Phylogeny of the bee subtribe Caenohalictina Michener (Hymenoptera, Apidae s.l., Halictinae s.l.)

Recently, Caenohalictina Michener, 1954 was formally proposed as a group within Halictini based on a phylogenetic analysis using DNA data. Morphological synapomorphies for the subtribe are not stabilized and the relationships among its attributed genera were not completely reconstructed. Also, there are different propositions for the scope and classification of the genera. This study investigates the monophyly of Caenohalictina based on morphological characters and presents a hypothesis for the relationships among its genera and subgenera. For this purpose, a matrix of 36 terminals and 96 characters was coded. The cladistic analysis using character equal weighting resulted in one most parsimonious tree with 189 steps. According to this hypothesis, the subtribe is monophyletic with five synapomorphies supporting it. The relationships among Caenohalictina taxa are: Habralictus(Caenohalictus (((Agapostemon s.s. + Notagapostemon) (Agapostemonoides (Rhinetula (Paragapostemon + Dinagapostemon)))) + ((Ruizanthedella (Ruizantheda + Oragapostemon)) + (Brasilagapostemon (Pseudagapostemon s.s. + Neagapostemon))))). The subgenus Habralictus s.s. is paraphyletic with respect to Habralictus (Zikaniella) crassipes, hence both subgenera are not recognized. Comments on alternative generic classifications and biogeographic patterns are presented.