Speciation of the Wandering Shrew

BY

JAMES S. FINDLEY

CONTENTS

PAGE
[Introduction]4
[Materials Methods and Acknowledgments]4
[Non-geographic Variation]7
[Characters of Taxonomic Worth]8
[Pelage Change]9
[Geographic Distribution and Variation]9
[Pacific Coastal Section]9
[Inland Montane Section]11
[Great Basin and Columbia Plateau Section]12
[Summary of Geographic Variation]13
[Origin of the Sorex vagrans Rassenkreis]16
[Relationships With Other Species]26
[Conclusions]60
[Table of Measurements]62
[Literature Cited]66

FIGURES

Figs. 1-2.—Cranial Measurements[5]
Fig. 3.—Graph Illustrating Wear of Teeth[8]
Fig. 4.—Graph Illustrating Heterogonic Growth of Rostrum[10]
Fig. 5.—Present Geographic Distribution of Sorex vagrans[15]
Fig. 6.—Skulls of Sorex vagrans[17]
Figs. 7-10.—Past Geographic Distribution of Shrews[19]-[20]-[22]-[27]
Figs. 11, 12.—Medial View of Lower Jaws of Two Shrews[30]
Figs. 13, 14.—Second Unicuspid Teeth of Shrews[30]
Fig. 15.—Diagram of Probable Phylogeny of Shrews[32]
Figs. 16-18.—Geographic Distribution of Subspecies[33]-[40]-[53]

INTRODUCTION

The purpose of this report is to make clear the biological relationships between the shrews of the Sorex vagrans-obscurus "species group." This group as defined by H. H. T. Jackson (1928:101) included the species Sorex vagrans, S. obscurus, S. pacificus, S. yaquinae, and S. durangae. The last mentioned species has been shown (Findley, 1955:617) to belong to another species group. Sorex milleri, also assigned to this group by Jackson (1947:131), seems to have its affinities with the cinereus group as will be explained beyond. The position of the vagrans group in relationship to other members of the genus will be discussed.