| Biologists who study shrews are always taking measurements and recording other observations of their specimens - not only the length of each specimen, or the weight, but also precise measurements of various parts of the skull, especially the teeth. Before molecular biology was widely available, small but consistent differences in these multiple measurements have been an important key to classification of specimens; scientists working with these specimens continue to use these techniques today.
The Olympic Shrew was discovered during the careful study of museum specimens collected years ago and specimens from field trips in the Pacific Northwest.
Various features were compared among specimens from several western Washington areas and British Columbia locations (body size, how much hair on the tail, iron pigment intensity in the front teeth, various dental measurements). Several specimens were markedly different from other shrews collected in these areas, leading to the proposal that these particular shrews be designated as a new species, Sorex rohweri. The distinct nature of this group was confirmed by molecular analyis. Since the initial study, more specimens have been found that originated in western Oregon, expanding the range of this species.
Rausch, R. L., Feagin, J. E. and Rausch, V. R. 2007. Sorex rohweri sp. nov. (Mammalia, Soricidae) from northwestern North America. Mammalian Biology 72: 93-105.
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