Cladistic analysis of the tribes of Dytiscinae and the phylogenetic position of the genus Notaticus Zimmermann (Coleoptera: Dytiscidae)

Abstract

Abstract

A hypothesis of the phylogeny of the tribes of Dytiscinae is presented based on a cladistic analysis of adult morphological characters. All tribes of Dytiscinae were included with larger tribes represented by multiple genera. Outgroups included members of all major lineages (subfamilies) of Dytiscidae. The matrix consists of 22 taxa and 45 characters. A single most parsimonious cladogram was produced by the analysis. It is concluded from the analysis that Dytiscinae is paraphyletic with respect to the genus Notaticus Zimmermann which has been previously recognized as the only member of the subfamily Aubehydrinae. Its position within the subfamily requires that it be placed within its own tribe, Aubehydrini. Additionally, Dytiscini was found to be paraphyletic, and a new tribe, Hyderodini, is proposed to contain the genus Hyderodes Sharp. Dytiscini is restricted to include only the genus Dytiscus Linneaus. Dytiscinae and all other tribes within the subfamily were found to be monophyletic. The proposed relationships of the tribes of Dytiscinae are Cybistrini + (Dytiscini + (Hyderodini + (Aubehydrini + (Hydaticini + (Eretini + Aciliini))))). Characters discovered to be useful for phylogenetic analysis of the subfamily are illustrated and described. The tribes are diagnosed and a key is presented for distinguishing them.