Molecular systematics of the tree bats (genus L̲a̲s̲i̲u̲r̲u̲s̲)

Abstract

Phylogenetic relationships among some members of the bat genus Lasiurus were investigated using a restriction enzyme analysis of the ribosomal genes of the mitochondrial molecule. A new restriction site mapping strategy was developed; it provides high resolution maps by partial endonuclease digestion of the target sequence. One hundred and thirty-five sites were mapped onto a 1.6 kb fragment that includes most of the 12S and 16S rRNA genes. The results of this study agree with previous work based on protein electrophoresis and, in some cases, do not support traditional taxonomic allocations based on morphology. Of the three species groups recognized in the genus, two (hoary and red bats) clustered together and separate from the third group (yellow bats) in some of the analyses, although in other analyses the yellow and red bats clustered closer to one another. Thus, the relationships among the three species groups in Lasiurus constitute an unresolved trichotomy. Species relationships within each of these groups were also analyzed. Among the hoary bats, the Hawaiian bat is similar to the North American hoary bat, but less similar to the South American subspecies. Separation of the North American red bats into two species, L. borealis and L. blossevillii is supported by the restriction site data. Also, L. pfeifferi from Cuba, considered as a subspecies of L. borealis, is closer to L. seminolus and probably should be considered a subspecies of this latter taxon. Among the yellow bats, L. xanthinus and L. insularis are shown to be distinct species separated from L. ega and L. intermedius, respectively. These last two species are shown to be closely related taxa, as previously suggested by karyotypic evidence. Rates of evolutionary divergence for the ribosomal genes, based on estimated time of origin of the genus Lasiurus, indicate that this region is evolving at about 0.87% divergence per million years, which is comparable to estimates in other mammalian groups based on sequence data.