Platyisao, Chiesa, Ignacio L. & Alonso, Gloria M., 2014

Chiesa, Ignacio L. & Alonso, Gloria M., 2014, A new genus and species of Platyischnopidae (Amphipoda: Gammaridea) from the Argentine Sea, South-West Atlantic Ocean, Zootaxa 3811 (1) : -

Platyisao gen. nov.

Etymology. The name Platyisao is a combination of the word “Platyi”, root of the family Platyischnopidae , and “sao” stands for the abbreviation of San Antonio Oeste (Río Negro province, Argentine), one of the localities where the new genus was found. The gender is neuter.

Diagnosis. Eyes absent. Antenna 1, peduncular article 1 suboval, much wider than article 2, article 2 elongate, rectangular, with dorsal and ventral margins without setae; accessory flagellum short, biarticulate. Antenna 2, peduncular articles 4 and 5 without setae on ventral margin. Mandibles with both incisors of medium size, broad at the base and tapering towards the apex; right lacinia mobilis thin, weakly bidentate, left lacinia mobilis longer and wider, slightly flabellate and conical distally, with 4 teeth; without accessory setal rows. Maxilla 1, outer plate elongate, bearing 7 ungrouped robust setae; palp uniarticulate bearing 2 very long plumose setae apically. Maxilla 2, inner plate thin, apical margin subrounded, outer plate subrectangular, both plates bearing a few setae. Maxilliped, inner plate short, medium width and apically truncate, without facial setae; outer plate medium to elongate, broad, suboval, with 6 spaced robust setae mediodistally; palp article 4 short, stout, apically rounded, with 1 long distal nail. Coxae 1–4 progressively longer and wider, ventral margins forming a near continuous line, strongly overlapping; coxa 3, anteroventral corner slightly expanded and concave, coxa 4 greatly covering coxa 3, very large, with posterior margin rounded medially and posterodorsal section oblique. Gnathopods subchelate, palms oblique; ischium short; carpus longer than propodus, carpus of ganathopod 2 twice as long as carpus of gnathopod 1. Pereopod 5, basis pear-shaped and of medium width, posteroventral margin sligtly expanded, rounded, with 2 notches. Pereopod 7, coxa short and wide, subovoid; basis very large, with anterior and posterior margins divergent, posterior and ventral margins slightly undulated, with small notches. Uropod 3, peduncle very short, article 2 of outer ramus short, of medium width, inner and lateral margins without setae. Pleonites 1–3 smooth dorsally; epimeral plate 2 with posteroventral corner strongly produced and acute, posterior margin slightly sinuous; epimeral plate 3, ventral margin somewhat rounded and posteroventral corner with a very small tooth. Telson elongate, completely cleft, each apex produced into 2 small sharp teeth bearing 2 short dorsal setae.

Type species. Platyisao holodividum sp. nov. by monotypy.