PHYLOGENY, MOLECULES VERSUS MORPHOLOGY, AND RATES OF CHARACTER EVOLUTION AMONG FRUITBATS (CHIROPTERA, MEGACHIROPTERA)

Andersen's 1912 monograph on megachiropterans remains the definitive w ork on the systematics of this group. Andersen argued that the Macrogl ossinae, containing the eonycterine and notopterine sections, are a mo nophyletic sister-group to other fruitbats (i.e. Andersen's Rousettus, Cynopterus and Epomophorus sections). Two recent molecular studies (D NA hybridisation and restriction mapping of ribosomal cistrons), as we ll as an analysis of female reproductive characters, challenge the mon ophyly of the Macroglossinae and several of Andersen's other conclusio ns such as the phylogenetic position of Nyctimene. We performed a clad istic analysis on 36 morphological characters, including 33 that were gleaned from Andersen, to determine whether phylogenetic hypotheses ba sed on modem phylogenetic methods are in agreement with Andersen's ori ginal conclusions and to compare morphological and molecular phylogene tic hypotheses. Minimum-length trees based on parsimony are largely co nsistent with Andersen and support (1) a monophyletic Macroglossinae, within which the eonycterine section is paraphyletic with respect to a monophyletic notopterine section, (2) a monophyletic Cynopterus secti on, excepting the exclusion of Myonycteris, (3) a monophyletic Epomoph orus section, excepting the exclusion of Plerotes, and (4) a paraphyle tic Rousettus section, with several of the Rousettus-like forms branch ing off near the base of the tree. Bootstrapping analyses on a reduced data-set that included taxa shared in common with the DNA hybridisati on study did not provide strong support (greater than or equal to 95%) for any clades but did provide moderate support (greater than or equa l to 70) for several clades, including a monophyletic Macroglossinae. These findings are in marked contrast to the DNA hybridisation phyloge ny. A high index of between-data-set incongruence is further evidence for the clash between DNA hybridisation and morphology. A phylogenetic framework was constructed on the basis of morphological data and DNA hybridisation data using a criterion of moderate support and shows lit tle resolution, whereas employing a criterion of strong support produc ed a framework resolving several additional nodes. One implication of this framework is that characteristic macroglossine features such as a long tongue with a thick carpet of filiform papillae have evolved ind ependently on several occasions (or evolved once and were lost several times). Rates of character evolution for the morphological characters employed in our analysis were calculated using divergence times estim ated from DNA hybridisation data. Rates have apparently been fastest i n the interior branches, and slower along the external branches, which suggests an early adaptive radiation in the history of fruitbats.