Aoridae Stebbing, 1899

Ariyama, Hiroyuki & Kawabe, Katsutoshi, 2022, Two New Species of Aoridae from Chichijima Island, the Ogasawara Islands in Japan (Crustacea: Amphipoda), Species Diversity 27 (1), pp. 113-128 : 114

Family Aoridae Stebbing, 1899

[Japanese name: Yumbo-sokoebi-ka] Genus Aoroides Walker, 1898 [Japanese name: Yumbo-sokoebi-zoku]

Aoroides Walker, 1898: 284 ; Myers 1988: 187; Barnard and Karaman 1991: 171; Myers and Lowry 2003: 465; Ariyama 2004a: 1.

Type species. Aoroides columbiae Walker, 1898 , fixed by monotypy.

Diagnostic description [emended from Barnard and Karaman (1991) and Ariyama (2004a)]. Body laterally compressed, smooth; urosomites free. Head, rostrum short, ocular lobes short; eyes small to large. Antenna 1 long, slender, peduncular article 3 shorter than article 1, accessory flagellum vestigial or absent; antenna 2 shorter than antenna 1, flagellum short, with 2–4 articles. Mandible, palp weak, slender, with 3 articles, article 3 longest, rod-shaped, with 1–7 setae [palp lacking in A. vitiosus Myers, 1995 ( Myers 1995) ]; left molar traversed with parallel channels. Maxilla 1, inner plate triangular or conical, with apical seta; outer plate with 10 apical robust setae; palp biarticulate, with several robust setae distally. Maxilla 2, outer plate broader than inner plate, both plates with row of marginal setae. Maxilliped, inner plate with several robust setae distally; outer plate reaching apex of palp article 2, with 7–12 marginal robust setae; palp consisting of 4 articles, article 3 with distal projection, article 4 bearing robust seta (nail) on tip. Male coxa 1 elongate, produced forward, usually with robust seta anteriorly, male coxae 2–7 and all coxae in female ordinary to short, weakly overlapping; gills present on coxae 2–6; oostegites of female broad, present on coxae 2–5. Male gnathopod 1 greatly enlarged, merochelate; basis long, excavated anterodistally; merus produced into long distal tooth; carpus long and broad; propodus shorter than carpus; dactylus slender. Female gnathopod 1 smaller than that of male, subchelate; carpus shorter than or subequal to propodus, palm angular or oblique. Gnathopod 2 of both sexes smaller than gnathopod 1, subchelate; propodus shorter than or as long as carpus in male, longer than or subequal to carpus in female, palm oblique or almost transverse. Pereopods 3, 4 similar to each other, slender; bases elongate. Pereopods 5–7 similar to each other, progressively longer; bases usually broad. Epimeral plates 1–3 each with notch on ventroposterior corner. Uropods biramous; uropod 1 peduncle shorter than or same length as rami, distal end of peduncle with long inter-ramal process, both rami subequal in length; uropod 2 shorter than uropod l, peduncle shorter than rami, rami subequal in length; uropod 3 shortest, peduncle relatively elongate, rami subequal in length, outer ramus with tiny second article. Telson entire, fleshy, with pair of hooked cusps.

Remarks. Main points of the emendation are as follows: eyes “small to large” from “small” because of the large eyes in Aoroides macrops sp. nov., and mandibular palp with “1–7 setae” from “2–7 setae” because of 1 or 2 setae in A. macrops .