Evaluation of craniofacial variation in the lesser bandicoot rat, Bandicota bengalensis (Rodentia: Muridae: Murinae): biological and statistical implications

We studied nongeographic intraspecific variation of craniofacial morphology in the lesser bandicoot rat ( Bandicota bengalensis ) by applying linear morphometric methods. Among 26 morphometric characteristics of 30 adult skulls (11 males and 19 females), males exhibited a slightly larger average size in 22 measurements, most of which were non-significant. Males were significantly larger than females only in short lateral facial length. Although, discriminant functions revealed large disparities between the sexes, leave-one-out cross-validation demonstrated that only 43.33% of specimens were properly classified into the sexes. K-means clustering indicated the correct assignment for 30% of specimens to their own clusters. The allometric slopes were also not significantly different between sexes. Therefore, common allometric trends were considered for subsequent investigation. Both bivariate regression (ordinary least-squares and reduced major axis) methods were consistent in allometric trends for most measurements and revealed distinct patterns of allometry in the major sub-regions of craniofacial morphology. In conclusion, we found a limited craniofacial sexual dimorphism in B. bengalensis with similar patterns of allometric growth.