a new basal sauropod dinosaur from the middle jurassic of niger and the early evolution of sauropoda一个新的基底中侏罗世的蜥脚类恐龙尼日尔和sauropoda的早期演化.pdfVIP

A New Basal Sauropod Dinosaur from the Middle Jurassic of Niger and the Early Evolution of Sauropoda 1 2 3 4 4 ´ ´ Kristian Remes *, Francisco Ortega , Ignacio Fierro , Ulrich Joger , Ralf Kosma , Jose Manuel Marın Ferrer3, for the Project PALDES¤a, for the Niger Project SNHM¤b, Oumarou Amadou Ide5, Abdoulaye Maga5 ´ ´ 1 Paleontology, Steinmann Institute for Geology, Mineralogy and Paleontology, University of Bonn, Bonn, Germany, 2 Departamento de Fısica Matematica y de Fluidos, ´ Facultad de Ciencias, UNED, Madrid, Spain, 3 Museo Paleontologico de Elche (MUPE), Elche, Spain, 4 Staatliches Naturhistorisches Museum Braunschweig, Braunschweig, ´ Germany, 5 Universite Abdou Moumouni, Institut pour Recherche et Science Humaine (IRSH), Niamey, Niger Abstract Background: The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification. Principal Findings: A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible ex