The geography of diversification in the mormoopids (Chiroptera: Mormoopidae)
The traditional explanation of the distribution of the Mormoopidae is that this family originated in southern Central America or northern South America, later expanding its range north to Mexico and the West Indies, and differentiating into eight species. An alternative fossil-based hypothesis argues that the family originated in the northern Neotropics, reached the Caribbean early in its history, and dispersed to South America after the completion of the Isthmus of Panama. The present study analyses new and previously published sequence data from the mitochondrial 12S, tRNAval, 16S, and cytochrome b, and the nuclear Rag2, to evaluate species boundaries and infer relationships among extant taxa. Fixed differences in cytochrome b often coincide with published morphological characters and show that the family contains at least 13 species. Two additional, morphologically indistinct, lineages are restricted to Suriname and French Guiana. Phylogeny-based inferences of ancestral area are equivocal on the geographical origin of mormoopids, in part because several internal nodes are not resolved with the available data. Divergences between Middle American and Antillean populations are greater than those between Mexico/Central America and South America. This suggests that mormoopids diversified in northern Neotropics before entering South America. A northern neotropical origin for mormoopids is congruent with both the Tertiary fossil record and recent phylogenetic hypotheses for the sister family to the Mormoopidae, the Phyllostomidae.
Exploring population genetic structure in three species of Lesser Antillean bats
We explore population genetic structure in phyllostomid bats (Ardops nichollsi, Brachyphylla cavernarum and Artibeus jamaicensis) from the northern Lesser Antilles by investigating the degree to which island populations are genetically differentiated. Our hypothesis, that the island populations are genetically distinct because of a combination of founding events, limited migration and genetic drift exacerbated by catastrophe‐induced fluctuations in population size, is derived from a priori hypotheses erected in the literature. The first prediction of this hypothesis, that within each species island populations are monophyletic, was tested using a parametric bootstrap approach. Island monophyly could not be rejected in Ardops nichollsi (P = 0.718), but could be rejected in B. cavernarum (P < 0.001) and Artibeus jamaicensis (P < 0.001). A second prediction, that molecular variance is partitioned among islands, was tested using an amova and was rejected in each species [Ardops nichollsi (P = 0.697); B. cavernarum (P = 0.598); Artibeus jamaicensis (P = 0.763)]. In B. cavernarum and Artibeus jamaicensis, the admixture in mitochondrial haplotypes from islands separated by > 100 km of ocean can be explained either by interisland migration or by incomplete lineage sorting of ancestral polymorphism in the source population. As an a posteriori test of lineage sorting, we used simulations of gene trees within a population tree to suggest that lineage sorting is an unlikely explanation for the observed pattern of nonmonophyly in Artibeus jamaicensis (PW < 0.01; PSE = 0.04), but cannot be rejected in B. cavernarum (PW = 0.81; PSE = 0.79). A conservative interpretation of the molecular data is that island populations of Artibeus jamaicensis, although isolated geographically, are not isolated genetically.
Phylogeny of the Lonchophyllini (Chiroptera: Phyllostomidae)
A combination of 1,140 base pairs of the mitochondrial cytochrome b gene of Platalina, Lionycteris, and several species of Lonchophylla (Chiroptera: Phyllostomidae) with 150 morphological, sex chromosome, and restriction site characters were used in an attempt to resolve relationships among the lonchophylline taxa. In addition, the monophyly of Lonchophylla was tested, particularly with respect to Platalina. The most parsimonious hypothesis of relationships using all available characters was (L. mordax ((L. chocoana (L. robusta, L. handleyi))(L. thomasi (Lionycteris, Platalina)))). Lonchophylla appears to be paraphyletic, but this arrangement is not well supported. Our analyses suggest that Platalina is not simply a large Lonchophylla, as had been suggested by previous morphological analyses. The low support values for basal relationships found in this study are probably caused by saturation in cytochrome b 3rd positions. Additionally, 2 alternative explanations are viable (if improbable): unsampled lonchophyllines are necessary to confidently resolve relationships at the base of the group, or the lack of resolution at the base of the lonchophylline phylogeny might be explained by rapid speciation following the separation from other glossophagines. Future work examining the phylogenetic relationships of lonchophylline bats should focus on describing new taxa, obtaining tissue samples from unsequenced representatives, and adding nuclear loci to this mitochondrial DNA data set.