Redescription of Griffithsius latipes (Griffiths, 1976) (Crustacea, Amphipoda, Phoxocephalidae) from the coast of Namibia

Abstract

Abstract A full redescription of Griffithsius latipes (Griffiths, 1976) is given. This is necessary because the original description is incomplete and contains inaccuracies. Griffiths (1976) gave a detailed description of Mandibulophoxus latipes, illustrated with two plates. From this publication the present author was initially convinced that her new material belonged to a new species. However, when the type material of M. latipes was examined in order to furnish a good differential diagnosis, it became clear that all specimens belong to a single species, but that Griffiths' drawings do not match his types in all details. The fuller description and complete illustrations given herein (see the accompanying Electronic Supplement, and Fig. 1) now enable the accurate determination of the species. The key features for recognition of Griffithsius latipes (Griffiths) are pereopods 5 and 6. In Griffiths' drawing of pereopod 5 the carpus has an almost circular shape, whereas in the studied specimens this article is rather ellipsoid. Pereopod 6 in Griffiths' figure has the merus much longer than wide, with the posterior margin weakly convex. In the types and the new material this article looks completely different: it is wider than long, as the posterior margin is strongly lobate. The dactylus is much shorter than the propodus in Griffiths' drawing, in the redescribed material these articles are subequal in length. Similar inconsistencies can be observed on antenna 2: the 4 th article of the peduncle is ovoid, whereas in Griffiths' drawing it appears subrectangular; on uropod 3 the second article of the outer ramus of the redescribed material is relatively longer (1:3) compared to the basal article in Griffiths' illustration (1:4).