title: A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials.
abstract: Marsupial mammal relatives (stem metatherians) from the Mesozoic Era (252-66 million years ago) are mostly known from isolated teeth and fragmentary jaws. Here we report on the first near-complete skull remains of a North American Late Cretaceous metatherian, the stagodontid Didelphodon vorax. Our phylogenetic analysis indicates that marsupials or their closest relatives evolved in North America, as part of a Late Cretaceous diversification of metatherians, and later dispersed to South America. In addition to being the largest known Mesozoic therian mammal (node-based clade of eutherians and metatherians), Didelphodon vorax has a high estimated bite force and other craniomandibular and dental features that suggest it is the earliest known therian to invade a durophagous predator-scavenger niche. Our results broaden the scope of the ecomorphological diversification of Mesozoic mammals to include therian lineages that, in this case, were linked to the origin and evolution of marsupials.
authors.affiliation: Department of Biology and Burke Museum, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Wilson
authors.affiliation: Department of Biology, San Diego State University, San Diego, California 92182, USA.|Department of Paleontology, San Diego Natural History Museum, San Diego, California 92101, USA.
authors.forename: Eric G
authors.initials: EG
authors.lastname: Ekdale
authors.affiliation: North Dakota Geological Survey, Bismarck, North Dakota 58505, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Hoganson
authors.affiliation: Department of Biology and Burke Museum, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Calede
authors.affiliation: Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: Abby
authors.initials: A
authors.lastname: Vander Linden
mesh_terms: D000818:Animals; D003817:Dentition; D005580:Fossils / Q000033:anatomy & histology*; D008394:Marsupialia; D010161:Paleodontology; D010802:Phylogeny; D012886:Skull / Q000033:anatomy & histology*