Hasinamelissa : a new genus of allodapine bee from Madagascar revealed by larval morphology and DNA sequence data

Allodapine bees have received attention because of their utility for studies of insect social evolution. The African genus Halterapis has been especially important because until very recently it was thought to contain non-social species. Owing to the extreme diversity in allodapine larval morphology, which is much greater than the variation in adult morphology, larvae have provided some of the most informative characters for allodapine taxonomy. The taxonomic position of Malagasy allodapine bees placed previously in the genus Halterapis has always been doubtful because the larval stages were unknown. We provide the first description of larval morphology for three Malagasy allodapine species currently placed in the genus Halterapis that span the range in adult morphology for this island fauna. Larvae of all three species exhibit a variety of traits that are strikingly different from those of other allodapine genera. Phylogenetic analyses based on DNA sequence data from one nuclear and two mitochondrial gene fragments indicate that the Malagasy species form a strongly supported monophyletic group that is the sister group to the combined African allodapine clades excluding Macrogalea. This endemic Malagasy bee clade further highlights the distinctiveness of the Malagasy bee fauna and raises biogeographical questions about how, when, and why the Malagasy biota became so distinctive. We erect Hasinamelissa gen.n., to contain the Malagasy species placed previously in Halterapis, and transfer 18 species [H. seyrigi (Benoist) (type-species) comb.n., H. keiseri (Benoist) comb.n., H. minuta (Brooks & Pauly) comb.n., H. isaloensis (Brooks & Pauly) comb.n., H. tulearensis (Michener) comb.n., H. albigena (Brooks & Pauly) comb.n., H. kraussi (Michener) comb.n., H. didyensis (Brooks & Pauly) comb.n., H. acaciae (Brooks & Pauly) comb.n., H. ankaratrensis (Brooks & Pauly) comb.n., H. platyprosoton (Michener) comb.n., H. rufa (Michener) comb.n., H. pentagonalis (Brooks & Pauly) comb.n., H. benoisti (Michener) comb.n., H. curtipilosa (Brooks & Pauly) comb.n., H. personata (Brooks & Pauly) comb.n., H. spatulata (Brooks & Pauly) comb.n. and H. spinipennis (Brooks & Pauly) comb.n.]