Taxonomic Revision of the Mammalian Genus Microsorex Coues

Abstract

The Recent pigmy shrews seem referable to two species containing seven subspecies, varying in color of pelage, cranial characters, and size in accordance with Bergmann's Rule. Microgeographic variation and intergradation with adjacent races seem most complex in M. h. hoyi, which name is applied differently here, to a subspecies ranging from Mackentie to Quebec to North Dakota, to the vicinity of Racine, Wisconsin. Probably all the subspecies differentiated in Pleistocene refugia, and the nominate subspecies apparently moved northward as the Wisconsin glaciation receded. The pigmy shrews, genus Microsorex, are among the smallest and rarest of mammals. Hardly anything is known of their biology. First reviewed by Miller (1895), who recognized only one kind (based on only 24 specimens), the growing collections of pigmy shrews were reviewed again by Jackson (1928). He recognized seven subspecies, all in North America, and all referred to Microsorex hoyi. Pigmy shrews preserved in Museums have more than doubled in number since Jackson's study undertaken 44 years ago. One new subspecies has been named since then, and herein I arrange one trinomen as a junior synonym. This arrangement is involved with a nomenclatural judgment concerning Baird's original descriptions, and hopefully returns to his taxonomic concepts in accordance with practicality and priority. Also, I tentatively list Microsorex thompsoni as a polytypic species. The known geographic range (Fig. 1) of Microsorex has expanded into the Yukon, onto Cape Breton Island, into eight additional states (and also lower Michigan), and on many fronts in the states and provinces wherein Jackson (1928) recorded the genus. Great gaps between named taxa have been closed. Nevertheless, the preserved material is in many instances meagre, the papery thin crania often broken, and the series from a given locality usually small. A taxonomic revision is a progress report, and in the study on Microsorex deEnite progress has been made. This content downloaded from 157.55.39.215 on Tue, 30 Aug 2016 06:22:43 UTC All use subject to http://about.jstor.org/terms 182 Transactions of the Kansvs Academy of Science The objective of this study was to taxonomically revise the mammalian genus Microsorex.