Scopelocheiropsis abyssalis Schellenberg, 1926a

Hendrycks, EA & Conlan, KE, 2003, New and unusual abyssal gammaridean Amphipoda from the north-east Pacific, Journal of Natural History 37, pp. 2303-2368 : 2327-2329

Scopelocheiropsis abyssalis Schellenberg, 1926a

(figure 10) Scopelocheiropsis abyssalis Schellenberg, 1926a: 260–262 , figure 12; Schellenberg, 1926b:

216–217, figure 26b; Birstein and Vinogradov, 1962: 37–38, figure 1; Birstein and

Vinogradov, 1964: 162; Barnard and Karaman, 1991: 527–528.

Material examined

Adult X, 5 mm, (appendages on one slide), CMNC 2002-0038 , Sta. 513, Cup # 1, 34°51.46∞N, 122°58.47∞W, 4000 m, 26 October 1990 .

Remarks

The collection contained one adult female of this rarely collected species. We have carefully figured the mandibles of this specimen (excluding the palp), as both Schellenberg (1926a, 1926b) and Birstein and Vinogradov (1962) did not describe or illustrate the mandibular molar of this species. The molar is present as a small, conical, non-triturative structure. Barnard and Karaman (1991: 527) in their diagnosis of the genus state, ‘Incisor ordinary, molar absent’. The left lacinia mobilis is present as a distally serrate, broad blade. The right lacinia is absent. There are only two small spines in the accessory spine row.

The type material should be critically examined to determine if Schellenberg overlooked the presence of a molar. If S. abyssalis does indeed possess a molar, which according to our specimen it does, then both Scopelocheiropsis and Paracallisoma should be re-evaluated and revised accordingly.

The single specimen agrees fairly well with the drawings of Birstein and Vinogradov (1962), but there are some minor differences. In our material, the propodus of peraeopods 3 and 4 tapers strongly distally and the posterior marginal spines are weaker. The dactylus of the maxilliped palp is shorter in our specimen. The lateral cephalic lobe is strongly produced and acute.

This is the first record of the species in the north-east Pacific and a new depth record.

Distribution

North and south Atlantic,? Antarctica, and the north-east Pacific off Point Conception, California in depths to 4000 m.