New materials of the diplodocid sauropod Leinkupal laticauda from the Bajada Colorada Formation (Berriasian-Valanginian), Neuquén Province, Argentina

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

san luis

Encuentro; Reunión de comunicaciones de la Asociación Paleontológica Argentina.; 2017

universidad de san luis

The last diplodocid sauropods inhabited Patagonia in the Early Cretaceous. This wasevidenced in 2014 by the finding of the first record of Diplodocidae for South America. Thefew recovered axial remains permitted the recognition of the new species Leinkupal laticaudaGallina, Apesteguía, Haluza, and Canale 2014. Successive fieldworks on the main quarryresulted in the discovery of additional material from the cranium and both the axial andappendicular skeleton. These include a partial preserved basicranium (MMCh-Pv232), an axis(MMCh-Pv158), an anterior cervical neural arch (MMCh-Pv173), an incomplete posteriorcervical vertebra (MMCh-Pv161), one anterior (MMCh-Pv159) and three mid-caudalvertebrae (MMCh-Pv137/214/165), plus a right coracoid (MMCh-Pv114). Several charactersshow clear diplodocid affinities such as box-like basal tubera; distal end of paroccipitalprocess rounded; neural spine of the axis situated entirely anterior to the postzygapophysealfacets; well-defined diapophyseal laminae and fossae in anterior caudal vertebrae; largepneumatic foraminae and ventral longitudinal hollows in anterior to mid-caudal centra; and asub-rectangular coracoid outline. Besides, the presence of autapomorphic traits such as welldevelopedtransverse process lateroventrally projected and very robustcentroprezygapophyseal laminae in anterior caudal vertebrae allows referral to Leinkupal. Aphylogenetic analysis recovers Leinkupal well-nested within Diplodocinae, but strikinglymore closely related to derived laurasian diplodocines instead of basal Gondwanan forms asoriginally thought. This result permits to hypothesize a late colonization of South America by this clade around Jurassic-Cretaceous boundary. The new evidence also augments theknowledge on the anatomy of this diplodocid taxon and, at the same time, improves itsdiagnosis. *Project funded by PICT 2013-0704 and NGS/Waitt Grant 465-16 (to P.A.G.), PIP 114 201101 00314 (to S.A.)and Municipalidad Villa El Chocón (to J.I.C).