title: A new symmetrodont mammal (Trechnotheria: Zhangheotheriidae) from the Early Cretaceous of China and trechnotherian character evolution.
abstract: We report the discovery of Anebodon luoi, a new genus and species of zhangheotheriid symmetrodont mammal from the Lujiatun site of the Lower Cretaceous Yixian Formation, China. The fossil is represented by an associated partial skull and dentaries with a nearly complete dentition, and with a dental formula of I4/3 C1/1 P5/4 M3/4. This new taxon lacks the high molar count typical of derived symmetrodonts, differing from the well-represented zhangheotheriids Zhangheotherium and Maotherium in having a postcanine dental formula that resembles more primitive tinodontid symmetrodonts on the one hand, and sister taxa to therians such as Peramus on the other. Upper and lower distal premolars are strongly molariform and are captured undergoing replacement, clarifying positional homology among related taxa. We also describe the rostrum and, for the first time in a symmetrodont, much of the orbital mosaic. Importantly, our new taxon occupies a basal position within the Zhangheotheriidae and permits discussion of trechnotherian character evolution, ultimately shedding additional light on the evolution of therians.
authors.affiliation: Department of Biology, Indiana University of Pennsylvania, Indiana, PA 15705, USA.|Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
authors.forename: Shundong
authors.initials: S
authors.lastname: Bi
authors.affiliation: Shandong Tianyu Museum of Nature, Pingyi, Shandong 273300, China.|Institute of Geology and Paleontology, Linyi University, Linyi, Shandong 276000, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Division of Paleontology, American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA.|Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Meng
authors.affiliation: Shandong Tianyu Museum of Nature, Pingyi, Shandong 273300, China.|Institute of Geology and Paleontology, Linyi University, Linyi, Shandong 276000, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biology, Indiana University of Pennsylvania, Indiana, PA 15705, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Robinson
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 S. Floyd St., Louisville, KY 40202, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Davis
mesh_terms: D000818:Animals; D002681:China; D005580:Fossils; D008322:Mammals / Q000033:anatomy & histology / Q000145:classification; D012886:Skull / Q000033:anatomy & histology*; D014070:Tooth / Q000033:anatomy & histology*