Claudicuma (Cumacea, Crustacea): First record from the marine environment, description of the second species of the genus and phylogenetic remarks

Abstract

The genus Claudicuma was erected to accommodate C. platense, a species reported from freshwater and very low-salinity areas at the Río de la Plata, Argentina. Unexpectedly, a large number of the second species of this genus, C. gosztonyii n. sp., was recently collected in the Patagonian Atlantic coast, from the intertidal zone to 13 m of depth. This news species differs from C. platense, mainly in the chaetotaxia of the male second antenna, the acuteness of female pseudorostrum, and the proportions of female uropods. The ovigerous female of C. gosztonyii n. sp. has both degenerated mouthparts and an empty gut, facts that suggest that this is not a feeding instar. The second antennae of the adult male are presumably used to clasp the female. The genus Claudicuma is compared to Picrocuma, Pseudopicrocuma, Bathypicrocuma, Thalycrocuma, Atlantocuma, Almyracuma and Spilocuma, whose males also have short, clasping or vestigial second antennae. Claudicuma differs from all these genera by the coalescence of pereonites 2 and 3 in ovigerous females. The diagnosis of the genus Claudicuma is emended and its phylogenetic position discussed.