New material and evaluation of the chronostratigraphic position of Daphoenictis tedfordi (Mammalia, Carnivora, Amphicyonidae), a cat-like carnivoran from the latest Eocene of northwestern Nebraska, USA

Abstract

One of the most enigmatic amphicyonid carnivorans, the cat-like Daphoenictis tedfordi, is now known from 12 cranio-dental specimens from North America. The most recently recovered specimen, a partial right hemimandible (UNSM 27015) described herein, adds considerably to our knowledge of this taxon, and in completeness rivals the holotype of the species. Daphoenictis tedfordi is distributed from Saskatchewan to Montana, continuing to Nebraska, Colorado, and Wyoming, with nearly 50% of the specimens coming from northwest Nebraska. The chronostratigraphy and geographic locus of the Nebraska hypodigm is the focus of this report. UNSM 27015 links the fragmentary fossils of the Nebraska hypodigm to the holotype (Cypress Hills, Saskatchewan). Chronologic evidence indicates this species is restricted to the Chadronian (late Eocene) age. Recent astronomical calibration applied to late Eocene-Oligocene tuffs places the species entirely in the middle Chadronian with a single individual found in the late early Chadronian biochron.