A New Large, Hypercarnivorous Oxyaenid (Mammalia, Creodonta) from the Middle Eocene of the Wind River Formation, Natrona County, Wyoming

Abstract Malfelis badwaterensis, gen.et sp. nov., represented by a nearly complete juvenile skull, isolated I1–2, P1, DP2, and a fragment of the dentary from the same individual (CM 62590), is described from the early middle Eocene (Gardnerbuttean, early Bridgerian) of the Wind River Formation, Wyoming in North America. M. badwaterensis preserves a unique combination of characters that set it apart from all other creodonts including the presence of a P1 and reduced M2, a carnassial complex from DP3–4–M1 with reduced protocones, simplified trenchant P2–3, and M1 with conjoined metacone and paracone, and metastylar blade. M. badwaterensis is referred to the Oxyaenidae based on the well-developed metastylar blade of M1, a reduced M2, and loss of M3. This new creodont was perhaps the largest of all animals from the type locality, which has yielded nearly 80 species of mammals.