Print ISSN: 0031-0247
Online ISSN: 2274-0333
Werneburg et al. New Permian Caseid from France
Small sauropod tracks, Southern France
Dortokid turtle from Late Cretaceous of Cruzy
Hypoplasia: CT-scan or naked eye?
Eocene otoliths (Clinchfield Formation), Georgia
Eocene (56) , Quercy phosphorites (37) , Systematics (31) , Rodents (29) , Mammalia (26)
The stratigraphic sequence of North American rodent faunas
Robert W. WilsonKeywords: North America; Rodents; Stratigraphic sequence
Rodents first appear in the latest Paleocene or earliest Eocene as very fragmentary specimens (Family Paramyidae) known largely from a single locality. After this sparse beginning, rodents are usually abundant in the North American record if proper recovery methods are used. Utilization of rodents for biostratigraphic purposes depends on 1/ extinction, and 2/ replacement by evolution of endemic groups and/or incursions of Old World rodents, and rarely and late by South American kinds. These incursions are separated by relatively long periods of isolation in the Paleogene, but more episodic in the Neogene. At least 10 rodent zones can be characterized by major distinctions, and these zones can be amplified into as many as 16 with little trouble. In general, rodent genera permit as refined a zonation as do genera of large mammals. Distinction at a specific level has not been attempted herein except in the Blancan and Post-Blancan.
Published in Vol. 9, Ext (1980)