Antarctodius Berge, Vader & Coleman, 1999

Ariyama, Hiroyuki, 2021, Five species of the family Odiidae (Crustacea: Amphipoda) collected from Japan with descriptions of a new genus and four new species, Zootaxa 5067 (4), pp. 485-516 : 512-513

Genus Antarctodius Berge, Vader & Coleman, 1999

[Japanese name: Mukashi-subeyokoebi-zoku]

Antarctodius Berge, Vader & Coleman, 1999: 244 ; Labay, 2010: 35 .

Type species. Odius antarcticus Watling & Holman, 1981 .

Diagnosis [emended from Ariyama (2011)]. Body, anterodorsal margin of pereonite 1 not produced; dorsal projections of pereonites absent, those of pleonites present or absent; posterolateral margin of pleonite 3 with or without projection. Eyes variable. Antenna 1, peduncle with article 2 shorter than article 1; accessory flagellum absent or present. Upper lip, tip incised asymmetrically. Mandible conical; incisor narrow; lacinia mobilis present on left side; palp somewhat distal to molar. Lower lip with outer lobes long, strongly notched inside. Maxilla 1 with inner plate bearing 3 apical plumose setae; outer plate relatively short, styliform, with many robust setae on tip; palp 2-articulated, wide, exceeding outer plate, with several apical setae. Maxilla 2, inner plate almost same length as outer plate, mediodistal margins of both plates strongly setose. Maxilliped, inner plate narrow; outer plate medium, reaching distal end of palp article 2; palp 4-articulated, article 2 not expanded medially, article 4 short or long. Coxa 1 a little shorter than coxa 2; coxae 2–4 progressively wider, equally long. Gills present on gnathopod 2–pereopod 7(?). Oostegites of female present on gnathopod 2–pereopod 5. Gnathopod 1, propodus not projected posterodistally, posterodistal corner with long robust seta; dactylus small, triangular, with several plumose setae. Gnathopod 2, propodus narrow, palm weakly transverse, distal margin serrated; dactylus with accessory spine. Pereopods 3–7, meri projected distally. Uropods, inner ramus of uropod 3 slightly wide; peduncles of uropods 1, 2 and both rami bearing many robust setae. Telson cleft or entire.

Species included. Antarctodius antarcticus ( Watling & Holman, 1981) ; A. japonicus Ariyama, 2011 ; A. noncarinatus Labay, 2010 ; and A. rauscherti Coleman & Kauffeldt, 2001 .

Remarks. The diagnosis of the genus is emended mainly because the presence of the accessory flagellum and the gill on the coxa 7 is confirmed in the present study. However, in the papers dealing with the other Antarctodius species , the accessory flagellum is stated to be absent and the gill is not mentioned ( Watling & Holman 1981, Coleman & Kauffeldt 2001, Labay 2010). A closer examination of them is needed.

Distribution. Antarctic Ocean, Okhotsk Sea and Japan.