Abstract: Parascaptor is a monotypic genus distributed across Asia,including Southwestern China,Assam (India),Bengal, and Northern Burma and Laos,all of which possess extremely complex and diverse topography,climate and habitat. To test whether morphological diversification has taken place in these different environments,we examined the mandibles of
49 P. leucura specimens from 18 localities throughout the distribution area. Geometric morphometric analyses were used to examine the shape variations.The specimens were clustered into three groups—Northeastern Yunnan (group 1),Southern Hengduan Mountain (group 2),and Indian groups (group 3)—congruent with their geographic distribution. We found important distinctions Among these different groups in the horizontal ramus shape such as the length of the lower molar row, the curvature of the ventral margin and the relative depth of the horizontal ramus. Among the three groups,the specimens from Northeastern Yunnan have the shortest molar row and the thinnest and most flattened horizontal ramus. Our results imply that the three geographic groups may represent three subspecies or even full species,strongly warranting a taxonomic revision using comprehensive methods.

Key words: Geometric morphometrics, Mandible, Parascaptor leucura, PCA