title: A Jurassic eutherian mammal and divergence of marsupials and placentals.
abstract: Placentals are the most abundant mammals that have diversified into every niche for vertebrates and dominated the world's terrestrial biotas in the Cenozoic. A critical event in mammalian history is the divergence of eutherians, the clade inclusive of all living placentals, from the metatherian-marsupial clade. Here we report the discovery of a new eutherian of 160 Myr from the Jurassic of China, which extends the first appearance of the eutherian-placental clade by about 35 Myr from the previous record, reducing and resolving a discrepancy between the previous fossil record and the molecular estimate for the placental-marsupial divergence. This mammal has scansorial forelimb features, and provides the ancestral condition for dental and other anatomical features of eutherians.
authors.affiliation: Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213, USA. luoz@carnegiemnh.org
authors.forename: Zhe-Xi
authors.initials: ZX
authors.lastname: Luo
authors.forename: Chong-Xi
authors.initials: CX
authors.lastname: Yuan
authors.forename: Qing-Jin
authors.initials: QJ
authors.lastname: Meng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ji
mesh_terms: D000818:Animals; D002681:China; D005260:Female; D005580:Fossils; D049690:History, Ancient; D008322:Mammals / Q000033:anatomy & histology* / Q000145:classification* / Q000196:embryology / Q000502:physiology; D008334:Mandible / Q000033:anatomy & histology; D008394:Marsupialia / Q000033:anatomy & histology* / Q000145:classification* / Q000502:physiology; D008963:Molar / Q000033:anatomy & histology; D010802:Phylogeny; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D013997:Time Factors