The synanthropic molossid bat, Mops leucostigma (Allen 1918), is widely distributed across Madagascar and has recently been described from the Comoros. M. leucostigma individuals from eastern Malagasy populations are markedly larger than those from the west, and Mops leucostigma populations from Madagascar are morphologically distinct from populations of its putative sister species, Mops condylurus from mainland Africa (Ratrimomanarivo et al. in press, Genetic diversity was assessed by sequencing the mitochondrial cytochrome b (n = 56) and displacement loop (D-loop) (n = 64) regions of Mops leucostigma individuals from a broad range of locations across Madagascar, and Mohéli and Anjouan in the Comoros. Specimens of Mops condylurus (n =3), Mops midas (n =3) and Otomops martiensseni (n = 1) were included in the study for comparative purposes as outgroups. Phenetic and cladistic analysis of cytochrome b and D-loop sequences strongly supported the reciprocally-monophyletic status of Mops condylurus and M. leucostigma. Comorian (Mohéli and Anjouan) and Malagasy M. leucostigma samples formed a monophyletic Mops leucostigma group, within which Comorian samples formed a poorly-supported subclade in the cytochrome b analysis only. Cytochrome b genetic distances of 13.8 % separated M. midas from M. condylurus and M. leucostigma, which formed reciprocally-monophyletic sister groups separated by genetic distances of 2.5 % for cytochrome b and 13 % for the D-loop. 49 M. leucostigma cytochrome b sequences yielded seven haplotypes, two of which were exclusive to the Comoros. D-loop haplotype analysis did not support the distinctiveness of the Comorian samples. Genetic distances within M. leucostigma samples were low (0.22 % for cytochrome b and 1.91 % for the D-loop). Comorian samples were found to be genetically attributable to M. leucostigma. Clear phylogenetic separation between M. condylurus and M. leucostigma was found in all analyses, consistent with their status as phylogenetic species within the genus Mops. There was no clear correlation between haplotype distribution and aspect (east/west-facing slopes), elevation or gender. Low mtDNA variation (cytochrome b and D-loop) and lack of phylogeographic concordance indicates that the observed morphometric variation between eastern and western Mops leucostigma populations may possibly be explained in terms of adaptation to local environmental conditions. / Thesis (M.Sc.)-Univeristy of KwaZulu-Natal, 2008.