Gerbillus Desmarest, 1804 . Tabi. Méth. Hist Nat., in Nouv. Diet. Hist. Nat., 24:22.

TYPE SPECIES: Gerbillus aegyptius Desmarest, 1804 (= Dipus gerbillus Olivier, 1801).

SYNONYMS: Dipodillus, Endecapleura, Hendecapleura, Monodia, Petteromys .

COMMENTS: This genus has never been adequately revised. Lay (1983) summarized taxonomic difficulties of the genus, discussed significant character complexes that would bear on any scheme to separate species into subgenera (nature of plantar surfaces, size of auditory bulla, relative tail length, dental traits, accessory tympanum, and karyotype), and provided an annotated checklist of the species he considered valid. Lack of concordance among the suites of characters discouraged Lay from allocating species to higher categories conventionally recognized as either subgenera or genera ( Dipodillus, Hendecapleura, Monodia, Petteromys; see Pavlinov et al., 1990), and Lay felt compelled to recognize a single genus without subgenera until the group was systematically re-evaluated. No such comprehensive revision has emerged since 1983, and Lay's taxonomic overview remains the best working hypothesis of specific diversity in Gerbillus . With a few departures, we follow his treatment. Pavlinov et al. (1990) recognized subgenera of Gerbillus but admitted the weakness of these categories.

An excellent account of species occurring east of the Euphrates River was provided by Lay and Nadler (1975). The distribution of six species endemic to North Africa was mapped and discussed by Cheylan (1990) in the context of assessing endemism and speciation of Mediterranean mammals. Tranier and Julien-Laferriere (1990) commented on suggested identities of several species from North Africa. A contribution to allozymic variation within and between species was offered by Nevo (1982). Evolutionary tendencies within Gerbillus, as reflected in dental traits, were discussed by Petter (1973c). And the significance of variation in incisor microstructure within the genus was reported by Flynn (1982). Species of Gerbillus were included by Bonhomme et al. (1985) and Pascale et al. (1990) in their assessment of phylogenetic relationships among muroid rodents with electrophoretic and DNAsequence data.