Taylor & Francis makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.

Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed of opisthodontians, the herbivorous branch of Sphenodontia, whose oldest members were until recently reported to be from the Kimmeridgian-Tithonian (Late Jurassic). Here, we report a new sphenodontian, Sphenotitan leyesi gen. et sp. nov., collected from the Upper Triassic Quebrada del Barro Formation of northwestern Argentina. Phylogenetic analysis identifies Sphenotitan as a basal member of Opisthodontia, extending the known record of opisthodontians and the origin of herbivory in this group by 50 Myr.

No abstract

ABSTRACT-Basal sauropodomorphs from the Ischigualasto Formation include Eoraptor lunensis, Panphagia protos, and Chromogisaurus novasi. Few comparisons have been made between these taxa, because Eoraptor was only recently reassessed as a basal sauropodomorph and because Panphagia and Chromogisaurus were described nearly simultaneously. We describe in detail the fully prepared bones of the holotype of Chromogisaurus novasi, examine the evidence for its taxonomic distinction, and analyze the phylogenetic relationships among basal sauropodomorphs. Our results support Chromogisaurus novasi as a valid genus and species and provide weak phylogenetic evidence favoring a series of stem taxa at the base of Sauropodomorpha. The analysis positions Panphagia as the basal-most sauropodomorph, followed by Eoraptor, Pampadromaeus, and a clade that includes Chromogisaurus and Saturnalia. RESUMEN-Los sauropodomorfos basales de la Formación Ischigualasto incluyen Eoraptor lunensis, Panphagia protos yChromogisaurus novasi. Pocas comparaciones se han hecho entre estos taxones, porque Eoraptor fue reevaluado recientemente como sauropodomorfo basal y porque Panphagia y Chromogisaurus se describieron de forma casi simultánea. Describimos en detalle los huesos totalmente preparados del holotipo de Chromogisaurus novasi, examinamos la evidencia de su distinción taxonómica, y analizamos la relación filogenética entre sauropodomorfos basales. Nuestros resultados apoyan a Chromogisaurus novasi como un género y especie válido y proporcionan débil soporte filogenético favoreciendo un arreglo parafilético en la base de Sauropodomorpha. El análisis posiciona a Panphagia como el sauropodomorfo más basal, seguido de Eoraptor, Pampadromaeus y un clado que incluye a Chromogisaurus y Saturnalia.

A new continental fauna from the Late Triassic of Argentina: Cynodonts, turtles, pseudosuchians, and dinosauromorphs.Remains from the Late Jurassic of Chile indicates high sauropod diversity in South America.Jurassic confierous wood from western Argentina and the role of basidiomycetes in wood decay during the Mesozoic in Gondwana.