Conflict and congruence in a combined DNA-morphology analysis of megachiropteran bat relationships (Mammalia: Chiroptera: Pteropodidae).

Abstract

The phylogeny of megabats (Mammalia: Chiroptera: Megachiroptera) has been addressed only on molecular grounds, as little effort has previously been made to describe the impressive morphological variation of the group in terms of phylogenetically informative characters. Here we provide a morphological matrix of 236 characters from the integument, dentition, cranial and post-cranial skeleton, digestive apparatus and urogenital system. This data set covers most characters discussed previously in more restricted taxonomic contexts, as well a large number of new characters. Our aim was to generate a phylogenetic hypothesis for megabats based on a combined analysis of morphological characters and available gene sequence data from four mitochondrial and one nuclear loci. We used direct optimization under conventional equal costs, as well as under a cost ratio that maximizes homology when inapplicables (gaps) are present. Our results contradict the allegedly high level of conflict between the molecular and morphological partitions. We found that, although morphology alone recovered trees different and to some extent incompatible with those from previous molecular analyses, the combination of the two sources of evidence easily accommodated the morphological and molecular signals, yielding a resolved and relatively well-supported phylogeny of Megachiroptera that is in reasonable agreement with the current morphology-based taxonomy of the group. Overall congruence favored the maximization of homology by a narrow margin. In addition, partial analyses showed that implied weighting of morphology performed slightly better than equal weighting with respect to the combined analyses.