Bathycallisoma schellenbergi (Birstein & Vinogradov, 1958)

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 : 10-11

Bathycallisoma schellenbergi (Birstein & Vinogradov, 1958) Figures 17, 18

? aff. Paracallisoma spec. Schellenberg, 1955: 185, fig. 1.

Scopelocheirus schellenbergi Birstein & Vinogradov, 1958: 224, figs 3, 4. - Birstein and Vinogradov 1960: 178. - Gurjanova 1962: 321, figs 104a, b. - Birstein and Vinogradov 1964: 161. - J.L. Barnard 1964: 319. - Birstein and Vinogradov 1970: 402, 417 (table 3). - ? Kamenskaya 1981: 42. - Barnard and Karaman 1991: 528. - ? Vinogradov and Vinogradov 1993: 130. - Lörz and Held 2004: 11 (Appendix A). - Blankenship and Yayanos 2005: 892, fig. 2. - Blankenship et al. 2006: 51, 53 (table 2), figs 2, 3. - De Broyer et al. 2007: 159. - Blankenship and Levin 2007: 1685, fig. 1, 1687 (table 1). - Jamieson et al. 2009: 1040. - Jamieson et al. 2011: 54, 55 (table 3), 58 (table 6). - Søreide and Jamieson 2013: 3, fig. 4.

Bathycallisoma pacifica Dahl, 1959: 222, figs 6-8. - Gurjanova 1962: 433. (Holotype, 1 female, about 33 mm, somewhat mutilated, ZMUC CRU-7674; Kermadec Trench, South Pacific Ocean (32°10'S, 177°14'W), brown clay with pumice, 6960-7000 m depth).

Bathycallisoma schellenbergi . - Wolff 1959: 255 (table 1). - Gurjanova 1962: 433. - Nagata 1963: 1. - Ortiz 1979: 19.

Type material.

Syntypes, 3 specimens, 26, 27 and 42 mm, ZMM.

Type locality.

North Pacific Ocean, Japan Trench (38°03'N, 143°57'E), 0-7000 m over bottom depth 7200 m; Kuril-Kamchatka Trench (43°48'N, 149°55'E), 0-8000 m over bottom depth 9180 m; and Kuril-Kamchatka Trench (44°08'N, 150°22'E), 0-6580 m over bottom depth 8900 m.

Depth range.

Approximately 5600-9104 m (current study, Blankenship et al. 2006).

These records represent the shallowest and deepest known certain depths in the literature for Bathycallisoma schellenbergi . Records of 0-8129 m over a bottom depth of 10437 m ( Birstein and Vinogradov 1960) are excluded as this equates only to length cabled out during mid-water trawls, thus the exact depth of capture is unknown.

Distribution.

Indian Ocean: Java Trench ( Birstein and Vinogradov 1964). North Pacific Ocean: Kurile-Kamchatka Trench ( Birstein and Vinogradov 1958, Birstein and Vinogradov 1970); Japan Trench ( Birstein and Vinogradov 1958, Nagata 1963). South Pacific Ocean: Kermadec Trench ( Dahl 1959, Blankenship et al. 2006); New Hebrides Trench ( Birstein and Vinogradov 1960, current study); Tonga Trench ( Birstein and Vinogradov 1960, Blankenship and Levin 2007, Jamieson et al. 2011). ? North Atlantic Ocean: Puerto Rico Trench ( Schellenberg 1955). ? South Atlantic Ocean: Orkney Trench ( Vinogradov and Vinogradov 1993).

Ecology.

This species has been taken frequently in baited traps ( Blankenship et al. 2006, Jamieson et al. 2011), and seems also to live a semi-pelagic lifestyle as it has been taken in mid-water trawls (e.g. Birstein and Vinogradov 1958). It appears to be a lower abyssal and hadal endemic.

Discussion.

Dahl (1959) described the genus Bathycallisoma for his new species Bathycallisoma pacifica from the Kermadec Trench, placing aff. Paracallisoma spec. Schellenberg 1955 from the Puerto Rico Trench in its synonymy. While Dahl’s publication was in press Birstein and Vinogradov (1958) published an account of the amphipods of the north-western Pacific, including a new species, Scopelocheirus schellenbergi , also with aff. Paracallisoma spec. Schellenberg 1955 in its synonymy. Dahl (1959) consequently included a footnote in his account, stating that Schellenberg’s specimen should be referred to Scopelocheirus schellenbergi , which in turn should be recombined as Bathycallisoma schellenbergi . He considered his Kermadec specimen to be a separate species from Bathycallisoma schellenbergi based on the shape of the first gnathopod and "some other minor characteristics". We cannot observe these differences and so prefer to retain Bathycallisoma pacifica as a junior subjective synonym of Bathycallisoma schellenbergi , thereby agreeing with most subsequent authors.