Taxonomic status and relationships of Sorex obscurus parvidens Jackson, 1921, from California

The San Bernardino shrew, Sorex obscurus parvidens Jackson, 1921, is a population inhabiting the San Bernardino and San Gabriel mountains of southern California. For the past 9 decades, this population has been considered either a subspecies of S. obscurus Merriam, 1895, S. vagrans Baird, 1857, or S. monticola Merriam, 1890; or an undifferentiated population of S. ornatus Merriam, 1895. Aside from the changing taxonomic landscape that contextualizes the genus Sorex, previous study of S. obscurus parvidens has been retarded by the perception of limited available samples (typically, fewer than 8 specimens); misinterpretation of the provenance of specimens identified as S. obscurus parvidens; misunderstanding of the type locality; and inclusion of specimens of this taxon in the type series of another species with which S. obscurus parvidens has been both contrasted and allied at different times. My investigation of S. obscurus parvidens indicates that it is a distinctive population that is morphologically closest to S. ornatus, and it corresponds to the Southern Clade of that species. However, the appropriate names for deep clades within S. ornatus remain uncertain. Until this uncertainty is resolved, S. obscurus parvidens should be considered a distinctive population within S. ornatus; for conservation purposes, it should be recognized as S. ornatus parvidens.