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Oerstedia fuscosparsa sp. nov. (Figs 1, 2) Material examined. ICHUM 8405, holotype; ICHU 8406, paratype. Sequences. From holotype: see Table 1. From paratype: OP256563 (16S), OP256565 (28S), OP265742 (COI), OP253977 (H3). Description. External features of holotype in living state (Fig. 1A, B, E, F). Body 7.9 mm long when stretched, width 0.6 mm, cylindrical, slender, firm, narrowing at anterior and posterior ends, with pale-yellow background postcerebrally (Fig. 1A, B). Head bluntly round anteriorly in dorsal view, not demarcated from body, whitish opaque in background colour, ornamented with a few, small, brownish dots on tip; single, wide, brownish, transverse cephalic colour band encircling all around head, with posterior edge mid-dorsally directing backward (Fig. 1E, F); another transverse colour band encircling posterior portion of head, deep brown in colour, mid-dorsally notched at anterior edge, situated post-cerebrally at short distance from cephalic colour band except on mid-ventral portion where these two bands are continuous (Fig. 1E, F); cephalic furrow not notable; with four squarely arranged orange ocelli contained within transverse cephalic colour band (Fig. 1E). Behind deep-coloured post-cerebral transverse colour band, additional 18 transverse bands present throughout body from posterior region of head to tail end, tightly arranged one after another, consisting of brown flecks; single, deep brown spot present on mid-dorsal portion of each of 18 bands (Fig. 1A). External features of paratype in living state (Fig. 1C, D, G, H, I). Body 10 mm in length, 0.6 mm in width; tip of head less pigmented than holotype; posterior end of body narrowed (Fig. 1C, D); cephalic colour band light brown; post-cerebral colour band lighter than that of holotype, with anterior edge mid-dorsally projected forward but not continuous with cephalic colour band on any place (Fig. 1G, H); ocelli more clearly visible with anterior pair smaller than posterior (Fig. 1G, H, I). Body covered with brown patches (Fig. 1C, D), but transverse banding pattern not apparent in posterior body; without mid-dorsal deep brown spots (Fig. 1C). Internal morphology in paratype. Proboscis nerves not distinct (Fig. 2A). Central stylet 42.0 µm in length; basis 36.7 µm in length, 11.2–15.2 µm in width, cylindrical in shape, bluntly round posteriorly; two accessory pouches, each containing 5–7 accessory stylets (Fig. 1J). Accessory lateral nerves present (Fig. 2B). Etymology. The new specific name is a participle of the 1st/2nd declension (- us, - a, - um), a combination of the Latin words fuscus (meaning “dark”, “dim”, “black”, “brown”) and sparsus (“scattered”, “sprinkled”, “spotted”, “freckled”; from the verb spargo, meaning “[I] scatter”). In combination, fuscosparsa pertains to the the brownish spots/freckles scattered throughout the body of the species. Diagnosis. An Oerstedia with a brownish cephalic colour band, a deep brown post-cerebral colour band in the posterior head region, and four orange ocelli. Post-cerebrally, the body is sprinkled with brownish aggregated spots or freckles in pale-yellow background forming transverse bands. Internally, the proboscis nerves are not distinct and accessory lateral nerves are present. Type locality and distribution. At present, the species is only known from its type locality along the Pacific coast of Honshu, off Kouyatsu, Tateyema, Chiba, Japan, between 34°59.293′ N, 139°48.59′ E and 34°59.094′ N, 139°48.195′ E, 11–18 m deep, mudstone and sandy bottom; the in-situ water temperature was 18–20°C when the holotype and the paratype were collected by Ryuta Yoshida. From this place, Tetrastemma parallelos Abato, Yoshida & Kajihara, 2022 has also been collected (Abato et al. 2022). Genetic distance and molecular phylogeny. The two specimens of O. fuscosparsa sp. nov. reported in this paper would belong to the same species with uncorrected COI p -distance value of 0.004 (0.4%) as to the 658-bp partial COI region, much lower than the 3%-rule COI genetic distance to infer that two ribbon worms are of different species (Sundberg et al. 2016). We therefore regard that the difference in pigmentation pattern observed between the two individuals in this paper is an intraspecific variation commonly observed among other Oerstedia species. The phylogenetic analysis shows that our species forms a highly supported subclade with Oerstedia species collected from Simushir, O. dorsalis sensu Iwata, and O. phoresiae. Further, it indicates that O. fuscosparsa sp. nov. is sister to O. phoresiae, suggesting its placement within the Paroerstediella clade sensu Chernyshev & Polyakova (2022) of the genus Oerstedia (Fig. 3). This also means that our species is more closely related to O. phoresiae than to O. dorsalis s.str. and is grouped with other species from the Northwest Pacific. COI p -distances between our species and O. phoresiae and with O. dorsalis s.str. is 8.5% and 11.9%, respectively. Taxonomic remarks. Of the 29 valid species of Oerstedia, two species have previously been known to possess transverse bands in the body; these are O. oculata and Oerstedia striata Sundberg, 1988, from both of which O. fuscosparsa sp. nov. can be distinguished in external features. Oerstedia polyorbis (Iwata 1954; Chernyshev 1993; Akhmatova et al. 2012) and O. striata are banded only dorsally, unlike O. fuscosparsa sp. nov. in which the bands are dorsoventrally continuous. In addition, one of the colour morphs of Oerstedia dorsalis s.l. (called “morph n”) was described to contain reddish-brown stripes/blotches transversally, although details on the continuity of these stripes were not given in Sundberg et al. (2009). However, these two “morph n” specimens are not closely related to the new species as supported by the phylogenetic analysis, with these “morph n” specimens being placed in a different clade (Fig. 3). DNA-based taxonomy for the members of the genus Oerstedia seems to be indispensable for the reliable establishment of new species since polymorphism and intraspecific variation are predominant among the species in the genus (Bürger 1895; Brunberg 1964; Sundberg 1984, 1988; Envall & Sundberg 1993; Sundberg & Andersson 1995; Zaslavskaya & Chernyshev 2008; Sundberg et al. 2009; Akhmatova et al. 2012). Polymorphism and intraspecific variation in Oerstedia often result in problematic taxonomy; these can hide some cryptic species or mistakenly be used as evidence for species delineation (Sundberg 1998; Sundberg et al. 2009; Akhmatova et al. 2012). The two specimens of Oerstedia fuscosparsa sp. nov. reported in this paper show distinct pigmentation patterns in the head and body; the holotype has deep brownish cephalic pigmentation, apparent transverse bands in the body, and deep brownish spots mid dorsally while the paratype has light brown cephalic pigmentation, no obvious transverse bands in the posterior body, and no deep brownish spots mid-dorsally. In traditional Oerstedia taxonomy, these obvious pigmentation differences could have been treated as evidence for different species (Iwata 1954; Kulikova 1987; Chernyshev 1993; Sundberg et al. 2009); however, the COI barcode sequences from the holotype and the paratype strongly suggested that both would belong to the same species despite the differences in external appearance. Here, we demonstrate, using our species, the necessity and importance of DNA-based taxonomy in the genus Oerstedia. The taxonomy of other selected polymorphic congeners of the genus has been verified using barcode sequences of these species (Sundberg & Andersson 1995; Strand & Sundberg 2005; Akhmatova et al. 2012). Utilizing barcode sequence data from these species has resolved inaccurate taxonomic reports established based only on internal and external morphology (Sundberg 1984, 1988; Sundberg & Janson 1988; Sundberg & Andersson 1995; Zaslavskaya & Chernyshev 2008; Akhmatova et al. 2012). With the recent developments in Oerstedia taxonomy, it is, therefore, appropriate to investigate polymorphism and intraspecific variation in those already named species using both morphological and barcode sequence data., Published as part of Abato, Jamael, Yoshida, Ryuta & Kajihara, Hiroshi, 2023, Species description and phylogenetics of Oerstedia fuscosparsa sp. nov. (Nemertea: Monostilifera: Oerstediidae) from Japan, pp. 589-597 in Zootaxa 5249 (5) on pages 592-595, DOI: 10.11646/zootaxa.5249.5.6, http://zenodo.org/record/7701406, {"references":["Abato, J. C., Yoshida, R. & Kajihara, H. (2022) Histology-free description and phylogenetics of Tetrastemma parallelos sp. nov. (Nemertea: Eumonostilifera) from Japan. Journal of Natural History, 56, 1265 - 1277. https: // doi. org / 10.1080 / 00222933.2022.2118642","Sundberg, P., Kvist, S. & Strand, M. (2016) Evaluating the utility of single-locus DNA barcoding for the identification of ribbon worms (phylum Nemertea). PLoS ONE, 11 (5), e 0155541. https: // doi. org / 10.1371 / journal. pone. 0155541","Chernyshev, A. V. & Polyakova, N. E. (2022) Nemerteans collected in the Bering Sea during the research cruises aboard the R / V Akademik MA Lavrentyev in 2016, 2018, and 2021 with an analysis of deep-sea heteronemertean and hoplonemertean species. Deep Sea Research Part II: Topical Studies in Oceanography, 199, 105081. https: // doi. org / 10.1016 / j. dsr 2.2022.105081","Iwata, F. (1954) The fauna of Akkeshi Bay XX. Nemertini in Hokkaido (revised report). Journal of the Faculty of Science, Hokkaido University, Series VI, Zoology, 12, 1 - 39.","Chernyshev, A. V. (1993) Overview of nemertean genera close to Oerstedia (Monostilifera, Tetrastemmatidae), with description of four new species. Zoologiceskij Zurnal, 72, 11 - 20. [in Russian with English abstract]","Akhmatova, A. F., Chernyshev, A. V. & Zaslavskaya, N. I. (2012) The species composition of the nemertean genus Oerstedia (Nemertea: Hoplonemertea) in the Far Eastern seas of Russia. Russian Journal of Marine Biology, 38 (6), 423 - 430. https: // doi. org / 10.1134 / S 1063074012060028","Sundberg, P., Vodoti, E. T., Zhou, H. & Strand, M. (2009) Polymorphism hides cryptic species in Oerstedia dorsalis (Nemertea, Hoplonemertea). Biological Journal of the Linnean Society, 98 (3), 556 - 567. https: // doi. org / 10.1111 / j. 1095 - 8312.2009.01310. x","Burger, O. (1895) Die Nemertinen des Golfes von Neapel und der angrenzenden Meeres-Abschnitte. Fauna und Flora des Golfes von Neapel und der Angrenzenden Meeresabschnitte, 22, 1 - 714.","Brunberg, L. (1964) On the nemertean fauna of Danish waters. Ophelia, 1, 77 - 111.","Sundberg, P. (1984) Multivariate analysis of polymorphism in the hoplonemertean Oerstedia dorsalis (Abildgaard, 1806). Journal of Experimental Marine Biology and Ecology, 78, 1 - 22. https: // doi. org / 10.1016 / 0022 - 0981 (84) 90068 - 6","Envall, M. & Sundberg, P. (1993) Intraspecific variation in nemerteans (Nemertea): synonymization of genera Paroerstedia and Oerstediella with Oerstedia. Journal of Zoology, 230 (2), 293 - 318. https: // doi. org / 10.1111 / j. 1469 - 7998.1993. tb 02687. x","Sundberg, P. & Andersson, S. (1995) Random amplified polymorphic DNA (RAPD) and intraspecific variation in Oerstedia dorsalis (Hoplonemertea, Nemertea). Journal of the Marine Biological Association of the United Kingdom, 75 (2), 483 - 490. https: // doi. org / 10.1017 / S 0025315400018324","Zaslavskaya, N. I. & Chernyshev, A. V. (2008) Allozyme comparison of three nemertean species of the genus Oerstedia (Nemertea: Monostilifera) from the Sea of Japan. Biochemical Systematics and Ecology, 36 (7), 554 - 558. https: // doi. org / 10.1016 / j. bse. 2008.03.013","Kulikova, V. I. (1987) New species of Oerstediella (Nemertini, Hoplonemertini) of the Vostok Bay, Sea of Japan. Izvestiya Akademii Nauk SSSR, Seriya Biologicheskaya, 6, 828 - 836. [in Russian with English abstract]","Strand, M. & Sundberg, P. (2005) Delimiting species in the hoplonemertean genus Tetrastemma (phylum Nemertea): morphology is not concordant with phylogeny as evidenced from mtDNA sequences. Biological Journal of the Linnaean Society, 86, 201 - 212.","Sundberg, P. & Janson, K. (1988) Polymorphism in Oerstedia dorsalis (Abilgaard, 1806) revisited. Hydrobiologia, 156, 93 - 98. https: // doi. org / 10.1007 / 978 - 94 - 009 - 4063 - 5 _ 11"]}

Tetrastemma parallelos sp. nov. (Figure 1 (a–d)) Material examined Holotype: ICHUM 8300, total DNA extracted from a single specimen dredged from a depth between 11 and 18 m on 2 December 2021, off Kouyatsu, Tateyama, Chiba, Japan (between 34.988°N, 139.809°E and 34.984°N, 139.803°E). Diagnosis A Tetrastemma with a reddish cephalic patch and two orange, parallel dorsal stripes on a semi-transparent/translucent body. Description External features: The holotype specimen in the anaesthetised state is 2.6 mm long and 0.52, 0.65 and 0.60 mm wide at the anterior, mid and posterior body, respectively. Generally, the body is nearly flat, colourless except for some pigmented regions and marginally round at both ends. Dorsally, the head is spatulate in shape, narrower, and not completely demarcated from the body. The cephalic lobe is dotted with a quadrangular reddish patch somewhat restricted and concentrated at the centre of the cephalic lobe, in the anterior-eye region, leaving a transparent lobe margin. Two pairs of distinct, oblique lateral cephalic furrows, anterior and posterior, are present. The cephalic furrows in each pair do not join with one another. Two large, dark red anterior eyes are prominently visible within the pigmented cephalic region (above the anterior cephalic furrow) (Figure 1 (a)). These anterior eyes appear to be almost black at higher magnification (Figure 1 (c)). The two posterior eyes are situated near the posterior cephalic furrows, smaller than the anterior ones, and visible only ventrally (Figure 1 (b)) or in squeezing preparation (Figure 1 (c)). Dorsally, the body is characterised by the presence of two orange-pigmented parallel lines, which originate near the posterior cephalic furrows and are transversely connected to each other at their anterior ends. These orange lines run through the entire body: anteriorly, the stripes appear thinner; posteriorly, the stripes are thicker and begin to converge near the anus but never connect to each other (Figure 1 (a)). Ventrally, the body is semi-transparent/translucent (Figure 1 (b)). Internal features: Dorsally, portions of the digestive system are visible through the transparent body as a wide, creamy to pale yellow region running along the body from below the neck area down to the posterior end (Figure 1 (a)). Ventrally, an opaque-white region is notable between the cephalic patch and the posterior eyes. The rhynchocoel is visible and as long as the body. Lateral diverticula of the intestine are apparent; the anterior-most intestinal caecal diverticula extend behind the brain (Figure 1 (c)). Gonads are very apparent (Figure 1 (b)). Central stylet is 67.2 µm long. Stylet basis is 93.0 µm long and 55.5 µm wide at the most posterior part. It is nearly triangular, with darker, truncated posterior region and lighter, nearly acute anterior region. Two accessory-stylet pouches are visible, each containing 2–3 accessory stylets (Figure 1 (d)). Etymology The new specific name is a noun in apposition (in the nominative case), derived from the Greek παράλληλος (parallelos, ‘parallel’). The specific name pertains to the orangepigmented parallel lines on the dorsal body, which are one of the diagnostic features of the new species. Type locality and distribution At present, the species is only known from its type locality, off Kouyatsu, Tateyema, Chiba Japan, 11–18 m depth, mudstone and sandy bottom (Figure 2); the in situ water temperature was 18–20°C when the holotype was collected. Molecular phylogeny The phylogenetic analyses confirmed that Tetrastemma parallelos sp. nov. belongs to the Asian–Australian Pacific Tetrastemma subclade. Our species was more closely related to those Tetrastemma species labelled as VE Vietnam, VI Vietnam and 1G4 Australia (in Chernyshev et al. 2021) than to the remaining species included in the analyses (Figure 3). Remarks Several Tetrastemma species are known to have one or more longitudinal dorsal stripes. In having two parallel dorsal stripes, Tetrastemma parallelos sp. nov. resembles some congeners such as Tetrastemma bilineatum Coe, 1904, Tetrastemma bistriatum (Timofeev, 1911), Tetrastemma herthae Corrêa, 1963, Tetrastemma nigrolineatum Wheeler, 1934 and Tetrastemma scutelliferum Bürger, 1895, as well as some varieties of Tetrastemma nigrifrons Coe, 1904 including bilineatum (Iwata 1954), bimaculatum (Chernyshev 1998) (see also Zaslavskaya et al. 2010) and trimaculatum (Chernyshev 1998). In T. bilineatum, the dorsal twin stripes are reddish brown to deep chocolate in colouration. Anteriorly, the stripes terminate somewhat in front of the ocelli but sometimes reach the very tip of the snout. Posteriorly, they extend nearly, though not quite, to the posterior extremity of the body and are sharp and conspicuous throughout. Anteriorly, these stripes are not transversely connected with one another but converge at the tail region (Coe 1904). Additionally, this species lacks a cephalic patch. Tetrastemma bistriatum has two dark brown stripes running dorsally that are separated by a wide area darker than the rest of the body. A dark-brown half-ring is present behind the posterior eyes, from which the two dorsal stripes extend (Timofeev 1911). Dorsally, T. herthae has two lateral longitudinal stripes strongly conspicuous for their deep brown colour. Sometimes they are not continuous but appear as rows of brown irregular spots placed closely together. The stripes do not join at the ends (Corrêa 1963). Tetrastemma nigrolineatum is characterised by two parallel black lines passing dorsally from the tip of the snout to the tip of the tail. At the head, these lines are thinner than they are in the body (Wheeler 1934). Tetrastemma scutelliferum has two wide, dark brown longitudinal dorsal stripes, which begin behind the cephalic region and almost reach the hind end of the body. Also, the two dark brown stripes are separated by a broad yellow stripe which similarly extends near the posterior end. It also has a dark brown, lobular cephalic patch, which is divided into four lobules: two large lobes at the front and two smaller ones at the sides (Bürger 1895). The three varieties of Tetrastemma nigrifrons commonly have brown or dark brown dorsal stripes, with varied colour and shape of the cephalic patch (dark brown, non-split cephalic patch in var. bilineatum; two dark brown, split cephalic patches in var. bimaculatum; and three dark brown, split cephalic patches in var. trimaculatum) (Iwata 1954; Chernyshev 1998; Zaslavskaya et al. 2010). Tetrastemma parallelos sp. nov. can be differentiated from these Tetrastemma species with two dorsal stripes by its orange-pigmented parallel lines transversely connected anteriorly and by its reddish cephalic patch. Although T. parallelos sp. nov. is smaller, the general body shape and the dorsal body feature of our species likely resemble those of T. bistriatum and T. scutelliferum. Our species is similar to T. bistriatum as the latter’s dorsal stripes appear to be connected anteriorly by way of its dark-brown half-ring. Internally, the morphology of the stylet basis differs between the two. The basis in T. bistriatum is rounded at the posterior end, unlike the truncated one in T. parallelos sp. nov. Aside from the slight dorsal-body feature resemblance, our species, like T. scutelliferum, has two accessory-stylet pouches. However, T. parallelos sp. nov. has only 2–3 accessory stylets in each pouch, compared with four accessory stylets per pouch in T. scutelliferum. In the resulting trees, T. parallelos sp. nov. was more closely related to the three undescribed forms in Chernyshev et al. (2021) – Tetrastemma sp. VE Vietnam, Tetrastemma sp. VI Vietnam, and Tetrastemma sp. 1 G4 Australia – than to other congeners (Figure 2). However, T. parallelos sp. nov. can be distinguished from these three by the presence of the reddish cephalic patch and dorsal stripes. In addition, our species is shorter in body size than Tetrastemma sp. VI Vietnam (8–12 mm long) and VE Vietnam (8 mm long); and it has a semi-transparent/translucent body compared to the pale yellowish-orange and pale yellow body colouration of Tetrastemma sp. VI Vietnam and Tetrastemma sp. VE Vietnam, respectively. In this study, the histology-free approach was successful because (1) the assessment of genus affiliation was facilitated by molecular phylogenetics and (2) the new species obviously differed from all congeners in external appearance. If the new species had nested in a clade to which no generic name was reliably applied, its generic affiliation would have had to be assessed by traditional histology. Our enumeration indicates that there are ~40 eumonostiliferous hoplonemertean genera that are not yet represented by any molecular data; until all of these generic names are molecularly tagged, histological examination will continue to be indispensable in eumonostiliferous hoplonemertean systematics. In Tetrastemma, body colouration and patterns have been considered effective morphological characters to delimit species (Strand and Sundberg 2005b). Meanwhile, two or more closely related, similar-looking species of eumonostiliferous hoplonemerteans can be distinguished by subtle differences such as the epidermal texture (Abato pers. obs.), which would have not been noticed and verbalised without the use of a high-quality digital camera. This indicates that external features of all the Tetrastemma species in living state – no matter if the species is already described or not – should be photographed at high resolution, so that future histology-free descriptions continue to be effective., Published as part of Abato, Jamael, Yoshida, Ryuta & Kajihara, Hiroshi, 2022, Histology-free description and phylogenetics of Tetrastemma parallelos sp. nov. (Nemertea: Eumonostilifera) from Japan, pp. 1265-1277 in Journal of Natural History 56 (29 - 32) on pages 1269-1273, DOI: 10.1080/00222933.2022.2118642, http://zenodo.org/record/7156370, {"references":["Chernyshev AV, Polyakova NE, Norenburg JL, Kajihara H. 2021. A molecular phylogeny of Tetrastemma and its allies (Nemertea, Monostilifera). Zool Scr. 50 (6): 824 - 836. doi: 10.1111 / zsc. 12511.","Coe WR. 1904. The nemerteans. Harriman Alaska Expedition. 11: 164 - 165.","Timofeev T. 1911. Nemertiny Villa-frankskoi bukhty. In: Dawydoff M, Spiczakow F, Korotneff AA, editors. Otchet (yubileinyi) o deyatelnosti Villa-Frankskoi Zoologicheskoi Stantsii za 1909 - 1910 gody. Kiev: Imperatorskii Universitet sv. Vladimira; p. 32 - 45. [In Russian].","Correa DD. 1963. Nemerteans from Curacao. Stud Fauna Curacao Other Caribb Islands. 17 (1): 41 - 56.","Wheeler JFG. 1934. Nemerteans from the South Atlantic and Southern Oceans. Discovery Rep. 9: 215 - 294.","Burger O. 1895. Die Nemertinen des Golfes von Neapel und der angrenzenden Meeres-Abschnitte. Berlin: Verlag von R. Friedlander & Sohn; p. 581.","Iwata F. 1954. The fauna of Akkeshi Bay: XX. Nemertini in Hokkaido. J Fac Sci Hokkaido Uni Ser VI Zool. 12 (6): 1 - 39.","Chernyshev AV. 1998. Nemerteans of the genus Tetrastemma (Enopla, Monostilifera) from the Far East seas of Russia. Zool Zhurnal. 77: 995 - 1002.","Zaslavskaya NI, Akhmatova AF, Chernyshev AV. 2010. Allozyme comparison of the species and colour morphs of the nemertean genus Quasitetrastemma Chernyshev, 2004 (Hoplonemertea: Tetrastemmatidae) from the Sea of Japan. J Nat Hist. 44 (37 - 40): 2303 - 2320. doi: 10.1080 / 00222933.2010. 504891.","Strand M, Sundberg P. 2005 b. Delimiting species in the hoplonemertean genus Tetrastemma (phylum Nemertea): morphology is not concordant with phylogeny as evidenced from mtDNA sequences. Biol J Linn Soc. 86 (2): 201 - 212. doi: 10.1111 / j. 1095 - 8312.2005.00535. x."]}

Preliminary results of the deep-sea faunal survey conducted from the TR/V Seisui-maru of Mie University in April 2018 are presented. 18 taxonomists and ecologists working on a wide variety of animal taxa participated in this survey. Surveyed areas included the Kumano Sea (off Mie Prefecture) and south of the Kii Strait (off Tanabe Bay, Wakayama Prefecture), at depths of 80-821 m. Sampling gears employed were beam trawl and biological dredge. The collection is represented by macrobenthos and meiobenthos from 11 animal phyla, including arthropods, echinoderms, annelids and molluscans. The number of phyla occurring in each station varied from 3 to 7. The station with most diverse fauna at the phylum level was St. 3B (south of the Kii Strait, 421-543 m depth, sandy mud bottom). Meiofauna includes priapulids and small arthropods, such as ostracods, tanaidaceans, isopods, cumaceans and acarus. In addition to free-living species, parasitic crustaceans, platyhelminthes, acanthocephalans, annelids and cnidarians were also collected from fishes, ascidians, urchins, holothurians, crustaceans and polychaetes. Preliminary identifications are given for Ostracoda, Cirripedia, Amphipoda, Decapoda, Asteroidea,Ophiuroidea, Holothuroidea, polychaetes, Echiura, Mollusca and Xenoturbellida., 紀伊水道南方海域および熊野灘の深海底生動物相を明らかにするために，2018年4月三重大学練習船勢水丸のNo.1803研究航海において，ドレッジ及びビームトロール調査を行った。この調査には幅広い動物門を対象とする，三重大学内外の系統分類学と生態学研究者18名が参加した。水深80m から821m の11か所で調査を行い，11の動物門が確認された。最も多様性が高い定点では1か所に100種以上の動物が確認された。節足動物，棘皮動物，環形動物，軟体動物のマクロベントスは大部分の調査定点から採集された。メイオベントスでは，節足動物の貝形虫類，タナイス類，等脚類，クーマ類，ダニ類，そして鰓曳動物が確認された。また自由生活性の生物の他に，甲殻類や多毛類，ナマコ類，ウニ類，ホヤ類，魚類に寄生する節足動物，扁形動物，鉤頭動物，環形動物，刺胞動物が認められた。甲殻類や多毛類，ユムシ類の未記載種や棘皮動物，珍渦虫類の日本初記録種及び海域初記録種が確認された。今後，試料を検討，種同定することにより，さらに確認種数は増加し，生物相が明らかにされるだろう。

The first record of the poorly known kelp crab species Menaethius orientalis (Sakai, 1969) from the Ryukyu Archipelago is provided based on a full-grown female specimen from Iriomote Island. Comparison with male characters described in previous studies suggested sexual dimorphism in the morphologies of anterolateral carapace part and chelipeds. Menaethius inornatus Dana, 1852, which had long been regarded as a junior subjective synonym of M. monoceros, is suggested to be treated as a valid species based on distinct morphological differences from the other two extant Menaethius species., 西表島より採集された1雌個体に基づき, ゴカクモガニMenaethius orientalis (Sakai, 1969) の琉球列島初記録を報告し, 既往研究において記載されていた雄の形態的特徴との比較から, 甲前側部や鉗脚長節の形態に性的二型があることを指摘した. また, イッカクガニM. monoceros (Latreille, 1825) の新参異名とされてきたM. inornatus Dana, 1852について, イッカクガニ属の既知2種との間に明瞭な形態的差異が認められることから, 正当な種と見なすことを提案した., 論文

分岐した吻をもつことで特徴的なハシゾメゴルゴンヒモムシ(新称)Gorgonorhynchus albocinctus Kajihara, 2015 (紐形動物門:異紐虫類)は竹富島から得られた1個体の断片標本から知られるのみであった.本論文ではタイプ産地から直線距離で約40km離れた外離島の水深10–30mで得られた完全個体を報告する.これにより本種は2つの同属他種と同様に尾毛状突起を有することが明らかになった., 論文

Both Iriomote-jima Island and Ishigaki-jima Island belong to the Ryukyu Islands and are located in the subtropical region of Japan. The echinorhynchid acanthocephalan Pseudoacanthocephalus bufonis (Shipley, 1903) was found to parasitize two species of frogs, Fejervarya sakishimensis Matsui, Toda & Ota, 2007 (Dicroglossidae) and Buergeria japonica (Hallowell, 1861) (Rhacophoridae), on Iriomote-jima Island, and one species of toad, Rhinella marina (Linnaeus, 1758) (Bufonidae), on Ishigaki-jima Island. No P. bufonis parasitized Rhacophorus owstoni (Stejneger, 1907) (Rhacophoridae) and Microhyla okinavensis Stejneger, 1901 (Microhylidae) on Iriomote-jima Island. Importance of frogs as the host of P. bufonis differs between host species on this island: F. sakishimensis was very frequently infected and is considered to be the most important host of P. bufonis, but since B. japonica was rarely infected and none of R. owstoni and M. okinavensis was parasitized, the role of these three frogs as the hosts of P. bufonis appears very low. This study also suggests that P. bufonis is native to Iriomote-jima Island.

本報告は, 日本に産するムツアシガニ類8種のうち6種とそれらが属する属の学名と和名を対応させるとともに, 分布や生息環境に関する追加情報をまとめた. 過去の文献には,昔から知られている種と最近記載された種を区別できていない場合が多いため, 直接標本を観察して同定したか, あるいは文献上の図より正確な再同定ができた場合のみ, その結果をシノニムリストに記した. 同様に, 日本産ムツアシガニ類の同定に信頼がおける過去の文献からのみ宿主の可能性がある種を限定してまとめた. 今回扱ったムツアシガニ類6種の内, ヤドリムツアシガニHexapinus simplex Rahayu & Ng,2014 はツバサゴカイ Chaetopterus cautusMarenzeller, 1879 の棲管に, ヒメムツアシガニMariaplax chenae Rahayu & Ng, 2014はトゲイカリナマコ Protankyra bidentata (Woodward &Barrett, 1858) の巣穴に, それぞれ生息することが確認された. ムツアシガニ Hexapinus latipes(De Haan, 1835), オオウラムツアシガニ (新称)Mariaplax ourabay Rahayu & Ng, 2014, 及びマエノソノムツアシガニ ( 新称) Rayapinusmaenosonoi Rahayu & Ng, 2014については, 他種と共生関係にあるかどうかが確認できなかった一方, イルンティムツアシガニ ( 新称)Mariaplax narusei Rahayu & Ng, 2014 は, 他種との共生ではなく単独で穴を掘って生活していることが示唆された., The present study matches up scientific and Japanese names of six out of the eight hexapodid species recorded from Japan and summarizes additional information on their distribution and habitat. It was often the case in previous studies that distributional records, host records, etc. of old and recently described species were not well separated. The present study limited the synonymy lists to those identities that were confirmed by examining actual specimens or by figures provided in the literature. Possible host species of the six hexapodids are also summarized from the literature by including records of reliably identified hexapodid species. Among the six hexapodid species treated in this paper, Hexapinus simplex Rahayu & Ng, 2014, inhabits the tube of Chaetopterus cautus Marenzeller, 1879 (Chaetopteridae), whereas Mariaplax chenae Rahayu & Ng, 2014, is from the tunnel of Protankyra bidentata (Woodward & Barrett, 1858) (Synaptidae). It is uncertain whether Hexapinus latipes (De Haan, 1835), Mariaplax ourabay Rahayu & Ng, 2014, and Rayapinus maenosonoi Rahayu & Ng, 2014, are commensal with other species, whereas Mariaplax narusei Rahayu & Ng, 2014, probably solely inhabits its own burrow. Standard Japanese names of each taxon are also reviewed., 論文

The heteronemertean Notospermus tricuspidatus (Quoy & Gaimard, 1833) [new Japanese name: mitsuyari-midori-himomushi] is known to be distributed in the tropical Indo–West- Pacific, but has not been formally reported from Japanese waters based on voucher material. We summarize records of the species based on recently collected specimens in the Nansei Islands. A specimen collected on Yakushima Island (ca. 30°N) represents the northern limit of the species’ distribution. For facilitating future studies, a synonym list for the species is compiled based on primary literature; nominal species of heteronemerteans with green body originally described from the temperate to tropical Indo–West- Pacific regions and their surrounding seas are listed and tentatively classified into 11 forms, 異紐虫類ミツヤリミドリヒモムシ (新称) Notospermus tricuspidatus (Quoy & Gaimard, 1833) はインド西太平洋熱帯域に分布する事が知られているが, 日本の海域からは証拠標本に基づいた正式な記録が無かった. 本論文では南西諸島 (本誌における「琉球列島」) から近年得られた標本に基づく本種の記録を報告する. 屋久島 (北緯約30度) で得られた標本は本種の分布の北限記録となる. 将来の研究に資するため一次文献に基づいて本種の異名表を作成した. またインド西太平洋の温・熱帯域およびその周辺海域において原記載された異紐虫類の名義種20種をリストし, それらを暫定的に11の型に分類した., 論文

Coral bleaching can be induced by many different stressors, however, the most common cause of mass bleaching in the field is higher than average sea surface temperatures (SST). Here, we describe an unusual bleaching event that followed very calm sea conditions combined with higher than average SST. Patterns of mortality differed from typical bleaching in four ways: 1) mortality was very rapid; 2) a different suite of species were most affected; 3) tissue mortality in Acropora spp. was often restricted to the center of the colony; 4) the event occurred early in summer. The two weeks prior to the event included 8 days where the average wind speed was less than 3 ms-1. In addition, SSTs in the weeks preceding and during the event were 1.0-1.5°C higher than the mean for the last 30 years. We hypothesize that this unusual bleaching event was caused by anoxia resulting from a lack of water movement induced by low wind speeds combined with high SST.

Note. This original form of this rebuttal was submitted to Science on 3 March 2017 (limited to 300 words as per Science editorial policy) but rejected on 13 March 2017. Herein, we elaborate on our original Science submission in order to more fully address the issue without the length limitations. This rebuttal is followed by the list of the signatories who supported our original submission.

Peltogaster unigibba n. sp. [Japanese name: Katakobu-nagahukuromushi] (Figs. 1–4) Material examined. Holotype: RUMF-ZC-3067 (transverse sections, six slides), Osawa Beach in Kita-kou Bay, Haha-jima, Tokyo, Japan; depth 10 m; coll. T. Sasaki et al., 26 February 2015 (host, RUMF-ZC-4039, SL 2.0 mm). Paratype: RUMF-ZC-3068 (whole externa 3.0 mm in length, 1.1 mm in width); Kominato Bay, Chichi-jima, Tokyo, Japan; coll. T. Naruse, 18 March 2014 (host, RUMF-ZC-4040, SL 1.8 mm). Description. External morphology: Externa irregularly elongated and ellipsoidal, approximately three times longer than maximum diameter (Figs. 1, 2). Externa appearing sinuous owing to vermicular movement when alive (Fig. 1), but appearing nearly straight after fixation in Bouin’s solution (Fig. 2). Embryos visible through mantle (Fig. 1). Left lobe incurved, prominently projecting 1.0 mm in front of mantle aperture. Mantle aperture slightly elevated as tube-like projection, opening at anterior end, slit-like in contracted specimens (Fig. 2). Shield elongated, with growth rings extending from stalk antero-posteriorly (Fig. 2). Anatomy of externa: Mantle aperture not attached to ovary (Fig. 3 a). Left lobe projecting 905 µm long, not containing ovary (Fig. 3 a). Right lobe slightly projecting 200 µm. Tube-like mantle aperture 290 µm long (Fig. 3 a). Tube-like aperture wall 150 µm thick. In serial section, ovary semicircular (Fig. 3 b). Mantle cuticle of lobes, dorsal side, and ventral sides 25 µm, 35 µm, and 10 µm thick, respectively. Mesentery nearly as broad as ovary. Inner surface of mantle without septa. Left and right colleteric glands 420 µm and 375 µm long, respectively. In serial section, anterior end of left colleteric gland reaching beyond level of anterior end of right colleteric gland (Fig. 4). Anterior and posterior parts of colleteric glands with unwrinkled walls, 6 µm thick (Fig. 3 b). Middle part of colleteric gland with few wrinkled walls, 20 µm thick (Fig. 3 c). Colleteric glands overlapped by stalk and receptacles (Fig. 3 d). Posterior end of left colleteric gland just reaching posterior end of stalk (Fig. 4). Posterior end of right colleteric gland reaching beyond posterior end of stalk (Fig. 4). Ganglion 70 µm long, 88 µm wide, 42 µm high (Fig. 3 c). Ganglion having appearance of squat triangle, appearing in same section containing middle portions of colleteric glands, but never overlapped by stalk and receptacles. Stalk 250 µm long and 220 µm wide, radiating from holdfast at point of insertion into body wall of host (Fig. 3 d). Stalk directly connected to ovary (Fig. 3 d). Anterior ends of two receptacles emerging posterior to that of stalk (Fig. 4). Two receptacles 170 µm long, present on stalk, walls comparatively thin up to 10 µm thick, internal layer of polygonal cells 33 µm in diameter, shaped like straight tubes, gradually passing into receptacle ducts (Figs. 3 d, 4).Left and right receptacle ducts 355 µm and 340 µm long, respectively. Receptacle ducts about twice as long as receptacles. Receptacle ducts beginning at level of stalk, spaced well apart from each other, c. 65 µm. Anterior part (c. 200 µm) of receptacle ducts 150 µm in diameter, with thick walls 30 to 88 µm thick, shaped like straight tubes (Fig. 3 e). Remaining posterior part of receptacle ducts 80 µm in diameter, with walls 30 µm thick, slightly coiled, directed posteriorly on lateral surface of ovary (Fig. 3 f). Retinacula absent. Coloration. Mature externa pink (Fig. 1). Interna light green. Position on host. On left side of pleon between second and third pleopods. Etymology. The specific name unigibba is derived from a combination of the Latin uni, meaning one, and gibba, meaning hump, alluding to the left lobe that projects in front of the mantle aperture. Distribution. Known from Haha-jima (type locality) and Chichi-jima, Bonin Islands, Japan. Remarks. Peltogaster unigibba n. sp. clearly belongs to the genus Peltogaster, as it possesses the following characteristics: parasitism on hermit crabs, mature externa with a cuticular shield around the stalk, the absence of septa on the inner surface of the mantle, and the absence of lateral semicircular expansions in cross-sections of the ovary. TABLE]. Character states of species of Peltogaster Rathke, 1842. Abbreviations: CG, colleteric glanđ; GA, ganglion; RE, receptacle; ST, stalk. Species Externa shape Arrangement of Anterior lobes Position of anterior top of Reference (Length: Wiđth) mantle aperture internal structures Peltogaster unigibba n. sp. Irregulatery elongateđ Anterior enđ Left lobe projecting CG> GA> ST> RE This stuđy ellipsoiđal (3:1) Peltogaster aelaniticus Boschma, 1969 Little curveđ (2:1) Anterior enđ Lobes not projecting CG> RE> ST Boschma (1969) GA unknown Peltogaster boschmai Reinharđ, 1944 Right curveđ (2.5:1) Anterior enđ Lobes not projecting CG> RE> GA> ST Reinharđ (1944) Peltogaster contorta Boschma, 1958 Little curveđ (2:1) Right siđe Left lobe projecting CG> RE> ST Boschma (1958) GA unknown Peltogaster curvata Kossmann, 1874 Right curveđ (2-3:1) Anterior enđ Both lobes projecting CG> RE> ST Høeg & Lützen (1985) GA unknown Peltogaster depressa Reinharđ, 1944 Little curveđ (2:1) Anterior enđ on đorsal Both lobes projecting GA> CG> RE> ST Reinharđ (1944) siđe Peltogaster lata Van Baal, 1937 Little or None curveđ (2:1) Anterior enđ Lobes not projecting CG> RE> ST Van Baal (1937) GA unknown Peltogaster lineata Shiino, 1943 Little curveđ (2.5:1) Anterior enđ Lobes not projecting CG> RE> ST Shiino (1943) GA unknown Peltogaster naushonensis Reinharđ, 1946 Little curveđ (2.5:1) Anterior enđ Lobes not projecting CG> GA> ST> RE Reinharđ (1946) Peltogaster reticulata Shiino, 1943 Strongly right curveđ Anterior enđ Both lobes projecting CG> RE> ST Shiino (1943) (4:1) GA unknown Peltogaster rugosa Boschma, 1931 Little curveđ (2:1) Anterior enđ Both lobes projecting CG> RE> ST Van Baal (1937) GA unknown Peltogaster senegalensis Guérin-Ganivet, 1911 Elongateđ (3:1) Anterior enđ Lobes not projecting ST>RE>CG Guérin-Ganivet (1911) GA unknown The external morphology of Peltogaster unigibba n. sp. is characterized by the anterior end of the left lobe being anterior to the mantle aperture and right lobe, and by the right and left lobes being asymmetric with respect to the mantle aperture (Fig. 2). Of the16 known species of Peltogaster now currently recognised,, P. unigibba n. sp. and P. contorta Boschma, 1958 share the feature of a left lobe that projects beyond the mantle aperture (Table 1; Boschma 1958: figs. 1, 2). However, P. uni gibba n. sp. can be easily distinguished from P. contorta as the mantle aperture of the former opens at the anterior end (Fig. 2), whereas that of the latter opens on the right side (Boschma 1958: figs. 1, 2). The anterior end of the internal structure in Peltogaster unigibba n. sp. is arranged from the front as follows: colleteric glands, ganglion, stalk, and receptacle, successively (Fig. 4). Although the arrangements of the internal structures of P. ovali s Krüger, 1912 and P. purpurea (Müller, 1862) have not yet been described, that of P. u ni g i b ba n. sp. is similar to that of P. naushonensis Reinhard, 1946 (Table 1). Peltogaster unigibba n. sp. also shares the following features with P. naushonensis: live coloration, a slit-like mantle aperture, receptacle ducts about twice the length of the receptacles, and a lack of retinacula. These two species, however, differ in their internal structure: the colleteric glands of P. u ni g i b ba n. sp. reach beyond the posterior end of the stalk (Fig. 4), whereas those of P. naushonensis reach the middle of the stalk (Reinhard 1946). Among fourteen Peltogaster species for which the internal structure has been studied, Peltogaster senegalensis Guérin-Ganivet, 1911, P. naushonesis, and P. unigibba n. sp. have anterior ends of the receptacle that are posterior to that of the stalk (Table 1; Fig. 4). In the other 11 species, the anterior end of the receptacle is anterior to that of the stalk. Peltogaster unigibba n. sp. and P. naushonesis differ from P. senegalensis in that the anterior ends of the colleteric glands are located beyond the posterior end of the stalk (Guérin-Ganivet 1911: Fig. 3). Peltogaster unigibba n. sp. can be differentiated from P. naushonensis by the above-mentioned characters. The paratype (RUMF-ZC-3068) and holotype (RUMF-ZC-3067) share the same live coloration, host species, and left lobes whose distal ends project beyond the ends of the right lobes. The mantle aperture of the paratype, however, was barely visible because it was retracted into the mantle. The retraction of the mantle aperture might have been caused by the area surrounding the mantle aperture expanding owing to the absorption of water between the cuticle and epidermis during the thawing process. Nauplius larvae of Peltogaster species are known to lack their nauplius eye in four out of 14 species (see Yoshida et al. 2011). Yoshida et al. (2011) mentioned the possibility that the absence of the nauplius eye may be a synapomorphy of Peltogaster species. Although the present study recognized embryos in the externa of the holotype of P. unigibba n. sp. (Fig. 1), we were unable to observe the condition of the eye as the embryos are still in the two-cell stage (Fig. 3 a). The hermit crab genus Pagurixus includes approximately 40 species that live in tropical and warm temperate waters of the Indo-Pacific region (Osawa et al. 2013). Because it is difficult to find Pagurixus species in their preferred habitats (e.g. under stones, in crevices of dead coral, and in underwater caves), their ecology is not yet well-characterized. Similarly, little is known about the ecology of species that parasitize Pagurixus. Indeed, P. unigibba n. sp. is only the second species of rhizocephalan parasite that has been reported for Pagurixus (McDermott et al. 2010; Yoshida et al. 2015). Further study of host hermit crabs, which are difficult to collect, may lead to the discovery of additional parasite species.

学位論文