a new basal sauropodomorph (dinosauria saurischia) from quebrada del barro formation (marayes-el carrizal basin), northwestern argentina一个新的基底sauropodomorph(恐龙蜥臀目)从山涧del barro形成(marayes-el carrizal盆地),西北阿根廷.pdfVIP

A New Basal Sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), Northwestern Argentina 1,2 1 1 2,3 Cecilia Apaldetti *, Ricardo N. Martinez , Oscar A. Alcober , Diego Pol ´ ´ 1 Museo de Ciencias Naturales, Universidad Nacional de San Juan, San Juan, Argentina, 2 Consejo Nacional de Investigaciones Cientıficas y Tecnicas (CONICET), Argentina, ´ 3 Museo Paleontologico Egidio Feruglio, Trelew, Argentina Abstract Background: Argentinean basal sauropodomorphs are known by several specimens from different basins; Ischigualasto, El Tranquilo, and Mogna. The Argentinean record is diverse and includes some of the most primitive known sauropodomorphs such as Panphagia and Chromogisaurus, as well as more derived forms, including several massospondylids. Until now, the Massospondylidae were the group of basal sauropodomorphs most widely spread around Pangea with a record in almost all continents, mostly from the southern hemisphere, including the only record from Antarctica. Methodology/Principal Finding: We describe here a new basal sauropodomorph, Leyesaurus marayensis gen. et sp. nov., from the Quebrada del Barro Formation, an Upper Triassic-Lower Jurassic unit that crops out in northwestern Argentina. The new taxon is represented by a partial articulated skeleton that includes the skull, vertebral column, scapular and pelvic girdles, and hindlimb. Leyesaurus is diagnosed by a set of unique features, such as a sharply acute angle (50 degrees) formed by the ascending process of the maxilla and the alveolar margin, a straight ascending