Tribe Gerbillini, Subtribe Rhombomyina. No modern systematic revision is available for Meriones. The early revision by Chaworth-Musters and Ellerman (1947), as updated and modified by Ellerman and Morrison-Scott (1951), Corbet (1978c), and Pavlinov et al. (1990), represents the most current review of species. Additional taxonomic, distributional, and evolutionary views are found in the taxonomic reports and regional faunal studies cited throughout the accounts below. Most workers agree on definitions of the species we list here, but careful systematic revision will probably uncover a greater number of species. Chromosomal data concerning Meriones was summarized by Nadler and Lay (1967) in the context of assessing relationships among the species and subsequent chromosomal information was summarized by Qumsiyeh and Schlitter (1991). Additional chromosomal data and its significance to understanding phylogenetic relationships among six species of Meriones reported by Benazzou et al. (1982a, b). Lay and Nadler (1969) summarized laboratory hybridization attempts among several species of Meriones. Records of species from Iran and Pakistan reported by Lay et al. (1970). Yiit et al. (1997b) reviewed ranges, diagnostic traits, and other characteristics of Turkish species. Comparisons of male genital morphology by Pavlinov (1986) pointed to the phylogenetic isolation of M. tamariscinus among the species of Meriones. Gromov and Erbajeva (1995) documented morphological and distributional contrasts among species of Meriones in Russia and Sokolov and Neronov (1993) provided a three-volume bibliography covering research dealing with Meriones that includes distribution maps for species in that country.
Pavlinov et al. (1990) recognized four subgenera in Meriones (Meriones, Parameriones, Pallasiomys, and Cheliones), and our subgeneric allocation of species generally follows their treatment. Evolutionary history as indicated by fossils first encountered in late Pliocene-early Pleistocene sediments of North Africa (Tong, 1998; Wessels, 1999), Holocene of East Africa (Denys, 1999), early Pleistocene of Israel (Tchernov, 1986, discussed under Parameriones), and middle Pleistocene strata in China (Lucas, 2001). Meriones is thought to have evolved from the extinct Pseudomeriones, the earliest known gerbilline, recorded from the early part of late Miocene in Turkey and Afghanistan, and later in late Miocene and Pliocene in those two countries and Spain, Greece, N Iran/Turkmenistan, and China (Wessels, 1998).