PRINTED BY
ROBERT R. (BOB) SANDERS, STATE PRINTER
TOPEKA, KANSAS
1968

31-4628

Evolution and Classification
of the Pocket Gophers of the
Subfamily Geomyinae

BY

ROBERT J. RUSSELL

CONTENTS

PAGE
[Introduction]477
[Materials and Acknowledgments]477
[Taxonomic Characters]478
[Prismatic character of molars]478
[Character of enamel patterns]479
[Grooving of incisors]480
[Masseteric ridge and fossa]480
[Basitemporal fossa]481
[Specializations of skull]481
[Fossil Record]484
[Miocene]485
[Pliocene]486
[Pleistocene]490
[Thomomys]492
[Zygogeomys]496
[Geomys]496
[Pappogeomys]503
[Orthogeomys]504
[History of Classifications]505
[Classification]512
[Family Geomyidae]512
[Subfamily *Entoptychinae]513
[Genus *Pleurolicus]514
[Genus *Gregorymys]514
[Genus *Grangerimus]514
[Genus *Entoptychus]514
[Subfamily Geomyinae]514
[Tribe *Dikkomyini]515
[Genus *Dikkomys]516
[Genus *Pliosaccomys]517
[Tribe Thomomyini]518
[Genus Thomomys]518
[Subgenus *Pleisothomomys]519
[Subgenus Thomomys]520
[Tribe Geomyini]521
[Genus *Pliogeomys]522
[Genus Zygogeomys]523
[Genus Geomys]525
[Genus Orthogeomys]528
[Subgenus Orthogeomys]529
[Subgenus Heterogeomys]530
[Subgenus Macrogeomys]531
[Genus Pappogeomys]532
[Subgenus Pappogeomys]534
[Subgenus Cratogeomys]535
[Phylogeny of the Geomyidae]536
[Primitive Morphotype]537
[Entoptychid Radiation]540
[Phyletic Trends in Subfamily Geomyinae]542
[Plio-Pleistocene Radiation of Geomyini]558
[Morphotype]559
[Specializations in Genera]560
[Zygogeomys]564
[Geomys]565
[Orthogeomys]568
[Pappogeomys]569
[Literature Cited]572