A Pliocene record of the giant marmot, Paenemarmota sawrockensis, in northern Utah [Un enregistrement de la marmotte géante, Paenemarmota sawrockensis, dans le Nord de l'Utah].

Résumé

A right dentary of the giant marmot, Paenemarmota sawrockensis, was collected from an unnamed loess unit in Box Elder County, Utah. The loess underlies an ash bed tentatively correlated with an ash bed exposed near Alturas, California, and an ash bed found in deep-sea cores off northern California. The age of the California ash is estimated as 4.8 Ma. Paenemarmota sawrockensisis now known from northeastern Nebraska, (Santee l.f. and Devils Nest Airstrip l.f.), southwestern Kansas (Sawrock Canyon l.f) and north-central Utah. The Sawrock Canyon l.f. is early Pliocene (early Blancan) as it contains two species of the definitive microtine immigrant, Mimomys. The Santee and Devils Nest Airstrip l.fs. contain native microtines and are late Miocene (late Hemphillian). Because of its association with the ash exposed near Alturas, California, and the record of Paenemarmota from the Sawrock Canyon 1. f., the Utah locality is considered to be earliest Pliocene (earliest Blancan)