Morphometric variability of Praomys misonnei (Rodentia: Muridae) in west central African forests reveals complex relationships between populations

This study addresses the morphological biometrics of Praomys misonnei and the signatures of its population history through a survey of external morphological characters measured on 133 individuals from eight West Central African (Gabon and Cameroon) localities. Four standard external characters were measured: head + body length, tail length, hindfoot length, and ear length. Using univariate and multivariate statistics, we inferred inter-population relationships from these morphometric characteristics and tested hypotheses of historical patterns of local adaptation (phylogenetic relationships) or of association with ecological gradients. We also tested the influence of sex on morphometric parameters. Our results support the existence of two morphometrically distinct groups of P. misonnei. The first one includes individuals from northern, central, and southern Gabon, while the second one includes individuals from southern Cameroon and one locality in southern Gabon (Mbaya). This result could be explained by the fact that the first group inhabits an area mainly covered by dense rainforest (about 90% of Gabon), while the second group is found in degraded forest or mosaics of forest-savanna habitats (Cameroon and southeastern Gabon). Another reason could be seasonal reversal, which has been postulated right at border between Gabon and Cameroon. The pattern of morphometric variation was correlated with local environmental factors. No sexual dimorphism was recorded.