Abstract:
Chaerephon pumilus, the little free-tailed bat, (family: Molossidae) has a distribution throughout most of sub-Saharan Africa and the eastern region of Madagascar. The vast geographical distribution of this species is accompanied by considerable phenotypic variation, which may conceal cryptic species. The cytochrome b (845 nucleotides) and D-loop (314 nucleotides) regions of the mitochondrial DNA were sequenced to assess phylogenetic relationships within C. pumilus (southern Africa) and in relation to Chaerephon species from Madagascar (C. pumilus, C. leucogaster). Samples were obtained from KwaZulu-Natal, South Africa, and localities in Swaziland. The cytochrome b sample (n = 11) comprised four haplotypes, with a haplotype diversity of 0.6727, whilst the D-loop (n = 34) dataset comprised 13 haplotypes with a haplotype diversity of 0.8342. Neighbour joining, maximum parsimony and Bayesian analyses revealed congruent tree structures for both mtDNA regions. All Chaerephon taxa in this study formed a monophyletic clade with respect to the outgroup Mops midas. Chaerephon pumilus from the eastern side of Madagascar formed a well-supported monophyletic group, sister to a clade comprising C. pumilus (southern Africa) and C. leucogaster, and is suggested to comprise a separate species. Southern African C. pumilus formed two paraphyletic clades, A and B, separated by a genetic distance of 0.9 %. Chaerephon leucogaster formed a monophyletic group nested within southern African C. pumilus, suggesting conspecificity. However, the well-characterized morphology of C. leucogaster lends support to its specific status, and suggests the possible existence of cryptic species among southern African C. pumilus. Population genetic analysis suggests that two C. pumilus (southern African) clades have been expanding, one for between 2432 and 4639 years, and the other for the 11156 to 21280 years. A combined cytochrome b analysis, trimmed to 343 nucleotides, was carried out on the data from this study and that of Jacobs et al. (2004), also on southern African C. pumilus. Haplotypes from the Jacobs et al. (2004) study, which also identified two 0.9 % divergent clades (light- and dark-winged) were found to be identical or very similar to haplotypes from this study and were interspersed among southern African C. pumilus haplotypes in phylogenetic analyses. Chaerephon pumilus haplotypes from Zambia and Tanzania were found to be more closely related to those from southern Africa and to C. leucogaster than to C. pumilus (Madagascar), further indicating that this may be a separate species. Haplotypes from the light-winged clade of Jacobs et al. (2004) were identical to those of dark-winged samples from this study, suggesting that wing shade may not be diagnostic of the two clades.
