A new genus and species of Platyischnopidae (Amphipoda: Gammaridea) from the Southwest Atlantic (Argentine Sea)

CHIESA I.L.; ALONSO G.M.

Szczawnica

Congreso; 15 th ICA International Colloquium on Amphipoda; 2013

The Department of Invertebrate Zoology & Hydrobiology, University of Lodz

Platyischnopidae is a gammaridean benthic family of fossorial amphipods, easily identifiable by the cone-shaped rostrum covered with apical sensory pits. They are abundant in soft bottom areas of the continental shelf and distributed all over the world, but principally they occur in temperate/cold waters. In addition to Platyisao gen. nov., eight other genera of Platyischnopidae are known: Eudevenopus Thomas & Barnard, 1983, Indischnopus Barnard & Drummond, 1979, Platyischnopus Stebbing, 1888, Skaptopus Thomas & Barnard, 1983,Tiburonella Thomas & Barnard, 1983, Tittakunara Barnard & Drummond, 1979, Tomituka Barnard & Drummond, 1979 and Yurrokus Barnard & Drummond, 1979. In the South Atlantic Ocean only Eudevenopus and Tiburonella had been recorded. Platyisao gen. nov. sp. nov is clearly distinguished from the other genera of the family by the following morphological characters: antenna 1, peduncular article 1 suboval, much wider than article 2; gnathopods subchelate, palms oblique, carpus longer than propodus, carpus of gnathopod 2 twice as long as carpus of gnathopod 1; pereopod 7, basis very large, lacking posterodistal tooth or deep notch, posteroventral corner slightly expanded and rounded; uropod 3, peduncle very short, outer ramus very elongate and broad, biarticulated, article 2 of medium width,short, without setae; posteroventral corner of epimera 2 strongly pointed, without setae, and telson long and fully cleft. Furthermore, Tiburonella viscana (Barnard J.L, 1964), previously recorded along the coast of Bahia and from 23.5°S to 25.03°S (Brazil), is reported more southern at 36°08,746S 55°51,937W at 17 m depth. Platyisao gen. nov. and Tiburonella viscana are the first records of platyischnopids for the Argentine Sea, as well as the southwest records in the South Atlantic Ocean.