Chiropteran (Chiroptera; Mammalia) taxonomy in light of modern methods and approaches

Bats are the second largest mammalian order with an almost worldwide distribution. Bat taxonomy remained almost unchanged for decades, and the diversity of the order was underestimated. The advent of molecular methods brought change to chiropteran taxonomy. The number of families increased from 17-18 to 21, and the relationships between them were revised, as were the composition of suborders and superfamilies. The number of recognized species and genera went up by almost a third. As a discipline, bat taxonomy has changed much methodologically and conceptually. After its long reign, comparative morphology has faded into the background. It has become clear that characters can diverge and converge in related species, masking true phylogenetic relationships. Not writing morphology off entirely, it does necessitate resorting to finer structures or multivariate data analysis. Karyology is of limited use in bat taxonomy, but methods such as FISH add to the understanding of relationships between suprageneric taxa. Mitochondrial DNA sequences are easy to obtain, and their analysis yields well-supported phylogenetic trees, but reticular processes and other factors may mask taxon boundaries. To resolve the uncertainty, nuclear markers are used, and their number and choice depends on taxon characteristics. Overall, building a consistent chiropteran system calls for an integration of all mentioned approaches.