Gerbillus mauritaniae Heim de Balsac 1943

Gerbillus mauritaniae Heim de Balsac 1943, Bull. Mus . Hist. Nat. Paris, 15: 287.

Type Locality: Mauritania, Aouker Region, south of Archane Titarek.

Vernacular Names: Mauritanian Gerbil.

Distribution: Known only by the holotype, which is apparently lost, from the type locality.

Conservation: IUCN – Critically Endangered.

Discussion: Gerbillini . Type species of Monodia (Heim de Balsac, 1943) . According to Lay (1983), F. Petter (1975 b), and Roche (1975), the diagnostic traits of Monodia (three large independent tubercles covered with short and stiff hair in metatarsal region with remainder of sole naked, M3 with small posterior cusp) do not warrant generic distinction. Pavlinov et al. (1990) recognized Monodia as a genus but with a question. Pavlinov (in litt., 2001) explained that he examined a locality sample of pigmy gerbils from Mauritania in USNM and recognized two different mandible morphologies within it. One of them is typical Gerbillus and another he thought to be atypical of Gerbillus and superficially resembling that of Desmodilliscus; the two kinds were figured in Pavlinov et al. (1990:42, fig. 16). He supposed the atypical mandible to represent Heim de Balsac’s Monodia, and so resurrected the genus as distinct in Pavlinov et al. (1990). We examined the same Mauritanian series, which does consist of two entities, three examples of a very small-bodied species and six of an even smaller one. Given the vagueness of Heim de Balsac’s description, apparent lack of type material, and need for careful revision of pygmy gerbils in West Africa, it is uncertain which series represents mauritaniae . General mandibular shape of both is similar and resembles mandibles of other small Gerbillus, such as G. henleyi or the larger G. nanus . Each of the sympatric Mauritanian species has a naked plantar surface, accessory tympanum, and multichambered mastoid bullae with the same number of compartments as in many Gerbillus proper. Until specimens can accurately be identified as mauritaniae and their diagnostic traits revealed, we depart from the treatment by Pavlinov et al. (1990) and submerge Monodia into Gerbillus, without even subgeneric status, as indicated by other gerbil taxonomists.