Geographic range, morphometric variation and niche differentiation in greater Egyptian jerboa, Jaculus orientalis 1)

Geographic range, morphometric skull variation and niche differentiation were analyzed in the greater Egyptian jerboa, Jaculus orientalis , and compared with published data on the species' phylogeographic structure. The species occurs in 15 separate areas, which are grouped into two main blocks and divided by a wide gap. The first block goes from Morocco to western Libya and the second from eastern Libya to Israel; the second block is subdivided into two sub-blocks, eastern Libya and Egypt and Israel and Sinai. Analysis of niche similarity indicated niche convergence within the eastern and western parts of the species' geographic range and niche divergence between these two major parts of the geographic range. There was a strong congruence among distributional, genetic and ecological patterns. Morphological variation in J. orientalis did not completely coincide with the distribution, genetic and ecological patterns. Three morphologically well-differentiated population groups were found within the geographic range of the species. The same level of morphological differentiation was demonstrated between highly isolated geographically and deeply diverged genetically and ecologically western and eastern groups of populations and between the weakly geographically isolated and ecologically similar populations of Egypt/Libya and Israel/ Sinai. A taxonomic revision of the sub-specific division of J. orientalis is proposed.