A systematic review of selected Afro-Asiatic Rhinolophidae (Mammalia: Chiroptera) : an evaluation of taxonomic methodologies
A taxonomic review of five members of the Rhinolophus ferrumequinum group (Mammalia: Chiroptera: Rhinolophidae) from Africa and Asia is undertaken. The study incorporates a suite of taxonomic methods, using both morphological data and sequence data of the cytochrome b gene of mitochondrial DNA. Six species of Rhinolophus are recognised from within the region, namely R. ferrumequinum, R. clivosus, R. bocharicus, R. rouxii, R. sinicus and R. affinis. R. sinicus is promoted to species rank, having previously been considered to represent a subspecies of R. rouxii. Intra-specific variation, both geographic and non-geographic is analysed, and revised classifications presented. Synonyms, and their original descriptions are given for each species, and species limits and distributions are defined. Diagnostic characters are described, and tables of measurements included. Inter- and intra-specific relationships are examined using classical taxonomic methods, numerical phenetics, cladistic analysis, molecular techniques, and the total evidence approach. Each method is discussed in detail, and the literature relevant to each technique reviewed. This rigorous methodological approach is undertaken in order to provide robust taxonomic classifications, and to allow for each of the methods employed to be evaluated in terms of their ability to solve a complex taxonomic problem. The use of a combination of methods is found to provide a high degree of taxonomic resolution. The relationships of the five study taxa are clarified, with the hitherto unresolved relationship between R. ferrumequinum, R. clivosus and R. bocharicus, and the taxonomic status of R. sinicus being of particular note. In addition, taxa requiring further systematic investigation are identified for future research, such as R. rouxii from southern India and Sri Lanka, and R. ferrumequinum nippon from Japan. The evolutionary history of the R. ferrumequinum, R. clivosus and R. bocharicus complex is discussed in the light of the results of systematic analysis, as are the specific and subspecific relationships of R. rouxii and R. affinis. It is concluded that R. clivosus and R. bocharicus may have evolved from populations of R. ferrumequinum as a result of allopatric speciation occurring during periods of climatic change in the Pliocene and Pleistocene. Methodologically, it is concluded that the comparison of results from a number of techniques provides a robust base from which to formulate taxonomic conclusions. The optimal approach is considered to be a combination of molecular analysis and classical morphological investigation.