Reevaluation of the taxonomic status of North African gerbils usually referred to as Gerbillus pyramidum (Gerbillinae, Rodentia): Chromosomal and biometrical data

The chromosomal and biometrical attributes of large-sized, hairy-footed ger bils from North Africa usually referred to as Gerbillus pyramidum were stud ied. High-resolution banding techniques as well as external and skull biome try were used to compare specimens from Mauritania and Algeria. All specime ns studied were characterized by the same karyotype, comprising 40 chromoso mes and 74 autosomal arms. Gerbils from Algeria were found to be larger tha n those from Mauritania for most of the skull measurements, as well as for some external measurements. Comparisons with published data from other Nort h African countries (Senegal, Morocco, Tunisia) suggest that all the previo usly figured 2n = 40 karyotypes do represent the same species, chromosomall y significantly distinct from 2n = 38 chromosome individuals found in Egypt and Sudan that correspond to true Gerbillus pyramidum. Based on our result s and awaiting contrary evidence, we propose that the 2n = 40 chromosome sp ecimens found from Senegal to Libya correspond to a unique species, for whi ch the name Gerbillus tarabuli should be applied. This species of wide dist ribution in northern Africa shows an apparently important biometrical varia bility, to be related with eco-climatological variations of the environment in which these populations live.