New primitive carnivorans (Mammalia) from the Paleocene of western Canada, and their bearing on relationships of the order

ABSTRACT

The earliest Carnivora are known from two families, the Miacidae, which retain M3/m3 and occur first in latest Paleocene (Clarkforkian) rocks, and the Viverravidae, which have lost M3/m3, but are known first in the middle Paleocene (Torrejonian). This paper describes two new genera and species of carnivorans, one (Pristinictis connata) a viverravid and the other (Ravenictis krausei) of uncertain familial affinities, from the early Tiffanian of Alberta and early Puercan of Saskatchewan, respectively; both have a molar structure more primitive than previously known for the order. The new carnivorans allow a reassessment of character state polarities in the early evolution of the Carnivora, thereby providing the opportunity for reexamination of the relationships of carnivorans to other eutherian orders. As a consequence of this study, it appears that carnivorans and creodonts share no uniquely derived character states of the dentition that might indicate they are sister-groups, and that carnivorans evolved from Cretaceous eutherians less specialized dentally than the Palaeoryctidae.