| Adaptive radiation has been used to explain the diversification of many organisms, but has been infrequently distinguished from non-adaptive radiation. Among mammals, the Neotropical bat family Phyllostomidae has been proposed as an adaptive radiation. The original shifts to the diverse feeding and roosting habits seen in this group may have resulted in increased ecological opportunity leading to enhanced speciation rates, a classic explanation of adaptive radiation. This study examined shifts in diversification rate within Noctilionoidea and their correlation with apomorphic feeding and roosting traits to test this hypothesis. Using a data set including new and previously published characters (213 morphological, 8 behavioral, 1 chromosomal, 13 restriction site, 1,363 bases of sequence from the nuclear recombination activating gene 2, and 1,140 bases of the mitochondrial cytochrome b gene), separate and combined parsimony analyses were conducted for 74 species, representing 52 phyllostomid genera and outgroups from four microchiropteran families. Phyllostomid taxa that share apomorphic feeding habits form clades. Under nearly all interpretations of the data, Mystacinidae is the sister taxon of Phyllostomidae and Phyllostorninae is not monophyletic. All other subfamilies are monophyletic. Shifts in diversification rate appear to occur near the base of the noctilionoid clade, but not at nodes with shifts to derived feeding and roosting habits. The significance of the test at the split of Mystacinidae from Phyllostomidae may be accounted for by the limited geographic distribution of Mystacina, which is found only in New Zealand. The shifts in rate detected between Noctilio and the remaining noctilionoids, and between Desmodontinae and the remaining phyllostomid species, remain to be explained. The single shifts to most derived feeding and roosting behaviors within Phyllostomidae preclude most statistical testing of the correlation of these characters with other traits, necessitating a more general approach to these issues. |
