Evolutionary Patterns of Morphology and Behavior as Inferred from a Molecular Phylogeny of New World Emballonurid Bats (Tribe Diclidurini)

Abstract

A molecular phylogeny of New World emballonurid bats based on parsimony and Bayesian analyses of loci from the three different nuclear genetic transmission pathways in mammals (autosomal, X, and Y chromosomes) is well supported and independently corroborated by each individual gene tree. This is in contrast to a single most parsimonious but poorly supported tree based on morphological data, which has only one intergeneric or higher relationship shared with the molecular phylogeny. Combining the morphological and molecular data partitions results in a tree similar to the molecular tree suggesting a high degree of homoplasy and low phylogenetic signal in the morphological data set. Behavioral data are largely incomplete and likewise produce a poorly resolved tree. Nonetheless, patterns of evolution in morphology and behavior can be investigated by using the molecular tree as a phylogenetic framework. Character optimization of the appearance of dorsal fur and preferred roosting sites maps consistently and are correlated on the phylogeny. This suggests an association of camouflage for bats with unusual appearance (two dorsal stripes in Rhynchonycteris and Saccopteryx, or pale fur in Cyttarops and Diclidurus) and roosting in exposed sites (tree trunks or under palm leaves). In contrast, the ancestral states for Old and New World emballonurids are typically uniform brown or black, and they usually roost in sheltered roosts such as caves and tree hollows. Emballonuridae is the only family of bats that has a sac-like structure in the wing propatagium, which is found in four New World genera. Mapping the wing sac character states onto the phylogeny indicates that wing sacs evolved independently within each genus and that there may be a phylogenetic predisposition for this structure. Ear orientation maps relatively consistently on the molecular phylogeny and is correlated to echolocation call parameters and foraging behavior, suggesting a phylogenetic basis for these character systems.