Pompilidae is a family of solitary wasps with more than 5000 species worldwide and approximately 260 in Australia. Despite their diversity and ubiquity, their taxonomy is poorly understood in many regions, including Australia. Pompilids are represented in Australia by four subfamilies: the Ceropalinae, Ctenocerinae, Pompilinae and Pepsinae, this last one is the most diverse and includes 22 Australian genera. Two Pepsinae genera, Cryptocheilus and Heterodontonyx, have had a problematic taxonomic history due to their morphological similarity and affinities to the Palaearctic genera. My project aims to: 1-delineate the two morphologically similar Cryptocheilus and Heterodontonyx, 2- build a molecular phylogeny of Cryptocheilus and closely related genera and generate an updated key for the group, 3- to reconstruct the historical biogeography of the genera, and 4- to provide a taxonomic revision of the Australian species.

Phylogenetic analyses show that all species from Australia previously known as Cryptocheilus and Heterodontonyx form a single clade, which is not sister to the world Cryptocheilus —a clade containing the type species of the genus. Therefore, all Australian species should be considered Heterodontonyx. This clade is found in Australia, Papua New Guinea, the Solomon Islands, and New Zealand and is sister to Cyphononyx. The distribution of Cryptocheilus is limited to the west side of Wallace’s line as hypothesized by Wahis (2008). Biogeographical results suggest that the majority of events producing their current distribution are dispersal and founder events. In the process of taxonomic revision, I have come up with one new synonymy, five sex associations, one new species, nine new combinations, and 27 new records.