Giant sawflies and their kin: morphological phylogeny of Cimbicidae (Hymenoptera)

Abstract

The Cimbicidae is a small family including the largest extant true sawflies (Tenthredinoidea). It comprises four subfamilies, three of which have a northern hemisphere distribution (Abiinae, Cimbicinae – Holarctic/Oriental; Corynidinae – Palaearctic), whereas the Pachylostictinae are restricted to South America. No previous attempts have been made to evaluate the subfamily classification in a cladistic context. In the present paper, 144 morphological characters from the adult anatomy for a total of 95 species of Cimbicidae and 26 outgroup taxa are scored. All subfamilies and all genera of Cimbicidae except one are represented; all families of Tenthredinoidea are represented in the outgroup. Equal weights (EW) and implied weights (IW) analyses are conducted in tnt. The results largely corroborate the existing subfamily classification, except for Pachylostictinae which are paraphyletic in IW analyses with low K-values. Abiinae + Cimbicinae is always retrieved and strongly supported; Corynidinae + Pachylostictinae is retrieved in most analyses but weakly supported. Revised diagnoses of the subfamilies are provided. Several genera are retrieved as monophyletic, notable exceptions being Praia and Trichiosoma, which are polyphyletic. The evolution of large body size in Cimbicidae is briefly discussed; possible related phenomena are intrasexual competition and mimicry, i.e. resemblance to large apids or vespids.