On the Identity of Spencebatea Abyssicola (Cumacea), with Additional Observations on the Genera Allied to Procampylaspis

In 1879 Norman described Spencebatea abyssicola, new genus, new species, on the basis of a single specimen from a deep-sea site off Ireland. The species was transferred to the genus Cumella by Stebbing in 1913, where it has remained. A reexamination of the specimen indicated that it belongs to the genus Procampylaspis, since it possesses the recurved, tooth-bearing dactyl on maxilliped 2 which characterizes the genus. Seven other genera also exhibit modified dactyls on maxilliped 2, and, in addition, have styliform mandible molars, thus forming a coherent group within the family Nannastacidae. Norman (1879) described the new genus, new species, Spencebatea abyssicola, from a single specimen dredged in 1869 by the Porcupine west of Donegal Bay [at Station 19, with coordinates 54?53'N, 10?56'W, and water depth 1,360 fathoms (2,487 m)]. The specimen was a subadult male and was described relatively completely (for the time), but was not illustrated. Nevertheless, Norman recognized that his species did not fit with any previously described genera. He gave as the diagnosis for this genus the following: "Characters of male.General aspect that of Diastylis. Five segments of cephalothorax exposed behind the carapace. All feet, except the last, palpigerous. No feet on the pleon. Telson rudimentary (as in Eudorella). Uropods with both branches two-jointed. Female unknown." This diagnosis served to distinguish his new genus from all other genera existing at the time, with the possible exception of Cumella, perhaps explaining why Stebbing (1913) moved the species to that genus with no comment (and, apparently, without examining the specimen). In a later revision of the genus Cumella, Watling (1991) failed to list the species. Bonnier (1896) described the genus Procampylaspis for two new species, P. armata and P. echinata. Both species were taken in 950 m at the Caudan Station 13 in the Gulf of Gascogne. Bonnier noted the principal distinguishing feature of his new genus to be "la structure si particuliere du dactylopodite du deuxieme maxillipede (p. 544)." The terminal article of this appendage bears strongly projecting and recurved teeth on its concave margin, which are now known to be highly characteristic of all species in this genus. In fact, all genera in the Campylaspis-Procampylaspis group have the dactyl of the second maxilliped modified in some way. A reexamination of Norman's specimen (BMNH No. 1911.11.8:6023) showed that it clearly belongs in the genus Procampylaspis. This paper deals first with the redescription of Norman's specimen in the genus Procampylaspis, since it appears not to have been examined since its original discovery, and second, with a comparison of the closely allied genera. Procampylaspis Bonnier, 1896 Spencebatea Norman, 1879, nomen oblitum Diagnosis.-Carapace elevated posteriorly, anterolateral (antennal) angle rudimentary to obtuse. Eye lobe rudimentary. Mandible molar styliform. Maxilliped 2 with 7 articles; carpus and propodus in line (not angled); propodus distal spine-seta absent; dactyl with 5 ventral teeth or spine setae, distalmost recurved. Procampylaspis abyssicola (Norman, 1879) Figs. 1, 2 Spencebatea abyssicola Norman, 1879. Cumella abyssicola Stebbing, 1913. Procampylaspis inermis Jones, 1984. Description (Modified from Norman).-Subadult male and female, length 3-3.5 mm. Carapace smooth, with some scattered setae, about twice as long as deep; pseudorostrum about one-seventh length of carapace; eye