The suprageneric groups ofthe Pimplinae (Hymenoptera: Ichneumonidae): a cladistic re-evaluationand evolutionary biological study

The phylogenetic relationships of the suprageneric groupsof the ichneumonid subfamily Pimplinae (Hymenoptera) are re‐assessedusing 166 morphological and biological characters for 162 species,representing all of the available described genera and subgenera.The cladistic analysis was repeated using abstracted genera, re‐codedfrom the ­initial set of species, as terminal taxa. Thetopology of the resulting cladograms was similar. In the first (primary) analysisseveral genera (including Neotheronia, Itoplectis, Dolichomitus, Dreisbachia, Polysphincta, Oxyrrhexis and Zonopimpla)were not retrieved as monophyletic groups; however, all except thelast were found to be monophyletic in the second analysis. Theseresults suggest that using abstracted taxa may force a ‘falsemonophyly’ on the preselected groups. Thus we reject theuse of such abstractions, preferring instead to use exemplar speciesthat together show much of the variation that occurs within a hypothesizedgenus. Within the Pimplinae three major groupings were recognized,the Delomeristini (including the Perithoini syn. nov.) , thePimplini and the Ephialtini. Within the Pimplini, two generic groupswere recovered, the Xanthopimpla and Pimpla genus‐groups,but a third postulated group, the Theronia genus‐group, wasfound to be paraphyletic. Within the Ephialtini five groups wererecognized, the Pseudopimpla, Alophosternum, Camptotypus, Ephialtes and Sericopimpla genus‐groups.The spider parasitizing complex of genera (the Polysphincta genus‐complex)was found to nest within the Sericopimpla genus‐group confirmingthe placement of Polysphinctini as a synonym of Ephialtini. Problemswith the status of some existing genera are highlighted, but formalnomenclatural changes are not proposed. The ancestral Pimplinaeare hypothesized to have been solitary ectoparasitic idiobiontson weakly concealed immature Hymenoptera. The major radiations withinthe Pimplinae are shown as: (1) a progressive exploitation of cocooned,then weakly cocooned, lepidopterous pupae in the Pimplini leadingto idiobiont endoparasitism; (2) increasing specialization to attackhosts deeply concealed in wood in the Ephialtes genus‐group,and (3) specialization on a variety of cocooned hosts, includingspider egg sacs, leading to koinobiont ectoparasitism of spiders.A brief synopsis of the distribution of the group is given, and somebiogeographical inferences drawn. The group is presumed to haveoriginated and radiated on Laurasia; no evidence for trans‐Antarcticrelationships can be found. © 2002 The LinneanSociety of London, Zoological Journal of the Linnean Society,2002, 136 , 421?485