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A new genus and species, Mauritiorchestia fayetta gen. nov., sp. nov., of talitrid amphipod is described from beaches in Mauritius. Mauritiorchestia differs significantly from the closely related genus Platorchestia in the maxilla 1 palp (absent in Mauritiorchestia, vestigial in Platorchestia) and in the dactylus of gnathopod 1 (simplidactylate in Mauritiorchestia, cuspidactylate in Platorchestia).

Platorchestia Bousfield, 1982 Platorchestia Bousfield, 1982: 26.��� Jo, 1988: 160.��� Richardson, 1991: 186.��� Morino & Ortal, 1995: 825.��� Miyamoto & Morino, 2004: 68. Type species. Orchestia platensis Kr��yer, 1845, original designation. Currently* included species: P. ano Lowry & Bopiah, 2013; P. crassicornis (Costa, 1867), not P. crassicornis (Derzhavin, 1937) = Demaorchestia joi (Stock & Biernbaum, 1994) com. nov.; P. munmui Jo, 1988; P. pachypus (Derzhavin, 1937); P. pacifica Miyamoto & Morino, 2004; P. paraplatensis Serejo & Lowry, 2008; P. platensis (Kr��yer, 1845); P. smithi Lowry, 2012. Ecological type. Beach-hopper. Habitat. Among stranded algae and beach detritus on marine shores. Size. 8���15 mm, Remarks. Platorchestia is very similar to the north-western Pacific genus Sinorchestia. They differ mainly in the ventral plate on antenna 2 peduncular article 3 (absent in Platorchestia); in the fourth article of the maxillipedal palp (reduced, button-shaped in Platorchestia, absent in Sinorchestia); and in gnathopod 1 (subchelate in Platorchestia, parachelate in Sinorchestia). Species inquirenda. Platorchestia chathamensis Bousfield, 1982 (based on a female). * A generic revision is currently in preparation by AAM and JKL, Published as part of Lowry, J. K. & Myers, A. A., 2022, Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species, pp. 1-53 in Zootaxa 5100 (1) on page 39, DOI: 10.11646/zootaxa.5100.1.1, http://zenodo.org/record/6127681, {"references":["Bousfield, E. L. (1982) The amphipod superfamily Talitroidea in the northeastern Pacific region. Family Talitridae. Systematics and distributional ecology. National. Museum of Natural Science, Publications in Biological Oceanography, 11, i - vii + 1 - 73.","Jo, Y. W. (1988) Talitridae (Crustacea - Amphipoda) of the Korean coasts. Beaufortia, 38 (7), 153 - 179.","Richardson, A. M. M. (1991) Two new species of landhoppers (Crustacea: Talitridae) from O'ahu, Hawaiian Islands, with redescription of Platorchestia pickering i and key to landhoppers of O'ahu. Bishop Museum Occasional Papers, 31, 185 - 201.","Morino, H. & Ortal, R. (1995) Two Platorchestia species (Amphipoda, Talitridae) from Israel. Crustaceana, 68, 824 - 832. https: // doi. org / 10.1163 / 156854095 X 00971","Miyamoto, H. & Morino, H. (2004) Taxonomic studies on the Talitridae (Crustacea, Amphipoda) from Taiwan. II. The genus Platorchestia. Publications of the Seto Marine Biological Laboratory, 40, 67 - 96. https: // doi. org / 10.5134 / 176317","Kroyer, H. (1845) Karcinologiske bidrag. Naturhistorisk tidsskrift, N. R., l, 283 - 345, pls. 2 + 3, 403 + 453 - 638, pls. 6 + 7.","Lowry, J. K. & Bopiah, A. (2013) The talitrid amphipods of Tonga (Crustacea, Amphipoda, Talitridae). Zootaxa, 3681 (4), 347 - 370. https: // doi. org / 10.11646 / zootaxa. 3681.4.2","Costa, A. (1867) Saggio della collezione di Crostacei del Mediterraneo del Museo zoologico della Universita di Napoli spedito alla Esposizione di Parigi del 1867. Annuario del Museo zoologico della R. Universitd di Napoli, 4, 38 - 46, pl. 3, fig. 1 - 2.","Derzhavin, A. N. (1937) Talitridae of the Soviet Coast of the Japan Sea. Issledovaniya Fauny Morej SSSR, 23, 87 - 112. [in Russian with English summary]","Stock, J. H. & Biernbaum, C. K. (1994) Terrestrial Amphipoda (Talitridae) from Ascension and Saint Helena (South Central Atlantic). Journal of Natural History, 28, 795 - 811. https: // doi. org / 10.1080 / 00222939400770411","Serejo, C. S. & Lowry, J. K. (2008) The coastal Talitridae (Amphipoda, Talitroidea) of Southern and Western Australia with Comments on Platorchestia platensis (Kroyer, 1845). Records of the Australian Museum, 60 (2 / 3), 161 - 206. https: // doi. org / 10.3853 / j. 0067 - 1975.60.2008.1491","Lowry, J. K. (2012) Talitrid amphipods of ocean beaches in New South Wales, Australia (Amphipoda, Talitridae). Zootaxa, 3575 (1), 1 - 26. https: // doi. org / 10.11646 / zootaxa. 3575.1.1"]}

This study targets surface activity of mobile macrofauna on pocket tidal beaches, undergoing different human use. We considered two beaches in Pittwater (NSW, Australia): Tennis beach on Scotland Island features artificial structures and provided with artificial lighting, while Portuguese beach (Ku-Ring-Gai Chase National Park) is only accessible by boat and has no artificial structures. At each site we placed pitfall traps across the littoral zone, with replicates at an opposite tidal period. Traps were kept active for 24 hours and emptied every three hours. The beach-hopper Platorchestia smithi was dominant in abundance at both sites; however Portuguese had a higher species number, including the burrowing isopod Actaecia bipleura . Circular summaries and behavioural models were calculated for abundant species. We found two different activity peaks for adults (nocturnal) and juveniles (sunrise) of P. smithi , consistent across sites, and a complex, tide-related pattern for A. bipleura . We also remarked the relevance of wrack presence on the littoral: this factor was found to modulate the activities of specific categories of macrofauna, such as females and juveniles of P. smithi , and A. bipleura . Results finally indicated no effect of artificial lighting on surface activity of abundant beach species.

Platorchestia platensis (Kr��yer, 1845) Synonymy restricted to South African records. Orchestia platensis. ― Griffiths, 1975: 170. Platorchestia platensis. ― Griffiths, Mead & Robinson, 2009: 242 (invasive). ― Griffiths, Robinson, & Mead 2011: 242. ― Mead, Carlton, Griffiths & Rius, 2011a: 1998, table 1. ― Mead, Carlton, Griffiths & Rius, 2011b: 2488. ― Milne & Griffiths, 2013: 77, 88 (Appendix). Types. Lectotype, male, 12.3 mm, ZMUC CRU 8221(selected by Serejo, 2004). Paralectotypes, 1 male, 6.8 mm; 1 female, 7.6 mm, 7 damaged specimens, ZMUC 7803 (selected by Serejo, 2004) Montevideo. 13/12 40. Type locality. Banks of the Rio Plata, Montevideo, Uruguay. Material examined. 11 specimens, AM P.88484, Plettenberg Bay, South Africa (~ 34��3.445'S 23��22.741'E), dissipative beach, underneath seagrass, F. Porri, March 2012 (in 95% ETOH). Remarks. Miyamoto & Morino, 2004 divided the genus into three groups. Group 1 which is characterised by antenna 2 and pereopods 6 and 7 sexually dimorphic, is represented by six supralittoral species: P. munmui Jo, 1988, P. pacifica Miyamoto & Morino, 2004; P. pachypus (Derzhavin, 1937), P. parapacifica Kim, Jung & Min, 2013; P. paraplatensis Serejo & Lowry, 2008; P. platensis (Kr��yer, 1845). Of these six species P. platensis appears to be the only traveller. According to Mead et al. (2011a) P. platensis was first discovered at Danger Point, Gansbaai in 1904, not an area of high ship activity. The new population discovered in 2010 from Plettenberg Bay, 440 km to the east is also not from an area of high ship activity. Mead et al. 2011b considered it to be an introduced species to South Africa mainly because of its restricted distribution. Its South African distribution is now confined to three disjunct bays along the southern coast. Distribution. South Africa. False Bay (Griffiths 1975); Danger Point, Gansbaai (Mead, Carlton, Griffiths & Rius 2011a); Plettenberg Bay (this study)., Published as part of Lowry, J. K. & Baldanzi, S., 2016, New talitrids from South Africa (Amphipoda, Senticaudata, Talitroidea, Talitridae) with notes on their ecology, pp. 151-174 in Zootaxa 4144 (2) on pages 169-170, DOI: 10.11646/zootaxa.4144.2.1, http://zenodo.org/record/272039, {"references":["Kroyer, H. (1845) Karcinologiske bidrag. Naturhistorisk tidsskrift, N. R., l, 283 - 345, pls. 2, 3, 403, 453 - 638, pls. 6, 7.","Griffiths, C. L. (1975) The Amphipoda of southern Africa. Part 5. The Gammaridea and Caprellidea of the Cape Province west of Cape Agulhas. Annals of the South African Museum, 67, 91 - 181.","Griffiths, C. L., Mead, A. & Robinson, T. B. (2009) A brief history of marine bio-invasions in South Africa. African Zoology, 44 (2), 241 - 247. http: // dx. doi. org / 10.3377 / 004.044.0212","Griffiths, C. L., Robinson, T. B. & Mead, A. (2011) The Alien and Cryptogenic Marine Crustaceans of South Africa. In the Wrong Place - Alien Marine Crustaceans: Distribution, Biology and Impacts Invading Nature. Springer Series in Invasion Ecology, 6, 269 - 282.","Mead, A., Carlton, J. Y., Griffiths, C. L. & Rius, M. (2011 a) Revealing the scale of marine bioinvasions in developing regions: a South African re-assessment. Biological Invasions, 13 (9), 1991 - 2008.","Mead, A., Carlton, J. Y., Griffiths, C. L. & Rius, M. (2011 b) Introduced and cryptogenic marine and estuarine species of South Africa. Journal of Natural History, 45 (39 - 40), 2463 - 2524.","Milne, R. & Griffiths, C. L. (2013) Additions to and revisions of the amphipod (Crustacea: Amphipoda) fauna of South Africa, with a list of currently known species from the region. African Natural History, 9, 61 - 90.","Serejo, C. S. (2004) Talitridae (Amphipoda, Gammaridea) from the Brazilian coastline. Zootaxa, 646, 1 - 29.","Miyamoto, H. & Morino, H. (2004) Taxonomic studies on the Talitridae (Crustacea, Amphipoda) from Taiwan. II. The genus Platorchestia. Publications of the Seto Marine Biological Laboratory, 40, 67 - 96.","Jo, Y. W. (1988) Talitridae (Crustacea - Amphipoda) of the Korean coasts. Beaufortia, 38 (7), 153 - 179.","Derzhavin, A. N. (1937) Talitridae of the Soviet Coast of the Japan Sea. Issledovaniya Fauny Morej SSSR, 23, 87 - 112. [in Russian with English summary]","Kim, M. - S., Jung, J. - H. & Min, G. - S. (2013) A new beach-hopper, Platorchestia parapacifica n. sp. (Amphipoda: Talitridae), from South Korea, with molecular phylogeny of the genus Platorchestia. Journal of Crustacean Biology, 33, 828 - 842. http: // dx. doi. org / 10.1163 / 1937240 X- 00002186","Serejo, C. & Lowry, J. K. (2008) The coastal Talitridae (Amphipoda, Talitroidea) of Southern and Western Australia with Comments on Platorchestia platensis (Kroyer, 1845). Records of the Australian Museum, 60 (2 / 3), 161 - 206. http: // dx. doi. org / 10.3853 / j. 0067 - 1975.60.2008.1491"]}

Platorchestia monodi (Mateus, Mateus and Afonso, 1986) BOLD:AAB3402 As Orchestia platensis Kr��yer 1845, p. 304, fig. 2; Platorchestia platensis Kr��yer 1845, Bousfield 1982, p. 26; Orchestia monodi Mateus, Mateus and Afonso, 1986, p. 100 ��� 110, figs 1 ��� 7; Platorchestia monodi Morino and Ortal 1993, p. 825 ��� 829, figs 1 ��� 3; LeCroy 2011, p. 754 ��� 757, fig. 597. Material examined From the following sampling locations: 4B, 4C, 5C, 7A, 8B, 9A, 10A, 11A, 12A, 12C, 14A, 14B, 15A (see Table 1 and Figure 2 for further details). Note that 9A is the same sample location as 5C, but made at a later date. Distribution Found on most suitable beaches throughout the islands where wrack can strand. Besides its primary ecotope, under and in wrack, some specimens were found at 4C (Hungry Bay) within the sand substratum, limited to a few centimetres depth (see also Bousfield 1984, who records P. platensis from a similar habitat). Circular holes of 5 ��� 8 mm diameter near the P. monodi ecotope were thought not be associated with the animals, but to result from physical effects after high tide. Such holes, lacking any evidence of digging wastes, were found on other sand substrata where talitrids were absent. Two other secondary ecotopes identified were: coastal terrestrial soil litter (two female individuals) associated with T. alluaudi (11A), and in driftwood (see below). Remarks Present in 13 of 19 sampling locations and the commonest wrack generalist taxon. Dorsal pigment patterns are obscured by background colours and are not useful for field identification., Published as part of Wildish, D. J., Smith, S. R., Loeza-Quintana, T., Radulovici, A. E. & Adamowicz, S. J., 2016, Diversity and dispersal history of the talitrids (Crustacea: Amphipoda: Talitridae) of Bermuda, pp. 1911-1933 in Journal of Natural History 50 on page 1919, DOI: 10.1080/00222933.2016.1180719, http://zenodo.org/record/3993348, {"references":["Mateus A, Mateus E, Afonso O. 1986. Amphipodes littoraux et l ' intereur recueilles aux Acores pendant la campagne \" Biacores \" sur le navire Jean Charcot. Anais Fac Ci c nce Porto. 65: 87 - 126.","KrOyer H. 1845. Karcinologiske Bidrag. Naturhistorisk Tidsskrift. 1: 304. Fig. 2.","Bousfield EL. 1982. The amphipod superfamily Talitroidea in the northeastern Pacific region. 1. Family Talitridae: systematics and distributional ecology. Ottawa: Publications in Biological Oceanography, No. 11; p. 73.","Morino H, Ortal R. 1993. The identity if Talitroides alluaudi (Chevreux) (Crustacea: Amphipoda: Talitridae) with notes on a new locality. Proc Biol Soc Wash. 106: 332 - 338.","LeCroy SE. 2011. An Illustrated Identification guide to the nearshore marine and estuarine gammaridean amphipoda of Florida. Vol. 5. Tallahassee, FL: Department of Environmental Protection; p. 739 - 763.","Bousfield EL. 1984. Recent advances in the systematics and biogeography of the landhoppers (Amphipoda: talitridae) of the Indo-Pacific region. Bishop Museum Spec Publ. 72: 171 - 210."]}

Platorchestia platensis (Kr��yer, 1845) BOLD:AAA2949 As Orchestia platensis Kr��yer 1845, p. 304, fig. 2; Platorchestia platensis (Kr��yer 1845), Bousfield 1982, p. 26. Material examined From the following sampling locations: 8C, 14A, 14C, 16B (see Table 1 and Figure 2 for further details). Distribution Found on similar sand beaches and under similar wrack piles as P. monodi. Found in single species samples (that is all three individuals analysed = BOLD:AAA2949), all on the northwest coast of Bermuda at Bailey ��� s Bay (8C), Tynes Bay (14C) and Lagoon Park (16B). One other sample at Tobacco Bay Park (14A) was a mixed sample containing one P. platensis and two P. monodi. Other locations on the northwest coast consisted of single species P. monodi, e.g. Coot Pond (14B), Gibbon ��� s Bay (7A) and Stovell ��� s Bay (5B). Remarks During this study this species was first recognized by its distinct molecular signature, which matched specimens identified as P. platensis from BOLD and GenBank. The same species is common on the Atlantic coast of North America, north of Charleston, North Carolina to New Brunswick (Radulovici 2012). Formalin-preserved specimens have not been checked for the possible occurrence of the two species of Platorchestia by morphological criteria, with the exception of sample 8C., Published as part of Wildish, D. J., Smith, S. R., Loeza-Quintana, T., Radulovici, A. E. & Adamowicz, S. J., 2016, Diversity and dispersal history of the talitrids (Crustacea: Amphipoda: Talitridae) of Bermuda, pp. 1911-1933 in Journal of Natural History 50 on pages 1919-1920, DOI: 10.1080/00222933.2016.1180719, http://zenodo.org/record/3993348, {"references":["KrOyer H. 1845. Karcinologiske Bidrag. Naturhistorisk Tidsskrift. 1: 304. Fig. 2.","Bousfield EL. 1982. The amphipod superfamily Talitroidea in the northeastern Pacific region. 1. Family Talitridae: systematics and distributional ecology. Ottawa: Publications in Biological Oceanography, No. 11; p. 73.","Radulovici AE. 2012. A tale of two biodiversity levels inferred from DNA barcoding of selected North Atlantic crustaceans. [Ph. D. thesis]. Rimouski (QC): University of Quebec at Rimouski; p. 245."]}

In this paper, we determined the complete mitochondrial genome (mitogenome) sequences of two talitrid amphipods, Platorchestia japonica and P. parapacifica. The complete mitogenomes of P. japonica and P. parapacifica were 14,780 and 14,787 bp in length, respectively, with the typical 13 protein coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a control region (CR). In the gene order analysis, two PCGs (nad3 and nad6) were rearranged in comparison to the typical pan-crustacean ground pattern. A maximum-likelihood tree, constructed based on 31 eumalacostracan mitogenomes, confirmed that P. japonica and P. parapacifica (Talitridae) were closely related to Parhyale hawaiensis (Hyalidae), and supports the monophyly of the superfamily Talitroidea.

A terrestrial talitrid amphipod, Platorchestia japonica (Tattersall, 1922), has been recorded for the first time from Korea. This species was collected from riversides (Han River, Bukhan River and Hantan River) in Korea. Descriptions of diagnostic characters of the species are provided in the text. A key to the four species of Korean Platorchestia is also provided.

Four species of talitrid Amphipoda based on the collection in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) are reported. Descriptions on two new species, Platorchestia bousfieldi n. sp. and Floresorchestia hanoiensis n. sp. are given. Differences between new species and related species are discussed.

Platorchestia ano sp. nov. (Figs 1���4) Platorchestia platensis.��� Myers, 1985: 134, figs 108, 109. Type material. Holotype male, 9 mm, AM P. 87313, from white sand beach with thick cover of fine Zostera and other plant debris (about 5���6 cm deep) at top of intertidal, Ano Beach, Pangaimotu Island, Vava���u, Tonga (18 �� 42 ���08.60���S 173 �� 59 ��� 19.62 ���W), talitrids very abundant, J.K. Lowry & G.C.B. Poore, 11 October 2011; paratypes: 1 female, AM P.87314, 29 males, 149 females and juveniles (many juveniles, only 2 ovigerous females) AM P. 87325, same locality as holotype. Additional material examined. Five males (only 1 mature), 95 females and juveniles (many juveniles) AM P. 87326, coarse coral rubble on top of fine white sand beach near the commercial harbour, Nuku���alofa, Tongatapu, Tonga (21 ��08.443���S 175 �� 10.426 ���W), talitrids under dried algae on sand under coarse rubble, J.K. Lowry & G.C.B. Poore, 13 October 2011; 1 specimen, AM P. 80738, Ano Beach, Pangaimotu Island, Vava���u, Tonga (18 �� 42 ���S 173 �� 59 ���W), Greg Towner, 19 September 2009. Type locality. Ano Beach, Pangaimotu Island, Vava���u, Tonga (18 �� 41.211 ���S 174 ��01.139���W). Etymology. Named for the type locality, Ano Beach, Tonga. Colour. Body evenly light tan, antenna 2 darker orange. Habitat. Beach-hoppers occurs on sandy shores under supralittoral wrack or terrestrial plant material. Description. Based on holotype male, 9 mm, AM P. 87313. Head. Eye medium (1 / 5 ��� 1 / 3 head length). Antenna 1 short, not longer than article 4 of antenna 2 peduncle. Antenna 2 up to half body length; peduncular articles incrassate; article 5 longer than article 4; peduncular articles with many small robust setae. Mandible left lacinia mobilis 5 -dentate. Maxilla 1 palp vestigial, 1 -articulate. Maxilliped palp article 2 distomedial lobe well developed, article 4 reduced, button-shaped. Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa smaller than coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; carpus 2 �� as long as propodus, 3.25 �� as long as broad; propodus 'subtriangular' with well developed posterodistal lobe, anterior margin with 3 groups of robust setae, lateral surface with 4 cuspidate setae, posterolateral surface with 6 serrate setae, medial surface with 4 cuspidate setae, posteromedial surface with 5 serrate setae; palm slightly obtuse, with 7 serrate setae; dactylus subequal in length to palm. Gnathopod 2 sexually dimorphic; subchelate; gill lobate; basis slightly expanded; ischium with rounded lobe on mid-anterior margin, without posterodistal lobe on medial surface; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; carpus triangular, reduced (enclosed by merus and propodus), posterior lobe absent; propodus subrhomboidal, 1.5 �� as long as wide; palm slightly acute, reaching about 25 % along posterior margin, lined with robust setae, evenly rounded, with weak palmar sinus or notch, without palmar protuberances, posteromedial surface of propodus with groove, with cuticular patch at corner of palm; dactylus slightly longer than palm, spatulate distally; gill bilobate, not incised. Pereopods 2���4 coxae as wide as deep. Pereopods 3���7 cuspidactylate; dactyli with distal patch of many rows of tiny denticles on the anterior margin. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3; dactylus thickened proximally with a notch midway along posterior margin. Pereopod 5 propodus distinctly longer than carpus. Pereopods 6���7 short (1 / 3 length of body). Pereopod 6 not sexually dimorphic; slightly shorter than pereopod 7; coxa posterior lobe inner view posteroventral corner rounded, posterior margin perpendicular to ventral margin, posterior lobe without ridge; gill convoluted, coxa not incised. Pereopod 7 not sexually dimorphic; basis lateral sulcus present, slightly pronounced, basis posterior margin with distinct minute serrations, each with a small seta, slight posterodistal lobe present, shallow, broadly rounded; merus and carpus slender; merus posterior margin straight. Pleon. Pleopods 1���3 well developed; biramous; outer ramus subequal in length to peduncle. Pleopods 1���2 peduncles with sparse marginal robust setae. Pleopod 3 peduncle without marginal setae. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posterior margin minutely serrate, with minute setae, posteroventral corner with small subacute tooth, ventral margin without robust setae. Uropod 1 not sexually dimorphic, peduncle with 8 robust setae, distolateral robust seta present, small (less than 1 / 4 length of outer ramus), with simple tip; inner ramus subequal in length to outer ramus, with 3 marginal robust setae; outer ramus without marginal robust setae. Uropod 2 not sexually dimorphic; peduncle with 7���8 robust setae; inner ramus subequal in length to outer ramus, with 4 marginal robust setae; outer ramus with 2 marginal robust setae. Uropod 3 peduncle with 3 robust setae; ramus subequal in length to peduncle, linear (narrowing), with 2 marginal robust setae, with 4���5 apical setae. Telson as broad as long, apically incised, dorsal midline at least halfway, with 7 marginal and apical robust setae per lobe. Female (sexually dimorphic characters). Based on paratype female, AM P. 87314. Antenna 2 peduncular articles slender, with sparse, small robust setae. Gnathopod 1 parachelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; carpus as long as propodus, 3.25 �� as long as broad; propodus subrectangular, medial surface with 1 cuspidate seta; palm transverse, without serrate setae; dactylus longer than palm. Gnathopod 2 mitten-shaped; basis expanded anteroproximally; ischium without rounded lobe on mid-anterior margin, posterior margin of merus, carpus and propodus each with lobe covered in palmate setae; carpus well developed (not enclosed by merus and propodus), posterior lobe present, projecting between merus and propodus; palm obtuse, smooth, lined with serrate setae, without protuberance or shelf near dactylar hinge; without cuticular patch at corner of palm; dactylus subequal in length to palm, not modified distally. Remarks. The populations of Platorchestia ano from Tonga and from Fiji (Myers 1985) are very similar. Both have similar palms and similar apical tips on male gnathopod 2. The Fijian population is much larger (15 mm) than the Tongan populations (9 mm), the length to width ratio of the male gnathopod 1 carpus is different (2.2 in the Fijian populations versus 3.2 in the Tongan one) and the telson is about as long as broad in the Tonga population (broader than long in the Fiji population). A molecular analysis of these populations would be informative. This is the first (group 2) species of Platorchestia from the western Pacific islands. It appears to be most similar to P. jo i Stock & Biernbaum, 1994 from the north-western Pacific coasts of Japan, Korea and Russia. Platorchestia ano differs from P. j o i, mainly in the shape of the palm of male gnathopod 2 which is smooth along the margin with a small proximal sinus (P. j oi has a distinct midmedial sinus). Distribution. Vava���u, Tonga (current study); Nasese, Suva, Fiji (Myers 1985)., Published as part of Lowry, J. K. & Bopiah, Arundathi, 2013, The talitrid amphipods of Tonga (Crustacea, Amphipoda, Talitridae), pp. 347-370 in Zootaxa 3681 (4) on pages 348-353, DOI: 10.11646/zootaxa.3681.4.2, http://zenodo.org/record/249123, {"references":["Myers, A. A. (1985) Shallow-water, coral reef and mangrove Amphipoda (Gammaridea) of Fiji. Records of the Australian Museum, Supplement, 5, 1 - 143. http: // dx. doi. org / 10.3853 / j. 0812 - 7387.5.1985.99"]}

Platorchestia Bousfield, 1982 Platorchestia Bousfield, 1982: 26.��� Jo, 1988: 160.��� Richardson, 1991: 186.��� Morino & Ortal, 1995: 825.��� Miyamoto & Morino, 2004: 68. Remarks. Miyamoto & Morino (2004) established three groups within Platorchestia based on the presence or absence of sexually dimorphic characters. Platorchestia (group 2) is based on a sexually dimorphic incrassate second antenna and no sexual dimorphism in pereopods 6 or 7 and contains P. ano sp. nov.; P. ashmoleorum Stock, 1996; P. monodi (Mateus, Mateus & Afonso, 1986); and P. s m i t h i Lowry, 2012. The possibility remains that within Platorchestia (group 2) mature males with sexually dimorphic pereopods 6���7 exist but have never been collected, in which case any group 2 species would become a group 1., Published as part of Lowry, J. K. & Bopiah, Arundathi, 2013, The talitrid amphipods of Tonga (Crustacea, Amphipoda, Talitridae), pp. 347-370 in Zootaxa 3681 (4) on page 348, DOI: 10.11646/zootaxa.3681.4.2, http://zenodo.org/record/249123, {"references":["Bousfield, E. L. (1982) The amphipod superfamily Talitroidea in the northeastern Pacific region. 1. Family Talitridae: systematics and distributional ecology. National Museum of Natural Sciences (Ottawa), Publications in Biological Oceanography, 11, 1 - 73.","Jo, Y. W. (1988) Talitridae (Crustacea-Amphipoda) of the Korean coasts, Beaufortia, 38 (7), 153 - 179.","Richardson, A. M. M. (1991) Two new species of landhoppers (Crustacea: Talitridae) from O'ahu, Hawaiian Islands, with redescription of Platorchestia pickering i and key to landhoppers of O'ahu. Bishop Museum Occasional Papers, 31, 185 - 201.","Morino, H. & Ortal, R. (1995) Two Platorchestia species (Amphipoda, Talitridae) from Israel. Crustaceana, 68 (7), 824 - 832. http: // dx. doi. org / 10.1163 / 156854095 X 02041","Miyamoto, H. & Morino, H. (2004) Taxonomic studies on the Talitridae (Crustacea, Amphipoda) from Taiwan. II. The genus Platorchestia. Publications of the Seto Marine Biological Laboratory, 40, 67 - 96.","Stock, J. H. (1996) The genus Platorchestia (Crustacea, Amphipoda) on the Mid-Atlantic islands, with description of a new species from Saint Helena. Miscellania Zoologica, 19 (1), 149 - 157.","Mateus, A, Mateus, E. & Afonso, O. (1986) Amphipodes littoraux et de l'interieur recueillis aux Acores pendant la Campagne \" Biacores \" (1971) sur le navire Jean Charcot. Anais da Faculdade de Ciencias do Porto, 65, 87 - 126.","Lowry, J. K. (2012) Talitrid amphipods of ocean beaches in New South Wales, Australia (Amphipoda, Talitridae). Zootaxa, 3575, 1 - 26."]}

Two Platorchestia species arc recorded from Israel and the Sinai: P. platensis from near the sea shore at Naqaz Jirada (Sinai), and P. monodi from near springs and wells at En Hameara in the Negev Desert. Platorchestia monodi is distinguished from P. platensis in having a smooth palmar margin on the propod of male gnathopod 2, and the dactyl of male gnathopod 1 distinctly shorter than the propod palm. The occurrence of inland species of Platorchestia is discussed.

Platorchestia Bousfield, 1982 Remarks. Miyamoto & Morino (2004) established three groups within Platorchestia based on the presence or absence of sexually dimorphic characters. Platorchestia (group 2) is based on having a sexually dimorphic second antenna (incrassate) and no sexual dimorphism in pereopods 6 or 7. According to Miyamoto & Morino (2004) Platorchestia (group 2) contains two species: P. ashmoleorum Stock, 1996 and P. monodi (Mateus, Mateus & Afonso, 1986). There are additional species of this distinctive group in the Australian Museum collections from the western South-Pacific islands of Fiji, Hawaii, Tonga and the new species P. smithi sp. nov., described below from eastern Australia., Published as part of Lowry, J. K., 2012, Talitrid amphipods from ocean beaches along the New South Wales coast of Australia (Amphipoda, Talitridae), pp. 1-26 in Zootaxa 3575 on page 14, {"references":["Bousfield, E. L. (1982) The amphipod superfamily Talitroidea in the northeastern Pacific region. 1. Family Talitridae: systematics and distributional ecology. National Museum of Natural Sciences (Ottawa). Publications in Biological Oceanography, 11, 1 - 73.","Miyamoto, H. & Morino, H. (2004) Taxonomic studies on the Talitridae (Crustacea, Amphipoda) from Taiwan. II. The genus Platorchestia. Publications of the Seto Marine Biological Laboratory, 40, 67 - 96.","Stock, J. H. (1996) The genus Platorchestia (Crustacea, Amphipoda) on the Mid-Atlantic islands, with description of new species from Saint Helena. Miscel-laia. Zooloica, 19 (1), 149 - 157.","Mateus, A., Mateus, E. & Afonso, O. (1986) Amphipodes Littoraux et de l'interieur recueillis aux Acores pendant la Campagne \" Biacores \" (1971) sur le navire Jean Charcot. Anais da Faculdadede Ciencias do Porto, 65, 87 - 126."]}

Platorchestia smithi sp. nov. (Figs 8–10) Types. Holotype, 7.9 mm, AM P.85703, Brooms Head Beach, New South Wales (29.61145°S 153.33557°E), under algae (present for about two weeks) in the supralittoral zone at south end of beach near the headland, J.K. Lowry, J. Dermand & K. Engelberg, 8 February 2010, NSW 3658. Paratypes: female, AM P.85704, same station data as holotype. Material examined. New South Wales. 5 males, 29 females and juveniles (only 1 ovigerous female), AM P.88063, Shelley Beach at Ballina, New South Wales (28.86613°S 153.59212°E), very flat, beach, talitrids at back of beach under woody debris and Pandanus leaves, J.K. Lowry, J. Dermand & K. Engelberg, 6 February 2010, NSW 3656; 3 males, 99 females and juveniles (less than 5 ovigerous females), AM P.88064, Broadwater Beach, Broadwater National Forest, New South Wales (29.03237°S 153.45595°E), very flat, beach with talitrids under light vegetated debris, 5 m high dunes at back of beach leading into dense vegetation, J.K. Lowry, J. Dermand & K. Engelberg, 6 February 2010, NSW 3655; 69 males, 251 females /juveniles, AM P.88065, Spooky Beach, Angourie, New South Wales (29.47958°S 153.35937°E), wide, very flat beach, bordering on vegetated boulder shelf, talitrids under pieces of dried algae, sticks and Pandanus fronds at back of beach, J.K. Lowry, J. Dermand & K. Engelberg, 5 February 2010, NSW 3654; many specimens including 20+ males, AM P.88066, Brooms Head Beach, New South Wales (29.61145°S 153.33557°E), under algae (present for about two weeks) in the supralittoral zone at south end of beach near the headland, J.K. Lowry, J. Dermand & K. Engelberg, 8 February 2010, NSW 3658; 15 males, 48 females and juveniles (3 ovigerous females), AM P.88067, Back Beach at Brooms Head, New South Wales (29.61662°S 153.33597°E), sandstone fingers emerging from vegetated dunes at back of beach, talitrids living at back of beach under light vegetative debris where freshwater seeps from dunes, J.K. Lowry, J. Dermand & K. Engelberg, 8 February 2010, NSW 3657; 7 males, 48 females and juveniles, AM P.88068, Minnie Waters, New South Wales (29.76937°S 153.29471°E), supra-littoral, flat beach with main population of talitrids at back of beach where fresh water was seeping onto beach. Found less commonly under pieces of the brown alga Hormosira banksii, J.K. Lowry, J. Dermand & K. Engelberg, 5 February 2010, NSW 3652; many specimens, AM P.88069, Wooli, New South Wales (29.87671°S 153.26378°E), under accumulated Zostera on sandy substrate at back of mangroves; J.K. Lowry, J. Dermand & K. Engelberg, 5 February 2010, NSW 3653; 5 males, 12 females /juveniles, AM P.88070, Little Beach at Red Rock, New South Wales, Australia (29.98272°S 153.23140°E), supra-littoral, flat broad beach with nearly vertical cliff faces at back of beach, talitrids sheltering under woody debris, Eucalyptus leaves, Casuarina needles, J.K. Lowry, J. Dermand & K. Engelberg, 5 February 2010, NSW 3651; 61 males, 210 females /juveniles (20 ovigerous), AM P.88071, Arrawarra Beach, New South Wales (30.06129°S 153.19977°E), supralittoral zone, flat beach, huge accumulation of the brown kelp, Ecklonia at south end of beach near headland, present for about two days, talitrids living up the beach under dryer algae, J.K. Lowry, J. Dermand & K. Engelberg, 9 February 2010, NSW 3659; 14 males, 69 females /juveniles (11 ovigerous), AM P.88072, Woolgoolga Beach, New South Wales (30.11119°S 153.20235°E), supralittoral zone, flat beach, gently sloping vegetated dune merging into top of beach, talitrids living under light algal debris at south end of beach near headland, J.K. Lowry, J. Dermand & K. Engelberg, 9 February 2010, NSW 3660; many specimens, 8+ males, AM P.88073, Moonee Beach, New South Wales (30.21464°S 153.16106°E), rocky cove with a lot of woody debris, talitrids living under woody debris in supralittoral zone, J.K. Lowry, J. Dermand & K. Engelberg, 9 February 2010, NSW 3661; 18 males, about 49 females /juveniles (5 ovigerous females), AM P.88074, Nambucca Heads, New South Wales (30.64939°S 153.01122°E), marine/brackish water pond separated from estuary by rocky training wall, talitrids living under heavy layer of Zostera and Casuarina needles, J.K. Lowry, J. Dermand & K. Engelberg, 10 February 2010, NSW 3663; 8 males, about 80 females /juveniles, including 4 ovigerous females, AM P.88075, Scotts Head Beach, New South Wales (30.74589°S 152.99184°E), supralittoral, very flat beach beach, talitrids found under woody debris in small depression just before vegetated dunes near south end of beach near headland, J.K. Lowry, J. Dermand & K. Engelberg, 11 February 2010, NSW 3664; 8 males, about 63 females /juveniles (none ovigerous), AM P.88076, Grassy Head Beach, New South Wales (30.79499°S 152.99788°E), supralittoral, flat beach beach, small population found under light woody debris at south end of beach near headland, J.K. Lowry, J. Dermand & K. Engelberg, 11 February 2010, NSW 3665; 16 males, about 31 females /juveniles (13 ovigerous), AM P.88080, Oxley Beach, Port Macquarie, New South Wales (31.43433°S 152.92207°E), small, flat beach with headlands north and south, talitrids living in supralittoral under woody and grassy debris at south end of beach just below grassy covered hillside, none found under washed up Ecklonia, J.K. Lowry, J. Dermand & K. Engelberg, 12 February 2010, NSW 3667; many specimens, AM P.87702, landward edge of rock platform between Bateau Bay beach and Crackneck Lookout from sand under leaf litter and wrack at landward edge of Avicennia mangroves (33.3889°S 151.4842°E), S. Keable, R. Keable, 5 September 2011; many specimens, AM P.88077, Tarum Road, North Avoca Beach, New South Wales (33.45891°S 151.43981°E), dry stream bed running onto beach behind rock platform, talitrids common among wrack in stream bed, well above high water, wrack mainly small sticks and pieces of leaves, J.K. Lowry, 28 March 2010, NSW 3673; many specimens, AM P.88078, McMasters Beach, New South Wales (~ 33°29'57.55''S 151°25'29.00''E), flat sandy beach with almost no wrack, some dried Ecklonia, near the southern headland there is a storm water drain at the back of the beach with talitrids living here under large stones among accumulated sticks and leaves, J.K. Lowry, 28 March 2010, NSW 3674; 6 specimens, AM P.87947, Maitland Bay, New South Wales (33°31.512'S 151°23.780'E), L. Fanini & J.K. Lowry, November 2011; 217 specimens, AM P.85970, north end of Putty Beach, Bouddi National Park, Central Coast, New South Wales, Australia (33°31.715'S 151°22.445'E), upper supralittoral under patches of dead Zostera, J.K. Lowry & I. White, 22 April, 2011, MI NSW 3686 (stn 3); 16 males, 53 females and juveniles (12 females ovigerous), AM P.88079, Pearl Beach, New South Wales (33.54786°S 151.30737°E), at the absolute southern end of the beach there are talitrids living under small patches of dried brown algae in a depressed moist area at the back of the beach where the forest begins, J.K. Lowry, 28 March 2010, NSW 3675; 66 specimens, AM P. 87948, Portuguese Bay, New South Wales (33°36.656'S 151°18.096'E), L. Fanini & J.K. Lowry, November 2011; 1 male, 11 mm, AM P.85953 (illustrated), female, xx mm, AM P.85954 (illustrated), 9 specimens, AM P.85952, Palm Beach ferry wharf, Pittwater, New South Wales, Australia (33°35.756'S 151°19.194'E), on sand under beach wrack, J.K. Lowry and R. Peart; many specimens, AM P.85951, east of Spit Bridge, Middle Harbour, New South Wales, Australia (33°48'12"S 151°14'45"E), under rocks and woody debris, 29 August 2002, S. Keable, NSW 1965; 7 specimens, AM P.88081, Bellambi Beach, just north of boat ramp, New South Wales (34°22'13"S 150°55'35"E), sand under leaf litter and wrack at landward edge of Avicennia mangroves, J.K. Lowry & A. Bopiah, 28 April 2010; 18 males, 76 females and juveniles, AM P.84394, mouth of Minnamurra River, New South Wales (34°37'41"S 150°51'27"E), sound and gravel beach, A.D. Murray & S.J. Keable, 6 May 2010, NSW 3979, many specimens, AM P.84394, south end of Minnamurra River entrance, west of boat ramp, New South Wales (34°37'41"S 150°51'27"E), A. Hegedus, 6 May 2010; many specimens, AM P.84006, north end of Jones Beach, Kiama Downs, New South Wales (34°38'9"S 150°51'23"E), R. T. Springthorpe, 6 May 2010; 63 specimens, AM P.86727, southern end of Washerwoman's Beach near rocks, New South Wales (35°14'40"S 150°32'9"E), A. Hegedus, 25 August 2011; 127 specimens, AM P.86720, 79 specimens, AM P.86721, north end of Bendalong Beach near rocks, New South Wales (35°14'40"S 150°32'10"E), A. Hegedus, 23 August 2011. Type locality. Brooms Head Beach, New South Wales, Australia (29.61145°S 153.33557°E), under algae in the supralittoral zone at south end of beach near the headland. Description. Based on holotype, male, 7.9 mm, AM P.85703. Head. Eye medium (1/5–1/3 head length). Antenna 1 short, rarely longer than article 4 of antenna 2 peduncle. Antenna 2 more than half body length; peduncular articles incrassate (expanded); article 5 subequal than article 4; peduncular articles with many small robust setae. Lower lip with vestigial inner plates. Mandible left lacinia mobilis 5-dentate. Maxilliped palp article 2 distomedial lobe well developed, 4 reduced, button-shaped. Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa smaller than coxa 2, subtriangular, about as broad as deep; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus subrectangular, anterior margin with 3 groups of robust setae, lateral surface with 3 cuspidate setae, posterolateral surface with 6 serrate setae, posteromedial surface with 4 serrate setae; palm transverse, with 7 serrate setae; dactylus subequal in length to palm. Gnathopod 2 sexually dimorphic; subchelate; coxa similar in size to coxa 3, broader than deep; basis slightly expanded; ischium without posterodistal lobe on medial surface; posterior margin of merus, carpus and propodus each without with lobe covered in palmate setae; carpus triangular, reduced (enclosed by merus and propodus), posterior lobe absent, not projecting between merus and propodus; propodus 2.5 × as long as wide; palm acute, reaching 30% along posterior margin, with small sinus midway, lined with robust setae, without protuberance near dactylar hinge, with small midpalmar sinus, posterodistal corner with groove; posteromedial surface of propodus with groove; with cuticular patch at corner of palm; dactylus subequal in length to palm, not attenuated distally. Pereopods 2–4 coxae as wide as deep. Pereopods 3–7 cuspidactylate. Pereopods 3–7 dactyli without distal patch of many rows of tiny setae on the anterior margin. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3; dactylus similar to that of pereopod 3. Pereopod 5 propodus distinctly longer than carpus. Pereopod 6 shorter than pereopod 7; coxa posterior lobe posteroventral corner rounded, posterior margin perpendicular to ventral margin, posterior lobe with ridge, posterior lobe with 3–4 marginal setae. Pereopod 7 basis lateral sulcus present, slightly pronounced, posterodistal lobe present, rounded, produced downwards almost to merus; distal articles (merus and carpus) slender; merus posterior margin evenly rounded. Pleon. Pleopods all well developed. Pleopod 1 peduncle with marginal robust setae; biramous, outer ramus shorter than peduncle. Pleopod 2 biramous, outer ramus shorter than peduncle. Pleopod 3 biramous, outer ramus shorter than peduncle. Epimeron 2 longer than epimeron 3 (slightly). Epimeron 3 posterior margin minutely serrate, with 7 or 8 setae, posteroventral corner with small subacute tooth, ventral margin without robust setae. Uropod 1 not sexually dimorphic, peduncle with 11 robust setae, peduncle distolateral robust seta absent; inner ramus subequal in length to outer ramus, with 3 marginal robust setae; outer ramus without marginal robust setae. Uropod 2 not sexually dimorphic; peduncle with 4 robust setae; inner ramus subequal in length to outer ramus, with 1 marginal robust setae; outer ramus with 1 marginal robust setae. Uropod 3 peduncle with 3 robust setae; ramus longer than peduncle, ramus linear (narrowing), ramus with 2 marginal robust setae, ramus with more than 5 apical setae. Telson as broad as long, apically incised, dorsal midline entire, with marginal and apical robust setae, with 3–6 robust setae per lobe. Female (sexually dimorphic characters). Based on paratype, female, AM P.85704. Antenna 2 peduncular articles slender. Gnathopod 1 parachelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae. Gnathopod 2 mitten-shaped; basis strongly expanded; posterior margin of carpus and propodus each with lobe covered in palmate setae; carpus well developed (not enclosed by merus and propodus), posterior lobe present, projecting between merus and propodus; palm obtuse, smooth, not lined with robust setae; without cuticular patch at corner of palm. Habitat. Under beach wrack on sand. Remarks. Platorchestia smithi is the common wide-spread beach-hopper along New South Wales ocean beaches. It belongs to the Platorchestia (group 2) complex with incrassate male second antennae and no sexual dimorphism in pereopods 6 or 7. These species are all similar. Platorchestia smithi is most similar to P. monodi in the shape of the male gnathopod 2 propodus palm, both of which have a weak proximal palmar sinus. Platorchestia smithi differs from P. monodi in having a relatively long propodus in relation to its width (2.5 ×) on male gnathopod 2 (1.3 × in P. monodi) and in the basis of pereopod 7 which is significantly longer (1.5 ×) than broad (about as long broad in P. monodi). Distribution. New South Wales: ocean beaches and bays from Shelley Beach at Ballina (29°S) to Bendalong Beach (35°S)., Published as part of Lowry, J. K., 2012, Talitrid amphipods from ocean beaches along the New South Wales coast of Australia (Amphipoda, Talitridae), pp. 1-26 in Zootaxa 3575 on pages 14-19

Platorchestia paludosus sp. nov. (Figures 2���9) Platorchestia japonica. ― Miyamoto & Morino 2004: 83 ���88 (non P. japonica). Materials examined. Holotype (NMNS��� 6519 -001) 1 male, Guan-du, Taipei County, Taiwan, Aug 2008, Coll. Y- T. Cheng. Paratypes (NMNS��� 6519 -002���06519-009) 4 males and 4 females, data same as holotype. Paratypes (AM���P. 84807) 2 males and 2 females, data same as holotype. Paratypes (ASIZCR���000230) 2 males and 2 females, data same as holotype. Comparative material. Platorchestia japonica (Tattersall, 1922). Lake Biwa, Japan. 2 males 2 females. Description. Male. Body smooth, without protuberance. Eyes sub-rounded, larger than 1 / 3 of head height. Antenna 1 (Figs 3 ���a, b, c and d) short with 6���7 articles (3 peduncle articles, 3���4 flagellated articles), slightly longer than article 4 of antenna 2, peduncle articles 1���3 equal in length, dorsal side convex, ventral side flattened, each peduncle article with simple setae, article 4 slightly curved, each flagellated article with 2 groups of simple setae type IV (Fig. 1 ���d) on the inner and outer side of the dorsal surface. Antenna 2 (Figs 3 ���e, f, and g) up to 1 / 3 of the body length, outer margin of ventral side of peduncle article 3 with 3���5 simple setae type IV (Fig. 1 ���d), a medial furrow extend from distal 1 / 3 of peduncle article 4 to entire peduncle article 5, length of article 5 equals to combined length of article 3 and 4, 11��� 14 flagellated articles each with medial furrow, flagellum subequal to peduncle 3���5 combined in length; tip of antenna 2 with simple setae type V (Fig. 1 ���e). Upper lip entire, apical margin with fine setule. Incisor of mandible (Figs 3 ���i, j) 5 to 6 dentate, left lacinia mobilis 5 ���dentate, right lacinia mobilis bi-fid, with serrated cutting edges; molar finely serrated, right molar convex, left molar concave; 3���4 pappose setae type I (Fig. 1 ���p) located in the region between the lacinia mobilis and molar, 1 pappose seta type II (Fig. 1 ���q) on the dorsal side of molar. Lower lip bi-lobed, lobes wide, with fine setule on the inner margin. Inner plate of maxilla 1 (Figs 3 ���l, m) narrow, with 2 apical papposerrate setae type I (Fig. 1 ���r); outer plate with 9 serrate setae type I (Fig. 1 ���j), with a row of 13���19 setule type I (Fig. 1 ���t) on ventral base of inner 4 serrate setae; palp very small, 2 articulate. Inner plate of maxilla 2 (Fig. 3 ���n, o, p, q, r and s) smaller than outer plate, distal margin with 17���19 simple setae type III (Fig. 1 ���c), a row of 8���10 serrate setae type II (Fig. 1 ���k) on ventral and a row of 6���11 serrate setae type IV (Fig. 1 ���m) on dorsal, inner margin with 2 papposerrate setae type I (Fig. 1 ���r), inner one longer; distal margin of outer plate with 15���20 simple setae type III (Fig. 1 ���c), a row of 9���12 serrate setae type II (Fig. 1 ���k) on ventral surface, a row of 3 serrate setae type IV (Fig. 1 ���m) and 2 serrulate setae type I (Fig. 1 ���n) on dorsal surface. FIGURE. 2. Platorchestia paludosus sp. nov. a. external view, male. b. female gnathopod 1. c. female gnathopod 2. Distal end of maxilliped inner plate (Figs 4 ���b, e) with 3 cuspidate setae type I (Fig. 1 ���g), a row of 3���4 papposerrate setae type II (Fig. 1 ���s) behind the cuspidate setae, dorsal surface (Fig. 4 ���b) with a row of papposerrate setae type II (Fig. 1 ���s) along inner margin, with fine setae situating behind the papposerrate setae; ventral surface (Fig. 4 ���e) with several papposerrate setae type II (Fig. 1 ���s); distal end of outer plate (Figs 4 ���n, o) with a row of 4���5 papposerrate setae type II (Fig. 1 ���s) along margin, along inner margin to ventral surface of distal corner with 2 rows of simple setae type VI (Fig. 1 ���f), ventral surface of medial inner margin (Fig. 4 ���q) with a row of 3���5 simple setae type VI (Fig. 1 ���f); palp article 1 wider than high, with a row of 3���4 simple setae type VI (Fig. 1 ���f) on ventral surface of distal inner corner (Fig. 4 ���a, m), distal outer margin (Figs 4 ���a, c, j and l) with 1���2 cuspidate setae type III (Fig. 1 ���i) and 2���3 simple setae type VI (Fig. 1 ���f); distal inner corner of ventral surface of palp article 2 (Figs 4 ���a, and h) with a row of 3���4 simple setae type VI (Fig. 1 ���f), along the inner margin (Figs 4 ���a, and k) with 2 rows of simple setae VI (Fig. 1 ���f), distal outer margin (Figs 4 ���a, c, g and i) with 1���2 cuspidate setae type III (Figs 1 ���i) and 2���3 simple setae type VI (Fig. 1 ���f), article 3 rounded apically, dorsal surface (Figs 4 ���c, and f) with a row of 4���5 serrate setae type III (Fig. 1 ���l) and 2���3 simple setae type VI (Fig. 1 ���f) along the base of palp article 4, ventral surface with (Figs 4 ���a, d) several simple setae type VI (Fig. 1 ���f), outer distal corner (Fig. 4 ���a, c, d and f) with a group of 2���3 simple setae type IV (Fig. 1 ���d); article 4 small with several simple setae type III (Fig. 1 ���c) and simple setae type VI (Fig. 1 ���f) apically. Gnathopod 1 (Figs 5 ���a, and b) coxa with straight or convex anterior margin, ventral margin convex with a few setae; basis slightly expanded posterodistally, subequal with merus and carpus when combined in length; ischium shortest, anteroproximal margin with a notch; merus sub-triangular, rounded posteriorly; carpus (Figs 5 ���c, and d) with scabrous tumescent protuberance posterodistally, outer lateral surface (Figs 5 ���c) with a row of 2���3 serrate setae type III (Fig. 1 ���l) and 2���3 cuspidate setae type III (Fig. 1 ���o) at base of tumescent protuberance, inner lateral surface (Fig. 5 ���d) with 7���10 serrate setae type III (Fig. 1 ���l) without cuspidate setae; propodus (Figs 5 ���e, f) with scabrous tumescent protuberance posterodistally, outer lateral surface with a row of 4���6 serrate setae type III (Fig. 1 ���l) along posteroproximal margin to medial base of tumescent protuberance, outer lateral surface with a group of 4���5 simple setae type IV (Fig. 1 ���d) on protuberance base distal end, dactylus base with a group of 2���3 simple setae type IV (Fig. 1 ���d), anterodistal corner with a group of 2���3 simple setae type IV (Fig. 1 ���d); length of dactylus subequal to palm, and not reach posterodistal angle of propodus. Gnathopod 2 (Figs 5 ���g, h) coxa as wide as deep with posterior process, ventral margin convex, basis anterior margin straight, posterior margin convex and proximal end necked; ischium larger than merus, with a notch on proximal end of anterior margin; length of merus subequal to carpus, with convex posterior margin; carpus with convex anterior margin; propodus oval, palm margin curved, without notch, both lateral surface with a row of cuspidate setae type III (Fig. 1 ���i); dactylus curved, as long as palm. Pereopods 3���7 cuspidactylate. Pereopod 3 coxa (Fig. 6 ���a) subquadrate with posterior process, ventral margin slightly convex; basis longest, subequal to combined length of merus and carpus; ischium shortest, anteroproximal margin notched; merus longer than carpus, anterior margin slightly convex, posterior margin straight; carpus anterior and posterior margins parallel; propodus slender, longer than carpus, slightly shorter than merus; dactylus (Fig. 6 ���c) subequal to ischium in length, posterior nail base with 1 simple setae type I (Fig. 1 ���a). Pereopod 4 (Figs 6 ���d, and e) similar to pereopod 3, shorter, coxa (Fig. 6 ���d) subquadrate, with posterior process, ventral margin straight; basis longest, subequal to combined length of merus and carpus, slightly convex; ischium shortest, anteroproximal margin notched; merus longer than carpus, anterior margin slightly convex, posterior margin straight; carpus shorter than that of pereopod 3, both margins parallel; propodus slender, subequal to merus, dactylus (Fig. 6 ���f) pinched, posterior nail base with 1 simple seta type I (Fig. 1 ���a). Pereopod 5 coxa (Fig. 6 ���g) bilobed, anterior lobe larger than posterior lobe; basis oval; ischium shortest, posteroproximal margin notched; merus subequal to carpus in length, anterior margin straight, posterior margin slightly convex; carpus both margins parallel; propodus slender; dactylus (Fig. 6 ���i) with 1 simple seta type I (Fig. 1 ���a) on anterior nail base. Pereopod 6 coxa (Fig. 6 ���j) bilobed, anterior lobe very small, anterior margin of posterior lobe nearly vertical, anterodistal corner strongly curved; basis oval; ischium shortest, posteroproximal margin notched; merus subequal to carpus in length, anterior margin straight, posterior margin slightly convex; carpus both margins parallel; propodus slender, longest; dactylus (Fig. 6 ���l) with 1 simple seta type I (Fig. 1 ���a) on anterior nail base. Pereopod 7 coxa (Fig. 6 ���m) rounded posterodistally; basis oval, posterodistal lobe broader than pereopod 5���6; ischium shortest, posteroproximal margin notched; merus subequal to carpus, anterior margin straight, posterior margin slightly convex; carpus anterior and posterior margins parallel; propodus slender, longest; dactylus (Fig. 6 ��� o) with 1 simple seta type I (Fig. 1 ���a) on anterior nail base. Pleopods (Figs 7 ���a, b, c, d, e and f) biramous, peduncle and ramus subequal in length, pleopod 3 peduncle shortest, ramus with 7���10 articulated segments. Peduncle of uropod 1 (Figs 7 ���g, h) slightly longer than ramus, with 1 row of 4���5 cuspidate setae type III (Fig. 1 ���i) along each dorsal lateral margin; outer ramus with 3���5 cuspidate setae type II (Fig. 1 ���h) on distal end, without seta on medial region; inner ramus with 3���5 cuspidate setae type II (Fig. 1 ���h) on distal end, a row of 3���4 cuspidate setae type III (Fig. 1 ���i) along dorsal margin, without 1���2 cuspidate setae type III (Fig. 1 ���i) along outer lateral region. Peduncle of uropod 2 (Figs 7 ���i, j) subequal to ramus in length, with 3 cuspidate setae type III (Fig. 1 ���i) on dorsal region; outer ramus with 3 cuspidate setae type II (Fig. 1 ���h) on distal end, with 1 cuspidate seta type III (Fig. 1 ��� i) on medial region; inner ramus with 5 cuspidate setae type II (Fig. 1 ���h) on distal end, 2���3 cuspidate setae type III (Fig. 1 ���i) on dorsal margin, with 1���2 cuspidate setae type III (Fig. 1 ���i) on outer lateral region. Uropod 3 (Figs 7 ���k, l), 1��� 2 cuspidate setae type III (Fig. 1 ���i) on peduncle medial region, ramus with a group of 3 simple setae type I (Fig. 1 ���a) on distal end, 0���1 simple setae type I (Fig. 1 ���a) on medial region. Telson (Figs 7 ���m) bilobed, longer than wide, with a group of 3���4 cuspidate setae type III (Fig. 1 ���i) on distal end, 1���2 cuspidate setae type III (Fig. 1 ���i) as a group on dorsal lateral margin. Female. Antenna 1 short, slightly beyond article 4 of antenna 2, with 6���7 articles (3 peduncle articles, 3���4 flagellated articles), peduncle articles 1���3 equal in length, article 4 slightly curved, each flagellated article with two groups of simple setae on the inner and outer side of dorsal surface. Antenna 2 up to 1 / 3 of body length. Outer margin of ventral side of article 3 with 3���5 simple setae, a medial furrow extending from distal 1 / 3 of article 4 to the entire article 5, length of article 5 equals to total of article 3 and 4, 12��� 14 flagellated articles, each with medial furrow. Tip of antenna 2 with a group of simple setae. Coxa of gnathopod 1 (Figs 8 ���a, f) anterior margin straight or convex, ventral margin convex; basis straight; carpus without tumescent protuberance, posterior margin with 2 long and 4���6 short cuspidate setae type III (Fig. 1 ��� i); propodus (Figs 8 ���b, g) without tumescent protuberance, inner lateral surface medial region with 4���5 serrate setae type III (Fig. 1 ���l), outer lateral surface medial region with a row of 2���3 cuspidate setae type III (Fig. 1 ���i) along margin, posterior margin with 2 rows of cuspidate setae type III (Fig. 1 ���i), outer lateral surface with a group of 3���4 simple setae type IV (Fig. 1 ���d) on dactylus base, 3���4 simple setae type IV (Fig. 1 ���d) on posterodistal corner, anterodistal corner with 3���6 simple setae type IV (Fig. 1 ���d); dactylus longer than width of propodus. Gnathopod 2 (Figs 8 ���c, h) coxa as wide as deep with posterior process, convex ventral margin, basis expanded anteroproximally, posterior margin straight; ischium subequal to merus in length; merus (Figs 8 ���d, i) with small scabrous region posterodistally; carpus with scabrous tumescent protuberance posterodistally; propodus (Figs 8 ���e, j) with posterodistal tumescent protuberance elongated distally, scabrous region from posteroproximal end to posterodistal end, outer lateral surface with 10���14 serrate setae type III (Fig. 1 ���l) along scabrous region, inner lateral surface with 16���19 serrate setae type III (Fig. 1 ���l) along scabrous region, palm margin short, and outer lateral palm margin with a row of 4���5 simple setae type I (Fig. 1 ���a), anterodistal corner with 6���8 simple setae type I (Fig. 1 ���a); dactylus curved as long as palm. Habitat. This salt marsh in Guan-du, Taiwan is dominated by Phragmites communis (L.) Trin. and Brachiaria mutica (Forsk) Stapf., with irregular flooding after raining. Platorchestia paludosus sp. nov. was found under leaflitter of Brachiaria mutica (Forsk) on the water front of estuarine marshes. Etymology. The word ���paludosus��� indicates that the species is common in marshy habitats. Molecular analysis. We got 618 b.p. aligned sequence of COI (GC ratio: 0.359), from 43 samples of P. paludosus sp. nov. and four samples of P. japonica. The number of total polymorphic sites was 102 within which 75 were parsimony informative sites (PIS), defining 13 haplotypes. There were 9 (3 PIS) and 50 (11 PIS) polymorphic sites for P. paludosus and P. japonica with 10 and 3 haplotypes respectively. The haplotype diversity (h) and nucleotide diversity (��) of P. paludosus samples were 0.743 �� 0.047 and 0.00183 �� 0.00024. Those of P. japonica samples were 0.833 �� 0.222 and 0.04396 �� 0.01253 (total: 0.784 �� 0.043 and 0.02088 �� 0.00826). Neighbor joining tree of P. paludosus, P. japonica and P. platensis (Radulovici et al. 2009, NCBI, FJ 581856 ��� FJ 581858) formed three distinct clades, with bootstrap value> 99 suggesting the clades were well separated (Fig. 9), and topology of BI and ML trees were essentially consistent with NJ. Average sequence divergence (Tab. 2) of P. paludosus from P. japonica was 13.3 % (11.9���15.3 %) from P. japonica, which was comparable to the interspecific difference of other Platorchestia species including P. platensis (Radulovici et al. 2009, NCBI, FJ 581856 ��� FJ 581858; 14.5 and 17.2 %). Platorchestia P. japonica P. japonica P. platensis Orchestia cav- Parorchestia sp. nov. Japan China imana sp. Platorchestia sp. nov. 0.2 P. japonica (Japan) 13.3 4.8 P. japonica (China) 10.4 14.3 _ P. p l a t e n s i s 14.5 17.2 16.1 0.01 Orchestia cavimana 19.1 21.1 19.9 23.2 _ Parorchestia sp. 22.0 24.0 23.4 22.6 26.0 _ Discussion. In the present study, Platorchestia paludosus sp. nov. is considered as a new species based on morphological and molecular evidence. The morphology is very close to P. japonica sensu stricto (Tattersall 1922). Miyamoto & Morino (2004) considered their material collected from North Taiwan as P. japonica and Miyamoto & Morino (2004) noted their Taiwanese specimens differed from P. japonica collected from the Lake Biwa, Japan in the degree of sexual dimorphisms in peduncle articles 4 and 5 of antenna 2 and carpus of pereopod 7, shape of coxal plate of pereopod 6 and anterodistal corner of the posterior, morphology of marginal spines in peduncles of pleopods 2 and 3 and the spine patterns in pereopod 6 and 7. In the present study, we found that P. japonica identified by Miyamoto & Morino (2004) in Taiwan was P. paludosus identified in the present study. We used scanning electron microscopy and additionally noted consistent morphological differences between P. paludosus (10 individuals) and P. japonica (4 individuals) collected from the Lake Biwa, in the distribution pattern of setae on the lateral margin of telson, and in the shape of the ramus tip of uropod 3. Platorchestia paludosus has one group of cuspidate setae type III on the lateral margin of telson, whilst P. japonica contains two groups of cuspidate setae type III on the lateral margin of telson (Fig. 10 a). P. paludosus has a sharper ramus of uropod 3, whilst the tip of ramus in uropod 3 of P. japonica is blunt (Fig. 10 b). However, the number of setae on peduncle of uropod 3 varied from 1���3 in both P. paludosus and P. japonica, and thus, this cannot be considered as a taxonomic important character (Fig. 10 b). Miyamoto & Morino (2004) divided the genus Platorchestia into three groups based on the different gradient of sexual dimorphism character of antenna 2 and pereopod 6 and 7. The ���group 3 ��� defined by Miyamoto & Morino (2004) included species ���displaying no sexual dimorphism��� and having ���antenna 2 and pereopod 6 and 7 barely (or slightly) sexual dimorphic���. Currently six species are placed within this group, including P. japonica (Tattersall 1922), P. humicola, P. k a a l e n s i s, P. lanipo and P. pickeringi, and the P. paludosus in the present study also belong to this group. Platorchestia paludosus can be differentiated from P. pickeringi, P. kaalensis and P. lanipo by having normal maxilliped palps (vs. slender maxilliped palps) and differs from P. humicola by possessing longer pleopod ramus: 0.8���0.9 times as long as peduncle (v.s. 0.5���0.6 times in P. humicola). Results from DNA barcoding further supports P. paludosus as different from P. japonica and is therefore a new species. Average sequence divergence of P. paludosus from P. japonica was 13.3 % (11.9���15.3 %), which is comparable to the interspecific difference P. platensis (NCBI, FJ 581856 ��� FJ 581858; 14.5 and 17.2 %). Platorchestia platensis differs from P. japonica in the morphology of palm of mature male gnathopod 2 and degree of sexual dimorphism in antenna 2 and pereopod 6 and 7 (Miyam, Published as part of Cheng, Yu-Ting, Nakazono, Kenji, Lin, Kirk & Chan, Benny K. K., 2011, Cryptic diversity of the semi-terrestrial amphipod Platorchestia japonica (Tattersall, 1922) (Amphipoda: Talitrida: Talitridae) in Japan and Taiwan, with description of a new species, pp. 1-18 in Zootaxa 2787 on pages 4-16, DOI: 10.5281/zenodo.207935, {"references":["Miyamoto, H. & Morino, H. (2004) Taxonomic studies on the Talitridae (Crustacea, Amphipoda) from Taiwan II. The genus Platorchestia. Publications of the Seto Marine Biological Laboratory, 40, 67 - 96.","Tattersall, W. M. (1922) Zoological results of a tour in the far east. Amphipoda with notes on an additional species of Isopoda. Memoirs of the Asiatic Society of Bangal, 6, 437 - 495.","Radulovici, A. E., Sainte-Marie, B. & Dufresne, F. (2009) DNA barcoding of marine crustaceans from the Estuary and Gulf of St Lawrence: a regional-scale approach. Molecular Ecology Resources, 9 (Suppl. 1), 181 - 187.","Hou, Z., Fu, J. & Li, S. (2007) A molecular phylogeny of the genus Gammarus (Crustacea: Amphipoda) based on mitochondrial and nuclear gene sequences. Molecular Phylogenetics and Evolution, 45, 596 - 611.","Morino, H. & Dai, A. - y. (1990) Three amphipod species (Crustacea) from east China. Publications of the Itako Hydrobiological Station, 4, 7 - 27.","Iwasa, M. (1965) On a small collection of amphipods and isopods from Korea, Formosa, and the Loo-choo islands. Researches on Crustacea. Carcinological Society of Japan, 2, 56 - 59.","Bousfield, E. L. (1982) The amphipod superfamily Talitroidea in the northeastern Pacific region. I. Family Talitridae: systematics and distributional ecology. Publications in Biological Oceanography, 11, 1 - 75."]}

Platorchestia platensis (Kr��yer, 1845) Figs 25���26 Platorchestia platensis.��� Stock, 1996: 153, Figs 2D, 3D; Jo, 1988: 166, fig. 8; Miyamoto & Morino, 2004: 81: fig. 7; Serejo, 2004: 19: fig. 10. Material examined. Type material of Orchestia platensis Kr��yer, 1854, PARALECTOTYPES: male, 6.8 mm, female, 7.6 mm, ZMC CRU7803, Rio de la Plata, Montevideo, Uruguay. Diagnosis. Outer plate of maxilla 2 with pectinate setae. Male antenna 2 and pereopod 7 strongly sexually dimorphic. Carpus of pereopod 7 incrassate, laterally elliptic. Male gnathopod 1 cuspidactylate. Male gnathopod 2 with palm sinuous, lacking conspicuous notch; dactylus not narrowing distally. Coxa 6 posterior lobe with anterodistal corner subquadrate, with process, 1���3 marginal setae, posterior margin perpendicular to ventral margin. Pleopod 1 lacking marginal setae. Pleopod 2 with 4 median marginal robust setae; pleopod 3 with 4 median marginal robust setae. Coxal gills convoluted or simple. Pereopods 3���5 gills smaller than gills 2 and 6. Oostegites 2���4 moderately setose (around 20 setae). Oostegite 5 with 9 setae, posterior margin with fewer setae than anterior margin. Remarks. Considering the similarity of P. platensis with P. paraplatensis n.sp. herein described, other characters, based on the lectotype, such as shape of coxa 6, oostegite 5 setae, and number of setae on pleopods of the former species were observed and used to differentiate these taxa as discussed above. Recent studies on Platorchestia, including P. platensis, were based on material from Europe (Jo, 1988; Miyamoto & Morino, 2004), despite the fact that the type locality of this species is Montevideo, Uruguay. Small differences were noted when comparing the type material with some European redescriptions of P. platensis, such as the dactylus of gnathopod 2, which is narrowing distally in material from Kent, England (Miyamoto & Morino, 2004) (versus not narrowing), the palm of gnathopod 2, which is notched (versus sinuous), and the dactylus of gnathopod 1 in Denmark specimens (Jo, 1988), which fits the palm (versus shorter). As new characters of the P. platensis complex come to light it is important for future studies on the group to show clearly the diagnostic features noted herein for an accurate assessment. For the time being, we consider the European species as P. platensis, although a careful examination from the southern population of Montevideo with the European specimens may prove that we are dealing with different taxa. Genetic studies would be helpful in this case., Published as part of Serejo, C. S. & Lowry, J. K., 2008, The Coastal Talitridae (Amphipoda: Talitroidea) of Southern and Western Australia, with Comments on Platorchestia platensis (Kr��yer, 1845), pp. 161-206 in Records of the Australian Museum 60 (2) on page 194, DOI: 10.3853/j.0067-1975.60.2008.1491, http://zenodo.org/record/5238681, {"references":["Stock, J. H., 1996. The genus Platorchestia (Crustacea, Amphipoda) on the Mid-Atlantic islands, with description of a new species from Saint Helena. Miscelania Zoologica 19.1: 149 - 157.","Jo, Y. W., 1988. Talitridae (Crustacea - Amphipoda) of the Korean coasts. Beaufortia 38 (7): 153 - 179.","Serejo, C. S., 2004. Talitridae (Amphipoda, Gammaridea) from the Brazilian coastline. Zootaxa 646: 1 - 29. http: // www. mapress. com / zootaxa / 2004 / zt 00646. pdf"]}

Key to the Brazilian coastline talitrid species and some sibling species within Platorchestia 1. Male gnathopod 1 simple; pereopod 5 with 3–4 very robust round­tipped setae on anterior margin of carpus, dactylus thick and distinct from the others; pleopods 1–3 reduced, uniramous............................... Atlantorchestoidea brasiliensis (Dana, 1853) ­ Male gnathopod 1 subchelate; pereopod 5 with pointed­tipped robust setae on anterior margin of carpus, dactylus not thickened, similar to the others; pleopods 1–3 not reduced, biramous........................................................................................................ 2 2. Female gnathopod 1 simple; palm of male gnathopod 2 with a well developed proximal concavity and a corresponding process on the dactylus; dorsal margin of outer ramus of uropod 1 with robust setae............. “ Talorchestia ” tucurauna (Müller, 1864) ­ Female gnathopod 1 subchelate (palm short); palm of male gnathopod 2 not as above; outer ramus of uropod 1 lacking marginal robust setae.............................................. 3 3. Male antenna 2 with peduncle articles 4–5 incrassate; male gnathopod 1, merus lacking posterior lobe; dactylus cuspidactylate; uropod 1 lacking disto­lateral robust setae; ramus of uropod 3 subequal or slightly smaller than peduncle; basis of female gnathopod 2 anteriorly expanded (in juveniles it is not so expanded)................................... 4 ­ Male antenna 2 not incrassate; male gnathopod 1, merus with posterior lobe; dactylus simplydactylate; uropod 1 with a distinct disto­lateral robust setae; ramus of uropod 3 half length of peduncle; basis of female gnathopod 2 not expanded......................................................................................................... Chelorchestia darwini (Müller, 1864) 4. Coxae 2–4 shallow,much wider than deep; dactylus of male gnathopod 1 subequal to palm ....................................................................................... Platorchestia munmui Jo, 1988 ­ Coxae 2–4 as wide as deep; dactylus of male gnathopod 1 distinctly shorter than palm....................................................................................................................................... 6 5. Male pereopod 7 incrassate; oostegite 5 posterior margin with less setae than anterior margin.............................................................. Platorchestia platensis (Kroyer, 1845) ­ Male pereopod 7 not incrassate; oostegite 5 posterior and anterior margin with about the same number of setae............................. Platorchestia monodi Mateus et al. 1986

Platorchestia monodi (Mateus, Mateus & Afonso, 1986) (Figs 7���10) Orchestia monodi Mateus, Mateus & Afonso, 1986: 100: figs. 1���7. Orchestia platensis ��� Oliveria, 1953: 329, figs. 10���12; Soares, 1979: 98. Platorchestia platensis (Kroyer, 1845) forma monodi (Mateus, Mateus & Afonso, 1986) ��� Stock & Biernbaum, 1994: 796, fig. 1. Platorchestia monodi ��� Morino & Ortal, 1995: 825, figs. 1���3; Stock, 1996: 150, figs. 2���4 (part). Material examined. Para��ba ��� Cabedelo Harbor, PB, 9 males and 17 females, I/ 1964, MNRJ 9762. Pernambuco ��� Maria Farinha, Paulista, in mangrove, PE, 4 females, 31 / VII/ 1985, MNRJ 9790. Alagoas �� Munda�� Lagoon, Macei��, AL, 1 male and 2 females, A. Lemos de Castro col., 2 /VIII/ 1978, MNRJ 10841. Esp��rito Santo ��� Santa Cruz, ES, 6 males and 30 females, A. Lemos de Castro col., 19 /I/ 1973, MNRJ 9758; Barra de Itabapoana, ES, 2 males and 3 females, A. Lemos de Castro and B. dos Prazeres col., 7 /XI/ 1973, MNRJ 9768. Rio de Janeiro ��� Rodrigo de Freitas Lagoon, RJ, 6 males and 9 females, C. Serejo col., 25 /V/ 2002, MNRJ 18448; Gua��ba Island, Mangaratiba, RJ, 12 males, 35 females, 24 /VII/ 2002, MNRJ 18443; Mambucaba, RJ, A. Lemos de Castro & B. dos Prazeres col., 16 /XII/ 1974, MNRJ 9759. S��o Paulo ��� Canan��ia, Arrozal, SP, 13 females, A. S. Tararam col., X/ 1988 to I/ 1989, MNRJ 15074; 2 females, MNRJ 15078; 1 female, MNRJ 15081; 2 males, MNRJ 15084; 1 female, MNRJ 19108; Iguape, SP, 5 males and 16 femlaes, Y. Wakabara col, 19 /VII/ 1985, MNRJ 15126. Paran�� ��� Fortaleza beach, Ilha do Mel, PR, 50 males, 65 females, C. Serejo and P. Young col., 04/II/ 1999, MNRJ 18442; Pontal do Sul beach, PR, 1 male and 17 females, C. Serejo and P. S Young col., 3 /II / 18445, MNRJ 18445. Santa Catarina ��� Caieria beach, Florian��polis, SC, 6 males and 45 females, C. Serejo & P. Young col., 16 /II/ 1999, MNRJ 18440; Brava beach, Cambori��, SC (near river estuary), 1 male, C. Serejo and P.S. Young col., 18 /II/ 1999, MNRJ 18441; Porto Belo, SC, 100 specimens, 28 /XI/ 1987, MNRJ 9765. Comparative type material. " Orchestia platensis Kr., Montevideo. 13 / 12 40. Beslemte oj opstill. af Kroyer. Silbert hans Anj. Exemplares". Lectotype, 1 male, 12.3 mm, ZMUC 8221; Paralectotypes, 1 male, 6.8 mm; 1 female, 7.6 mm; 7 damage specimens, ZMUC 7803. Diagnosis. Male gnathopod 1 subchelate, dactylus cuspidactylate and shorter than palm. Male gnathopod 2 palm with very shallow medial concavity. Posterior lobe of coxa 6, antero��distal corner with or without distinct process. Male pereopod 7 merus and carpus not expanded. Oostegite 5 posterior margin with the same number of setae of anterior margin. Uropod 3, peduncle and ramus subequal in length. Telson emarginated, each side with two pairs of robust setae on lateral margin and 3 distal robust setae. Description. Male, 12.8 mm. Antenna 1 reaching the end of article 4 of peduncle of antenna 2, flagellum with about 6 articles. Antenna 2 with peduncle incrassate, flagellum with about 14 articles (Fig. 7 A). Mandible with left lacinia mobilis 5 ��dentate. Maxilla 1, inner plate with two distal plumose setae; outer plate with 9 dentate robust setae, palp reduced and 1 ��articulate. Maxilla 2, inner plate with several distal setae and a robust proximal plumose seta; outer plate a little larger than inner plate. Maxilliped palp 3 ��articulate and densely setose, article 2 with medio��distal inner lobe, medial robust setae absent. Gnathopod 1 subchelate (Fig. 7 B, C), carpus and propodus with well��developed postero��distal lobe, dactylus cuspidactylate and shorter than palm. Gnathopod 2 robust (Fig. 7 D), palm with several robust setae and a very shallow medial concavity, dactylus not attenuated distally. Coxa 2���4 about as wide as deep, with well developed posterior process (Fig. 7 D���F). Pereopod 4 distinctly shorter than pereopod 3; carpus about 2 X longer than wide; dactylus thickened (Fig. 7 F). Pereopod 5 (Fig. 7 G) slightly longer than half of pereopod 6, pereopods 6���7 subequal in length (Fig. 8 A, B). Posterior lobe of coxa 6 with a 90 �� antero��ventral angle, antero��distal process absent (Brazilian population). Pereopod 6, basis oval (Fig. 8 A). Pereopod 7 not sexually dimorphic, basis rounded; merus and carpus not expanded (Fig. 8 B). Coxal gills 2���6 simple or slightly convoluted, gills 2 and 6 larger than gills 3���5. Pleopods 1���3 similar and not reduced, rami subequal in length and slightly shorter than peduncle. Peduncle of pleopod 1 lacking setae; pleopods 2 peduncle with 4���5 medial robust setae; pleopod 3 peduncle with 4���5 sub��distal robust setae and 2 proximal robust setae. Uropod 1 inner ramus, inner margin with 5 robust setae and outer margin with 4 robust setae; outer ramus lacking marginal setae (Fig. 8 C). Uropod 2 (Fig. 8 D) outer ramus with one marginal robust seta. Uropod 3 (Fig. 8 E), peduncle and ramus subequal in length, peduncle with 3 to 4 sub��distal robust setae, ramus with marginal and distal setae. Telson (Fig. 8 F) longer than wide, emarginated and with a distinct medial line, each side with two pairs of robust setae on lateral margin and 3 distal robust setae. Female, 8.5 mm. Peduncle of antenna 2 not incrassate. Gnathopod 1 (Fig. 9 A) minutely subchelate. Gnathopod 2 (Fig. 9 B), basis enlarged. Coxal gill 2 as long as gnathopod 2 basis. Oostegites 2���5 oval (Fig. 9 C���F). Oostegites 2���4 long and slender, about 4 times longer than wide, with 9���11 marginal setae; oostegite 5 shorter, about 2.5 times longer than wide, with 4���5 setae, posterior margin with the same number of setae of the anterior margin. Variation. The medial concavity present in the palm of male gnathopod 2 is variable according with the development of the specimens. Juveniles observed (7.3 to 10 mm) do not present this concavity. Type locality. Azores Island, Atlantic Ocean. Distribution. Mid��Atlatic Islands: Azores, Ascension, Madeira; Western Atlantic: Guadeloupe (West Indies); West Florida and Charleston, USA (Biernbaum & Stock, 1994; Stock, 1996); Negev Desert, Israel (Morino & Ortal, 1995). Records from Madeira and Guadeloupe are as P. platensis, although Stock (1996) considered them as possible P. m o n �� odi. Careful examination of material from these areas is needed for confirmation of the above records. Ecology. Found on the sea shore of Azores and Brazilian coast. Prefer protected beaches and can be found in estuarine areas and mangroves. Some authors found this species on inland areas on altitudes of 762���792 m (Stock, 1996) and near springs and wells (Morino & Ortal (1995). Remarks. Bousfield (1982) erected the genus Platorchestia, including 5 species from North Pacific, and P. platensis, considered a nearly cosmopolitan species along tropicaltemperate coastlines. Nowadays, the genus includes 13 described species (Table 2), although the generic status of some species has been questioned, especially within the terrestrial taxa (Jo, 1988; Richardson, 1991). Among these, there are three Atlantic sibling species that needs careful examination for an accurate identification. These are P. platensis originally described from Montevideo, Uruguay, P. monodi from warm��temperate and subtropical zones of the Atlantic Ocean, and P. aschmoleorum Stock, 1996 from low��latitude zones of St. Helena Island (Stock, 1996). Jo (1988) observed the cuspidactylate male gnathopod 1 to distinguished P. platensis from other similar species within the genus. Only three species within Platorchestia has a cuspidactylate male gnathopod 1, P. platensis, P. monodi, and P munmui Jo (1988). For distinguishing these three species see key bellow. As discussed by Stock & Biernbaum (1994) and Stock (1996) the distinction of P. platensis and P. monodi are sometimes quite difficult to observe, mainly because most of the characters used are age dependent. Thus, the syntype series of P. platensis was examined, a lectotype designated and compared with the Brazilian material (Fig. 10 A���D). The diagnostic character pointed out by Jo (1988) for P. platensis as the cuspidactylate gnathopod 1, and posterior lobe of coxa 6 with antero��distal lobe was confirmed. The sexual dimorphism on male antenna 2 and pereopod 7 was also observed (Fig. 10 A, E). The presence of one or two notches on the palm of male gnathopod 2 has been used to diagnostic P. platensis (Jo, 1988; Stock & Biernbaum, 1994). The lectotype (12.3 mm) showed a sinuous palm, without a definite notch, although this character seems to be extremely variable within the development of general talitrids and its use as diagnostic should be carefully applied. The Brazilian material has the palm of gnathopod 2 with a shallow medial notch and also more robust setae when compared with P. platensis lectotype. Also, the former lacks the process on antero��distal corner of coxa 6 (present in P. p l a t e n s i s) and carpus of male pereopod 7 is not expanded. Specimens observed by Oliveira (1953) from Guanabara Bay, RJ also do not have pereopod 7 expanded, suggesting that his material might be P. monodi or a juvenile form of P. p l a t e n s i s. The Brazilian specimens agrees with the original description of P. monodi Mateus et al. (1986) in general aspects, except that the former has the antero��distal corner of posterior lobe of coxa 6 without process (vs. with process). Distinction from Stocks (1996) material was noticed on the female gnathopod 2 with gill as long as the basis (vs. half size of basis). Comparing with material from Israel (Morino & Ortal, 1995), they also described coxa 6 posterior lobe without process, although the maxilliped palp article 2 lacks robust setae (vs. present or absent), and male antenna 2 is well��incrassate (vs. slightly incrassate). This is the first record of P. monodi from the Brazilian coast., Published as part of Serejo, Cristiana S., 2004, Talitridae (Amphipoda, Gammaridea) from the Brazilian coastline, pp. 1-29 in Zootaxa 646 on pages 14-21, DOI: 10.5281/zenodo.158648, {"references":["Mateus, A, Mateus, E. & Afonso, O. (1986) Amphipodes Littoraux et de l'interieur recueillis aux Acores pendant la Campagne \" Biacores \" (1971) sur le navire Jean Charcot. Anais da Faculdade de Ciencias do Porto, 65, 87 - 126.","Soares, C. M. A. (1979) Estudo ecologico da regiao de Itamaraca, Pernambuco, Brasil. III. Anfipodos das familias Talitridae e Ampithoidae (1). Trabalhos Oceanograficos da Univiversidade Federal de Pernambuco, 14, 93 - 104.","Stock, J. H. & Biernbaum, C. K. (1994) Terrestrial Amphipoda (Talitridae) from Ascension and Saint Helena (South Central Atlantic). Journal of Natural History, 28, 795 - 811.","Morino, H. & Ortal, R. (1995) Two Platorchestia species (Amphipoda, Talitridae) from Israel. Crustaceana, 68, 824 - 832.","Stock, J. H. (1996) The genus Platorchestia (Crustacea, Amphipoda) on the Mid-Atlantic islands, with description of a new species from Saint Helena. Miscelania Zoologica, 19.1, 149 - 157.","Bousfield, E. L. (1982) The amphipod superfamily Talitroidea in the northeastern Pacific region: 3. Family Talitridae. Systematics and distributional ecology. Publications in Biological Oceanography, 11, 1 - 73.","Jo, Y. W. (1988) Talitridae (Crustacea - Amphipoda) of the Korean coasts. Beaufortia, 38 (7), 153 - 179.","Richardson, A. M. M., 1991. Two new species of landhoppers (Crustacea: Talitridae) from O'ahu, Hawaiian Islands, with redescription of Platorchestia pickering i and key to landhoppers of O'ahu. Bishop Museum Occasional Papers, 31, 185 - 201.","Oliveira, L. P. H. (1953) Crustacea Amphipoda do Rio de Janeiro. Memorias do Instituto Oswaldo Cruz, 51, 289 - 376."]}

Platorchestia japonica (Tattersall, 1922) (figures 1–4) Talorchestia japonica Tattersall, 1922: 452, pl. XXI, figures 1–10. Platorchestia japonica Bousfield, 1982: 27. Platorchestia japonica Morino and Dai, 1990: 7, figures 9–11. Material examined. Sixty-five males and 24 females (one male and one female were illustrated in this paper); paddyfield north-west of Beijing; 22 August 2000; collected by Shuqing Li and Zhong-e Hou. Other material from the following localities was also examined. Five males and five females; a river at the foot of Mt Yuquanshan, Beijing; 22 May 2001; collected by Shuqiang Li and Zhong-e Hou. Four males, eight females and four juveniles; Lake Xuanwuhu, Nanjing; 22 September 1988; collected by Shuqiang Li and H. Morino. Four females and six juveniles; Yanghe River, Shanghai; 26 September 1988; collected by Shuqiang Li. Two females; Lake Donghu, Wuhan; 18 September 1988; collected by Hiroshi Morino. Fifteen males, 52 females and 15 juveniles; Lake Taihu, Wuxi; 23 September 1988; collected by H. Morino and Shuqiang Li. Fourteen males and 27 females; Lake Nanhu, Wuhan; 12 September 1988; collected by Shuqiang Li and H. Morino. Description. Male (IZCAS-I-A0013), body length 8.5 mm. Eyes subcircular, based on the basis of antenna 1, about 0.36 times of head diameter. Inferior antennal sinus distinct. Buccal mass directed beneath head. Antenna 1 short, barely reaching end of peduncular article 4 of antenna 2; peduncular articles 1–3 subequal in length; flagellum four-articulate. Antenna 2: peduncular article 5 a little longer than article 4, with short spines along both margins; flagellum 12-articulate, each article with some bristles. Upper lip convex, with minute setae. Left mandible: incisor five-dentate, lacinia mobilis with five weak teeth, molar triturative with one long seta. Right mandible: incisor five-dentate, lacinia mobilis bifurcate, with weak definitions. Lower lip concave, with fine setae, inner lobes lacking. Maxilla 1 with rudimentary palp, inner plate with two plumose distal setae, outer plate with nine apical serrated spines. Maxilla 2: inner plate with one plumose seta at medial margin, outer plate armed with two rows of incurved setae. Maxilliped: inner plate with three spines and some plumose setae on distal margin; outer plate with slender spines on medial margin; article 2 of palp broad, article 4 distinct, positioned on subdistal part of dorsal surface. Gnathopod 1: coxal plate anteriorly rounded, ventral margin spinose; basis straight and narrow, both anterior and posterior margins with short spines; merus without tumescent humps, posterior margin spinose; carpus subtriangular-shaped, with tumescent humps at posterodistal angle, and a row of long spines at base of hump; propodus about 0.6 times as long as carpus, with tumescent hump at posterodistal angle, with rows of spines, palmar margin with some stiff setae; dactylus shorter than palm of propodus, bearing one seta at joint of nail. Gnathopod 2: coxal plate spinose, with cuspidate posterior margin; anterior margin of basis bare, posterior margin with four small spines; propodus large, oval, palmar margin smoothly convex and fringed with many spines; dactylus attenuated distally, with fine setae. Pereopod 3 longer than pereopod 4, coxal plates with posterior cusp; carpus of pereopod 4 shorter than that of pereopod 3; propodus with a distal spine at dactylar hinge; dactylus cuspidactylate, with a stiff spine on concave margin. Pereopod 5 about as long as pereopod 3, coxal plate anterolobate, with two and three setae on ventral and posterior margins, respectively; posterior margin of basis expanded roundly, armed with five short spinules, anterior margin of basis with seven spines; dactylus cuspidactylate, about 0.35 times as long as article 6. Pereopod 6 much longer than pereopod 5, coxal plate posterolobate, with two posterior marginal setae; basis subrounded with 10 anterior spines and six posterior setae; dactylus slender, about 0.37 times of article 6 in length. Pereopod 7 slightly longer than pereopod 6, coxal plate non-lobate, ventral margin with three short setae; basis strongly expanded, with 10 short spines on anterior margin and 14 setae on posterior margin; dactylus 0.38 times as long as article 6. Coxal gill of gnathopod 2 anchor-shaped, gills of pereopods 3 and 4 hooked at middle, gills of pereopods 5 and 6 subcircular. Epimeral plates with slightly pointed posterior angles, ventral margin unarmed, posterior margin with two or three minute setae. Pleopods well developed, peduncles with two retinaculae, peduncle of pleopod 3 postero-distally setulose, with five short spines along intero-posterior margin; both rami fringed with plumose setae. Uropod 1: peduncle longer than rami, with three and four spines on inner and outer margins, respectively; outer ramus a little shorter than inner ramus, outer ramus marginally bare, with three distal spines; inner ramus with one inner marginal and three outer marginal and four distal spines. Uropod 2: peduncle with three and four spines on inner and outer margins, respectively, inner ramus with one mid-marginal spine, outer ramus with one and two spines on inner and outer margins, respectively, both rami with distal spines. Uropod 3: peduncle with two spines on distal corner, ramus slightly shorter than peduncle, with two lateral and three distal spines. Telson longer than wide, apically notched, each lobe with two to three distal spines and one sublateral spine. Dimorphism. Female (IZCAS-I-A0014) 8.6 mm. Gnathopod 1: carpus and propodus not tumescent, propodus about 0.53 times as long as carpus, parallel-sided, with many spines along posterior margin, palmar margin short, with four slender spines at posterodistal corner; dactylus exceeding palmar margin. Gnathopod 2: coxal plate with cuspidate posterior margin; basis anteriorly broadened, anterior margin with many minute spines evenly, posterior margin with few spines; merus with small facial spines; carpus and propodus tumescent posteriorly; propodus with spine-row on lateral surface, palm margin with five stiff setae; dactylus about half of palmar margin, with a seta at hinge of nail. Uropod 3: peduncle with two subdistal and one distal spine, ramus with one subdistal and four distal spines. Oostegites of pereopods 2–4 elongate, parallel-sided, with dozens of setae; oostegite of pereopod 5 triangular, with 10 setae on distal margin and two spines on surface. Remarks. Tattersall (1922) firstly recorded Talorchestia japonica from Lake Biwa. Bousfield (1982) ascribed it to the genus Platorchestia Bousfield according to the following characters: (1) left mandibular lacinia five-dentate; (2) male gnathopod 1 with tumescent carpus and propodus; (3) gnathopod 2 powerfully subchelate; (4) female gnathopod 2 with anteriorly broadened basis and posteriorly tumescent carpus and propodus; (5) carpus of pereopod 4 short; and (6) marginally unarmed outer ramus of uropod 1. Morino and Dai (1990) redescribed Platorchestia japonica with material from China. The present material well accords with the figures and description of P. japonica given by Morino and Dai (1990), except that the eyes are less than 40% of the diameter of the head and the pleopods have many packs. These features may be the result of a small size and parasites. Habitat. P. japonica is distributed along the Yangtze River and the shore of the Jingmiyinshuiqv River, Beijing. All material was found under decaying straw or silt beside the water., Published as part of Hou, Z. - E. & Li, S., 2003, Terrestrial talitrid amphipods (Crustacea: Amphipoda) from China and Vietnam: studies on the collection of IZCAS, pp. 2441-2460 in Journal of Natural History 37 on pages 2442-2448

Platorchestia bousfieldi n. sp. (figures 5–8) Material examined. One female (holotype), one female and one juvenile (paratypes). Collection label not seen. Blind terrestrial talitrids are rare, especially in China, where this phenomenon has been found for the first time. Description of this taxon may be important for the phylogeny of landhoppers. Etymology. The species name is in honour of Dr E. L. Bousfield, who kindly gave us much help when we were in a difficult period during the present research. Description. Female (  , IZCAS-I-A0015), body length 7.5 mm. Head subrectangular, inferior antennal sinus distinct. Eyes lacking. Antenna 1: peduncle segments subequal, with distal spines, flagellum four-articulate with some spines. Antenna 2: peduncular article 4 about 71% of length of article 5, thicker than article 5, both with marginal spines; flagellum 1.67 times as long as peduncular article 5, nine-articulate, armed with fine marginal spines. Upper lip convex, with minute setae apically. Left mandible: incisor five-dentate, lacinia mobilis with five weak teeth. Right mandible: incisor five-dentate, lacinia mobilis bifurcate, ridge of each cusp minutely serrate. Lower lip: inner shoulder and margin of central trough pilose. Maxilla 1: inner plate with two apical spinulate setae, outer plate with nine saw-like spines on distal margin, palp minute. Maxilla 2: inner plate with one large seta on outer distal angle, outer plate with several long setae near outer distal angle. Maxilliped: inner plate with three distal spines, article 4 of palp distinct. Gnathopod 1: coxal plate smoothly rounded anterodistally, low margin with three spines and some setae; basis with two spines on posterior margin; ischium with a marginal and two distal spines; merus without tumescent hump, posterior margin spinose; carpus and propodus lacking tumescent hump, propodus about 0.67 times as long as carpus, palm truncate, with a spine and two setae at posterior angle; dactylus longer than palm of propodus, with one stiff setae on concave margin. Gnathopod 2: coxal plate with cuspidate posterior margin; basis expanded anteriorly, anterior margin with seven small spines evenly; merus with spines on posterior margin and lateral surface; carpus and propodus tumescent posteriorly, propodus shorter than carpus, with spines-row on lateral surface; dactylus hooked distally, grasping margin with a row of four setae. Pereopods 3 and 4: coxal plates wider than deep, ventral margin straight, with short setae, posterior margin cuspidate; bases almost parallel-sided; carpus short, posterior margins of merus to propodus with denser spines than anterior margins; dactylus with a spine at hinge of nail. Pereopod 3 longer than pereopod 4, carpus of pereopod 4 shorter than that of pereopod 3. Pereopod 5: anterior lobe of coxal plate larger than posterior one, posterior margin with four fine setae; posterior margin of basis expanded roundly, armed with several short setae, anterior margin with spines; dactylus cuspidactylate, with a spine near hinge of nail. Pereopod 6 much longer than pereopod 5, coxal plate posterolobate; basis ovate, posterior margin with some spinules; merus to propodus with groups of spines along anterior and posterior margins. Pereopod 7: coxal plate shallow, non-lobate, ventral margin weakly convex; basis expanded posteriorly. Coxal gills of pereopods 2–6 present. Oostegites of pereopods 2–4 parallel-sided and elongate, oostegite 5 shortest and widened in the middle. All without marginal setae. Epimeral plates 1–3 with slightly pointed posterior angles, ventral margin unarmed, posterior margin with one to three setae. Pleopods 1–3 similar, peduncles with two retinaculae, peduncles of pleopods 1 and 2 marginally bare, peduncle of pleopod 3 with a few setae on outer margin; both rami with about 10 particles, fringed with long plumose setae. Uropod 1: peduncle longer than rami, with five spines on outer margin, three spines on inner margin; outer ramus a little shorter than inner ramus, marginally bare; inner ramus with three spines on outer margin; both rami with distal spines. Uropod 2: peduncle with three spines on both margins, outer ramus with one midmarginal and two distal spines, inner ramus with three outer marginal and three distal spines. Uropod 3: peduncle longer than deep, with three distal spines; ramus about 0.6 times as long as peduncle, with one subdistal and two distal spines. Telson apically notched, longer than wide, bearing one or two spines on dorsal surface and three distal spines. Male unknown. Remarks. The new species is similar to Platorchestia japonica in the parallelsided propodus of gnathopod 1, the tumescent carpus and propodus of gnathopod 2, and pereopod 5 smaller than pereopods 6 and 7. It differs from Platorchestia japonica in the absence of eyes, the telson notched apically bearing two facial and three to four distal spines, and the oostegites bearing few marginal setae. Although there is no information on the habitats of the present blind species, it is very unusual. We are sure it is definitely terrestrial because it has narrow oostegites. The long and biramous pleopods of the present species are more like those of some of the Tasmanian cuspidactylate species, which are less terrestrially adapted than simplidactylate species (Friend, 1987).

Biogeographia — vol. XX - 1999 (Pubblicato il 31 ottobre 1999) Biogeografia del|’Anatolia Strutturazione genetica e pattern di flusso genico in quattro specie di Anfipodi Talitridi sopralitorali dell’area egeal ELVIRA DE MATTHAEIS, VALERIO KETMAIER, DOMENICO DAVOLOS, l\/IARINA COBOLLI Dipzzrtimento di Biologia Animals 6 de[[’Uamo (Zoo/ogizz), Universitiz di Roma “La Szzpienzzz ”, Vizzle a’e1[’Uniz/erritfz, 32 — [—00185 Roma (Itzzlia) Key words: gene flow, population genetic structure, Orchestia, Platorchestia, Talitrus. SUMMARY Allozymic variation was studied at 22 loci in 5 populations of Talimzrraltrttor, 6 populations of Or:/Jertia mozztagui, 5 populations of Or:/Jertizz step/yemerzi and 1 population OFP/zltorc/Jestiap/ateruis from the Aegean area. These data were compared with the well documented allozymic variation within each species at the scale of the whole Mediterranean. Interspecific mean values of Nei's genetic distance (D; Nei. 1978) ranged from 0.495 to 1.410, while the intraspecific mean values of D ranged from 0.007 (P. platmris) to 0.256 (T. mltator). Levels of gene flow (Nm) were calculated by using F5, parameter, according to Weir and Cocllerham’s method (1984). The Slatlcin’s approach (1993) was used to analyse the relationship between Nm values and geographic distances to test for the presence of an isolation by distance pattern in the spatial genetic variation within each species. Difirerent levels of gene flow were detected within each species both at the scale of the whole Mediterranean and of the Aegean area: Nm values 2 1 resulted among 0. nlmztagui and P. plttteizris populations, while Nm values l 1 were obtained for T. mltator and O. rtep/Jemeni populations. Interestingly, a pattern of isolation by distance is usefiil to describe the genetic structuring of the study species in all Meditertanea areas but Aegean insular ones. INTRODUZIONE Il grado di strutturazione genetica di una specie e strettamente legato ai livelli di flusso genico che intercorrono tra le diverse popolazioni della specie stessa. La strut- tura genetica di una specie puo quincli non essere omogenea nello spazio, ma pre- sentare gradi diversi di eterogeneita a seconda della scala geografica considerata. Utilizzando i modelli maternatici di genetica di popolazione, elaborati da Wright (1931; 1943; 1946; 1965) e recentemente riconsiderati da Slatkin (1987; 1993; 1994), e possibile ottenere stime indirette di flusso genico partendo dai dati di fre- quenze alleliche ai loci allozimici e analizzare il tipo di relazione esistente tra i livel- li di flusso genico e la distanza geografica tIa le popolazioni in esame. In questo I Ricerdte zoologiche dell'Universitz‘9. di Roma nel vicino Oriente: 188, e delle navi oceanografiche del CNR nelle isole del Mediterraneo orientale: 13. Lavoro eseguito con contributi del Ministero dell’Universit‘a e della Ricerca Scientifica e Tecnologica (MURST 40%) e del Consiglio Nazionalc delle Ricerche, CNR (Comitato Ambicnte).

One new genus and four species of talitrid amphipods are described from Tonga: Platorchestia ano sp. nov.; Talorchestia spinipalma (Dana, 1852); Tongorchestia pangaimotu gen. nov., sp. nov.; T. towneri sp. nov.

The sand-hopper Bellorchestia mariae sp. nov. is described from Honeymoon Bay on the north coast of Jervis Bay, NewSouth Wales, Australia. It is the sister species of B. richardsoni Serejo & Lowry, 2008 and appears to have a limited dis-tribution from about Narrawallee in the south to northern Jervis Bay. The distribution of B. richardsoni Serejo & Lowry,2008 is extended from Point Ricardo, Victoria, northwards to Ulladulla on the New South Wales coast. A new synonymyis proposed for the sand-hopper Notorchestia quadrimana (Dana, 1852) which includes N. novaehollandiae (1899) and N. lobata Serejo & Lowry, 2008. It is considered to be a wide-ranging species from Shark Bay in Western Australia aroundthe south coast to at least Maitland Bay in central New South Wales. The beach-hopper Orchestia dispar Dana, 1852 isdescribed from Valla Beach in northern New South Wales and moved to the new genus Vallorchestia. This is the first re-cord of V. dispar since its original description 160 years ago. The beach-hopper Platorchestia smithi sp. nov. is describedfrom Brooms Head, New South Wales, Australia. It is common on ocean beaches from Bendalong in the south to Ballina in northern New South Wales. South of Bendalong beach-hoppers on ocean beaches appear to be absent.