Morphological And Genetic Variability In Ghanaian Populations Of Noack's Leaf-Nosed Bat (Hipposideros Aff. Ruber) Alonga Latitudinal Gradient

Abstract

The Hipposideros caffer complex consists of several taxa whose taxonomic relationships are not fully resolved. Genetic diversity and skull morphology of Ghanaian populations of the Noack’s leaf-nosed bat Hipposideros aff. ruber (Noack, 1893) attributed to mitochondrial D lineages were investigated using nucleotide sequences of mitochondrial cytochrome b gene and geometric morphometrics. Cytb sequences of H. aff. ruber populations from Ghana were compared to other available West African sequences and their phylogenetic relationships were inferred under maximum likelihood, maximum parsimony and Bayesian methods. Phylogenetic reconstruction based on 63 cytb sequences (725 base pairs) showed a paraphyly in the Ghanaian populations. Individuals from the southern part of Ghana (Kwamang, Buoyem and Forikrom sites) formed a monophyletic group with individuals from Cote d’Ivoire, which corresponds to the previously identified sublineage D3. On the other hand, individuals from the northern part of Ghana clustered together with individuals from Senegal and Benin within sublineages D1 and D2, respectively. Interestingly, the Ghanaian populations exhibited a rather large genetic divergence of up to 6.1% based on pairwise Kimura two-parametric distances. This suggests possible presence of cryptic species, but reproductive isolation is yet to be investigated to confirm species status of the divergent genetic forms. Differences in size and shape of skull morphology of the D lineage were investigated using 10, 11, and 13 digitized landmarks on dorsal, ventral and lateral views respectively. Intra-lineage shape differences analyzed by Canonical Variate Analysis (CVA) and Discriminate Function Analysis (DFA) with leave-one-out cross validation of the Procrustes superimposed landmarks showed variation in the region of the zygomatic arch. Individuals assigned to sub-lineages D3 are distinguished from the other two sub-lineages (D1, D2) by having a slightly wider zygomatic arch. Cross-validated classification results were greater than 70% for sub-lineages D1 and D3 as well as D2 and D3 for all three cranial views analyzed but were as low as 47% when comparing D1 and D2. Classification success for the three cranial views for northern and southern Ghana populations ranged from 68%-85%. Log centroid size differed among lineages, sexes as well as northern and southern Ghana populations. Mechanisms of isolation by distance and historical environmental changes may have played a major role in the evolution of the D sub-lineages. Broader geographical sampling throughout West Africa and the use of both nuclear and mitochondrial data are necessary for resolving the phylogeography of the complex.