Bathya, Wang & Zhu & Sha & Ren, 2020

Wang, Yan-Rong, Zhu, Chao-Dong, Sha, Zhong-Li & Ren, Xian-Qiu, 2020, Bathya brevicarpus gen. et sp. nov. (Amphipoda: Senticaudata: Calliopiidae), from hydrothermal vents, Okinawa Trough, North-west Pacific, European Journal of Taxonomy 693, pp. 1-12 : 3-4

Genus Bathya gen. nov.

urn:lsid:zoobank.org:act:AA9C504C-CE7E-426A-A988-27098BD64D25

Type species

Bathya brevicarpus gen. et sp. nov.

Diagnosis

Antennae calceoli absent. Antenna 1 longer than antenna 2; accessory flagellum absent. Mandible molar triturative, columnar; palp 3-articulate, extremely elongated, article 3 longer than article 2. Maxilla 1 inner plate bearing one apical seta; palp article 1 shorter than article 2. Maxilla 2 inner plate without oblique setal row. Maxilliped outer plate not reaching end margin of palp article 2. Gnathopod 1 similar in shape to gnathopod 2, slightly smaller than gnathopod 2; subchelate; carpus much shorter than propodus; with posterior lobe. Coxae 5–6 bilobate, posterior lobe larger than anterior lobe; coxa 7 rounded. Pereopod 5 slightly longer than pereopod 7; anterior margin of propodus with bifid robust setae; dactylus simple, with small nail. Epimerons 2–3 posterior margin smooth, posteroventral corner of epimeron 2 subacute. Uropods 1–2 inner ramus longer than outer ramus, both inner and outer ramus with marginal robust setae. Uropod 3 inner ramus about twice longer than outer ramus, both inner and outer ramus with marginal robust setae, without simple or plumose setae. Telson entire, linguiform, longer than broad.

Etymology

The generic name Bathya refers to the type species designated herein that was collected from bathyal waters.

Distribution

North-west Pacific, Okinawa Trough, the hydrothermal vents at a depth of 996.9 m.

Remarks

Actually, it is a little questionable that Bathya gen. nov. is placed under the Calliopiidae G.O. Sars, 1893 for having the pereopod 5 longer than pereopod 7. The phylogenetic study by Lowry & Myers (2013) based on morphology analyzed showed that the Calliopiidae and Pontogeneiidae Stebbing, 1906 cluster together and form a clade with Hornelliidae d’Udekem d’Acoz, 2010 and Cheirocratidae d’Udekem d’Acoz, 2010 . The new genus is not listed under Cheirocratidae or Hornelliidae , which are also not having antennae calceoli, for having the following characteristics: the inner plate of maxilla 1 only bearing apical seta, maxilla 2 without oblique setal row, the rami of uropod 3 unequal in length, and the entire telson. The new genus is not suited to be placed in Pontogeneiidae for the propodus of gnathopod 2 having robust setae along the palmar margin. Moreover, Sanchoidae Lowry, 2006 , which are known as endemic to Australia and associated with sponges ( Lowry & Barnard 2001), have been listed under the Calliopiidae . However, the present genus cannot be incorporated in this family for the lack of a nonrecessed head and a dorsoventrally flattened urosome ( Lowry 2006). Hence, it is more reasonable that this new genus is to be placed under Calliopiidae with an emendation of the diagnosis of this family.

Besides having the pereopod 5 longer than pereopod 7, Bathya gen. nov. can be distinguished its congeners of the Calliopiidae by having the combination of the following characters: eyes present but not well pigmented; antenna 1 longer than antenna 2; the absence of an accessory flagellum; the inner plate of maxilla 1 only bearing one apical seta; maxilla 2 without oblique setal row; gnathopod 1 similar in shape and size to gnathopod 2; pleonites 1–3 without dorsal carinae; the rami of uropod 3 unequal in length; the entire telson.