Speciation in the desert pocket mouse (Chaetodipus penicillatus Woodhouse)

Abstract

Variation in mitochondrial DNA was studied across the range of Chaetodipus penicillatus. Sequence data from the COIII gene and restriction-enzyme analysis of a 2,150 base pair fragment indicated a significant genetic demarcation between samples assigned to C. p. pricei and those assigned to C. p. eremicus. Sequence and restriction data also show that populations assigned to C. p. eremicus share a common history not shared by populations assigned to C. p. pricei. These data are concordant with independent evidence from nuclear data of divergence among populations of C. penicillatus at protein and chromosomal levels. Furthermore, the overall pattern of phylogeographic population structure in C. penicillatus is consistent with an hypothesis of long-term isolation and divergence of Chihuahuan and Sonoran desertscrub biotas. We recommend that C. p. eremicus be recognized as a distinct species. The appropriate binomial for populations thus far examined from the Chihuahuan Desert is Chaetodipus eremicus.