Revisiting the Early Cretaceous sauropod Agustinia ligabuei (Dinosauria: Diplodocoidea) from southern Neuquén Basin (Patagonia, Argentina), with implications on the early evolution of rebbachisaurids

ABSTRACT

The Lohan Cura Formation (Albian) at the Cerro de los Leones locality (Neuquén Province, Patagonia, Argentina) yielded several fossil materials, especially sauropod specimens. Among these, Agustinia ligabuei includes postcranial elements of a single individual, with widely debated taxonomy and phylogeny. Here, we provide an extended osteological description and illustrations of the axial and appendicular elements of Agustinia, as well as a revised diagnosis. Moreover, the phylogenetic analysis including a new combination of morphological features recognises Agustinia as a basal Rebbachisauridae, closely related with other South American rebbachisaurids. Our results suggest a more diversified sauropod fauna in the Neuquén Basin, where different members of both neosauropod lineages (i.e. Macronaria and Diplodocoidea) survived in the same region during the Albian age. The reassessment of Agustinia as a basal rebbachisaurid improves our knowledge about the early stages of evolutionary history of Rebbachisauridae, adding new information on the morphological and taxonomic diversification of the clade during the Early Cretaceous of southwestern Gondwana.

KEYWORDS:

• Rebbachisauridae
• Albian
• Lohan Cura Formation
• neural laminae
• osteology

Acknowledgments

We thank E. Montes for preparing part of the fossil materials in the laboratory of the Museo Municipal “Carmen Funes” of Plaza Huincul (MCF); L. Coria of MCF for the collection access; the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Dirección Provincial de Patrimonio Cultural of Neuquén Province (DPPC), the Municipalidad de Plaza Huincul, and the Universidad Nacional de Río Negro (UNRN) for institutional support. A special thanks to S. Apesteguía, J.L. Carballido and A. Otero for the technical assistance during the osteological and phylogenetic analysis of Agustinia; as well as, the anonymous reviewers for providing constructive criticism and suggestions that improved the original manuscript. This work was partially supported by the Jurassic Foundation under Grant (FB, Grant 2014). Finally, we thank K. Kamra for English editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08912963.2022.2142911

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Jurassic Foundation [2014].