systematics

Earth history and the evolution of Caribbean bats

Although the natural history of the Caribbean is better understood now than ever before, a general biogeographic explanation for the peculiar faunal composition of the islands remains elusive. New molecular phylogenetic and divergence analyses …

Accounting for molecular stochasticity in systematic revisions: Species limits and phylogeny of Paroaria

Different frameworks have been proposed for using molecular data in systematic revisions, but there is ongoing debate on their applicability, merits and shortcomings. In this paper we examine the fit between morphological and molecular data in the systematic revision of Paroaria, a group of conspicuous song- birds endemic to South America. We delimited species based on examination of 600 specimens, and developed distance-gap, and distance- and character-based coalescent simulations to test species limits with molecular data. The morphological and molecular data collected were then analyzed using parsi- mony, maximum likelihood, and Bayesian phylogenetics. The simulations were better at evaluating the new species limits than using genetic distances. Species diversity within Paroaria had been underesti- mated by 60%, and the revised genus comprises eight species. Phylogenetic analyses consistently recov- ered a congruent topology for the most recently derived species in the genus, but the most basal divergences were not resolved with these data. The systematic and phylogenetic hypotheses developed here are relevant to both setting conservation priorities and understanding the biogeography of South America.

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.

Molecular phylogeny of funnel-eared bats (Chiroptera: Natalidae), with notes on biogeography and conservation

Two assumptions have framed previous systematic and biogeographic studies of the family Natalidae: that it comprises a few widespread species, and that extant lineages originated in Mexico and/or Central America. This study analyzes new sequence data from the mitochondrial cytochrome b and the nuclear Rag2, to clarify species boundaries and infer relationships among extant taxa. Fixed differences in cytochrome b coincide with published morphological characters, and show that the family includes at least eight species. One newly recognized species is known to live from a single locality in Jamaica, suggesting immediate conservation measures and underscoring the urgency of taxonomic revision. Among the three genera, Chilonatalus and Natalus form a clade, to the exclusion of Nyctiellus. This phylogeny and the geographic distribution of natalids, both extant and extinct, are hardly compatible with a Middle American origin for the group. Instead, extant natalids appear to have originated in the West Indies. The threat of Caribbean hurricanes early in their evolutionary history might account for the specialized cave roosting that characterizes all natalids, even continental species.

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.