Bisbalia vossi n. g., n. sp. (Nematoda: Onchocercidae), a filarial worm from a geomyoid rodent, Heteromys anomalus, in Venezuela.

Bisbalia vossi n. g., n. sp. is described from Heteromys anomalus (Rodentia: Geomyoidea: Heteromyidae) in northern Venezuela (Aragua). The filariae were found in a membranous pocket in the pleural cavity, and almost all had ingested red blood cells of their host. The morphology of this onchocercine species is highly evolved (advanced reduction of head and caudal papillae; short undivided oesophagus). Its very short microfilariae (60 microm) and the shape of the tail of the female (two terminal median pairs of bosses) suggest that this species could be derived from Ackertia Vaz, 1934, a South American genus parasitic in caviomorph rodents which is related to the Dipetalonema-line, but Ackertia has several pairs of precloacal papillae, which are absent in the new genus. In North America, where the geomyoid rodents originated and diversified, the two previously described filarial species differ from this new material and show affinities with Old World bat parasites (Litomosa van Beneden, 1871).