Six Species of the Family Odiidae (Crustacea: Amphipoda) from Japan, with Descriptions of a New Genus and Four New Species

Bull. Natl. Mus. Nat. Sci., Ser. A, Suppl. 5, pp. 1–39, February 21, 2011

Hiroyuki Ariyama

Marine Fisheries Research Center, Research Institute of Environment, Agriculture and Fisheries, Osaka Prefectural Government, Tanagawa, Misaki, Osaka, 599–0311 Japan E-mail: [email protected]

Abstract Six species of the family Odiidae (Amphipoda), including four new species, are recorded from Japan: Postodius imperfectus Hirayama, 1983; P. igneus sp. nov.; P. ornatus sp. nov.; P. striatus sp. nov.; Gordonodius zelleri (Berge, Vader and Coleman, 1999) comb. nov.; and Antarc- todius japonicus sp. nov. Postodius imperfectus, the type species of the genus Postodius, is redescribed and the diagnosis of the genus is revised. It has been shown that Postodius zelleri is distinct from the four species here assigned to Postodius, and thus a new genus Gordonodius is pro- posed to accommodate P. zelleri. The four species of Postodius are morphologically similar for one another, but are differentiated by some minor morphological characters and the coloration in life. Antarctodius japonicus is the ﬁrst representative of the genus from Japanese waters. Key words : Crustacea, Amphipoda, Odiidae, new genus, new species, Japan.

The amphipod family Odiidae was established fectus, is redescribed on the basis of the holotype by Coleman and J. L. Barnard (1991a) with and newly obtained specimens, and mistakes in Odius Liljeborg, 1865 as its type genus. After- the original descriptions are clarified; three new wards Berge et al. (1999) carried out a cladistic species referred the genus, viz., P. igneus sp. analysis using 46 morphological characters and nov.; P. ornatus sp. nov.; P. striatus sp. nov., are united the Odiidae to the Ochlesidae Stebbing, described. It has been found that Postodius zel- 1910. However, Lowry and Myers (in Coleman leri is distinct from the four species referred to and Lowry, 2006) questioned the classification of Postodius, and thus a new monotypic genus Gor- Berge et al. (1999). In this study, Odiidae is re- donodius is established to accommodate P. garded as a distinct family. The family presently zelleri. Furthermore, a new species of the genus contains 11 species and one subspecies in four Antarctodius, A. japonicus, is also described. genera (J. L. Barnard and Karaman, 1991; Moore, 1992; Brandt and Vassilenko, 1995; Materials and Methods Berge et al., 1999; Coleman and Kauffeldt, 2001; Labay, 2010). In Japan, several species of the Samples were collected from the coasts from family have been recorded (Ishimaru, 1994), but Miyagi to Ehime Prefectures and the bottom of only two species, Postodius imperfectus Hiraya- Ariake Sound. Thirty-one individuals were dis- ma, 1983, and P. zelleri Berge, Vader and Cole- sected. Drawings were made with the aid of a man, 1999, are recognized with certainty. drawing tube mounted on a phase-contrast micro- During my survey of the amphipod fauna of scope. Body length was measured from the apex Japan, six species referable to the family, includ- of the rostrum along the dorsal margin excluding ing four undescribed species, were obtained. This dorsal projections to the posterior end of uro- material enabled me to reassess the status of Pos- somite 3. The examined specimens, including the todius. The type species of Postodius, P. imper- type series of the new species, are deposited in 2 Hiroyuki Ariyama the National Museum of Nature and Science, Remarks. Based on the cladistic analysis, Tokyo (NSMT), the Osaka Museum of Natural Berge et al. (1999) estimated that the Odiidae History (OMNH), the Coastal Branch of Natural was paraphyletic, and consequently the family History Museum and Institute, Chiba (CMNH), was synonymized with the Ochlesidae. However, and the Amakusa Marine Biological Laboratory, their analysis did not consider characters of taxo- Kyushu University (AMBL). nomic importance, including 1) the combination of the chelate gnathopod 1 and the subchelate gnathopod 2, and 2) the size and shape of the Systematics coxae of pereopods (J. L. Barnard and Karaman, Family Odiidae Coleman and J. L. Barnard, 1991 1991). The first character is unique for the taxa [Japanese name: Subeyokoebi-ka] assigned to the Odiidae. With regard to the sec- Odiidae Coleman and J. L. Barnard, 1991a: 262; Moore, ond character, the taxa assigned to the Odiidae 1992: 913. have coxae 1–4 being subequal or becoming Ochlesidae: Berge et al., 1999: 242 (in part). gradually longer posteriorly, but species of the Ochlesidae sensu stricto all have unequal coxae Emended diagnosis. Body compressed lateral- 1–4 (coxae 1 and 4 are shorter than coxae 2 and ly. Rostrum well developed. All pereonites dor- 3); coxa 4 has a large acute projection posteriorly sally flush, usually raised into thin keels. in the species of the Odiidae, whereas such a pro- Pleonites often with dorsal projections. Antennae jection is absent in the species of the Ochlesidae short, accessory flagellum present or absent. sensu stricto (Sars, 1895; Stebbing, 1910; K. H. Mouthparts conically developed. Upper lip nar- Barnard, 1940; Schellenberg, 1953; J. L. Barnard, row, tip asymmetrically incised. Mandible styli- 1970, 1972; Gurjanova, 1972; Watling and Hol- form, incisor minutely toothed, accessory blades man, 1981; Ledoyer, 1982, 1986; Hirayama, strong or absent, molar small and triturative; palp 1983; Thomas, 1983; Coleman and J. L. Barnard, 3-articulated, attached at almost same level as 1991b; Moore, 1992; Brandt and Vassilenko, molar, article 1 shorter than half length of article 1995; Berge et al., 1999; Coleman and Kauffeldt, 3. Lower lip without inner lobes, outer lobes thin. 2001; Lowry and Myers, 2003; Coleman and Maxilla 1 with inner plate small, bearing 1–3 Lowry, 2006; Ortiz et al., 2007; Souza-Filho and apical setae, outer plate conical, palp 1- or 2-ar- Serejo, 2008; Labay, 2010). Furthermore, Berge ticulated. Maxilla 2 with inner plate lacking fa- et al. (1999) made misinterpretation in some cial row of setae. Maxillipedal palp 3- or 4-artic- characters used in their analysis. For example, ulated, article 2 expanded distomedially or not. they considered that the distal projection on the Coxae 1–4 subequal in length or gradually carpus of gnathopod 2 does not exceed the mid- longer, coxae 1–3 weakly tapering, coxa 4 with length of the propodus in Postodius imperfectus, large acute posterior projection. Gnathopod 1 but I confirmed that it actually exceeds it. The weak, chelate, carpus and propodus elongate. number of the articles of the maxilla 1 palp in the Gnathopod 2 subchelate, merus and carpus pro- genus Antarctodius was given as one, but actual- duced posterodistally. Pereopods 5–7 with bases ly there are two articles. In conclusion, phyloge- expanded posteriorly. Urosomites free. Uropods netic analysis based on a revised data is strongly biramous, both rami of uropod 1 subequal in recommended to establish the status of the Odi- length, outer rami shorter than inner in uropods 2 idae and Ochlesidae, although this is beyond the and 3. Telson entire or incised. scope of this paper. In this study, I maintain the Genera included. Odius Liljeborg, 1865 (type Odiidae as a valid family for the time being. genus); Postodius Hirayama, 1983; Cryptodius Moore, 1992; Antarctodius Berge, Vader and Coleman, 1999; and Gordonodius gen. nov. Six species of Odiidae 3

process holding anterior coxa together with coxal Key to the genera of the family Odiidae plate. Gnathopod 1 propodus projected pos- in the world terodistally, projection with short robust seta; 1. Accessory flagellum present2 dactylus small, triangular, with several thick —Accessory flagellum absent3 setae. Gnathopod 2 propodus wide, palm trans- 2. Dorsal projections indistinct; maxillipedal verse, distal margin serrated, with 2–3 robust palp 4-articulated; telson minutely cleft setae on posterodistal corner. Gills present on Postodius Hirayama, 1983 pereopods 2–6. Dactyli of pereopods 3–7 each —Dorsal projections distinct; maxillipedal palp with nail. Uropods spinous, inner ramus of uro- 3-articulated; telson entire pod 3 relatively wide. Telson minutely cleft, lat- Gordonodius gen. nov. eral margin with pair of 2 penicillate setae. Fe- 3. Maxilla 1 palp powerful, 2-articulated male similar to male, but antenna 1 less setose, Antarctodius Berge, Vader and Coleman, 1999 oostegites present on pereopods 2–5. —Maxilla 1 palp reduced, 1-articulated 4 Species included. Postodius imperfectus Hi- 4. Maxillipedal palp article 2 produced distomedi- rayama, 1983 (type species); P. igneus sp. nov.; P. ally; telson entireCryptodius Moore, 1992 ornatus sp. nov.; and P. striatus sp. nov. —Maxillipedal palp article 2 not produced dis- Remarks. Hirayama (1983) established Pos- tomedially; telson cleft todius with P. imperfectus Hirayama, 1983 as its Odius Liljeborg, 1865 type species. Reexamination of the holotype has shown that the original diagnosis of the genus Genus Postodius Hirayama, 1983 contains some mistakes in accessory flagellum, upper lip, maxillipedal palp and telson as stated [Japanese name: Hime-subeyokoebi-zoku] below; therefore, I rediagnose Postodius herein. Postodius Hirayama, 1983: 97; J. L. Barnard and Kara- The three new species described in this study are man, 1991: 400; Coleman and J. L. Barnard, 1991a: assigned to Postodius, because all the characters 263; Moore, 1992: 913; Ishimaru, 1994: 65; Berge et al., 1999: 246 (in part). coincide with the diagnosis of the genus. Distribution. Japan. Emended diagnosis. Anterodorsal corner of pereonite 1 strongly produced. Dorsal projections Key to the species of the genus Postodius of pereonites 1–6 absent, on pleonites present, but indistinct. Posterolateral margin of pleonite 3 1. Anterior margin of basis of pereopod 3 with- with acute, upwardly directed projection at mid- out plumose setae in male and with 0–4 point. Eyes reniform. Antenna 1 peduncle with plumose setae in female article 2 shorter than article 1; accessory flagel- P. imperfectus Hirayama, 1983 lum present, 1-articulated; flagellum heavily se- —Anterior margin of basis of pereopod 3 with tose in male. Mandible long; incisor narrow; 1–12 plumose setae in male, with more than lacinia mobilis present on left side, slender; palp 11 plumose setae in female 2 at the same level as molar. Lower lip with outer 2. Basis of pereopod 7 relatively broad (Figs. lobes long, weakly notched inside. Maxilla 1 15G, 16I) P. striatus sp. nov. with inner plate bearing 2 apical setae, outer —Basis of pereopod 7 relatively narrow3 plate styliform, with several toothed robust setae 3. Posterior margin of basis of pereopod 7 ex- on tip; palp 1-articulated, short, with long apical panded at 0.65 of length (Figs. 7G, 8J) seta. Maxillipedal palp 4-articulated, article 4 P. igneus sp. nov. minute. Coxae 1–4 progressively becoming —Posterior margin of basis of pereopod 7 ex- wider, equally long; inner surfaces of coxae 2–4 panded at 0.75–0.8 of length (Figs. 13G, 14I) each with “holder structure”, its triangular P. ornatus sp. nov. 4 Hiroyuki Ariyama

Postodius imperfectus Hirayama, 1983 Island, Ehime Prefecture, 34°16N, 133°09E, 3 [Japanese name: Hime-subeyokoebi] m deep, among bush of brown alga Sargassum (Figs. 1–4, 21A) macrocarpum, snorkeling, 3 August 2002, coll. H. Ariyama; NSMT-Cr 21270, 1 female (3.7 Postodius imperfectus Hirayama, 1983: 97, figs. 5–8; Ishi- maru, 1994: 65; Matsuo et al., 2007: 22. mm), St. 78 (Matsuo et al., 2007), off Kita- arima,, Ariake Sound, 32°36N, 130°17E, 43 m Material examined. Holotype: AMBL-Amph deep, gravel bottom, Smith-McIntyre grab, 19 62, 1 male (2.0 mm), Ariake Sea, June 1976, coll. June 2002, coll. M. Azuma and M. Matsuo. T. Kikuchi and M. Tanaka. Description. Male (based on NSMT-Cr Other material: NSMT-Cr 21267, 1 female 21268). Body (Fig. 1) somewhat stout. Eyes (2.4 mm), Himagajima Island, Aichi Prefecture, large. Dorsal margin of pereonite 7 without pro- 34°42N, 137°00E, 5 m deep, among bush of jection, pleonites 1 and 2 slightly produced pos- brown alga Dictyopteris prolifera, snorkeling, 5 terodorsally, dorsal margin of pleonite 3 with August 2001, coll. H. Ariyama; OMNH-Ar 8376, blunt projection at mid-length, posterolateral 1 male (2.8 mm), Kii-nagashima, Mie Prefecture, margins of pleonites 1 and 2 slightly projected at 34°11N, 136°20E, among algae, snorkeling, 3 0.65 of length and at midlength, respectively. August 1986, coll. H. Ariyama; NSMT-Cr Antenna 1 (Fig. 2A, A1) stout; ratio of lengths 21268, 21269, 1 male (3.4 mm), 1 female (4.4 of peduncular articles 1–3 1 : 0.7 : 0.5; accessory mm), Myojinzaki coast in Misaki, Osaka Prefec- flagellum slender, tip with 1 plumose and 2 sim- ture, 34°19N, 135°06E, lower intertidal zone, ple setae; flagellum with 7 articles, article 1 elon- under stone, 14 May 2006, coll. H. Ariyama; gate. Antenna 2 (Fig. 2B) short, about 0.6 times OMNH-Ar 8377, 8378, 1 male (3.1 mm), 1 fe- as long as antenna 1, with ratio of lengths of pe- male (3.4 mm), Nagasaki coast in Misaki, Osaka duncular articles 3–5 1 : 1.6 : 1.6; flagellum with Prefecture, 34°20N, 135°09E, lower intertidal 6 articles. zone, under stone, 17 May 2003, coll. H. Ariya- Left mandible (Fig. 2D, D1) with incisor rela- ma; OMNH-Ar 8379, 1 female (1.8 mm), Iwagi tively wide, bearing denticles; lacinia mobilis

Fig. 1. Postodius imperfectus Hirayama, 1983, male (3.4 mm), NSMT-Cr 21268. Habitus, left lateral view. Scale: 0.5 mm. Six species of Odiidae 5

Fig. 2. Postodius imperfectus Hirayama, 1983, male (3.4 mm), NSMT-Cr 21268. A, left antenna 1, lateral view; A1, left accessory ﬂagellum, lateral view; B, left antenna 2, lateral view; C, upper lip, dorsolateral view; D, left mandible (palp removed), lateral view; D1, tip of left mandible, lateral view; E, right mandible, medial view; E1, tip of right mandible, medial view; F, lower lip, ventral view; G, left maxilla 1, ventral view; G1, tip of outer plate of left maxilla 1, ventral view; H, right maxilla 2, ventral view; I, left maxilliped, ventral view; I1, tip of palp article 3 of left maxilliped, ventral view; I2, tip of inner plate of left maxilliped, ventral view. Scales: 0.1 mm. 6 Hiroyuki Ariyama

Fig. 3. Postodius imperfectus Hirayama, 1983, male (3.4 mm), NSMT-Cr 21268. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, posterodistal corner of propodus of left gnathopod 2, lateral view; C–G, left pereopods 3–7 (gills of pereopods 5 and 6 lost), lateral views. Scales: 0.1 mm. Six species of Odiidae 7 denticulate; accessory blades 6 in number, wide anterodistally, with 2 anterior, 1 anterodistal, 5 to narrow; palp long, article 3 with numerous posterior and 1 posterodistal robust setae; carpus ﬁne setae on lateral surface and 2 thick setae on with 1 anterodistal, 1 posterior and 4 posterodis- tip. Right mandible (Fig. 2E, E1) with narrow ac- tal robust setae; propodus with 4 couples of ro- cessory blades. Maxilla 1 (Fig. 2G, G1) with bust setae posteriorly; dactylus with plumose outer plate bearing large spine and 6 serrated ro- seta. bust setae apically, distal half of dorsomedial sur- Pereopod 5 (Fig. 3E) subequal in length to face with many short setae. Maxilla 2 (Fig. 2H) pereopod 4; coxal plate lobate, anteroventral with inner plate bearing distal and medial setae, margin with 2 plumose setae on inner surface; outer plate with several distal setae. Maxilliped basis produced posterodistally, bearing 3 (Fig. 2I, I1, I2) with inner plate bearing 2 distal plumose and 2 short robust setae on anterior robust setae. margin, 2 robust setae on anterodistal corner, and Gnathopod 1 (Fig. 3A, A1) small; coxal plate 5 short setae on anterolateral surface; ischium narrow; basis relatively wide, anterior margin with 3 robust setae on anterior margin; merus without plumose setae; propodus with 1 robust, 1 projected posterodistally, projection reaching plumose and 4 short setae posterodistally; dacty- about 0.15 length of propodus, margin with 3 an- lus with 1 needle-shaped seta, 6 plumose setae terior, 1 anterodistal, 3 posterior, and 1 pos- and 1 short simple seta. Gnathopod 2 (Fig. 3B, terodistal robust setae, anteromedial surface with B1) larger than gnathopod 1; coxal plate with short robust seta; carpus with 1 anterior and 3 blunt posterior projection, inner surface with tiny anterodistal robust setae; propodus with 3 cou- triangular process; basis without plumose setae ples of robust setae anteriorly; dactylus with on anterior margin, bearing robust seta on pos- plumose seta. Pereopod 6 (Fig. 3F) almost 1.1 terodistal corner; ischium with robust seta on times as long as pereopod 5; coxal plate lobate, posterodistal corner; merus with 3 and 2 robust anteroventral margin with 6 plumose setae; basis setae on posterior margin and posterodistal cor- produced posterodistally, bearing 1 plumose and ner, respectively; carpus with 1 anterodistal and 8 2 robust setae on anterior margin, 2 robust setae posterodistal robust setae; propodus with 2 ro- on anterodistal corner, and 7 short robust setae bust setae on posterodistal corner; dactylus with on anterolateral surface; ischium with 3 robust nail. setae on anterior margin; merus projected pos- Pereopod 3 (Fig. 3C) larger than gnathopod 2; terodistally, projection reaching about 0.15 coxal plate with blunt posterior projection, inner length of propodus, margin with 3 anterior, 3 surface with medium triangular process; basis posterior and 1 posterodistal robust setae, antero- without plumose setae on anterior margin, bear- medial surface bearing 2 robust setae; carpus ing robust seta on posterodistal corner; ischium with 2 anterior and 3 anterodistal robust setae; with 3 robust setae on posterior margin; merus propodus with 4 couples of robust setae anterior- projected anterodistally, with 4 anterior, 1 an- ly; dactylus with plumose seta. Pereopod 7 (Fig. terodistal, 4 posterior and 1 posterodistal robust 3G) subequal in length to pereopod 6; coxal plate setae; carpus with 1 anterodistal, 1 posterior and small, unlobed, anterior margin with 2 plumose 5 posterodistal robust setae; propodus with 4 setae; basis wide, roundish, produced posterodis- couples of robust setae posteriorly; dactylus with tally, posterior margin expanded at 0.65 of plumose seta. Pereopod 4 (Fig. 3D) subequal in length, anterior margin with 3 robust setae, but length to pereopod 3; coxal plate wide, inner sur- without plumose setae, anterodistal corner with face with large triangular process; basis without robust seta, anterolateral surface with 3 short ro- plumose setae on anterior margin, bearing robust bust setae; ischium with 2 anterior and 1 antero- seta on posterodistal corner; ischium with 4 ro- medial robust setae; merus projected posterodis- bust setae on posterior margin; merus projected tally, projection reaching about 0.15 length of 8 Hiroyuki Ariyama

Fig. 4. Postodius imperfectus Hirayama, 1983. A–F, male (3.4 mm), NSMT-Cr 21268; G, G1, H, female (4.4 mm), NSMT-Cr 21269. A, right pleopod 1, anterior view; B, left pleopod 2, anterior view; C, left pleopod 3, posterolateral view; D, E, left uropods 1, 2, lateral views; F, left uropod 3 and telson, dorsal view; G, left antenna 1, medial view; G1, left accessory flagellum, medial view; H, left gnathopod 2, lateral view. Scales: 0.1 mm. propodus, margin with 2 anterior, 1 anterodistal, setae; propodus with 4 couples of robust setae 4 posterior and 1 posterodistal robust setae, an- anteriorly. teromedial surface bearing 2 short robust setae; Pleopods (Fig. 4A–C) relatively long, pleopod carpus with 2 anterior and 4 anterodistal robust 3 shortest; peduncles each with 2 coupling Six species of Odiidae 9 hooks, peduncle of pleopod 2 bearing 2 plumose been clarified that Hirayama’s (1983) original de- and 8 simple setae, peduncles of pleopods 1 and scription contains mistakes in some important 3 bare; outer rami longer than inner, outer and points as follows: (1) the accessory flagellum of inner rami with 11 and 7–8 articles, respectively. the antenna 1 is actually present, although Hi- Uropod 1 (Fig. 4D) long; peduncle bearing 6, 4 rayama (1983) stated that it was absent; (2) the and 1 robust setae on lateral margin, medial mar- “upper lip with entire tip” is another organ (prob- gin and distolateral corner, respectively; outer ably pharynx), while the tip of the true upper lip ramus with 5 lateral, 3 medial and 3 terminal ro- is invisible because the portion is obscured by bust setae, inner ramus with 2 lateral, 3 medial dust; (3) the maxillipedal palp is four-articulated, and 4 terminal robust setae. Uropod 2 (Fig. 4E) contrary to “three-articulated” in the original de- short, about 0.65 length of uropod 1; peduncle scription; and (4) the telson is actually minutely bearing 3 and 1 robust setae on lateral margin incised, rather than entire. The newly obtained and distomedial corner, respectively; outer ramus specimens from Aichi, Mie, Osaka and Ehime with 3 lateral and 3 terminal robust setae, inner prefectures closely agree with the holotype. In ramus with 2 lateral, 1 medial and 4 terminal ro- addition, the propodus of male gnathopod 2 (Fig. bust setae. Uropod 3 (Fig. 4F) somewhat shorter 3B) is narrower than that illustrated in the origi- than uropod 2; peduncle with distolateral robust nal description. The present examination of all seta; outer ramus about 0.6 length of inner specimens indicates that the length-width ratio ramus, with 2 lateral robust setae and terminal becomes larger with the body size. short seta, inner ramus with 3 lateral and 2 medi- Distribution. Known only from Japan. Aichi, al robust setae and terminal short seta. Telson Mie, Osaka and Ehime Prefectures (present (Fig. 4F) longish triangular, incised tip with 2 study). Ariake Sound (Hirayama, 1983; Matsuo short setae. et al., 2007; present study). From lower intertidal Female (NSMT-Cr 21269). Eyes smaller than zone to depth of 43 m. those of male. Antenna 1 (Fig. 4G, G1) more Habitat. Under stones, among algae and on slender than that of male; ratio of lengths of pe- gravel bottom. duncular articles 1–3 1 : 0.6 : 0.5; accessory flagellum tiny, tip with 1 plumose and 2 simple setae; flagellum with 7 articles. Gnathopod 2 Postodius igneus sp. nov. (Fig. 4H) subequal to that of male except for [New Japanese name: Homura-subeyokoebi] oostegite, but basis with 3 plumose setae on ante- (Figs. 5–8, 21B) rior margin; anterior margins of pereopods 3–7 also with 2–10 plumose setae. Peduncles of Material examined. Holotype: NSMT-Cr pleopods 1–3 with 29, 15 and 2 plumose setae, 21271, male (5.8 mm), Nazumado, Hachijo Is- respectively. land, Izu Islands, 33°09N, 139°43E, 10 m deep, Coloration in life (female, NSMT-Cr 21269; SCUBA, 16 June 2009, coll. K. Tanaka. Fig. 21A). Body and appendages whitish, light Paratypes: NSMT-Cr 21272–21274, 1 female orange internal organs seen through; eyes bright (9.7 mm), 1 male (5.4 mm), 1 female (7.4 mm), red, flagellar articles 1 of both antennae red; dor- same data as holotype; OMNH-Ar 8380, 8381, 1 sal margins of pereonites 1–7 and pleonites 1–3 male (4.9 mm), 1 female (9.6 mm), same data as each with dark red spot; coxae 1–4 each with 2 holotype; CMNH-ZC 02401, 1 female (9.1 mm, light orange blotches; coxa 5, bases of pereopods not dissected), same data as holotype. 5–7, pleonites 1–3 and urosomite 1 each with Description. Holotype male. Body (Fig. 5) light orange blotch. stout. Eyes medium. Pereonite 7, pleonites 1 and Remarks. During this study, I have reexamined 2 slightly produced posterodorsally, dorsal mar- the holotype of Postodius imperfectus. It has gin of pleonite 3 produced mid-posteriorly, pos- 10 Hiroyuki Ariyama

Fig. 5. Postodius igneus sp. nov., holotype, male (5.8mm), NSMT-Cr 21271. Habitus, left lateral view. Scale: 0.5 mm. terolateral margins of pleonites 1 and 2 slightly without plumose setae; propodus with 1 robust, 2 projected at 0.65 of length. plumose and 2 short setae posterodistally; dacty- Antenna 1 (Fig. 6A, A1) stout, short; ratio of lus with 1 needle-shaped and 6 plumose setae. lengths of peduncular articles 1–3 1 : 0.7 : 0.4; ac- Gnathopod 2 (Fig. 7B, B1) larger than gnathopod cessory flagellum tiny, tip with plumose seta; fla- 1; coxal plate with blunt posterior projection, gellum with 6 articles, article 1 relatively short, inner surface with tiny triangular process; basis anterior margin of article 1 shorter than posterior. without plumose setae on anterior margin, bear- Antenna 2 (Fig. 6B) subequal in length to anten- ing 2 robust setae on posterodistal corner; ischi- na 1, with ratio of lengths of peduncular articles um with robust seta on posterodistal corner; 3–5 1 : 1.5 : 1.2; flagellum with 5 articles. merus with 5, 2 and 3 robust setae on posterior Left mandible (Fig. 6D) with incisor relatively margin, posterodistal corner and distal margin, wide; accessory blades indistinct, anterior margin respectively; carpus with 2 anterodistal and 12 distal to palp expanded; palp long, article 3 with posterodistal robust setae; propodus with 2 ro- many fine setae on lateral surface and 3 setae on bust setae each on posterior margin and pos- tip. Right mandible (Fig. 6E) subequal to left ex- terodistal corner; dactylus with nail. cept for lacinia mobilis. Maxilla 1 (Fig. 6G, G1) Pereopod 3 (Fig. 7C) larger than gnathopod 2; with outer plate bearing large spine and 7 robust coxal plate with blunt posterior projection, inner setae apically, distal half of dorsomedial surface surface with medium triangular process; basis with many short setae. Maxilla 2 (Fig. 6H) with with 4 plumose setae on anterior margin, posteri- inner plate bearing distal setae, outer plate with or margin bearing 1 plumose and 3 robust setae, distal setae and lateral fine setae. Maxilliped posterodistal corner with 3 robust setae; ischium (Fig. 6I, I1) with inner plate bearing 3 distal ro- with 3 robust setae each on posterior margin and bust setae. posterodistal corner; merus projected anterodis- Gnathopod 1 (Fig. 7A, A1) small; coxal plate tally, with 4 anterior, 1 anterodistal, 7 posterior narrow; basis relatively wide, anterior margin and 2 posterodistal robust setae; carpus with 1 Six species of Odiidae 11

Fig. 6. Postodius igneus sp. nov. A–E, A1, G–I, G1, I1, holotype, male (5.8 mm), NSMT-Cr 21271; F, paratype, female (9.7 mm), NSMT-Cr 21272. A, left antenna 1, lateral view; A1, left accessory ﬂagellum, medial view; B, left antenna 2, lateral view; C, upper lip, dorsolateral view; D, left mandible, medial view; E, right mandible, medial view; F, lower lip, ventral view; G, left maxilla 1, ventral view; G1, tip of outer plate of left maxilla 1, dorsal view; H, left maxilla 2, ventral view; I, maxilliped, ventral view; I1, tip of left inner plate of maxilliped, ventral view. Scales: 0.1 mm. 12 Hiroyuki Ariyama

Fig. 7. Postodius igneus sp. nov., holotype, male (5.8mm), NSMT-Cr 21271. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, posterior part of merus–propodus of left gnathopod 2, lateral view; C–G, left pereopods 3–7, lateral views. Scales: 0.1 mm. Six species of Odiidae 13

Fig. 8. Postodius igneus sp. nov. A–G, holotype, male (5.8 mm), NSMT-Cr 21271; H–J, H1, paratype, female (9.7 mm), NSMT-Cr 21272. A, left pleopod 1, posterior view; B, left pleopod 2, medial view; C, left pleopod 3, posterior view; D, E, left uropods 1, 2, lateral views; F, left uropod 3, dorsal view; G, telson, dorsal view; H, left antenna 1, lateral view; H1, left accessory flagellum, lateral view; I, left gnathopod 2, lateral view; J, basis of left pereopod 7 (setae omitted), lateral view. Scales: 0.1 mm. 14 Hiroyuki Ariyama anterodistal, 4 posterior and 5 posterodistal ro- terodistal robust setae; propodus with 1 single bust setae; propodus with 5 couples of robust and 5 couples of robust setae anteriorly; dactylus setae posteriorly; dactylus with plumose seta. with plumose seta. Pereopod 7 (Fig. 7G) some- Pereopod 4 (Fig. 7D) subequal in length to pere- what shorter than pereopod 6; coxal plate small, opod 3; coxal plate wide, inner surface with large unlobed, anterior margin with 8 plumose setae; triangular process; basis with 5 and 2 plumose basis relatively wide, produced posterodistally, setae on anterior and posterior margins, respec- posterior margin expanded at about 0.65 of tively, bearing 3 robust setae on posterodistal length, anterior margin with 4 robust setae, an- corner; ischium with 4 and 1 robust setae on posterodistal corner bearing 3 robust setae, antero- terior margin and posterodistal corner, respec- lateral and anteromedial surfaces with 6 and 5 tively; merus projected anterodistally, with 3 an- short robust setae, respectively; ischium with 4 terior, 1 anterodistal, 8 posterior and 2 pos- robust setae on anterior margin; merus projected terodistal robust setae; carpus with 1 anterodistal, posterodistally, projection reaching about 0.45 4 posterior and 6 posterodistal robust setae; length of propodus, margin with 3 anterior, 5 propodus with 5 couples of robust setae posteri- posterior and 1 posterodistal robust setae, antero- orly; dactylus with plumose seta. medial surface with 5 robust setae; carpus with 2 Pereopod 5 (Fig. 7E) about 1.1 times as long anterior and 5 anterodistal robust setae; propodus as pereopod 4; coxal plate lobate, anteroventral with 4 couples of robust setae anteriorly; dacty- margin with 2 plumose setae on inner surface; lus with plumose seta. basis produced posterodistally, posterior margin Pleopods (Fig. 8A–C) relatively long, pleopod weakly expanded at mid-length, anterior margin 1 shortest; peduncle of pleopod 1 with 13 with 3 robust setae distally, anterodistal corner plumose setae and 5 coupling hooks (abnormal, bearing 3 robust setae, anterolateral surface with 2 in all paratypes), peduncle of pleopod 2 with 15 short robust setae, anteromedial surface with 10 plumose setae, 2 simple setae and 5 coupling 8 short robust setae and 2 long setae; ischium hooks (abnormal, 2 in all paratypes), peduncle of with 5 robust setae on anterior margin; merus pleopod 3 with 10 plumose setae and 2 cou- projected posterodistally, projection reaching pling hooks; outer rami longer than inner, outer about mid-length of propodus, margin with 7 an- and inner rami with 12–16 and 11–13 articles, re- terior, 2 posterior and 1 posterodistal robust spectively. Uropod 1 (Fig. 8D) long; peduncle setae, anteromedial surface bearing 4 robust bearing 13, 7 and 1 robust setae on lateral mar- setae; carpus with 3 anterior, 4 anterodistal and 1 gin, medial margin and distolateral corner, re- posterodistal robust setae; propodus with 5 cou- spectively; outer ramus with 11 lateral, 8 medial ples of robust setae anteriorly. Pereopod 6 (Fig. and 3 terminal robust setae, inner ramus with 5 7F) subequal in length to pereopod 5; coxal plate lateral, 7 medial and 3 terminal robust setae. lobate, anterior margin with 12 plumose setae; Uropod 2 (Fig. 8E) short, about 0.8 length of basis produced posterodistally, posterior margin uropod 1; peduncle bearing 10 and 1 robust setae weakly expanded at mid-length, anterior margin on lateral and medial margins, respectively; outer with 5 robust setae, anterodistal corner bearing 3 ramus with 6 lateral and 3 (1 lost) terminal ro- robust setae, anterolateral and anteromedial sur- bust setae, inner ramus with 4 lateral, 5 medial faces with 15 and 5 short robust setae, respec- and 3 terminal robust setae. Uropod 3 (Fig. 8F) tively; ischium with 5 robust setae on anterior somewhat shorter than uropod 2; peduncle with 3 margin; merus projected posterodistally, projec- distolateral robust setae; outer ramus about 0.6 tion reaching about mid-length of propodus, mar- length of inner ramus, with 4 lateral robust setae gin with 4 anterior, 5 posterior and 1 posterodis- and terminal short seta, inner ramus with 6 (1 tal robust setae, anteromedial surface bearing 6 lost) lateral and 5 (1 lost) medial robust setae and robust setae; carpus with 2 anterior and 4 an- 1 terminal short seta. Telson (Fig. 8G) longish Six species of Odiidae 15 triangular, incised tip with short seta. blue line, pleonites 1 and 2 each with black Paratype female (NSMT-Cr 21272). Eyes curved line; coxa 1 with blue waved mark, coxa 3 smaller than those of male holotype. Antenna 1 with 3 black blotches, coxa 4 with blue mark, (Fig. 8H, H1) more slender than that of male coxa 5 with black curved line; bases of pere- holotype; ratio of lengths of peduncular articles opods 5 and 6 each with blue mark. 1–3 1 : 0.6 : 0.3; accessory flagellum tiny, tip with Remarks. The four species here assigned to 1 plumose and 2 short setae; flagellum with 7 ar- Postodius are morphologically very similar for ticles, article 1 elongate. Gnathopod 2 (Fig. 8I) one another. Differences among these four subequal to that of male holotype except for species are summarized in Table 1. Postodius oostegite, but basis with 8 plumose setae on ante- igneus sp. nov. can be distinguished from the rior margin; anterior margins of gnathopod 1 and other three species in the elongated projections pereopods 3–7 also with plumose setae. Pereo- of the meri of pereopods 5–7 and the coloration pod 7 basis (Fig. 8J) subequal to that of male in life. holotype. Distribution. Hachijo Island, Izu Islands, 10 m Paratype male (NSMT-Cr 21273, 5.4 mm). An- deep (present study). tenna 1 subequal in shape to that of female Habitat. Rocky bottom. paratype (NSMT-Cr 21272), but flagellum more Etymology. From the Latin igneus (flame- setose. color), referring to the body coloration. Coloration in life (paratype female, NSMT-Cr 21274; Fig. 21B). Body and appendages bright orange, eyes red; pereonite 1 with U-shaped Postodius ornatus sp. nov. black–blue line, pereonites 2–4 each with L- [New Japanese name: Nishiki-subeyokoebi] shaped black–blue line, pereonite 5 with large (Figs. 9–12, 21C) blue quadrate mark connected with black line, pereonites 6 and 7 each with L-shaped black– Material examined. Holotype: NSMT-Cr

Table 1. Comparison among four species of Postodius.

P. imperfectus Characters/species P. igneus sp. nov. P. ornatus sp. nov. P. striatus sp. nov. Hirayama, 1983

Maximum body 3.4 mm in male, 5.8 mm in male, 4.0 mm in male, 4.8 mm in male, length 4.4 mm in female 9.7 mm in female 10.4 mm in female 10.0 mm in female Eyes in male large medium large medium Expansion on anterior absent present present present margin of mandible Plumose setae on absent in male, 0–4 3–4 setae in male, 5 setae in male, 1–12 setae in male, anterior margin of setae in female 11–17 setae in 15 setae in female 20 setae in female basis of pereopod 3 female Posterodistal short, reaching about long, reaching about medium, reaching medium, reaching projections of meri 0.15 length of 0.45–0.50 length of about 0.25–0.35 about 0.25–0.35 of pereopods 5–7 propodus propodus length of propodus length of propodus Basis of pereopod 7 relatively broad, relatively narrow, relatively narrow, relatively broad, posterior margin posterior margin posterior margin posterior margin expanded at 0.65 expanded at 0.65 expanded at expanded at of length of length 0.75–0.80 of length 0.65–0.70 of length Uropods weakly spinous strongly spinous strongly spinous strongly spinous Coloration in life whitish with light bright orange with orange with dark blue reddish orange with orange blotches black–blue lines and lines and red spots light blue lines and dark red spots blue quadrate marks 16 Hiroyuki Ariyama

Fig. 9. Postodius ornatus sp. nov., holotype, male (4.0mm), NSMT-Cr 21275. Habitus, left lateral view. Scale: 0.5 mm.

21275, male (4.0 mm), Nishi-izu, Shizuoka Pre- anterior margin distal to palp expanded; palp fecture, 35°02N, 138°47E, 18–22 m deep, on long, article 3 with many fine setae on lateral sur- rock or artificial structure, SCUBA, 8 April face and 2 thick setae on tip. Right mandible 2010. (Fig. 10E) subequal to left except for lacinia mo- Paratypes: NSMT-Cr 21276, ovigerous female bilis. Maxilla 1 (Fig. 10G, G1, G2) with outer (6.9 mm), same data as holotype; OMNH-Ar plate bearing large spine and 5 serrated robust 8382, 1 ovigerous female (10.4 mm), same data setae apically, distal half of dorsomedial surface as holotype; CMNH-ZC 02402, 2 females (8.7, with several short setae, serrated robust seta and 4.2 mm, not dissected), same data as holotype. many short setae. Maxilla 2 (Fig. 10H) with Description. Holotype male. Body (Fig. 9) inner plate bearing distal setae and medial fine stout. Eyes large. Pereonite 7, pleonites 1 and 2 setae, outer plate with distal setae and lateral fine slightly produced posterodorsally, dorsal margin setae. Maxilliped (Fig. 10I, I1) with inner plate of pleonite 3 with blunt projection at mid-length, bearing 3 distal robust setae, base with 5 posterolateral margin of pleonite 1 slightly pro- plumose setae. jected at 0.75 of length. Gnathopod 1 (Fig. 11A, A1) small; coxal plate Antenna 1 (Fig. 10A, A1) stout, short; ratio of narrow; basis relatively wide, anterior margin lengths of peduncular articles 1–3 1 : 0.6 : 0.3; ac- without plumose setae; propodus with 1 robust, 2 cessory flagellum tiny, tip with 1 plumose and 1 plumose and 3 short setae posterodistally; dacty- simple setae; flagellum with 6 articles, article 1 lus with 1 needle-shaped and 6 plumose setae. long. Antenna 2 (Fig. 10B) 0.75 length of anten- Gnathopod 2 (Fig. 11B, B1) larger than gnatho- na 1, with ratio of lengths of peduncular articles pod 1; coxal plate with blunt posterior projection, 3–5 1 : 2 : 1.8; flagellum with 5 articles. inner surface with tiny triangular process; basis Left mandible (Fig. 10D) with incisor relative- without plumose setae on anterior margin, bear- ly wide, denticulate; accessory blades indistinct, ing robust seta on posterodistal corner; ischium Six species of Odiidae 17

Fig. 10. Postodius ornatus sp. nov., holotype, male (4.0mm), NSMT-Cr 21275. A, left antenna 1, lateral view; A1, left accessory ﬂagellum, lateral view; B, left antenna 2, medial view; C, upper lip, ventral view; D, left mandible, medial view; E, right mandible, medial view; F, lower lip, ventral view; G, left maxilla 1, ventral view; G1, inner plate of left maxilla 1, dorsal view; G2, tip of outer plate of left maxilla 1, ventral view; H, left maxilla 2, dorsal view; I, maxilliped, ventral view; I1, tip of right inner plate of maxilliped, ventral view. Scales: 0.1 mm. 18 Hiroyuki Ariyama

Fig. 11. Postodius ornatus sp. nov., holotype, male (4.0mm), NSMT-Cr 21275. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, posterior part of merus–dactylus of left gnathopod 2, lateral view; C–G, left pereopods 3–7, lateral views. Scales: 0.1 mm. Six species of Odiidae 19

Fig. 12. Postodius ornatus sp. nov. A–G, holotype, male (4.0 mm), NSMT-Cr 21275; H–J, H1, paratype, female (6.9 mm), NSMT-Cr 21276. A, left pleopod 1, posterior view; B, left pleopod 2, anterior view; C, left pleopod 3, posterior view; D–F, left uropods 1–3, dorsal views; G, telson, dorsal view; H, left antenna 1, medial view; H1, left accessory flagellum, medial view; I, left gnathopod 2, lateral view; J, basis of left pereopod 7 (setae omitted), lateral view. Scales: 0.1 mm with robust seta on posterodistal corner; merus robust setae each on posterior margin and pos- with 2 robust setae each on posterior margin and terodistal corner; dactylus with accessory spine. posterodistal corner; carpus with 1 anterodistal Pereopod 3 (Fig. 11C) large; coxal plate with and 7 posterodistal robust setae; propodus with 2 blunt posterior projection, inner surface with 20 Hiroyuki Ariyama medium triangular process; basis with 5 plumose posterior and 1 posterodistal robust setae, antero- setae on anterior margin, bearing 3 robust setae medial surface bearing 5 robust setae; carpus on posterodistal corner; ischium with 2 and 1 ro- with 2 anterior and 3 anterodistal robust setae; bust setae on posterior margin and posterodistal propodus with 3 couples of robust setae anterior- corner, respectively; merus projected anterodis- ly; dactylus with plumose seta. Pereopod 7 (Fig. tally, with 2 anterior, 1 anterodistal and 2 pos- 11G) subequal in length to pereopod 6; coxal terodistal robust setae. Pereopod 4 (Fig. 11D) plate small, unlobed, anterior margin with 4 probably subequal in length to pereopod 3; coxal plumose setae; basis produced posterodistally, plate wide, inner surface with large triangular posterior margin expanded at 0.8 length, anterior process; basis with 6 plumose setae on anterior margin with 3 robust setae, anterodistal corner margin, bearing 2 robust setae on posterodistal bearing 2 robust setae, anterolateral and antero- corner; ischium with robust seta each on posteri- medial surfaces with 4 and 3 short robust setae, or margin and posterodistal corner; merus pro- respectively; ischium with 2 and 3 robust setae jected anterodistally, with 3 anterior, 1 anterodis- on anterior margin and anteromedial surface, re- tal, 5 posterior and 2 posterodistal robust setae; spectively; merus projected posterodistally, pro- carpus with 1 anterodistal, 2 posterior and 4 pos- jection reaching about 0.25 length of propodus, terodistal robust setae; propodus with 4 couples margin with 2 anterior, 5 posterior and 1 pos- of robust setae posteriorly; dactylus with terodistal robust setae, anteromedial surface with plumose seta. 5 robust setae; carpus with 1 anterior and 4 an- Pereopod 5 (Fig. 11E) about 1.1 times as long terodistal robust setae; propodus with 4 couples as pereopod 4; coxal plate lobate, anteroventral of robust setae anteriorly; dactylus with plumose margin without setae; basis produced posterodis- seta. tally, posterior margin weakly expanded at mid- Pleopods (Fig. 12A–C) relatively long, pleo- length, anterior margin with 2 plumose setae dis- pod 3 shortest; peduncles each with 2 coupling tally, anterodistal corner bearing robust seta, an- hooks, peduncle of pleopod 2 bearing 5 simple terolateral and anteromedial surfaces with 3 and setae, peduncles of pleopods 1 and 3 bare; outer 2 short robust setae, respectively; ischium with 3 rami longer than inner, outer and inner rami with robust setae on anterior margin; merus projected 11–12 and 8–9 articles, respectively, outer ramus posterodistally, projection reaching about 0.25 articles 1 of pleopods 1–3 bearing many fine length of propodus, margin with 4 anterior, 4 setae laterally. Uropod 1 (Fig. 12D) long; pedun- posterior and 1 posterodistal robust setae, antero- cle bearing 10, 1, 1 and 1 robust setae on lateral medial surface bearing 4 robust setae; carpus margin, medial margin, distolateral corner and with 2 anterior and 3 anterodistal robust setae; distomedial corner, respectively; outer ramus propodus with 4 couples of robust setae anterior- with 7 lateral, 4 medial and 3 terminal robust ly; dactylus with plumose seta. Pereopod 6 (Fig. setae, inner ramus with 3 lateral, 5 medial and 3 11F) subequal in length to pereopod 5; coxal terminal robust setae. Uropod 2 (Fig. 12E) short, plate lobate, anterior margin with 4 plumose about 0.65 length of uropod 1; peduncle bearing setae; basis produced posterodistally, posterior 6, 1 and 1 robust setae on lateral margin, distolat- margin weakly expanded at mid-length, anterior eral corner and distomedial corner, respectively; margin with 1 plumose and 4 robust setae, an- outer ramus with 4 lateral and 3 terminal robust terodistal corner bearing 2 robust setae, antero- setae, inner ramus with 2 lateral, 2 medial and 3 lateral and anteromedial surfaces with 5 and 2 terminal robust setae. Uropod 3 (Fig. 12F) some- short robust setae, respectively; ischium with 3 what shorter than uropod 2; peduncle with disto- robust setae on anterior margin; merus projected lateral robust seta; outer ramus about 0.6 length posterodistally, projection reaching about 0.3 of inner ramus, with 3 lateral robust setae and length of propodus, margin with 4 anterior, 4 terminal short seta, inner ramus with 3 lateral Six species of Odiidae 21 and 3 medial robust setae and 1 terminal short with curved dark blue line and red spot. See Fig. seta. Telson (Fig. 12G) longish triangular, incised 21C. tip with short seta. Remarks. This new species can be distin- Paratype female (NSMT-Cr 21276). Eyes guished from the other Postodius species in the smaller than those of male holotype. Antenna 1 more distally located expansion on the basis of (Fig. 12H, H1) more slender than that of male pereopod 7 and the coloration in life (Table 1). holotype; ratio of lengths of peduncular articles Distribution. Shizuoka Prefecture: Nishi-izu, 1–3 1 : 0.6 : 0.4; flagellum with 6 articles. 18–22 m deep (present study). Gnathopod 2 (Fig. 12I) subequal to that of male Habitat. On rock or artificial structure. holotype except for oostegite, but basis with 8 Etymology. From the Latin ornatus plumose setae on anterior margin; anterior mar- (adorned), referring to the body coloration. gins of gnathopod 1 and pereopods 3–7 also with plumose setae. Basis of pereopod 7 (Fig. 12J) Postodius striatus sp. nov. subequal to that of male holotype, with expansion of posterior margin situated at 0.75 of [New Japanese name: Aosuji-subeyokoebi] length. (Figs. 13–16, 21D) Coloration in life. Body and appendages orange, eyes red; pereonite 1 with U-shaped dark Material examined. Holotype: NSMT-Cr blue line, pereonites 2–7, pleonites 1 and 2 each 21277, male (4.8 mm), off Aoshima Island, with bent dark blue line, dorsal margins of pere- Shizugawa, Miyagi Prefecture, 38°39N, onites 1–7 and pleonites 1–3 each with red band, 141°29E, 6 m deep, on bryozoans, SCUBA, 16 ventral parts of cephalic lobe, pereonites 1–7 and July 2009, coll. N. Sato. pleonites 1–3 each with red spot; coxae 1–4 each Paratypes: NSMT-Cr 21278, female (10.0 with curved dark blue line and red spot, coxa 5 mm), same data as holotype; OMNH-Ar with curved dark blue line, coxae 6 and 7 each 8383–8385, 1 male (4.0 mm), 2 females (8.5, 8.1 with red spot, bases of pereopods 5 and 6 each mm), same data as holotype; CMNH-ZC 02403,

Fig. 13. Postodius striatus sp. nov., holotype, male (4.8mm), NSMT-Cr 21277. Habitus, left lateral view. Scale: 0.5 mm. 22 Hiroyuki Ariyama

Fig. 14. Postodius striatus sp. nov., holotype, male (4.8mm), NSMT-Cr 21277. A, left antenna 1, lateral view; A1, left accessory ﬂagellum, medial view; B, left antenna 2, lateral view; C, upper lip, dorsolateral view; D, left mandible, medial view; E, right mandible, medial view; F, lower lip, ventral view; G, left maxilla 1, dorsal view; G1, tip of outer plate of left maxilla 1, dorsal view; H, left maxilla 2, dorsal view; I, maxilliped, ventral view; I1, tip of right inner plate of maxilliped, ventral view. Scales: 0.1 mm. Six species of Odiidae 23

Fig. 15. Postodius striatus sp. nov., holotype, male (4.8mm), NSMT-Cr 21277. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, posterior part of merus–dactylus of left gnathopod 2, lateral view; C–F, left pereopods 3–6, lateral views; F1, gill of left pereopod 6, lateral view; G, right pereopod 7, lateral view. Scales: 0.1 mm. 24 Hiroyuki Ariyama

3 females (8.5, 8.4, 8.2 mm, not dissected), same Pereopod 3 (Fig. 15C) larger than gnathopod data as holotype. 2; coxal plate with blunt posterior projection, Description. Holotype male. Body (Fig. 13) inner surface with medium triangular process; stout. Eyes medium. Pleonites 1 and 2 slightly basis with 12 plumose setae on anterior margin, produced posterodorsally, dorsal margin of bearing 2 robust setae on posterodistal corner; is- pleonite 3 produced mid-posteriorly, posterolat- chium with 2 robust setae each on posterior mar- eral margin of pleonites 1 and 2 slightly project- gin and posterodistal corner; merus projected an- ed at 0.65 of length. terodistally, with 4 anterior, 1 anterodistal and 7 Antenna 1 (Fig. 14A, A1) stout, short; ratio of posterior robust setae. Pereopod 4 (Fig. 15D) lengths of peduncular articles 1–3 1 : 0.6 : 0.3; ac- subequal in length to pereopod 3; coxal plate cessory flagellum slender, tip with 1 plumose and wide, inner surface with large triangular process; 2 simple setae; flagellum with 6 articles, article 1 basis with 13 plumose setae on anterior margin, long. Antenna 2 (Fig. 14B) about 0.8 length of bearing 3 robust setae on posterodistal corner; is- antenna 1, with ratio of lengths of peduncular ar- chium with 2 robust setae each on posterior mar- ticles 3–5 1 : 2.4 : 2; flagellum with 5 articles. gin and posterodistal corner; merus projected an- Left mandible (Fig. 14D) with incisor relative- terodistally, with 4 anterior, 1 anterodistal and 8 ly wide, denticulate; accessory blades indistinct, posterior robust setae; carpus with 2 posterior anterior margin distal to palp expanded; palp and 6 posterodistal robust setae; propodus with 4 long, article 3 with many fine setae on lateral sur- couples of robust setae posteriorly; dactylus with face and 3 setae on tip. Right mandible (Fig. plumose seta. 14E) subequal to left except for lacinia mobilis. Pereopod 5 (Fig. 15E) about 1.1 times as long Maxilla 1 (Fig. 14G, G1) with outer plate bearing as pereopod 4; coxal plate lobate, anteroventral large spine and 6 serrated robust setae apically, margin without setae; basis produced posterodis- distal half of dorsomedial surface with many tally, posterior margin weakly expanded at mid- short setae; palp setose. Maxilla 2 (Fig. 14H) length, anterior margin with 6 plumose and 2 dis- with inner plate bearing distal setae, medial fine tal robust setae, anterolateral surface bearing 5 setae and lateral short setae, outer plate with dis- short robust setae; ischium with 4 robust setae on tal setae and lateral fine setae. Maxilliped (Fig. anterior margin; merus projected posterodistally, 14I, I1) with inner plate bearing 3 distal robust projection reaching about 0.3 length of propodus, setae, base with 7 (1 lost) plumose setae. margin with 6 anterior, 3 posterior and 1 pos- Gnathopod 1 (Fig. 15A, A1) small; coxal plate terodistal robust setae, anteromedial surface narrow; basis relatively wide, anterior margin bearing 4 robust setae; carpus with 2 anterior and with 2 plumose setae; propodus with 1 robust 5 anterodistal robust setae; propodus with 4 cou- and 3 short setae posterodistally; dactylus with 2 ples of robust setae anteriorly; dactylus with needle-shaped, 5 plumose and 1 pectinate setae. plumose seta. Pereopod 6 (Fig. 15F) subequal in Gnathopod 2 (Fig. 15B, B1) larger than gnatho- length to pereopod 5; coxal plate lobate, anterior pod 1; coxal plate with blunt posterior projection, margin with 7 plumose setae; basis produced inner surface with tiny triangular process; basis posterodistally, anterior margin with 2 plumose without plumose setae on anterior margin, bear- and 3 robust setae, anterodistal corner bearing 3 ing robust seta on posterodistal corner; ischium robust setae, anterolateral surface with 6 short with robust seta on posterodistal corner; merus robust setae; ischium with 4 robust setae on ante- with 3 robust setae each on posterior margin and rior margin; merus projected posterodistally, pro- posterodistal corner; carpus with 1 anterodistal jection reaching about 0.25 length of propodus, and 8 posterodistal robust setae; propodus with 2 margin with 4 anterior, 4 posterior and 1 pos- robust setae on posterodistal corner; dactylus terodistal robust setae, anteromedial surface with accessory spine. bearing 4 robust setae; carpus with 2 anterior and Six species of Odiidae 25

6 anterodistal robust setae; propodus with 4 cou- times as long as pereopod 6; coxal plate small, ples of robust setae anteriorly; dactylus with unlobed, anterior margin with 8 plumose setae; plumose seta. Pereopod 7 (Fig. 15G) about 0.9 basis broad, roundish, produced posterodistally,

Fig. 16. Postodius striatus sp. nov. A–F, holotype, male (4.8 mm), NSMT-Cr 21277; G–I, G1, paratype, female (10.0 mm), NSMT-Cr 21278. A–C, left pleopods 1–3, posterior views; D, left uropod 1, dorsal view; E, left uropod 2, lateral view; F, left uropod 3 and telson, lateral view; G, left antenna 1, medial view; G1, left accessory flagellum, lateral view; H, left gnathopod 2, lateral view; I, basis of left pereopod 7 (setae omitted), lateral view. Scales: 0.1 mm. 26 Hiroyuki Ariyama posterior margin expanded at 0.65 of length, an- with 1 plumose and 2 simple setae; flagellum terior margin with 3 robust setae, anterodistal with 7 articles. Gnathopod 2 (Fig. 16H) subequal corner bearing 2 robust setae, anterolateral and to that of male holotype except for oostegite, but anteromedial surfaces with 7 and 1 short robust basis with many (ca. 18) plumose setae on anteri- setae, respectively; ischium with 3 robust setae or margin; anterior margins of gnathopod 1 and each on anterior margin and anteromedial sur- pereopods 3–7 also with plumose setae. Basis of face; merus projected posterodistally, projection pereopod 7 (Fig. 16I) subequal to that of male reaching about 0.25 length of propodus, margin holotype, with expansion of posterior margin sit- with 4 anterior, 4 posterior and 1 posterodistal uated at 0.7 of length. robust setae, anteromedial surface bearing 5 ro- Coloration in life. Body and appendages red- bust setae; carpus with 1 anterior and 6 an- dish orange, eyes red, tips of antennae white, terodistal robust setae; propodus with 4 couples propodi and dactyli of pereopods 3–7 light or- of robust setae anteriorly; dactylus with plumose ange; pereonite 1 with U-shaped light blue line, seta. pereonites 2–7 each with bent light blue line, Pleopods (Fig. 16A–C) relatively long, pleo- pleonites 1–3 each with straight light blue line, pod 3 shortest; peduncles each with 2 coupling anterodorsal corners of pereonites 2–7 and hooks, peduncle of pleopod 1 with 4 plumose pleonites 1–3 each with small white mark; coxae setae, peduncle of pleopod 2 with 5 plumose and 1–5 each with curved light blue line. See Fig. 6 simple setae, peduncle of pleopod 3 with 8 21D. plumose setae; outer rami longer than inner, Remarks. This new species is distinguishable outer and inner rami with 12–13 and 10–11 arti- from the other Postodius species by the combina- cles, respectively, outer ramus articles 1 of tion of the short projections on the meri of pere- pleopods 1–3 bearing many fine setae laterally. opods 5–7 and the more proximally located ex- Uropod 1 (Fig. 16D) long; peduncle bearing 12, pansion on the basis of pereopod 7, and the body 1 and 1 robust setae on lateral margin, distolater- coloration in life (Table 1). al corner and distomedial corner, respectively; Distribution and habitat. So far known only outer ramus with 9 lateral, 5 medial and 5 termi- from the type locality, Shizugawa, Miyagi Pre- nal robust setae, inner ramus with 4 lateral, 6 me- fecture, 6–8 m deep. Found on bryozoans or on dial and 3 terminal robust setae. Uropod 2 (Fig. rock. 16E) short, about 0.7 length of uropod 1; pedun- Etymology. From the Latin striatus (= striat- cle bearing 8 and 1 robust setae on lateral margin ed), referring to the body coloration. and distolateral corner, respectively; outer ramus with 5 lateral and 3 terminal robust setae, inner Gordonodius gen. nov. ramus with 3 lateral, 2 medial and 3 terminal ro- [New Japanese name: Gôdon-subeyokoebi-zoku] bust setae. Uropod 3 (Fig. 16F) shorter than uropod 2; peduncle with distolateral robust seta; Diagnosis. Anterodorsal corner of pereonite 1 outer ramus about 0.55 length of inner ramus, strongly produced. Dorsal projections of pere- with 3 lateral robust setae and terminal short onites present, those of pleonites distinct. Pos- seta, inner ramus with 4 lateral and 3 medial ro- terolateral margin of pleonite 3 without projec- bust setae and 1 terminal short seta. Telson (Fig. tion. Eyes reniform. Antenna 1 peduncle with ar- 16F) triangular, incised tip with 2 minute setae. ticle 2 shorter than article 1; accessory flagellum Paratype female (NSMT-Cr 21278). Eyes present, 1-articulated; flagellum heavily setose in smaller than those of male holotype. Antenna 1 male. Mandible long; incisor relatively wide; (Fig. 16G, G1) more slender than that of male lacinia mobilis present on left side, broad; palp holotype; ratio of lengths of peduncular articles somewhat proximal to molar. Lower lip with 1–3 1 : 0.6 : 0.3; accessory flagellum short, tip outer lobes long, weakly notched inside. Maxilla Six species of Odiidae 27

1 with inner plate bearing 2 apical setae, outer ulated; and the telson is minutely cleft. These plate styliform, with several toothed robust setae characters are generically diagnostic, and conse- on tip; palp 1-articulated, short, with long apical quently I propose to establish a new genus, Gor- seta. Maxillipedal palp 3-articulated. Coxae 1–4 donodius, to accommodate P. zelleri. progressively becoming wider, equally long; Distribution. Japan. coxae 2–4 each with holder structure on inner Etymology. Derivative of Odius, alluding to surface. Gnathopod 1 propodus projected pos- the collector (Richard Gordon Smith) of the type terodistally, projection with short robust seta; species (Berge et al., 1999). dactylus small, triangular, with several long thick setae. Gnathopod 2 propodus wide, palm trans- Gordonodius zelleri (Berge, Vader and verse, distal margin serrated, with 2 robust setae Coleman, 1999) comb. nov. on posterodistal corner. Gills present on pere- [New Japanese name: Gôdon-subeyokoebi] opods 2–6. Dactyli of pereopods 3–7 each with (Figs. 17–20, 21E) nail. Uropods spinous, inner ramus of uropod 3 relatively wide. Telson entire, lateral margin with Postodius zelleri Berge, Vader and Coleman, 1999: 246, ﬁgs. 3–7. pair of 2 penicillate setae. Female similar to male, but antenna 1 less setose, oostegites pre- Material examined. NSMT-Cr 21279–21283, 2 sent on pereopods 2–5. male (2.7, 3.2 mm), 3 female (5.1, 4.6, 3.2 mm), Type species. Postodius zelleri Berge, Vader Kodomari, Takahama, Fukui Prefecture, and Coleman, 1999. 35°32N, 135°31E, 10 m deep, among bush of Remarks. Berge et al. (1999) described Pos- brown alga Sargassum macrocarpum, SCUBA, todius zelleri as the second species of Postodius. 25 April 1980, coll. H. Ariyama and H. Naka- However, I have conﬁrmed that this species is hara; OMNH-Ar 8386, 1 male (2.1 mm), Hima- distinct from the four species here assigned to gajima Island, Aichi Prefecture (34°42N, Postodius in the following characters: prominent 137°00E), 2 m deep, among colony of red alga dorsal projections are present on the pereonites Gelidium elegans, snorkeling, 5 August 2001, and pleonites; the maxillipedal palp is three-ar- coll. H. Ariyama; OMNH-Ar 8387, 1 male and 1 ticulated; and the telson is entire. In Postodius, female (2.7, 3.9 mm, not dissected), Kamishima dorsal projections on the pereonites and pleonites Island, Mie Prefecture (34°33N, 136°59E), are indistinct; the maxillipedal palp is four-artic- among algae, snorkeling, 6–7 August 1983, coll.

Fig. 17. Gordonodius zelleri (Berge, Vader and Coleman, 1999), male (2.7mm), NSMT-Cr 21279. Habitus, left lateral view. Scale: 0.5 mm. 28 Hiroyuki Ariyama

Fig. 18. Gordonodius zelleri (Berge, Vader and Coleman, 1999), male (2.7mm), NSMT-Cr 21279. A, left antenna 1, lateral view; A1, left accessory ﬂagellum, medial view; B, left antenna 2, lateral view; C, upper lip, dorsolateral view; D, left mandible (palp removed), lateral view; E, right mandible (palp removed), lateral view; F, lower lip (split), ventral view; G, right maxilla 1, ventral view; G1, tip of outer plate of right maxilla 1, ventral view; H, left maxilla 2, dorsal view; I, right maxilliped, dorsal view. I1, tip of inner plate of right maxilliped, dorsal view. Scales: 0.1 mm. Six species of Odiidae 29

Fig. 19. Gordonodius zelleri (Berge, Vader and Coleman, 1999), male (2.7mm), NSMT-Cr 21279. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, tip of dactylus of left gnathopod 2, lateral view; B2, posterior part of merus–propodus of left gnathopod 2, lateral view; C–F, left pereopods 3–6 (gill of pereopod 6 lost), lateral views; G, right pereopod 7, lateral view. Scales: 0.1 mm.

H. Ariyama; OMNH-Ar 8388, 8389, 1 male (3.1 135°04E, lower intertidal zone, among colony of mm) and 1 female (3.8 mm), Jogasaki coast in red alga Gelidium japonicum, 8 June 1997, coll. Wakayama, Wakayama Prefecture, 34°17N, H. Ariyama; NSMT-Cr 21284, 1 ovigerous fe- 30 Hiroyuki Ariyama

Fig. 20. Gordonodius zelleri (Berge, Vader and Coleman, 1999). A–C, E, F, male (2.7 mm), NSMT-Cr 21279; D, G, male (3.2 mm), NSMT-Cr 21280; H, female (5.1mm), NSMT-Cr 21281; I, I1, J, female (4.6 mm), NSMT-Cr 21282. A, left pleopod 1, anterior view; B, left pleopod 2, posterior view; C, left pleopod 3, pos- teromedial view; D, left uropod 1, lateral view; E, left uropod 2, medial view; F, left uropod 3 and telson, dorsal view; G, telson, dorsal view; H, dorsal outline of body, lateral view; I, left antenna 1, medial view; I1, left accessory flagellum, medial view; J, left gnathopod 2 (oostegite lost), lateral view. Scales: 0.1 mm. Six species of Odiidae 31 male (4.5 mm, not dissected), Jogasaki coast in robust setae; propodus with 2 robust setae on Wakayama, Wakayama Prefecture, lower inter- posterodistal corner; dactylus with nail. tidal zone, among colony of red alga Gelidium Pereopod 3 (Fig. 19C) larger than gnathopod japonicum, 3 April 2010, coll. H. Ariyama. 2; coxal plate with blunt posterior projection, Description. Male [based on NSMT-Cr 21279 inner surface with wide triangular process; basis and NSMT-Cr 21280 (uropod 1 and telson)]. without plumose setae on anterior margin, bear- Body (Fig. 17) somewhat stout. Eyes large. Pere- ing robust seta on posterodistal corner; ischium onites 6 and 7 slightly produced posterodorsally, with short robust seta on posterior margin; merus pleonites 1 and 2 strongly projected posterodor- projected anterodistally, projection not reaching sally, pleonite 3 strongly produced middorsally, distal end of carpus, margin with 3 anterior, 1 an- posterolateral margins of pleonites 1 and 2 weak- terodistal, 1 posterior and 1 posterodistal robust ly expanded at 0.65 of length, posterolateral mar- setae; carpus with 3 posterior and 3 posterodistal gin of pleonite 3 slightly expanded. robust setae; propodus with 5 couples of robust Antenna 1 (Fig. 18A, A1) stout; ratio of setae posteriorly. Pereopod 4 (Fig. 19D) with lengths of peduncular articles 1–3 1 : 0.9 : 0.3; ac- coxal plate wide, inner surface with large trian- cessory flagellum slender, tip with 1 plumose and gular process; basis without plumose setae on an- 1 simple setae; flagellum with 6 articles, article 1 terior margin, bearing 2 robust setae on pos- long. Antenna 2 (Fig. 18B) about 0.7 length of terodistal corner; ischium without robust setae; antenna 1, with ratio of lengths of peduncular ar- merus projected anterodistally, margin with 3 an- ticles 3–5 1 : 1.7 : 1.6; flagellum with 5 articles. terior, 1 anterodistal, 5 posterior and 1 pos- Left mandible (Fig. 18D) with incisor denticu- terodistal robust setae. late; accessory blades 5 in number; palp long, ar- Pereopod 5 (Fig. 19E) with coxal plate lobate, ticle 3 with many fine setae on lateral surface and anteroventral margin without setae; basis pro- 2 thick setae on tip. Right mandible (Fig. 18E) duced posterodistally, anterior margin with 3 ro- subequal to left except for lacinia mobilis. Maxil- bust setae, anterolateral surface bearing 3 short la 1 (Fig. 18G, G1) with outer plate bearing large robust setae; ischium with 3 robust setae on ante- spine and 6 serrated robust setae apically, distal rior margin; merus projected posterodistally, pro- half of dorsomedial surface with many short jection not reaching distal end of carpus, margin setae. Maxilla 2 (Fig. 18H) with inner plate bear- with 3 anterior, 3 posterior and 1 posterodistal ing distal thick setae and medial fine setae, outer robust setae, anteromedial surface bearing 2 ro- plate with distal setae. Maxilliped (Fig. 18I, I1) bust setae; carpus with 3 anterior and 4 an- with inner plate bearing 2 distal robust setae. terodistal robust setae; propodus long, with 6 sin- Gnathopod 1 (Fig. 19A, A1) small; coxal plate gle and 2 couples of robust setae anteriorly. Pere- narrow; basis relatively wide, anterior margin opod 6 (Fig. 19F) subequal in length to pereopod without plumose setae; propodus with 1 robust 5; coxal plate lobate, anterior margin with 2 and 3 short setae posterodistally; dactylus with 2 plumose setae; basis produced posterodistally, simple and 5 plumose long setae and 1 plumose anterior margin with short plumose seta and 4 ro- short seta. Gnathopod 2 (Fig. 19B, B1, B2) larger bust setae, anterodistal corner bearing robust than gnathopod 1; coxal plate with blunt posteri- seta; ischium with 2 robust setae on anterior mar- or projection, inner surface with tiny triangular gin; merus projected posterodistally, projection process; basis without plumose setae on anterior not reaching distal end of carpus, margin with 2 margin, bearing robust seta on posterodistal cor- anterior, 3 posterior and 1 posterodistal robust ner; ischium with robust seta on posterodistal setae, anteromedial surface bearing 3 robust corner; merus with 2 and 3 robust setae on poste- setae; carpus with 2 robust setae each on anterior rior margin and posterodistal corner, respective- margin, anteromedial corner and anterodistal cor- ly; carpus with 1 anterodistal and 6 posterodistal ner; propodus long, with 5 couples of robust 32 Hiroyuki Ariyama setae anteriorly. Pereopod 7 (Fig. 19G) somewhat setae, anterodistal corner bearing robust seta, an- shorter than pereopod 6; coxal plate small, un- terolateral surface with 3 short setae; ischium lobed, anterior margin with 3 plumose setae; with 2 robust setae each on anterior margin and basis broad, produced posterodistally, posterior anteromedial surface; merus projected pos- margin roundish, anterior margin with 4 robust terodistally, projection not reaching distal end of

Fig. 21. A, Postodius imperfectus Hirayama, 1983, female (4.4 mm), NSMT-Cr 21269; B, Postodius igneus sp. nov., paratype female (7.4mm), NSMT-Cr 21274, photography by K. Tanaka; C, Postodius ornatus sp. nov., female (not preserved), Osezaki, Nishi-izu, Shizuoka Prefecture, 20 m deep, sandy bottom, 26 April 2009, photography by S. Yamamoto; D, Postodius striatus sp. nov., female (not preserved), northwest of Aoshima Island, Shizugawa, Miyagi Prefecture, 8 m deep, on rock, 10 January 2005, photography by N. Sato; .E, Gor- donodius zelleri (Berge, Vader and Coleman, 1999), female (4.5mm), NSMT-Cr 21284. Six species of Odiidae 33 carpus, margin with 2 anterior, 2 posterior and 1 opods 5–7 brownish; eyes red; antennae white, posterodistal robust setae, anteromedial surface but flagellar articles 1 of both antennae red; dor- bearing 3 robust setae; carpus with 3 robust setae sal margins of pereonites 1–7 and pleonites 1–3 each on anterior margin and anterodistal corner; each with 2 red marks. propodus long, with 6 single and 2 couples of ro- Remarks. The present specimens generally bust setae anteriorly. agree with the original description by Berge et al. Pleopods (Fig. 20A–C) relatively long, pleo- (1999) except for the following points: (1) the ac- pod 3 shortest; peduncles each with 2 coupling cessory flagellum is present, although in the orig- hooks, peduncle of pleopod 2 bearing 3 plumose inal description, it is not mentioned; (2) the fla- setae, peduncles of pleopods 1 and 3 bare; outer gella of antennae are relatively long, and (3) the rami longer than inner, outer and inner rami with posterodistal corner of the propodus of gnatho- 9 and 7 articles, respectively. Uropod 1 (Fig. pod 1 is less produced than in the original de- 20D) long; peduncle bearing 3 and 1 robust setae scription. The latter two discrepancies are minor on lateral margin and distolateral corner, respec- and could be within intraspecific variation. tively; outer ramus with 5 lateral, 2 medial and 3 The type locality of this species was indicated terminal robust setae, inner ramus with 3 lateral as “Joshi Island, close to Kobe” by Berge et al. and 3 terminal robust setae. Uropod 2 (Fig. 20E) (1999), but this island could not be located. Ac- short, about 0.7 length of uropod 1; peduncle cording to Smith (1993), Richard Gordon Smith, bearing 3 lateral, 1 medial, 1 distolateral and 1 the collector of the type specimens, dwelled mediodistal robust setae; outer ramus with 4 lat- mainly in Kobe, Hyogo Prefecture and visited eral and 2 terminal robust setae, inner ramus with twice Toshi Island, Mie Prefecture in October 2 lateral, 2 medial and 3 terminal robust setae. 1905 and July 1906. Thus it is highly likely that Uropod 3 (Fig. 20F) shorter than uropod 2; pe- the type locality was misjudged to be close to duncle with distolateral robust seta; outer ramus Kobe and that “Toshi” was incorrectly spelled as about 0.55 length of inner ramus, with 2 lateral “Joshi” on the original label. In addition, this robust setae and terminal short seta, inner ramus species was collected from Himagajima and with 4 lateral and 2 medial robust setae and ter- Kamishima Islands near Toshi Island. minal short seta. Telson (Fig. 20F, G) roundish Distribution. Japan, Aichi Prefecture to triangular, tip with single short seta or pair of Wakayama Prefecture in the Pacific coast, Fukui minute notches bearing short seta. Prefecture in the Japan Sea coast; lower intertidal Female [NSMT-Cr 21281 (body) and NSMT- to 10 m (present study). Cr 21282 (antenna 1 and gnathopod 2)]. Body Habitat. Among algae. (Fig. 20H), eyes smaller than those of male; pereonites 5–7, and pleonites 1 and 2 strongly produced posterodorsally, pleonite 3 strongly pro- Genus Antarctodius Berge, Vader and jected middorsally. Antenna 1 (Fig. 20I, I1) more Coleman, 1999 slender than that of male; ratio of lengths of pe- [New Japanese name: Mukashi-subeyokoebi-zoku] duncular articles 1–31: 0.6 : 0.4; accessory flagel- Antarctodius Berge et al., 1999: 244; Labay, 2010: 35. lum vestigial, tip with 1 plumose and 1 simple setae; flagellum with 5 articles. Gnathopod 2 Emended diagnosis. Anterodorsal margin of (Fig. 20J) similar to that of male, but all articles pereonite 1 not produced. Dorsal projections of wider than those of male and anterior margin of pereonites absent, those of pleonites present or basis with plumose seta. absent. Posterolateral margin of pleonite 3 with Coloration in life (female, NSMT-Cr 21284; or without projection. Eyes variable. Antenna 1 Fig. 21E). Body and appendages mottled orange peduncle with article 2 shorter than article 1; ac- and white, coxae 1–7 and bases–meri of pere- cessory flagellum absent. Mandible relatively 34 Hiroyuki Ariyama short; incisor narrow; lacinia mobilis present on stated that this genus is most plesiomorphic with- left side; palp somewhat distal to molar. Lower in the family Ochlesidae sensu lato. lip with outer lobes long, strongly notched inside. Distribution. Antarctic Ocean, Okhotsk Sea, Maxilla 1 with inner plate bearing 3 apical and Japan. plumose setae, outer plate relatively short, styliform, with many robust setae on tip; palp 2-artic- Antarctodius japonicus sp. nov. ulated, wide, exceeding outer plate, with several [New Japanese name: Mukashi-subeyokoebi] apical setae. Maxillipedal palp 4-articulated. (Figs. 22–25) Coxa 1 almost as large as coxa 2, coxae 2–4 pro- Postodius sp. A: Matsuo et al., 2007: 22. gressively becoming wider, equally long. Gnathopod 1 propodus not projected posterodis- Material examined. Holotype: NSMT-Cr tally, posterodistal corner with long robust seta; 21285, male (2.9 mm), St. 84 (Matsuo et al., dactylus small, triangular, with several thick 2007), midway between Kuchinotsu and Ohyano, setae. Gnathopod 2 propodus narrow, palm weak- Ariake Sound, 32°34N, 130°15E, 47 m deep, ly transverse, distal margin serrated, dactylus sandy gravel bottom, Smith–McIntyre grab, 5 with accessory spine. Gills present on pereopods June 1997, coll. M. Azuma. 2–6. Uropods spinous, inner ramus of uropod 3 Description. Holotype male. Body (Fig. 22) relatively wide. Telson cleft or entire. relatively slender. Eyes very large; posterolateral Species included. Antarctodius antarcticus margins of pleonites 1 and 2 slightly projected at (Watling and Holman, 1981) (type species); A. 0.65 length, posterolateral margin of pleonite 3 rauscherti Coleman and Kauffeldt, 2001; A. non- notched at 0.25 of length, with small projection carinatus Labay, 2010; and A. japonicus sp. nov. on ventral corner. Remarks. The diagnosis of the genus is Antenna 1 (Fig. 23A) stout, short; ratio of emended because the previous diagnoses were lengths of peduncular articles 1–3 1 : 0.5 : 0.2; too simple and contain some errors. The genus is flagellum with 4 articles, article 1 long. Antenna unique in having the two-articulated palp of max- 2 (Fig. 23B) about 0.9 length of antenna 1, with illa 1 in the family Odiidae. Berge et al. (1999) ratio of lengths of peduncular articles 3–5 1 : 2.1 :

Fig. 22. Antarctodius japonicus sp. nov., holotype, male (2.9mm), NSMT-Cr 21285. Habitus, left lateral view. Scale: 0.5 mm. Six species of Odiidae 35

Fig. 23. Antarctodius japonicus sp. nov., holotype, male (2.9mm), NSMT-Cr 21285. A, left antenna 1, medial view; B, left antenna 2, medial view; C, upper lip, dorsolateral view; D, left mandible, medial view; E, right mandible, medial view; F, lower lip, ventral view; G, right maxilla 1, ventral view; H, left maxilla 1, dorsolateral view; I, right maxilla 2, dorsal view; J, left maxilliped, ventral view. Scales: 0.1 mm.

1.9; ﬂagellum with 3 articles. with 3 thick setae. Right mandible (Fig. 23E) Left mandible (Fig. 23D) with incisor denticu- with 10 accessory blades, palp article 3 bearing 2 late; accessory blades developed, 9 in number; apical thick setae. Maxilla 1 (Fig. 23G, H) with palp long, article 3 with 4 thick setae on ventral outer plate bearing large spine and 10–11 robust margin and many ﬁne setae on lateral surface, tip setae mediodistally; palp with plumose seta and 36 Hiroyuki Ariyama

Fig. 24. Antarctodius japonicus sp. nov., holotype, male (2.9mm), NSMT-Cr 21285. A, left gnathopod 1, lateral view; A1, tip of left gnathopod 1, lateral view; B, left gnathopod 2, lateral view; B1, posterior part of merus–dactylus of left gnathopod 2, lateral view; C–G, left pereopods 3–7, lateral views; F1, gill of pereopod 6, lateral view. Scales: 0.1 mm. several normal setae on tip. Maxilla 2 (Fig. 23I) Gnathopod 1 (Fig. 24A, A1) small; coxal plate with inner and outer plates bearing many distal narrow; basis relatively wide, anterior margin and medial setae. Maxilliped (Fig. 23J) with without plumose setae; propodus with 1 long ro- inner plate bearing 2 distal and 6 median robust bust and 2 short setae posterodistally; dactylus setae, outer plate with 4 robust setae laterodistal- with 1 needle-shaped and 5 plumose setae. ly; palp article 4 slender. Gnathopod 2 (Fig. 24B, B1) slightly larger than Six species of Odiidae 37 gnathopod 1; coxal plate almost straight; basis terodistal corner; merus projected anterodistally, without anterior plumose setae, bearing robust with 1 anterior, 1 anterodistal, 4 posterior and 1 seta on posterodistal corner; ischium with robust posterodistal robust setae. seta on posterodistal corner; merus with 2 and 6 Pereopod 5 (Fig. 24E) with coxal plate lobate, robust setae on posterior margin and posterodis- anteroventral margin without setae; basis tal corner, respectively; carpus with 1 anterodis- roundish, produced posterodistally, anterior mar- tal, 6 posterior, 10 posterodistal and 2 posterome- gin with several simple setae and distal robust dial robust setae; propodus with 4 robust setae on seta; ischium with 3 robust setae on anterior mar- posterodistal corner. gin; merus projected posterodistally, margin with Pereopod 3 (Fig. 24C) with coxal plate almost 3 anterior, 1 anterodistal, 4 posterior and 5 pos- straight; basis with 8 plumose setae on anterior terodistal robust setae. Pereopod 6 (Fig. 24F) margin, bearing 2 robust setae on posterodistal with coxal plate slightly lobate, anterior margin corner; ischium with robust seta each on posteri- without plumose setae; basis roundish, produced or margin and posterodistal corner; merus pro- posterodistally, anterior margin with 3 long sim- jected anterodistally, margin with 3 anterior, 1 ple setae and 4 short robust setae, anterodistal anterodistal, 4 posterior and 1 posterodistal ro- corner bearing robust seta, anterolateral surface bust setae. Pereopod 4 (Fig. 24D) with coxal with 6 short robust setae; ischium with 2 robust plate wide, ventral margin long; basis with 7 setae on anterior margin; merus projected pos- plumose setae on anterior margin, bearing 2 ro- terodistally, margin with 2 anterior, 1 anterodis- bust setae on posterodistal corner; ischium with tal, 5 posterior and 1 posterodistal robust setae. robust seta each on posterior margin and pos- Pereopod 7 (Fig. 24G) with coxal plate small, un-

Fig. 25. Antarctodius japonicus sp. nov., holotype, male (2.9mm), NSMT-Cr 21285. A, B, left pleopods 1, 2, posterior views; C, left pleopod 3, anterior view; D–F, left uropods 1–3, dorsal views; G, telson, dorsal view. Scales: 0.1 mm. 38 Hiroyuki Ariyama lobed, anterior margin without plumose setae; Acknowledgements basis broad, quadrate, produced posterodistally, I express my sincere thanks to Kotaro Tanaka, anterior margin with 8 robust setae, anterodistal Satoshi Yamamoto, Shingo Kawai and Nagaaki corner bearing 2 robust setae, anterolateral sur- Sato for donating precious specimens and/or face with 4 short robust setae; ischium with 3 ro- beautiful photographs. I also thank Drs. bust setae on anterior margin; merus projected Masatoshi Matsuo and Akio Tamaki of Nagasaki posterodistally, margin with 2 anterior, 1 an- University for donating specimens of Ariake terodistal, 5 posterior and 1 posterodistal robust Sound, Dr. Satoshi Nojima of the Amakusa Ma- setae. rine Biological Laboratory, Kyushu University Pleopods (Fig. 25A–C) relatively long, pleo- for loan of the type specimen of Postodius imper- pod 3 shortest; peduncles each with 2 coupling fectus, and Akihiro Dazai of Shizugawa Nature hooks, peduncles of pleopod 1–3 bearing 2 sim- Center for sending material. I am greatly indebt- ple setae, 4 simple setae and 2 robust setae, re- ed Junji Okuno of the Coastal Branch of Natural spectively; outer rami longer than inner, outer History Museum and Institute, Chiba who gave and inner rami with 8–10 and 7–9 articles, re- me the chance to carry out the present study. I spectively. Uropod 1 (Fig. 25D) long; peduncle am grateful to Dr. Tomoyuki Komai of the Natur- bearing 16, 5, 1 and 1 robust setae on lateral mar- al History Museum and Institute, Chiba, Dr. gin, medial margin, distolateral corner and disto- Charles Oliver Coleman of Museum für medial corner, respectively; outer ramus with 5 Naturkunde, Berlin, and an anonymous reviewer lateral, 3 medial and 3 (1 lost) terminal robust for critical readings of manuscript. setae, inner ramus with 3 lateral, 4 medial and 3 terminal robust setae. Uropod 2 (Fig. 25E) short, about 0.75 length of uropod 1; peduncle bearing Literature Cited 5 and 1 robust setae on lateral margin and distolateral corner, respectively; outer ramus with 3 Barnard, J. L. 1970. Sublittoral Gammaridea (Amphipo- lateral, 2 medial and 2 terminal robust setae, da) of the Hawaiian Islands. Smithsonian Contributions to Zoology, (34): 1–286. inner ramus with 3 lateral, 2 medial and 3 termi- Barnard, J. L. 1972. Gammaridean Amphipoda of Aus- nal robust setae. Uropod 3 (Fig. 25F) shorter than tralia, Part I. Smithsonian Contributions to Zoology, uropod 2; peduncle with 1 distolateral and 1 dis- (103): 1–333. tomedial robust setae; outer ramus about 0.6 Barnard, J. L. and G. S. Karaman. 1991. The families and length of inner ramus, with 2 lateral and 2 medial genera of marine gammaridean Amphipoda (except robust setae and terminal short seta, inner ramus marine gammaroids). Records of the Australian Muse- um, Supplement, (13) (Parts 1 and 2): 1–866. with 4 lateral and 4 medial robust setae and ter- Barnard, K. H. 1940. Contributions to the crustacean minal short seta. Telson (Fig. 25G) deeply cleft, fauna of South Africa. XII. Further additions to the both tips each with minute seta. Tanaidacea, Isopoda, and Amphipoda, together with Coloration in preservative. Eyes pale orange, keys for the identiﬁcation of the hitherto recorded ma- other parts white. rine and freshwater species. Annals of the South African Museum, 32: 381–543. Remarks. Antarctodius japonicus sp. nov. dif- Berge, J., W. Vader and O. Coleman. 1999. A cladistic fers from the three congeneric species in the rela- analysis of the amphipod families Ochlesidae and Odi- tively wider bases of pereopods 5–7 and the ab- idae, with description of a new species and genus. In: sence of a triangular projection on the posterolat- Schram, F. R. and J. C. von Vaupel Klein (eds.), Crus- eral margin of pleonite 3. This new species is the taceans and the Biodiversity Crisis. Pp. 239–265. Brill, ﬁrst representative of the genus from Japanese Leiden. Brandt, A. and S. Vassilenko. 1995. Amphipoda from waters. north east Greenland: a new genus and two new species Distribution and habitat. Ariake Sound, 47 m (Crustacea: Peracarida). Journal of Natural History, 29: deep (present study). Sandy gravel bottom. 1447–1459. Six species of Odiidae 39

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