Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual
Werneburg et al. New Permian Caseid from France
Embrithopod from Croatia
Field trip guides/EAVP Annual Conference/2023
Early Oligocene Fishes from Alabama, USA
Two enigmatic rodents from Lavergne (MP 16), Quercy Phosphorites
Eocene (57) , Quercy phosphorites (37) , Systematics (32) , Rodents (29) , Mammalia (26)
New late Paleocene rodents (Mammalia) from Big Multi Quarry, Washakie Basin,Wyoming.Mary R. Dawson and Christopher K. BeardKeywords: Clarkforkian; North America; Paleocene; RodentiaAbstract The earliest North American rodents occur in basal Clarkforkian beds of the Fort Union Formation at Big Multi Quarry near Bitter Creek, northern Washakie Basin, Sweetwater County, Wyoming, and in closely correlative Fort Union beds formerly accessible in the Eagle Coal Mine near Bear Creek, northern Clark's Fork Basin, Carbon County, Montana. Two new species of early Clarkforkian rodents, Paramys adamus and Alagomys russelli, are described from Big Multi Quarry. Paramys adamus is represented by virtually complete upper and lower dentitions, which demonstrate that this species is one of the most primitive North American paramyids yet discovered. These specimens form the basis for a reevaluation of the content and stratigraphic range of P. atavus, which is known with certainty only from Bear Creek. Alagomys russelli is the first North American record for the enigmatic rodent family Alagomyidae, otherwise known from ?late Paleocene-early Eocene localities in Mongolia and China. Phylogenetic analysis of dental and gnathic traits suggests that Alagomyidae form the sister group of all other undoubted rodents. At least two rodent clades, alagomyids and basal paramyids, seem to have invaded North America from Asia at the beginning of Clarkforkian time, but only the paramyids persisted to undergo a significant evolutionary radiation in North America. Article infos Published in Vol. 25, Fasc. 2-4 (1996) |
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The stratigraphic sequence of North American rodent faunasRobert W. WilsonKeywords: North America; Rodents; Stratigraphic sequenceAbstract 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. Article infos Published in Vol. 9, Ext (1980) |
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On the genus Dikkomys (Geomyoidea, Mammalia)Morton Green and Philip R. BjorkKeywords: Dikkomys; Geomyoidae; North AmericaAbstract The geomyoid genus Dikkomys is well represented in a sample from the Black Bear Quarry Il local fauna of Early Hemingfordian age in Bennett County, South Dakota. Isolated unworn P/4's of Dikkomys matthewi WOOD have a prominent median cristid (sagicristid) with a connection to the metaconid and the hypolophid. With wear, P/4 does not become as molariform as P/4 because of this cristid. Article infos Published in Vol. 9, Ext (1980) |
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