Family Odiidae Coleman & Barnard, 1991

[Japanese name: Subeyokoebi-ka]

Odiidae Coleman & Barnard, 1991: 262 .— Moore, 1992: 913.— Ariyama, 2011: 2.— Lowry & Myers, 2017: 55.

Iphimediidae: Barnard & Karaman, 1991: 378 (in part).

Ochlesidae: Berge, Vader & Coleman, 1999: 242 (in part).— Labay, 2010: 35 (in part).— Labay, 2019: 503 (in part).

Type genus. Odius Liljeborg, 1865 .

Diagnosis [emended from Ariyama (2011)]. Body compressed laterally. Rostrum well developed. Pereonites dorsally flush, usually raised into thin keels. Pleonites often with dorsal projections. Antennae short, accessory flagellum present or absent. Mouth parts conically developed. Upper lip narrow, tip asymmetrically incised. Mandible styliform; incisor toothed, accessory blades strong or absent, molar triturative; palp 3-articulated, article 1 shorter than half length of article 3. Lower lip without inner lobes, outer lobes thin. Maxilla 1 with small inner plate bearing 1–3 apical setae; outer plate conical; palp 1- or 2-articulated. Maxilla 2 with inner plate lacking facial row of setae. Maxilliped, palp 3- or 4-articulated. Gnathopod 1 weak, chelate, carpus and propodus elongate. Gnathopod 2 subchelate, merus and carpus produced posterodistally. Coxa 4 with large acute posterior projection. Pereopods 5–7 with bases expanded posteriorly. Urosomites free. Uropods biramous, both rami of uropod 1 subequal in length, outer rami shorter than inner in uropods 2, 3. Telson entire or incised.

Genera included. Antarctodius Berge, Vader & Coleman, 1999; Cryptodius Moore, 1992; Gordonodius Ariyama, 2011; Metodius gen. nov.; Odius Liljeborg, 1865; and Postodius Hirayama, 1983 .

Key to the genera in the world. As the presence of accessory flagellum was revealed recently in two Cryptodius species (Kim & Hong 2014, Labay 2019) and is confirmed in Antarctodius japonicus as stated below, Ariyama’s (2011) key is revised herein.

1. Maxilla 1 palp powerful, 2-articulated.................................. Antarctodius Berge, Vader & Coleman, 1999

– Maxilla 1 palp reduced, uniarticulated.................................................................... 2

2. Maxilla 1 palp short, rounded, tip bare...................................................... Metodius gen. nov.

– Maxilla 1 palp slender, tip with 1–2 setae.................................................................. 3

3. Maxillipedal palp 3-articulated.................................................... Gordonodius Ariyama, 2011

– Maxillipedal palp 4-articulated.......................................................................... 4

4. Fourth article of maxillipedal palp vestigial............................................ Postodius Hirayama, 1983

– Fourth article of maxillipedal palp not vestigial, triangular.................................................... 5

5. Pereopod 7 basis with projection on posterior margin, telson incised........................... Odius Liljeborg, 1865

– Pereopod 7 basis smooth in posterior margin, telson entire or slightly incised.................. Cryptodius Moore, 1992