Species limits in the Le Conte's thrasher

Abstract

We studied patterns of mitochondrial DNA (mtDNA) and colorimetric variation in the Le Conte's Thrasher (Toxostomsa lecontei) to determine patterns of geographic variation, and to clarify subspecific and species limits. We sequenced 619 base pairs of mtDNA (parts of cytochrome b and ND6) for 14 Le Conte's Thrashers from 9 localities representing the three putative subspecies (leconrei, macmillanorum, and arenicola). Haplotypes were shared between leconrei and macmillanorum, and we do not support recognition of the latter. However, haplotypes of arenicola differed bq 3.5% sequence divergence from those of lecontei and macmillanorum, and we suggest that arenicola be recognized as a species. Colorimetric analyses of 105 specimens indicated that arenicola differed consistently from lecontei and macmillanorum, corroborating the mtDNA results.