GEOGRAPHIC-VARIATION OF ARVICANTHIS (RODENTIA, MURIDAE) IN THE NILE VALLEY

The size and shape differences in the skulls of nine populations of th e rodents Arvicanthis along the Nile Valley (Egypt and Sudan) and one from Yemen were analysed. A three dimensional (x, y and z) landmark ap proach (Procrustes analysis) was used to study morphometric variation in these populations, in an attempt to evaluate differences between A. niloticus and A. testicularis and patterns of geographic variation. S ize and shape differences were correlated to ''ecogeographic'' paramet ers (latitude, longitude, rainfall, temperature). Morphometric variati on suggests that the two taxa have diversified in this area; and that variation reflects adaptation to current conditions. However, Partial Least Squares analysis showed that patterns of size and shape changes are different across species which suggests an independent evolutionar y history.