Cladistic analysis and evolutionary relationships of the “Megaxylocopa clade” of the genus Xylocopa Latreille, 1802 (Insecta: Hymenoptera: Apidae)

Computerized cladistic analysis was used to (1) develop a hypothesis of phylogenetic relationships among the three species of the well-defined “Megaxylocopa clade” within subgenus Neoxylocopa Michener, of the genus Xylocopa Latreille, and (2) examine relationships between the members of this clade and other species in the subgenus Neoxylocopa. Twenty-four adult morphological characters were scored for the three species in the “Megaxylocopa clade” plus 10 outgroup taxa from subgenus Neoxylocopa Michener. Xylocopa (Xylocopoides) virginica (Linnaeus) was used as a distant outgroup taxon to root the tree. A single most parsimonious tree was recovered by cladistic analysis using the computer software program TNT. The three species of the “Megaxylocopa clade” form a well-supported monophyletic group that is the sister-lineage of another monophyletic group that includes the other 10 species of subgenus Neoxylocopa. Within the “Megaxylocopa clade,” Xylocopa nautlana Cockerell and X. frontalis (Olivier) are sister-species, relative to X. fimbriata Fabricius.