Phylogeny and classification of the Xeromelissinae (Hymenoptera : Apoidea, Colletidae) with special emphasis on the genus Chilicola

A phylogenetic analysis and classification are provided for the bee subfamily Xeromelissinae based on 248 morphological characters, many of which are novel and illustrated. A total of 47 ingroup species was included in the analysis, representing at least two divergent members from each described genus or subgenus and seven taxa, which did not readily fall within previously described subgenera. Three most parsimonious trees were found (length, 1508; consistency index, 40; retention index, 70). The result shows that Xeromelissa renders Chilimelissa paraphyletic, and the 20 known Chilimelissa species are reassigned to Xeromelissa, giving the following new combinations: X. luisa (Toro & Moldenke) (this is the type species of Chilimelissa), X. mucar (Toro & Moldenke), X. xanthorhina (Toro), X. brevimalaris (Toro), X. rosie (Toro and Packer), X. laureli (Toro and Packer), X. chusmiza (Toro), X. longipalpa (Toro), X. pedroi (Toro & Moldenke), X. australis (Toro & Moldenke), X. chillan (Toro & Moldenke), X. farellones (Toro & Moldenke), X. machi (Toro), X. minuta (Toro & Moldenke), X. nortina (Toro & Moldenke), X. sielfeldi (Toro & Moldenke), X. obscura (Toro & Moldenke), X. irwini (Toro & Moldenke), X. nolanai (Toro & Moldenke) and X. rozeni (Toro & Moldenke). Group support was estimated using symmetric resampling and group supported/contradicted (GC) ratios, which compare the frequency of each most parsimoniously resolved clade with the alternative arrangement that was most commonly found in resampling. Relationships among subgenera for Chilicola are weakly supported. By contrast, when three previously synonymized subgenera (Stenoediscelis, Heteroediscelis and Oediscelisca) are resurrected, there is good support for all subgenera (GC >= 99), except two: a paraphyletic Oediscelis and a polyphyletic Anoediscelis. Both of these subgenera became monophyletic following successive approximations character weighting. Four distinctive new subgenera are described: Unicarinicola Packer subgen.n., Obesicola Packer subgen.n., Capitatiscopa Packer subgen.n. and Toroediscelis Packer subgen.n., and a revised key to the subgenera of Chilicola is provided.