First Record of the Family Gynodiastylidae Stebbing, 1912 (Crustacea: Malacostraca: Cumacea) from Antarctic Waters with the Description of \u3ci\u3eGynodiastylis jazdzewskii\u3c/i\u3e, a New Species

An adult male of an undescribed gynodiastylid cumacean was collected in a Menzies trawl sample taken at a depth of between 388 and 399 m in the Ross Sea (76 degrees 01.5\u27-76 degrees 01.0\u27S, 179 degrees 49.9\u27-179 degrees 52.3\u27 E) during February 1972. The specimen, which had lost its third maxillipeds and the last four articles of the first pereopods, is placed in the genus Gynodiastylis Calman, 1911. Gynodiastylis jazdzewskii, new species, the first member of its family reported from Antarctic waters, can be distinguished from the 59 previously described species of Gynodiastylis and members of the other five gynodiastylid genera by a combination of characters, including the finer, more irregularly wavy, longitudinal ridges, and the length and setation of the telson, on the carapace, the shape and terminal setation of the telson, the length of telson in relation to that of the last abdominal somite and uropodal peduncles, and the setation and relative length of the uropodal rami