Systematics and zoogeography of Tatera [Rodentia gerbillinae] of north-east Africa and Asia

Abstract

A taxonomic revision of Tatera (Rodentia: Gerbillinae) from tha study area of north-east Africa and Asia is undertaken. The results are discussed in terms of the zoogeography and evolutionary history of the genus Tatera. Five species of Tatera are recognized in north-east Africa; Tatera robusta. T. nlgricauda. T. valida, T.boehmi and T. phillipsi. T. philllpsi isreinstated from the synonymy of T. robusta. T. minuscula from Ethiopia is considered a taxon incertae sedis. A single species, T. indica. is present in Asia.The taxonomic study Is based on the statistical analysis of morphometrlc data, the evaluation of morphological characters and karyological data where available. Intraspecific variation, both non-geographlc and geographic is analysed. Species and their geographical races are defined and their distributions mapped. A matrix of diagnostic characters is included. The palaeontological literature of Tatera is reviewed. The faunal similarities, both present and past, of Africa and Asia are discussed, as are the major climatic and geophysical changes which are known to have occurred in the study area during the late Tertiary and Quaternary. The present day ecological requirements of the relevant Tatera taxa are also assessed. It is concluded that the genus Tatera probably evolved in Africa in the Pliocene and subsequently dispersed into Asia in the Pleistocene, possibly by way of a southern Red Sea landbridge. Evidence cited, includes the presence of fossil Tatera in the Middle Pliocene deposits of East Africa; the occurrence of Asiatic faunal elements in the fossil record of eastern Ethiopia; the presence of subsaharan African mammals in isolated localities in the south-west of peninsular Arabia; sea-bed cores supporting the view that the south of the Red Sea was periodically dry and the absence, to date, of fossil Tatera from palaeontological sites in North Africa and the Near East.