Calesinae (Hymenoptera: Chalcidoidea): morphology and molecular phylogenetics of an enigmatic taxon

Although the monophyly of some groups of Chalcidoidea is strongly supported by morphological and/or molecular synapomorphies, higher-level relationships within the superfamily remain uncertain. Several families are regarded as either paraphyletic or even polyphyletic. This uncertainty regarding sister-group relationships, combined with hyperdiversity of form and function, has left some chalcid groups unplaced into higher taxonomic categories Establishing relationships within Chalcidoidea is further hindered by a dearth of comprehensive morphological studies, either across character systems or across taxa. Calesinae (Howard) is a small group of Australian and Neotropical parasitoids of whiteflies, comprising a single genus, Cales. Historically, the Calesinae have been included within the Trichogrammatidae and Mymaridae, though they are most often associated with the Aphelinidae. In addition, they share some features with the Eulophidae. The subfamily is currently unplaced within the superfamily Chalcidoidea. Here we present a detailed morphological examination and a molecular phylogenetic analysis of the three described species in addition to a newly discovered species from New Zealand. The apparently apomorphic characteristics of the head, mouthparts, antennae, wings, mesosoma and genitalia, are weighed against characteristics suggesting affinities with established chalcidoid families. In addition, we provide a species-level molecular phylogeny of the group, suggesting a possible cryptic species complex within the new world species, Cales noacki.