Pergamaster Koehler 1920

Pergamaster Koehler, 1920

Koehler, 1920: 237; Fisher, 1940: 121; A.M. Clark, 1962: 22 (key); Bernasconi, 1963: 23; H.E.S. Clark 1963: 43.

Diagnosis. Body strongly stellate with elongate arms. Abactinal plates distinct, round to polygonal in outline. Abactinal and marginal plate surfaces bare, smooth. Peripheral granules, angular to polygonal-round flush with abactinal, marginal plate surfaces. Superomarginal plates abutting over midline in some individuals. Actinal surface bare or covered with angular, flattened granules. Pedicellariae absent.

Comments. Two species of Pergamaster are recognized herein, including P. triseriatus from the Ross Sea and P. i n c e r t u s (with synonym P. synaptorus below), known primarily from the Weddell Quadrant. Both species show several discrete morphological differences as summarized in the diagnostic key and in descriptions herein. However, these two species are also sampled from two of the most heavily studied regions in the Southern Ocean. There is discontinuous sampling from Pergamaster populations. Regions between the Weddell Quadrant and the Ross Sea have been poorly explored and new records, such as the those of P. i n c e r t u s from Prydz Bay suggest a continuous species complex for this genus across the Southern Ocean.