The oldest noasaurid (Theropoda, Ceratosauria) from South America

JUAN IGNACIO CANALE; GALLINA, PABLO A.; APESTEGUÍA, SEBASTIÁN; ALEJANDRO HALUZA

corrientes

Jornada; las XXVIII Jornadas Argentinas de Paleontología de Vertebrados; 2018

universidad del litoral

Noasauridae is a group of poorly-known, small-sized theropod dinosaurs, wichshow a wide geographical distribution (Gondwana and China) during a temporalrange from Middle Jurassic to Upper Cretaceous times. Classically, this groupincluded derived, Upper Cretaceous forms, but the recent inclusion ofElaphrosaurinae ceratosaurs, pushed the origins of the clade toward the Jurassic.Therefore, a temporal gap in the knowledge of this group occupies most of theCretaceous. Here we report a new specimen of theropod from the Berriasian-Valanginian Bajada Colorada Formation (Neuquén Province, Argentina), includingan axis (MMCh-Pv 67), a mid-posterior cervical vertebra (MMCh-Pv 199), a partialsacral centrum (MMCh-Pv 233), five caudal centra (MMCh-Pv 76, 77, 195, 225,235) and a partial left femur (MMCh-Pv 234). The combination of long epipophysison the axis, low and anteroposteriorly short cervical neural spine, and mediodistalcrest of femur developed as a long flange allows referring this specimen toCeratosauria. Its inclusion in two different published datasets focused onCeratosaurian phylogeny recovered the specimen as part of the Noasauridae,closer to Late Cretaceous forms after the cervicals with long centra, narrow pre-and postspinal fossa in cervical vertebrae and cervical postzigapophysesoverhanging the centrum posteriorly. The available evidence shows that noasauridtheropods were present in South America at least from the beginning of theCretaceous.