A new genus from Madagascar with strongly enlarged labium (Ephemeroptera, Baetidae)

Abstract

A new genus of Baetidae, Megalabiops gen. nov., and a new species, M. madagasikara sp. nov., are described from Madagascar based on nymphs. The new genus is characterized by having a strongly enlarged mentum; pedicelli with many long, stout, pointed setae; a brush of dense, short setae between prostheca and mola of both mandibles; an apically pointed maxillary palp with a stout seta at the tip; and a labium with many long, simple setae ventrally on glossae. The patellotibial suture is absent on the fore tibia and present on middle and hind tibiae. The claw is strongly elongated with two rows of denticles. The imago remains unknown and the relationships with other African genera of Baetidae are tentative. Despite being easily identifiable, only two nymphs were found in two highly sampled localities in Madagascar.