Description of the ‘stargazer mysid’ Mysidopsis zsilaveczi sp. nov. (Mysida, Mysidae, Leptomysinae) from the Cape Peninsula, South Africa

Abstract

Mysidopsis zsilaveczi sp. nov. shows colour patterns on the eye that mislead the observer in thinking that the eyes are facing upwards, largely irrespective of their actual orientation, and have resulted in local divers naming these animals ‘stargazer mysids’. To date, only males of the new species could be sampled. Within the species-rich genus Mysidopsis G. O. Sars, 1864 the males of M. zsilaveczi are characterized, besides their unique colour patterns, by a subdivided antennal scale; by a small, mid-dorsal protuberance on the carapace; by endopods of all pleopods having a large, expanded, plate-like exite on the basal segment; by the comparatively large, two-segmented endopod of pleopod 1; by uropodal endopods that extend well beyond the telson; and by having a linguiform telson with spines all along its lateral margins. The new species also shows diverse, very small, lobe-like structures on basis and dactylus of thoracic endopods 3-8. Closely similar structures were for the first time also found in Mediterranean material of M. angusta G. O. Sars, 1864 and M. gibbosa G. O. Sars, 1864. This new species raises the number of southern African Mysidopsis species to nine, confirming the coastal waters of this subcontinent as being one of the major hotspots of diversity in this genus. An updated key to the Mysidopsis species from southern Africa (Namibia plus South Africa) is provided.