The genus Aerotegmina (Orthoptera, Tettigoniidae, Hexacentrinae): chromosomes, morphological relations, phylogeographical patterns and description of a new species

Abstract

The genus Aerotegmina Hemp is common on East African mountains. Two species are known and a third, A. taitensis n. sp., is described in this paper. A. kilimandjarica Hemp is widespread while A. shengenae Hemp is endemic to the South Pare Mountains and A. taitensis n. sp. is known only from the Taita Hills. Morphologically, and from their song, A. shengenae and A. taitensis n. sp. are closely related. In chromosome number A. kilimandjarica (2n = 33) differs clearly from A. shengenae (2n = 27). Data presented on other flightless Orthoptera suggest that the South Pare Mountains and the Taita Hills, both belonging to the geologically old mountain chain of the Eastern Arc, show a faunistic similarity not shared by any other mountain range in the area. The mechanisms that led to this phylogeographic pattern in flightless Orthoptera in the Eastern Arc Mountains of northern Tanzania and southern Kenya and the inland volcanoes are discussed. A key to the three Aerotegmina species is presented, as well as bioacoustical data of all species compared to the phaneropterine species Euryastes jagoi.