Basal sauropodomorphs from the Ischigualasto Formation

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 second species ofEucnemesaurusVan Hoepen, 1920 (Dinosauria, Sauropodomorpha): new information on the diversity and evolution of the sauropodomorph fauna of South Africa's lower Elliot Formation (latest Triassic)

“…The data matrix for this analysis was drawn from the data matrix originally introduced by Yates (2007b) and subsequently employed (with various alterations) by a number of other sauropodomorph workers (Smith and Pol, 2007;Ezcurra, 2010;Yates et al, 2010;Apaldetti et al, 2011;Otero and Pol, 2013;Mart ınez et al, 2012;McPhee et al, 2014). It was further modified in the current study via the alteration of several preexisting characters and the addition of two novel ones (see below).…”

“…The lateral wall of this fossa (homologous to the 'brevis shelf'; e.g., Novas, 1996;Mart ınez et al, 2012) appears to have been more strongly developed than the medial, and at its tallest point measures approximately 2 cm from its ventral margin to the base of the fossa. The morphology of the brevis fossa in E. entaxonis differs from the same structure in the holotype of Riojasaurus (PVL 3808), which, although of proportionally similar dorsoventral depth, is mediolaterally expanded to an almost autapomorphic extent for sauropodomorph dinosaurs (see Discussion).…”

New dinosaur remains from the Late Triassic of southern Brazil (Candelária Sequence, Hyperodapedon Assemblage Zone)

“…The lateral margin is slightly depressed just ventral to the transverse process and forms a faint lateral fossa. The neural spine occupies the entire dorsal margin, with its more robust portion interposed between the postzygapophyses, which are in turn separated by a deep median notch similar to that seen in Saturnalia and Guaibasaurus (Ezcurra 2010) and Chromogisaurus (Martínez et al 2013b, contra Ezcurra 2010. The articular surfaces of the prezygapophyses face mediodorsally and articulate with the ventrolaterally oriented postzygapophyses.…”

The femoral anatomy of Pampadromaeus barberenai based on a new specimen from the Upper Triassic of Brazil

“…First, the specimen was codified in the data-matrix published by Martínez et al (2012a), which is mainly modified from Yates (2007), Smith and Pol (2007) and Ezcurra (2010). It includes 51 taxa plus CAPPA/UFSM 0027 and 378 characters.…”