Phylogenetic evaluation of the tropical Camptotypus genus-group (Hymenoptera: Ichneumonidae), with a key to the world genera

Abstract

The phylogeny of the disjunct pantropical Camptotypus genus-group (Hymenoptera, Ichneumonidae, Pimplinae) was reconstructed using 40 morphological characters.The monophyly of many established genera (Parvipimpla, Clydonium, Odontopimpla) was found to be supported, but Hemipimpla was found to nest within Camptotypus and has thus been treated as a junior synonym of it (syn. n.). A group of undescribed Neotropical species were found to form a separate monophyletic group, herein referred to as Genus A. Species of the Neotropical genus Zonopimpla formed a basal paraphyletic grade which could not satisfactorily be resolved into discrete monophyletic units. Rather than subsuming all the more derived genera within one large group, or attempting to erect numerous new and probably ephemeral genera (for isolated species of Zonopimpla), we propose the retention of this grade-group as a separate genus at present. The host utilization patterns of the genus-group, and the biogeography of the genus-group are discussed. The group is hypothesized as having originated and radiated in the Neotropics, as ectoparasitoids of weakly concealed lepidopterous hosts. One lineage, Clydonium, has become specialized at attacking hosts in woody galls where it utilizes coleopterous as well as lepidopterous hosts. The Old World genera (Camptotypus and Parvipimpla) comprise a monophyletic group and are suggested to have originated from a single dispersal event across the widening Atlantic. No evidence for either a southern or northern circum-polar dispersal was observed in this entirely tropical genus-group. One lineage in the Afrotropical region has switched from attacking lepidopterous hosts, to attacking pre-pupal and pupal polistine vespids.