, incisor bearing 5 and 4 cusps in left and right, respectively, left lacinia mobilis 4-dentate, right lacinia mobilis 3-dentate, both with many accessory setae; palp article 1 with acute distal tooth, articles 1 ��� 3 length ratio (excluding distal tooth of article 1) 1:2.8���2.9:1.6, articles 2 ��� 3 setose. Lower lip with inner lobes, distal margins of outer lobe weakly setose, mandibular processes small. Maxilla 1, inner plate with 3 long and 3 minute apical setae, medial and lateral margins bearing feeble setae, outer plate with 9 apical robust setae and lateral feeble setae, palp with many apical setae. Maxilla 2, outer plate larger than inner plate; both plates bearing many apical setae, medial margin of inner plate with 2 normal and many feeble setae. Maxilliped, inner plate truncate, distally setose; outer plate with many long-to-short robust setae on distomedial margin; palp 4-articulate, article 2 setose medioventrally, article 3 with many distolateral setae, article 4 with large apical robust seta. Pereon (Fig. 4). Gnathopod 1, coxa anteroventral corner produced, but rounded, anteroventral margin with several short setae; basis setose on anterior and posterior margins and medial surface; ischium and merus each with setae on posterior margin; carpus swollen posterodistally, posterior margin and medial surface heavily setose; propodus about 85% as long as carpus, anterior and posterior margins setose, palmar margin bearing many small robust setae laterally and medially; dactylus slender, almost straight, anterior margin setose. Gnathopod 2, coxa subtrapezoidal, posteroventral margin with 3 minute notches; basis relatively narrow, about 2.7 times as long as width, anteroproximal margin, anterodistal corner and posterior margin setose; merus with acute posterodistal spine; carpus swollen posterodistally, anterior and posterior margins setose; propodus subrectangular, length about 1.3 times width, anteromedial surface and posterior margin setose; palm slightly oblique, defined by blunt tooth bearing strong robust seta, palmar margin with 9 small teeth, bearing 8 lateral and 17 medial small robust setae; dactylus curved distally, anterior margin with many (> 40) setae. Pereopods 3���4, shapes subequal, pereopod 3 about 1.1 times length of pereopod 4; coxae trapezoidal, gills large, subequal to bases lengths; bases rectilinear, anterior and posterior margins setose proximally; dactyli slender, simple. Pereopods 5���7, shapes subsimilar, about 1.2, 1.6, 1.7 times length of pereopod 4 respectively; coxa 5 anterior lobe minutely serrated ventrally, anteroventral margins of coxae 6���7 with 5 and 3 robust setae, respectively; bases rectangular, lengths about 2.7, 2.4, 2.2 times widths respectively, posteroproximal corners projected, anterior margins with many short robust setae, posterior margins minutely serrate, posterodistal corners square; dactyli short, simple. Pleon (Fig. 5). Epimera 1���3 each with small tooth on posteroventral corner and lateral ridge, ventral margins with 4, 12, 16 robust setae respectively. Pleopods 1���3, pleopod 3 shortest; peduncles with 7, 7, 9 coupling hooks respectively; both rami each with 20���25 articles. Uropod 1, peduncle with 6 dorsolateral and 15 dorsomedial robust setae, bearing large distolateral robust seta; outer ramus subequal length to inner ramus, about 0.8 times as long as peduncle, with 8 dorsomedial and 2 terminal robust setae; inner ramus with 4 lateral, 14 dorsomedial and 4 terminal robust setae. Uropod 2 about 65% length of uropod 1; peduncle laterodistal corner projected, dorsolateral margin, dorsomedial margin and distomedial corner with 3, 5 and 4 robust setae, respectively; outer ramus about 0.9 times length of inner ramus, about 95% length of peduncle, with 6 dorsomedial and 2 terminal robust setae; inner ramus with 5 lateral, 16 dorsomedial and 3 terminal robust setae. Uropod 3 about 1.1 times as long as uropod 2; peduncle laterodistal and mediodistal corners bearing 5 and 1 robust setae, respectively; both rami rectilinear, outer ramus slightly shorter than inner ramus, about 2.1 times length of peduncle, lacking vestigial second article; lateral and medial margins of both rami lined with robust setae, distal margins bearing a few setae, longest seta about 0.1 times length of outer ramus. Telson about 1.5 times longer than wide, each lateral margin with 5���7 small robust setae, tips acutely projected, each with inner notch bearing 0���1 short robust seta. Description of female (51.7 mm, OMNH-Ar-10624). Gnathopod 2 (Fig. 5 F-G2) subsimilar to that of male except for oostegite. Coloration. Unknown. Remarks. Morphological characters of the present specimens almost agree with those in the literature (Bruzelius 1859, Sars 1895, Krapp-Schickel & Jarrett 2000). However, a few characters as follows are different: (1) mandibular palp article 1 acutely projected, (2) distal setae of uropod 3 rami fewer and shorter, and (3) short robust setae present on lateral margins of telson. Body sizes of the specimens (58.3 mm in male, 51.7 mm in female) are also different from the previous records [maximum: 37 mm (Shoemaker 1930)]. This species is characterized by the strong robust setae directly sitting on the palmar corner of the gnathopod 2 (Krapp-Schickel & Jarrett 2000). Habitat. Clay, sand or shell bottom (Bryazgin 1997), 20���400 m depth (Gurjanova 1951). Burrowing in sandymud bottom (Atkinson et al. 1982). Distribution. From the Gulf of St. Lawrence, Nova Scotia and W. Greenland to Spitzbergen, N. Norway and Great Britain (Stephensen 1940a, b). Russia: Barents Sea, Sea of Okhotsk (Gurjanova 1951). Northeast Pacific: Washington (Krapp-Schickel & Jarrett 2000). Sea of Japan (present study)., Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on pages 453-459, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Bruzelius, R. M. (1859) Bidrag till kannedomen om skandinaviens Amphipoda Gammaridea. Kongliga Svenska Vetenskaps- Akademiens Handlingar, New Series, 3 (1), 1 - 104, 4 pls. https: // doi. org / 10.5962 / bhl. part. 28297","Bate, C. S. (1862) Catalogue of the Specimens of Amphipodous Crustacea in the Collection of the British Museum. The British Museum, London, 399 pp., 58 pls.","Oldevig, H. (1917) Die Amphipoden, Isopoden und Cumaceen des Eisfjords. Kungliga Svenska Vetenskapsakademiens Handlingar, New Series, 54 (8), 1 - 56.","Norman, A. M. (1868) On Crustacea Amphipoda new to science or to Britain. Annals and Magazine of Natural History, Series 4, 2, 411 - 421, pls. 21 - 23. https: // doi. org / 10.1080 / 00222936808695843","Sars, G. O. (1895) An Account of the Crustacea of Norway with Short Descriptions and Figures of All the Species. Vol. I. Amphipoda. A. L. B. Cammermeyers Forlag, Christiania and Copenhagen, 711 pp., 240 pls., 8 suppl. pls. https: // doi. org / 10.5962 / bhl. title. 1164","Stebbing, T. R. R. (1906) Amphipoda I. Gammaridea. Das Tierreich, 21, 1 - 806.","Stephensen, K. (1927) Revideret Fortegnelse over Danmarks Arter af Amphipoda (3. Del: Gammaridea: Fam. Gammaridae til Fam. Podoceridae (Dulichiidae aut.); Caprellidea). Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 84, 107 - 150.","Shoemaker, C. R. (1930) The Amphipoda of the Cheticamp Expedition of 1917. Contributions to Canadian Biology and Fisheries, New Series, 5, 221 - 359. https: // doi. org / 10.1139 / f 30 - 010","Stephensen, K. (1940 a) The Amphipoda of N. Norway and Spitsbergen with adjacent waters. TromsO Museums Skrifter, 3, 279 - 362.","Stephensen, K. (1940 b) Marine Amphipoda. The Zoology of Iceland, 3 (26), 1 - 111.","Gurjanova E. F. (1951) Bokoplavy morej SSSR i sopredel'nykh vod (Amphipoda-Gammaridea). Akademiia Nauk SSSR, Opredeliteli po Faune SSSR, 41, 1 - 1031. [in Russian]","Stephensen, K. (1913) Groenlands Krebsdyr og Pycnogonider (Conspectus Crustaceorem et Pycnogonidorum Groenlandiae). Meddelelser om GrOnland, 22, 1 - 479. https: // doi. org / 10.5962 / bhl. title. 10674","Barnard, J. L. (1962) Benthic marine Amphipoda of southern California: families Tironidae to Gammaridae. Pacific Naturalist, 3, 73 - 115.","Krapp-Schickel, T. & Jarrett, N. E. (2000) The amphipod family Melitidae on the Pacific coast of North America. Part II. The Maera - Ceradocus complex. Amphipacifica, 2, 23 - 61.","Bryazgin, V. (1997) Diversity, distribution and ecology of benthic amphipods (Amphipoda, Gammaridea) in the Barents Sea sublittoral. Polish Polar Research, 18, 89 - 106.","Atkinson, R. J. A., Moore, P. G. & Morgan, P. J. (1982) The burrows and burrowing behaviour of Maera loveni (Crustacea: Amphipoda). Journal of Zoology, 198, 399 - 416. https: // doi. org / 10.1111 / jzo. 1982.198.4.399"]}

Ariyama, Hiroyuki (2020): Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae). Zootaxa 4743 (4): 451-479, DOI: https://doi.org/10.11646/zootaxa.4743.4.1

Orientomaera Ariyama, 2018 [Japanese name: Tōyō- sunnariyokoebi-zoku] Orientomaera Ariyama, 2018: 217. Diagnosis. See Ariyama (2018). However in the gnathopod 2 palm, ���margin with several blunt teeth��� is modified to ���margin with several blunt teeth or two distinct teeth���., Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on page 471, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Ariyama, H. (2018) Species of the Maera - clade collected from Japan. Part 1: genera Maeropsis Chevreux, 1919 and Orientomaera gen. nov. (Crustacea: Amphipoda: Maeridae). Zootaxa, 4433 (2), 201 - 244. https: // doi. org / 10.11646 / zootaxa. 4433.2.1"]}

Maera sagamiensis sp. nov. [Japanese name: Sagami-sunnariyokoebi, new] (Figs 6���10) Type material. Holotype: male, 10.1 mm (OMNH-Ar-10625), Sagami Bay, off J��gashima Island in Miura City, Kanagawa Prefecture, 35��08���31���N 139��32���28���E (Fig. 1A), 133���274 m depth, using dredge, 12 February 2015, coll. H. Kohtsuka. Type locality. Sagami Bay, off Jōgashima Island in Miura City, Kanagawa Prefecture, Japan. Etymology. Referring to the type locality. Diagnosis. Eyes present. Mandible, palp article 1 with acute distal tooth. Gnathopod 1, coxa anteroventral corner acutely produced, posteroventral margin with 3 notches. Gnathopod 2 in male, coxa posteroventral margin with 3 notches, palm strongly oblique, defined by acute tooth. Pereopods dactyli simple; coxa 3 posteroventral margin bearing 2 notches posteroventrally, bases of pereopods 5���7 rectangular, posterodistal corners square. Pleonal e pimera 1���3 acutely projected posteroventrally. Uropod 3, outer ramus longer than inner ramus, rami 2.2���2.5 times as long as peduncle. Telson longer than wide, distal ends pointed. Description. Based on holotype, male, 10.1 mm (OMNH-Ar-10625). Head (Figs 6���7). Eyes oval, about 0.2 times length of head. Antenna 1 poorly setose; peduncle with ratio of lengths of articles 1���3 1:1.15:0.3, article 1 with 4 small posteromedial robust setae; accessory flagellum with 7 articles, terminal article minute; primary flagellum damaged. Antenna 2 about 0.35 times length of body; peduncle weakly setose posteriorly, with ratio of lengths of articles 3���5 1:3.7:2.5; flagellum setose, with 9 articles, terminal article minute. Upper lip, ventral margin rounded, weakly setose. Mandible, incisor bearing 5 and 4 cusps in left and right, respectively, each lacinia mobilis 4-dentate, with 9 accessory setae; palp article 1 with acute distal tooth, articles 1 ��� 3 length ratio (excluding distal tooth of article 1) 1:2.5:1.5, articles 2 ��� 3 setose. Lower lip with inner lobes, distal margins and ventral surfaces of both lobes weakly setose, mandibular processes small. Maxilla 1, inner plate with 3 long and 1 short apical setae, medial and lateral margins and ventral surface bearing feeble setae, outer plate with 10 apical robust setae and medial and ventral feeble setae, palp article 1 with several laterodistal setae, article 2 bearing many apical setae. Maxilla 2, outer plate larger than inner plate; both plates bearing many apical setae, medial margin of inner plate with 1 normal and many feeble setae. Maxilliped, inner plate truncate, distally setose, distomedial corner with 4 robust setae ventrally; outer plate with 23 long-to-short robust setae on distomedial margin; palp 4-articulate, article 2 setose medioventrally, article 3 with many distolateral setae, article 4 with large apical robust seta. Pereon (Fig. 8). Gnathopod 1, coxa anteroventral corner acutely produced, ventral margin with 3 small notches posteriorly; basis setose on posterior margin; carpus swollen posterodistally, posterior margin and medial surface heavily setose; propodus about 90% as long as carpus, anterior and posterior margins setose, palmar margin bearing many small robust setae medially; dactylus slender, almost straight, anterior margin with single seta. Gnathopod 2, coxa subquadrate, posteroventral margin with 3 small notches; basis relatively narrow, about 2.9 times as long as width, posterior margin with several setae; merus with acute posterodistal spine; carpus swollen posterodistally, posterior margin setose; propodus slender, length about 1.95 times width, anteromedial surface and posterior margin setose; palm strongly oblique, defined by acute tooth, palmar margin with 5 small teeth, bearing 9 lateral and 13 medial robust setae; dactylus curved distally, anterior margin with 10 setae. Pereopods 3���4, shapes subequal; coxae trapezoidal, coxa 3 with 2 small notches posteroventrally, gills large, subequal to bases lengths; bases rectilinear, anterior and posterior margins each with a few long setae proximally; dactylus of pereopod 4 slender, simple. Pereopods 5���7, shapes subsimilar, pereopods 5, 7 about 1.2, 1.6 times length of pereopod 4, respectively; coxae 6���7, anteroventral margins each with single robust seta; bases rectangular, lengths about 2.9, 2.6, 2.2 times widths respectively, posteroproximal corners roundly projected, anterior margins with many short robust setae, posterior margins serrate, posterodistal corners square; dactyli short, simple. Pleon (Fig. 9). Epimera 1���3 acutely projected posteroventrally, each with lateral ridge, ventral margins with 3, 2, 5 (1 lost) robust setae respectively. Pleopods 1���3, pleopod 3 shortest; peduncles with 2, 2, 4 coupling hooks respectively; both rami each with 7���9 articles. Uropod 1, peduncle with 15 dorsolateral and 11 dorsomedial robust setae, bearing large distolateral robust seta; outer ramus subequal length to inner ramus, about 0.75 times as long as peduncle, with 4 dorsolateral, 4 dorsomedial and 4 terminal robust setae; inner ramus with 9 dorsomedial and 4 terminal robust setae. Uropod 2 about 0.6 times length of uropod 1; peduncle laterodistal corner projected, dorsolateral margin, dorsomedial margin and distomedial corner with 11, 6 and 3 robust setae, respectively; outer ramus about 0.85 times length of inner ramus, about 95% length of peduncle, with 8 dorsomedial and 3? terminal robust setae; inner ramus with 4 lateral, 9 dorsomedial and 5 terminal robust setae. Uropod 3 long, about 175% as long as uropod 2; peduncle, lateral, medial and ventral margins with 3, 1 and 2 robust setae, respectively, mediodistal corner bearing 4 robust setae; both rami rectilinear, outer ramus about 115% length of inner ramus, about 2.5 times length of peduncle, with vestigial second article; lateral and medial margins of both rami lined with robust setae, distal margins bearing several setae, longest seta about 0.15 times length of outer ramus. Telson about 1.25 times longer than wide, each lateral margin with 4 small robust setae, tips acutely projected, dorsal surfaces of each lobe with a robust seta and 3 sensory setae. Coloration in life (Fig. 10). Eyes black and white, mouth parts orange, other parts faint orange; yellow internal organs seen through. Remarks. The presence of small notches on the coxae 1���3 is a distinct character in the genus, although Japanese specimens of Maera loveni and M. pachytelson from France and Israel have minute notches on the coxa 2 and the coxae 1���2, respectively (Fig. 4-G 2, G. Karaman & Ruffo 1971). Maera sagamiensis sp. nov. can be distinguished from M. loveni by the shape of the gnathopod 2 palm, and from M. pachytelson by the shape of the telson. Habitat. Bottom sediment unknown, 133���274 m depth (present study). Distribution. Sagami Bay in Japan (present study)., Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on pages 459-460, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Karaman, G. & Ruffo, S. (1971) Contributo alla conoscenza della specie Mediterranee del genere Maera. Memorie del Museo Civico di Storia Naturale, Verona, 19, 113 - 176."]}

Order Amphipoda Latreille, 1816 Suborder Senticaudata Lowry & Myers, 2013, Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on page 452, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Latreille, P. A. (1816) AMPHIPODES. In: Societe de Naturalistes et d'Agriculteurs (Ed.), Nouveau Dictionaire d'Histoire Naturelle, appliquee aux Arts, a l'Agriculture, a l'Economie rurale et domestique, a la Medecine, etc. Vol 1. New Edition. Chez Deterville, Paris, pp. 467 - 469.","Lowry, J. K. & Myers, A. A. (2013) A phylogeny and classification of the Senticaudata subord. nov. (Crustacea: Amphipoda). Zootaxa, 3610 (1), 1 - 80. https: // doi. org / 10.11646 / zootaxa. 3610.1.1"]}

Meximaera Barnard, 1969a [Japanese name: Mekishiko-sunnariyokoebi-zoku, new] Meximaera Barnard, 1969a: 209.��� Krapp-Schickel, 2008a: 22.��� Krapp-Schickel, 2008b: 1425.��� Lowry & Myers, 2013: 36. Type species. Meximaera diffidentia Barnard, 1969a, monotypy. Emended diagnosis. Body smooth. Head, rostrum obsolescent, lateral cephalic lobe rounded, antennal sinus shallow, anteroventral corner rounded or projected; eyes oval, about 0.15���0.3 times as long as head. Antennae slender; antenna 1, peduncular articles 1���2 longer than article 3, accessory flagellum with 4���6 articles. Mandible, palp article length 2>3>1, article 1 usually without distal tooth. Coxae short, anteroventral corner of coxa 1 rounded or produced acutely, coxae 5���6 lobate; gills present on coxae 2���6, oostegites present on coxae 2���5. Gnathopod 1 subchelate; carpus longer than or subequal to propodus; propodus longish ovate, palm oblique. Gnathopod 2 larger than gnathopod 1, symmetrical, subchelate; merus with or without acute posterodistal spine; carpus short, lobate; propodus longish ovoid, length 1.6���2.1 times width; palm moderately or strongly oblique, margin with several robust setae; dactylus with single seta on anterior margin. Pereopods, dactyli simple; pereopods 3���4 slender; pereopods 5 ��� 7, bases more or less expanded. Uropods biramous; uropods 1���2, peduncle and both rami with many robust setae; uropod 3, peduncle short, rami subequal in length, wide, outer ramus 1.5 ��� 3.3 times as long as peduncle, distal margins of rami truncate, with several robust setae, longest distal seta of outer ramus 0.1 ��� 0.8 times as long as outer ramus. Telson slightly longer than or as long as wide, deeply incised, each lobe with 2 ��� 5 distal robust setae, longest robust seta 0.3 ��� 0.9 times of telson. Included species (4). Meximaera briani Krapp-Schickel, 2008b; M. diffidentia Barnard, 1969a; M. mooreana (Myers, 1989); M. tulearensis (Ledoyer, 1972). Remarks. This genus resembles Ruffomaera Krapp-Schickel, 2008b and a part of Orientomaera Ariyama, 2018 in having the symmetrical male gnathopod 2 with oblique palm, the simple dactyli of the pereopods 3 ��� 7, and the truncate tips of the uropod 3 rami. However, Meximaera differs from Ruffomaera in the smooth posterior margins of the pleonal epimera 2 ��� 3 and the smooth posterodorsal margins of the urosomites 1 ��� 2 (Krapp-Schickel 2008b), and from Orientomaera in the fewer (, Published as part of Ariyama, Hiroyuki, 2020, Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae), pp. 451-479 in Zootaxa 4743 (4) on pages 463-464, DOI: 10.11646/zootaxa.4743.4.1, http://zenodo.org/record/3690502, {"references":["Barnard, J. L. (1969 a) Gammaridean Amphipoda of the rocky intertidal of California: Monterey Bay to La Jolla. Bulletin of the United States National Museum, 258, 1 - 230. https: // doi. org / 10.5479 / si. 03629236.258.1","Krapp-Schickel, T. (2008 a) What has happened with the Maera - clade (Crustacea, Amphipoda) during the last decades? Bollettino del Museo Civico di Storia Naturale di Verona, 32, 3 - 32.","Krapp-Schickel, T. (2008 b) On the genera Meximaera, Ruffomaera gen. nov., Maeropsis and Ceradocus from Atlantic coasts (Amphipoda: Melitidae). Journal of the Marine Biological Association of the United Kingdom, 88, 1425 - 1432. https: // doi. org / 10.1017 / S 0025315408002014","Lowry, J. K. & Myers, A. A. (2013) A phylogeny and classification of the Senticaudata subord. nov. (Crustacea: Amphipoda). Zootaxa, 3610 (1), 1 - 80. https: // doi. org / 10.11646 / zootaxa. 3610.1.1","Myers, A. A. (1989) Amphipoda from the South Pacific: the Society Islands. Records of the Australian Museum, 41, 63 - 82. https: // doi. org / 10.3853 / j. 0067 - 1975.41.1989.136","Ledoyer, M. (1972) Amphipodes gammariens vivant dans les alveoles des constructions organogenes recifales intertidales de la region de Tulear (Madagascar). Etude systematique et ecologique. Tethys, Supplement 3, 165 - 285.","Ariyama, H. (2018) Species of the Maera - clade collected from Japan. Part 1: genera Maeropsis Chevreux, 1919 and Orientomaera gen. nov. (Crustacea: Amphipoda: Maeridae). Zootaxa, 4433 (2), 201 - 244. https: // doi. org / 10.11646 / zootaxa. 4433.2.1"]}

Protodulichia scandens Ariyama and Hoshinoı sp. nov. (Figures 1 ��� 5) [Japanese name: Bōnobori-yokoebiı new] Type locality Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı Japanı 34��47 �� 15 ��� Nı 139��24 �� 31 ��� Eı 25 m depth. Material examined Holotype. Male (OMNH-Ar-11171)ı 2.8 mmı Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı 25 m depthı coarse sand bottomı 13 June 2017ı coll. O. Hoshino. Paratypes: 2 males and 1 ovigerous female (OMNH-Ar-11172 ��� 11174)ı 3.0ı 2.4ı 3.1 mmı same data as holotype; ovigerous female (OMNH-Ar-11175)ı 2.7 mmı same locality as holotypeı 11 June 2017ı coll. O. Hoshino. Description Male [based on holotypeı 2.8 mm (OMNH-Ar-11171)ı and paratypeı 3.0 mm (OMNH Ar-11172) for mandible]. Body (Figure 1) smooth; headı dorsal margin roundedı lateral cephalic lobe trianguları posteroventral margin with small projectionı eyes about 0.4 times as long as head; pereonite 7ı posterodistal margin rotated posteriorly; pleonal epimera roundedı smooth; urosomite 1 not longı about 115% length of pleonite 3. Antenna 1 (Figure 2 (aıa1)) with ratio of lengths of peduncular articles 1 ��� 3 1:1.2:0.95ı peduncular article 1 without ventral robust setae; accessory flagellum 2-articulate; primary flagellum with 6 articlesı posterior margin bearing aesthetascs. Antenna 2 (Figure 2 (b)) about 1.3 times length of antenna 1; peduncleı ratio of lengths of articles 3 ��� 5 1:2.35:3.55ı posterior margin sparsely setose; flagellum slenderı with 4 articlesı terminal article minute. Upper lip (Figure 2 (c)) broadı fleshyı ventral margin with minute setae. Mandible (Figure 2 (dıd1ıd2ıeıe1ıe2))ı incisor with 4 and 5 cuspsı lacinia mobilis with 3 and 4 cusps in left and rightı respectivelyı 3 wide accessory blades present in both sides; molar developedı with spatula-like process; palpı length ratio of articles 1 ��� 3 1:2.5 ��� 2.6:2.0 ��� 2.1ı articles 2ı 3 setose. Lower lip (Figure 2 (f)) with well-developed inner lobesı outer lobes each with mandibular lobeı distal margins covered with thin setae. Maxilla 1 (Figure 2 (gıg1))ı inner plate long trianguları without setae; outer plate bearing 9 terminal robust setae distally; palp 2-articulateı article 2 bearing 5 robust setae apically and several setae dorsally. Maxilla 2 (Figure 2 (h))ı both plate with distal setaeı inner plate lacking mediofacial row of setae. Maxilliped (Figure 2 (iıi1))ı inner plate with 3 short ventrodistal robust setae; outer plate bearing 8 marginal robust setae mediodistally; palp consisting of 4 articlesı article 2 longı article 4 with slender nail. Gnathopod 1 (Figure 3 (a))ı coxa longer than wideı posteroventral corner with small notch; basis slightly curved anteriorly; posterodistal margin of merus and posterior margin of carpus setose; propodus setose mediallyı posterior margin with several thick setae; dactylus longı slender. Gnathopod 2 (Figure 3 (bıb1))ı coxa subtrapezoidalı posteroventral corner with small notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus trianguları posterodistal corner setose; propodus largeı about 1.85 times length of carpusı palm smoothı bearing 6 robust setae; dactylus narrow. Pereopods 3ı 4 (Figure 2 (cıc1ıd)) subsimilar to each other; coxae subquadrateı posteroventral corner of coxa 4 slightly produced; bases widened in middleı many granules present in each gland; meri ��� dactyli slender. Pereopod 5 (Figure 2 (eıe1)) shorter than pereopod 4; coxa wideı bilobedı both lobes each with robust seta; basis subovateı length about 1.65 times widthı anterior margin with lateral ridgeı posterodistal corner expanded; carpus and merus each bearing several robust setae. Pereopod 6 (Figure 3 (fıf1)) about 1.25 times length of pereopod 5; coxa narrowı bilobedı anterior lobe with robust seta; basis ovalı length about 1.4 times widthı anterior margin with lateral ridgeı posterodistal corner widely expanded; carpus and merus each with several robust setae. Pereopod 7 (Figure 4 (a)) about 1.55 times length of pereopod 6; coxa roundish triangular; basis narrowed distallyı length about 1.75 times widthı anterior margin with lateral ridgeı posteroproximal corner projectedı posterodistal corner not expanded; carpus ��� propodus slenderı elongateı each with several robust setae. Pleopods 1 ��� 3 (Figure 4 (bıcıd))ı peduncles each with 2 coupling hooksı pleopods 2ı 3 bearing 2 and 4 setaeı respectively; outer rami slightly longer than inner ramiı outer rami with 9ı 10ı 10 articles and inner rami with 8ı 8ı 9 articlesı respectively. Uropod 1 (Figure 4 (e))ı peduncle with 3 dorsomedial robust setaeı mediodistal corner slightly projected; outer ramus about 0.9 times as long as peduncleı about 0.8 times length of inner ramusı outer ramus with 4 dorsalı 2 subterminal and 1 terminal robust setaeı inner ramus bearing 5 dorsomedialı 2 subterminal and 1 terminal robust setae. Uropod 2 (Figure 4 (f)) about 0.75 times length of uropod 1; peduncle mediodistal corner slightly projectedı with robust seta; outer ramus about 1.3 times as long as peduncleı about 0.65 times length of inner ramusı outer ramus with 3 dorsal and 1 terminal robust setaeı inner ramus bearing 4 dorsomedial and 2 terminal robust setae. Uropod 3 (Figure 4 (g)) about half length of uropod 2; peduncle laterodistal corner slightly projectedı medial margin with seta; outer ramus about 2.05 times as long as peduncleı about 0.9 times length of inner ramusı outer and inner rami with 0 ��� 1 dorsal and 2 dorsomedial robust setaeı respectivelyı both rami each bearing minute terminal robust seta. Telson (Figure 4 (h)) smoothı without setaeı length about 1.3 times widthı dorsodistal end slightly produced. Ovigerous female [based on paratypeı 3.1 mm (OMNH-Ar-11174)]. Gnathopod 2 (Figure 4 (iıi1))ı coxa largeı anterior margin swollen in middleı posteroventral corner without notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus longish trianguları posterior margin setose; propodus slenderı about 1.2 times length of carpusı palm smoothı bearing 4 robust setae; dactylus longı slender. Variation. Uropod 3ı outer and inner rami with 0 ��� 1 and 1 ��� 2 dorsal robust setaeı respectively (Table 1)ı minute terminal robust seta present on each ramus in all specimens. Colouration in life Male (Figure 5 (a)): whole body light red and whiteı eyes silver. Female (Figure 5 (b)): head pale orangeı anterior pereonites dark redı other parts of body almost whiteı eyes silver. Distribution Known only from the type locality. Ecology This new species builds a mast and clings to the mast on a coarse sand bottom at a depth of 25 m (Figure 5). The mast is about 6 ��� 7 mm in length and light grey in colourı and several sand grains are attached on. Such behaviour was observed only in the family Dulichiidae (e.g. Mattson and Cedhagen 1989; Neretin et al. 2017)ı and this is the first record in the other amphipods. Etymology From the Latin scandens (= scandentı climbing)ı referring to the ecology., Published as part of Ariyama, Hiroyuki & Hoshino, Osamu, 2019, A new superfamily�� family�� genus and species of marine amphipod�� Protodulichia scandens�� from Japan (Crustacea: Amphipoda: Senticaudata: Corophiida), pp. 2467-2477 in Journal of Natural History 53 (39) on pages 2470-2476, DOI: 10.1080/00222933.2019.1704588, http://zenodo.org/record/3666407, {"references":["Mattson Si Cedhagen T. 1989. Aspects of the behaviour and ecology of Dyopedos monacanthus (Metzger) and D. porrectus Batei with comparative notes on Dulichia tuberculata Boeck (Crustacea: Amphipoda: Podoceridae). J Exp Mar Biol Eco 1. 127: 253 - 272.","Neretin NYi Zhadan AEi Tzetlin AB. 2017. Aspects of mast building and the fine structure of \" amphipod silk \" glands in Dyopedos bispinis (Amphipodai Dulichiidae). Contr Zool. 86: 145 - 168."]}

Protodulichia Ariyamaı gen. nov. [Japanese name: Bōnobori-yokoebi-zokuı new] Type species Protodulichia scandens Ariyama and Hoshinoı sp. nov. Diagnosis As for the superfamily. Etymology From the Greek proto (= firstı earliest) and Dulichia (related genus). Included species At present this genus contains only one speciesı Protodulichia scandens sp. nov. Protodulichia scandens Ariyama and Hoshinoı sp. nov. (Figures 1 ��� 5) [Japanese name: Bōnobori-yokoebiı new] Type locality Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı Japanı 34��47 �� 15 ��� Nı 139��24 �� 31 ��� Eı 25 m depth. Material examined Holotype. Male (OMNH-Ar-11171)ı 2.8 mmı Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı 25 m depthı coarse sand bottomı 13 June 2017ı coll. O. Hoshino. Paratypes: 2 males and 1 ovigerous female (OMNH-Ar-11172 ��� 11174)ı 3.0ı 2.4ı 3.1 mmı same data as holotype; ovigerous female (OMNH-Ar-11175)ı 2.7 mmı same locality as holotypeı 11 June 2017ı coll. O. Hoshino. Description Male [based on holotypeı 2.8 mm (OMNH-Ar-11171)ı and paratypeı 3.0 mm (OMNH Ar-11172) for mandible]. Body (Figure 1) smooth; headı dorsal margin roundedı lateral cephalic lobe trianguları posteroventral margin with small projectionı eyes about 0.4 times as long as head; pereonite 7ı posterodistal margin rotated posteriorly; pleonal epimera roundedı smooth; urosomite 1 not longı about 115% length of pleonite 3. Antenna 1 (Figure 2 (aıa1)) with ratio of lengths of peduncular articles 1 ��� 3 1:1.2:0.95ı peduncular article 1 without ventral robust setae; accessory flagellum 2-articulate; primary flagellum with 6 articlesı posterior margin bearing aesthetascs. Antenna 2 (Figure 2 (b)) about 1.3 times length of antenna 1; peduncleı ratio of lengths of articles 3 ��� 5 1:2.35:3.55ı posterior margin sparsely setose; flagellum slenderı with 4 articlesı terminal article minute. Upper lip (Figure 2 (c)) broadı fleshyı ventral margin with minute setae. Mandible (Figure 2 (dıd1ıd2ıeıe1ıe2))ı incisor with 4 and 5 cuspsı lacinia mobilis with 3 and 4 cusps in left and rightı respectivelyı 3 wide accessory blades present in both sides; molar developedı with spatula-like process; palpı length ratio of articles 1 ��� 3 1:2.5 ��� 2.6:2.0 ��� 2.1ı articles 2ı 3 setose. Lower lip (Figure 2 (f)) with well-developed inner lobesı outer lobes each with mandibular lobeı distal margins covered with thin setae. Maxilla 1 (Figure 2 (gıg1))ı inner plate long trianguları without setae; outer plate bearing 9 terminal robust setae distally; palp 2-articulateı article 2 bearing 5 robust setae apically and several setae dorsally. Maxilla 2 (Figure 2 (h))ı both plate with distal setaeı inner plate lacking mediofacial row of setae. Maxilliped (Figure 2 (iıi1))ı inner plate with 3 short ventrodistal robust setae; outer plate bearing 8 marginal robust setae mediodistally; palp consisting of 4 articlesı article 2 longı article 4 with slender nail. Gnathopod 1 (Figure 3 (a))ı coxa longer than wideı posteroventral corner with small notch; basis slightly curved anteriorly; posterodistal margin of merus and posterior margin of carpus setose; propodus setose mediallyı posterior margin with several thick setae; dactylus longı slender. Gnathopod 2 (Figure 3 (bıb1))ı coxa subtrapezoidalı posteroventral corner with small notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus trianguları posterodistal corner setose; propodus largeı about 1.85 times length of carpusı palm smoothı bearing 6 robust setae; dactylus narrow. Pereopods 3ı 4 (Figure 2 (cıc1ıd)) subsimilar to each other; coxae subquadrateı posteroventral corner of coxa 4 slightly produced; bases widened in middleı many granules present in each gland; meri ��� dactyli slender. Pereopod 5 (Figure 2 (eıe1)) shorter than pereopod 4; coxa wideı bilobedı both lobes each with robust seta; basis subovateı length about 1.65 times widthı anterior margin with lateral ridgeı posterodistal corner expanded; carpus and merus each bearing several robust setae. Pereopod 6 (Figure 3 (fıf1)) about 1.25 times length of pereopod 5; coxa narrowı bilobedı anterior lobe with robust seta; basis ovalı length about 1.4 times widthı anterior margin with lateral ridgeı posterodistal corner widely expanded; carpus and merus each with several robust setae. Pereopod 7 (Figure 4 (a)) about 1.55 times length of pereopod 6; coxa roundish triangular; basis narrowed distallyı length about 1.75 times widthı anterior margin with lateral ridgeı posteroproximal corner projectedı posterodistal corner not expanded; carpus ��� propodus slenderı elongateı each with several robust setae. Pleopods 1 ��� 3 (Figure 4 (bıcıd))ı peduncles each with 2 coupling hooksı pleopods 2ı 3 bearing 2 and 4 setaeı respectively; outer rami slightly longer than inner ramiı outer rami with 9ı 10ı 10 articles and inner rami with 8ı 8ı 9 articlesı respectively. Uropod 1 (Figure 4 (e))ı peduncle with 3 dorsomedial robust setaeı mediodistal corner slightly projected; outer ramus about 0.9 times as long as peduncleı about 0.8 times length of inner ramusı outer ramus with 4 dorsalı 2 subterminal and 1 terminal robust setaeı inner ramus bearing 5 dorsomedialı 2 subterminal and 1 terminal robust setae. Uropod 2 (Figure 4 (f)) about 0.75 times length of uropod 1; peduncle mediodistal corner slightly projectedı with robust seta; outer ramus about 1.3 times as long as peduncleı about 0.65 times length of inner ramusı outer ramus with 3 dorsal and 1 terminal robust setaeı inner ramus bearing 4 dorsomedial and 2 terminal robust setae. Uropod 3 (Figure 4 (g)) about half length of uropod 2; peduncle laterodistal corner slightly projectedı medial margin with seta; outer ramus about 2.05 times as long as peduncleı about 0.9 times length of inner ramusı outer and inner rami with 0 ��� 1 dorsal and 2 dorsomedial robust setaeı respectivelyı both rami each bearing minute terminal robust seta. Telson (Figure 4 (h)) smoothı without setaeı length about 1.3 times widthı dorsodistal end slightly produced. Ovigerous female [based on paratypeı 3.1 mm (OMNH-Ar-11174)]. Gnathopod 2 (Figure 4 (iıi1))ı coxa largeı anterior margin swollen in middleı posteroventral corner without notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus longish trianguları posterior margin setose; propodus slenderı about 1.2 times length of carpusı palm smoothı bearing 4 robust setae; dactylus longı slender. Variation. Uropod 3ı outer and inner rami with 0 ��� 1 and 1 ��� 2 dorsal robust setaeı respectively (Table 1)ı minute terminal robust seta present on each ramus in all specimens. Colouration in life Male (Figure 5 (a)): whole body light red and whiteı eyes silver. Female (Figure 5 (b)): head pale orangeı anterior pereonites dark redı other parts of body almost whiteı eyes silver. Distribution Known only from the type locality. Ecology This new species builds a mast and clings to the mast on a coarse sand bottom at a depth of 25 m (Figure 5). The mast is about 6 ��� 7 mm in length and light grey in colourı and several sand grains are attached on. Such behaviour was observed only in the family Dulichiidae (e.g. Mattson and Cedhagen 1989; Neretin et al. 2017)ı and this is the first record in the other amphipods. Etymology From the Latin scandens (= scandentı climbing)ı referring to the ecology. Protodulichia scandens Ariyama and Hoshinoı sp. nov. (Figures 1 ��� 5) [Japanese name: Bōnobori-yokoebiı new] Type locality Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı Japanı 34��47 �� 15 ��� Nı 139��24 �� 31 ��� Eı 25 m depth. Material examined Holotype. Male (OMNH-Ar-11171)ı 2.8 mmı Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı 25 m depthı coarse sand bottomı 13 June 2017ı coll. O. Hoshino. Paratypes: 2 males and 1 ovigerous female (OMNH-Ar-11172 ��� 11174)ı 3.0ı 2.4ı 3.1 mmı same data as holotype; ovigerous female (OMNH-Ar-11175)ı 2.7 mmı same locality as holotypeı 11 June 2017ı coll. O. Hoshino. Description Male [based on holotypeı 2.8 mm (OMNH-Ar-11171)ı and paratypeı 3.0 mm (OMNH Ar-11172) for mandible]. Body (Figure 1) smooth; headı dorsal margin roundedı lateral cephalic lobe trianguları posteroventral margin with small projectionı eyes about 0.4 times as long as head; pereonite 7ı posterodistal margin rotated posteriorly; pleonal epimera roundedı smooth; urosomite 1 not longı about 115% length of pleonite 3. Antenna 1 (Figure 2 (aıa1)) with ratio of lengths of peduncular articles 1 ��� 3 1:1.2:0.95ı peduncular article 1 without ventral robust setae; accessory flagellum 2-articulate; primary flagellum with 6 articlesı posterior margin bearing aesthetascs. Antenna 2 (Figure 2 (b)) about 1.3 times length of antenna 1; peduncleı ratio of lengths of articles 3 ��� 5 1:2.35:3.55ı posterior margin sparsely setose; flagellum slenderı with 4 articlesı terminal article minute. Upper lip (Figure 2 (c)) broadı fleshyı ventral margin with minute setae. Mandible (Figure 2 (dıd1ıd2ıeıe1ıe2))ı incisor with 4 and 5 cuspsı lacinia mobilis with 3 and 4 cusps in left and rightı respectivelyı 3 wide accessory blades present in both sides; molar developedı with spatula-like process; palpı length ratio of articles 1 ��� 3 1:2.5 ��� 2.6:2.0 ��� 2.1ı articles 2ı 3 setose. Lower lip (Figure 2 (f)) with well-developed inner lobesı outer lobes each with mandibular lobeı distal margins covered with thin setae. Maxilla 1 (Figure 2 (gıg1))ı inner plate long trianguları without setae; outer plate bearing 9 terminal robust setae distally; palp 2-articulateı article 2 bearing 5 robust setae apically and several setae dorsally. Maxilla 2 (Figure 2 (h))ı both plate with distal setaeı inner plate lacking mediofacial row of setae. Maxilliped (Figure 2 (iıi1))ı inner plate with 3 short ventrodistal robust setae; outer plate bearing 8 marginal robust setae mediodistally; palp consisting of 4 articlesı article 2 longı article 4 with slender nail. Gnathopod 1 (Figure 3 (a))ı coxa longer than wideı posteroventral corner with small notch; basis slightly curved anteriorly; posterodistal margin of merus and posterior margin of carpus setose; propodus setose mediallyı posterior margin with several thick setae; dactylus longı slender. Gnathopod 2 (Figure 3 (bıb1))ı coxa subtrapezoidalı posteroventral corner with small notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus trianguları posterodistal corner setose; propodus largeı about 1.85 times length of carpusı palm smoothı bearing 6 robust setae; dactylus narrow. Pereopods 3ı 4 (Figure 2 (cıc1ıd)) subsimilar to each other; coxae subquadrateı posteroventral corner of coxa 4 slightly produced; bases widened in middleı many granules present in each gland; meri ��� dactyli slender. Pereopod 5 (Figure 2 (eıe1)) shorter than pereopod 4; coxa wideı bilobedı both lobes each with robust seta; basis subovateı length about 1.65 times widthı anterior margin with lateral ridgeı posterodistal corner expanded; carpus and merus each bearing several robust setae. Pereopod 6 (Figure 3 (fıf1)) about 1.25 times length of pereopod 5; coxa narrowı bilobedı anterior lobe with robust seta; basis ovalı length about 1.4 times widthı anterior margin with lateral ridgeı posterodistal corner widely expanded; carpus and merus each with several robust setae. Pereopod 7 (Figure 4 (a)) about 1.55 times length of pereopod 6; coxa roundish triangular; basis narrowed distallyı length about 1.75 times widthı anterior margin with lateral ridgeı posteroproximal corner projectedı posterodistal corner not expanded; carpus ��� propodus slenderı elongateı each with several robust setae. Pleopods 1 ��� 3 (Figure 4 (bıcıd))ı peduncles each with 2 coupling hooksı pleopods 2ı 3 bearing 2 and 4 setaeı respectively; outer rami slightly longer than inner ramiı outer rami with 9ı 10ı 10 articles and inner rami with 8ı 8ı 9 articlesı respectively. Uropod 1 (Figure 4 (e))ı peduncle with 3 dorsomedial robust setaeı mediodistal corner slightly projected; outer ramus about 0.9 times as long as peduncleı about 0.8 times length of inner ramusı outer ramus with 4 dorsalı 2 subterminal and 1 terminal robust setaeı inner ramus bearing 5 dorsomedialı 2 subterminal and 1 terminal robust setae. Uropod 2 (Figure 4 (f)) about 0.75 times length of uropod 1; peduncle mediodistal corner slightly projectedı with robust seta; outer ramus about 1.3 times as long as peduncleı about 0.65 times length of inner ramusı outer ramus with 3 dorsal and 1 terminal robust setaeı inner ramus bearing 4 dorsomedial and 2 terminal robust setae. Uropod 3 (Figure 4 (g)) about half length of uropod 2; peduncle laterodistal corner slightly projectedı medial margin with seta; outer ramus about 2.05 times as long as peduncleı about 0.9 times length of inner ramusı outer and inner rami with 0 ��� 1 dorsal and 2 dorsomedial robust setaeı respectivelyı both rami each bearing minute terminal robust seta. Telson (Figure 4 (h)) smoothı without setaeı length about 1.3 times widthı dorsodistal end slightly produced. Ovigerous female [based on paratypeı 3.1 mm (OMNH-Ar-11174)]. Gnathopod 2 (Figure 4 (iıi1))ı coxa largeı anterior margin swollen in middleı posteroventral corner without notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus longish trianguları posterior margin setose; propodus slenderı about 1.2 times length of carpusı palm smoothı bearing 4 robust setae; dactylus longı slender. Variation. Uropod 3ı outer and inner rami with 0 ��� 1 and 1 ��� 2 dorsal robust setaeı respectively (Table 1)ı minute terminal robust seta present on each ramus in all specimens. Colouration in life Male (Figure 5 (a)): whole body light red and whiteı eyes silver. Female (Figure 5 (b)): head pale orangeı anterior pereonites dark redı other parts of body almost whiteı eyes silver. Distribution Known only from the type locality. Ecology This new species builds a mast and clings to the mast on a coarse sand bottom at a depth of 25 m (Figure 5). The mast is about 6 ��� 7 mm in length and light grey in colourı and several sand grains are attached on. Such behaviour was observed only in the family Dulichiidae (e.g. Mattson and Cedhagen 1989; Neretin et al. 2017)ı and this is the first record in the other amphipods. Etymology From the Latin scandens (= scandentı climbing)ı referring to the ecology., Published as part of Ariyama, Hiroyuki & Hoshino, Osamu, 2019, A new superfamily�� family�� genus and species of marine amphipod�� Protodulichia scandens�� from Japan (Crustacea: Amphipoda: Senticaudata: Corophiida), pp. 2467-2477 in Journal of Natural History 53 (39) on pages 2470-2476, DOI: 10.1080/00222933.2019.1704588, http://zenodo.org/record/3666407, {"references":["Mattson Si Cedhagen T. 1989. Aspects of the behaviour and ecology of Dyopedos monacanthus (Metzger) and D. porrectus Batei with comparative notes on Dulichia tuberculata Boeck (Crustacea: Amphipoda: Podoceridae). J Exp Mar Biol Eco 1. 127: 253 - 272.","Neretin NYi Zhadan AEi Tzetlin AB. 2017. Aspects of mast building and the fine structure of \" amphipod silk \" glands in Dyopedos bispinis (Amphipodai Dulichiidae). Contr Zool. 86: 145 - 168."]}