Cenozoic out-of-Africa dispersal shaped diversification of the whirligig beetle genus Aulonogyrus (Coleoptera: Gyrinidae: Gyrinini)

Abstract

The whirligig beetle genus Aulonogyrus Motschulsky, 1853 comprises more than fifty species divided among five subgenera. The genus has high endemicity in southern Africa, with additional endemic species found on Madagascar, Australia, and New Caledonia. This distribution has been proposed to be of Gondwanan origin. In Africa and Madagascar, species of Aulonogyrus are relatively common freshwater macroinvertebrates inhabiting a variety of lotic and lentic habitats. The phylogenetic relationships and historical biogeography of the genus have never been examined, and it has been suggested that subgenera of Aulonogyrus are not natural groups. Here both Bayesian and maximum likelihood phylogenetic inference are conducted on the genus using data from six gene fragments to reconstruct the evolutionary history of the group. Ancestral range reconstructions are performed to infer the historical biogeography of the genus. Strong support for the monophyly of the genus Aulonogyrus and the subgenera Aulonogyrus s.str. and Afrogyrus Brinck, 1955 was recovered. The three Malagasy subgenera are synonymized with the primarily African subgenus Afrogyrus: Pterygyrus Brinck, 1955 n.syn., Lophogyrus Brinck, 1955 n.syn., and Paragyrus Brinck, 1955 n.syn. The ancestral range reconstruction supports an African origin for the genus with several independent Cenozoic out-of-Africa dispersal events to Madagascar, and the Palearctic and Oceania regions resulting in its current distribution.