Observations on Cumacea (Malacostraca: Peracarida) from Antarctic and Subantarctic Waters. I. Ekleptostylis debroyeri (Diastylidae), a New Species from Waters off the Antarctic Peninsula

Eighteen species of diastylid cumaceans have been described from Antarctic and subantarctic waters. A nineteenth species, Ekleptostylis debroyeri, n. sp., was collected in depths of 83 to 530 m off the Antarctic Peninsula. The new species appears to be closely allied to Ekleptostylis heardi McLelland & Meyer, 1998; E. inornata (Hale, 1937), n. comb.; E. pseudoinornata (Ledoyer, 1977); and E. vemae (Bacescu-Mester, 1967), all of which are known from subantarctic and Antarctic waters. Ekleptostylis debroyeri is distinguished from these species by a combination of characters including the size of the anterior-most pair of lateral spiniform setae of the telson and the proximal article of the uropodal endopod subequal to the combined length of the two distal most articles. The genera Diastylis Say, 1818, Ekleptostylis Stebbing, 1912, and Leptostylis G. O. Sars, 1869 have morphological features that appear to be transitional, especially among the subadults and females. The generic status of many species within these genera can only be determined with certainty by the morphology (length of antenna, structure of the second pereopod, ornamentation of telson) of the terminal male stage. Although the mature male of E. debroyeri is unknown, it is tentatively placed in Ekleptostylis based on the similarity of the female to other known species of the genus.