Description of a new tribe Cabralcandonini (Candonidae, Ostracoda) from karst aquifers in central Texas, U.S.A

摘要

Cabralcandonini tribe n., with the type genus Cabralcandona gen. n. from an artesian well in the San Marcos, Texas(U.S.A.) and six other genera from karst aquifers in Texas, is proposed as a new tribe of the subfamily Candoninae(Candonidae) (Crustacea, Ostracoda). The new tribe and genus have morphological features that distinguish themfrom other members of the subfamily. The most diagnostic characteristics of the type genus are (1) two horn-like structuresdeveloped on the antero- and postero-dorsal margins of the left valve, (2) numbers of central muscle scars, (3)hexagonal or pentagonal (honeycomb-like) ornamentation on the subrectangular shaped carapace, (4) four segmentedsecond antenna in both sexes, (5) absence of an exopod on A2, (6) shape and size of Y aesthetasc, (7) absence of e,f and g setae on cleaning leg, (8) flagellum (whip-like) uropod morphology, (9) shape of hemipenis, and (10) reductionin number of segments and setae on other limbs. Taxonomic keys for the tribes of the subfamily Candoninae includingCabralcandonini tribe n. are presented.