Bathycallisoma Dahl, 1959

Kilgallen, Niamh M. & Lowry, James K., 2015, A review of the scopelocheirid amphipods (Crustacea, Amphipoda, Lysianassoidea), with the description of new taxa from Australian waters, Zoosystematics and Evolution 91 (1), pp. 1-43 : 9

Bathycallisoma Dahl, 1959

Bathycallisoma Dahl, 1959: 220. - Gurjanova 1962: 433. - J.L. Barnard 1969: 305, key K, 328. - Ledoyer 1986: 733 (in part, part Scopelocheiropsis ).

Scopelocheirus . - Birstein and Vinogradov 1960: 178 (in part). - Gurjanova 1962: 319 (in part). - Barnard and Karaman 1991: 528 (in part).

Type species.

Bathycallisoma pacifica Dahl, 1959 by monotypy (= Scopelocheirus schellenbergi Birstein & Vinogradov, 1958).

Included species.

Bathycallisoma includes one species: Bathycallisoma schellenbergi (Birstein & Vinogradov, 1958).

Diagnostic description.

Mandible lacinia mobilis a long, slender robust seta. Maxilla 1 inner plate with pappose setae lining inner margin; palp 2-articulate. Maxilla 2 inner plate broader than outer plate; inner plate slightly shorter than outer plate. Maxilliped palp article 4 well developed. Gnathopod 1 coxa large, margins strongly diverging distally proximally slender, strongly broadened distally; dactylus small, simple, highly modified with blunt apical tip. Pereopod 3 carpus short to compressed, about as long as wide. Pereopod 4 coxa with weakly-developed, subacutely produced posteroventral lobe.

Discussion.

This monotypic taxon is very similar to Scopelocheiropsis Schellenberg, 1926. The main diagnostic character is the form of the lacinia mobilis, which is a long, narrow robust seta in Bathycallisoma , compared with a stemmed and distally expanded ‘blade’ in Scopelocheiropsis . Aside from this, there is a large difference in body size of these animals, Bathycallisoma schellenbergi being an order of magnitude larger than any Scopelocheiropsis species.