On Cytheridellawhitmani sp. nov. (Crustacea, Ostracoda) from Cape Cod (Massachusetts, USA), with a reappraisal of the taxonomy of the genus.

Abstract

Cytheridellawhitmani Martens, sp. nov. is described from lakes on Cape Cod (MA, USA). The species differs from its congeners mainly by the shape of the female carapace and by the morphology of the hemipenis, especially of the distal lobe and the copulatory process. The literature on the genus is reviewed and the synonymy of the fossil Cytheridellaboldii Purper, 1974 with the type species C.ilosvayi Daday, 1905, both described from South America, is confirmed. The status of Cytheridellaamericana (Furtos, 1936) is reverted to that of "uncertain species". Beside the type species and the new species, the genus currently includes only three further species from Africa: C.monodi Klie, 1936, C.damasi Klie, 1944 (with synonym C.chariessa Rome, 1977), and C.tepida Victor, 1987. The morphology of the new species is discussed in comparison with the congeneric species, especially regarding the valve ornamentation, the structure and function of the third thoracopod, the hemipenis and the caudal ramus. It is suggested that C.whitmani is a recent invasive species in the lakes of the Cape Cod peninsula. Its occurrence at northern latitudes is unexpected, as its congeneric species are consistently (sub-) tropical.