Genetic evidence for several cryptic species within the Scarturus elater species complex (Rodentia: Dipodoidea): when cryptic species are really cryptic

Phylogeographical study of the small five-Toed jerboa (Scarturus elater) and examination of the phylogenetic position of S. vinogradovi were performed using the mitochondrial cytochrome b (cytb) gene and fragments of the BRCA1 and IRBP nuclear genes. Phylogenetic analysis of the cytb data including 115 specimens of S. elater from 47 localities across the species range revealed the existence of three highly divergent (10-11.3%) genetic clades: North (N), South (S) and South-West (SW). The N and S clades are well supported by nuclear genes and occur in sympatry across a large part of the range south of the Aral Sea. We found no trace of admixture between these clades, which suggests their reproductive isolation. We detected no morphological differences in the skull or glans penis between these two lineages, which we consider to represent an intriguing example of cryptic species. Given the reciprocal monophyly and deep genetic divergence, the SW lineage also deserves full species rank. The data indicate that S. vinogradovi is not a close relative of S. elater. It is placed as a separate deep branch in a clade also containing S. elater s.l. and S. williamsi + S. euphratica.