Journal of Paleontology; May 2008; v. 82; no. 3;
p. 638-642; DOI: 10.1666/06-098.1
© 2008 Paleontological Society
An Unexpected Early Record of Mictomys vetus (Arvicolinae, Rodentia) from the Blancan (Pliocene) Glenns Ferry Formation, Hagerman Fossil Beds National Monument, Idaho
Dennis R. Ruez, Jr.1 and
Philip A. Gensler2
1 Department of Geological Sciences, Jackson School of Geosciences, University of Texas, Austin 78712-0254; current address: Department of Geology and Geography, 210 Petrie Hall, Auburn University, Auburn, Alabama 36849-5305, <ruezden@auburn.edu,>
2 Hagerman Fossil Beds National Monument, 221 North State Street, PO Box 570, Hagerman, Idaho 83332, <pgensler@yahoo.com>
| The first 20% of the full text of this article appears below.
|
 |
INTRODUCTION
|
|---|
THE COOLING during the Pliocene that preceded major continental glaciation in North America is recorded by thick fluvial and lacustrine sequences at Hagerman Fossil Beds National Monument (HAFO) in southcentral Idaho (McDonald et al., 1996). Fossiliferous beds at HAFO occur within the nearly 200 m of exposed Glenns Ferry Formation west of the Snake River. This formation extends from southwestern Idaho into easternmost Oregon (Malde and Powers, 1962). The Glenns Ferry Formation within HAFO contains hundreds of localities that are within the Blancan North American Land Mammal Age. Collection of specimens from these localities since the late 1920s has resulted in large repositories of fossils currently housed, in part, at the United States National Museum, the University of Michigan Museum of Paleontology (UMMP), and the Idaho Museum of Natural History (IMNH); additionally, smaller collections were accumulated by other museums (McDonald et al., 1996). Today the paleontological resources of HAFO are stewarded by the National Park Service. In spite of the extensive previous collections, significant new discoveries are still being made at HAFO.
The specimens described here are the first records of Mictomys vetus (Wilson, 1933) from HAFO. These fossils are also the earliest records of Mictomys anywhere and impact previously proposed scenarios of arvicoline biochronology (i.e., Repenning and Grady, 1988; Repenning et al., 1995; Fejfar and Repenning, 1998). The fossils described here are curated in the vertebrate paleontology collection of the IMNH in Pocatello, Idaho.
Abbreviations
AC, anterior cap; BRA1 and BRA2, buccal (=labial) reentrant angles 1 and 2; LaPW, labial primary wing; LiPW, lingual primary wing; LRA1, LRA2, and LRA3, lingual reentrant angles 1, 2, and 3; m1, lower first molar; m3, lower third molar; PL, posterior loop; T1, T2, and T3, triangles 1, 2, and 3.
 |
SYSTEMATIC PALEONTOLOGY
|
|---|
RODENTIA Bowdich, 1821
M. . . [Full Text of this Article]Diagnosis
Description
Material examined
Occurrence
 |
DISCUSSION
|
|---|
Copyright © 2008 by Paleontological Society