Madaglymbus, a new genus of Malagasy endemic diving beetles and description of a highly unusual species based on morphology and DNA sequence data (Dytiscidae: Copelatinae)

Abstract

Madaglymbus gen. nov. is described for ten species of Aglymbus Sharp, 1882, from Madagascar and the Comoro Islands based on their morphology and a phylogenetic analysis of DNA sequence data using Bayesian and parsimony analyses. Madaglymbus was retrieved as a well supported clade (100% posterior probability both estimating model parameters for all data combined and with different loci). Madaglymbus ruthwildae sp. nov. is described from Ankarana Special Reserve, NW Madagascar. This unusual species is characterised by four highly conspicuous snow‐white spots on the brownish black elytra, its small size, numerous strioles on the pronotum and elytra, a strong and very long anterodistal seta (but not a short spine) on male protarsomere 4, and bilobed male parameres. Copelatus gestroi Sharp, 1882, comb. nov. and C. multistriatus Nilsson, 1991, comb. nov. are transferred from the genus Aglymbus to Copelatus Erichson, 1832. The following name replacements are proposed: Copelatus neogestroi Balke, nom. nov. for Copelatus gestroi Régimbart, and Copelatus agaroensis Balke nom. nov. for Copelatus multistriatus Nilsson, comb. nov.