Tropischyrocerus, Just, 2009

Just, Jean, 2009, Ischyroceridae *, Zootaxa 2260 (1), pp. 463-486 : 466

Tropischyrocerus gen. nov.

Type species. Tropischyrocerus pugilus sp. nov.

Etymology. The name of the genus is a contraction of ‘tropical’ and Ischyrocerus alluding to the known distribution of the component species.

Diagnosis. Ischyrocerini with antenna 1 accessory flagellum 2-articulate, second article minute. Coxae 1– 5 of equal depth, all less deep than corresponding pereonite; coxa 2 of male wider than 1 and 3, wider than deep, ventral margin concave or straight. Male gnathopod 2 merus and carpus well developed of subequal size, not compressed; carpus anterior margin broadly convex; propodus elongate, posterior margin straight, distally with single projections near insertion of dactylus, posteriorly with thumb; dactylus posterior margin smooth. Female gnathopod 1 propodus slightly smaller than gnathopod 2 propodus, posterior margin evenly convex; gnathopod 2 palm concave (for T. socia fide Conlan 1995). Pereopod 5 basis posterior margin not concave.

Included species. Tropischyrocerus pugilus sp. nov.; T. socia ( Myers, 1989) comb. nov.

Remarks. Conlan (1995) reviewed the ischyrocerid genus Microjassa Stebbing, 1899 . As a result she removed two species to a new genus Neoischyrocerus , together with a species previously in the genus Jassa . Conlan (1995: 369) further discussed Jassa socia Myers, 1989 (Bora Bora, Society Islands), but despite its resemblance to Neoischyrocerus lilipuna (J.L. Barnard, 1970) , she rejected its inclusion in that genus on the grounds that it differed in six specific characters from the diagnosis of Neoischyrocerus . She transferred the species to Ischyrocerus , while noting that a new genus might be warranted for this and other Ischyrocerus species.

Ischyrocerus socia and the new species Tropischyrocerus pugilus described below share diagnostic characters which differ from I. anguipes Krøyer , the type species of Ischyrocerus ( Ischyrocerus still is in need of a full revision, a task beyond the scope of this study, hence the reference to its type species only). Ischyrocerus socia ( Myers, 1989) is here transferred to the new genus Tropischyrocerus .

Tropischyrocerus gen. nov. differs from Neoischyrocerus by shorter coxae, with male coxa 2 wider than deep, distinctly wider than 1 and 3; by the concave palm of gnathopod 2 in females; propodus of pereopod 3 and 4 lacking robust setae; and by the dactyli of gnathopods 1–2 and pereopods 5–7 lacking facial serration.