Paleohistology of <i>Malarguesaurus florenciae</i> remains from the Neuquén Group, Argentina

The Neuquén Basin in northwestern Patagonia, Argentina, holds the most important record of Cretaceous dinosaurs in South America. The Neuquén Group (Upper Cretaceous) is the richest dinosaur-bearing unit of the basin. It comprises the Río Limay, the Río Neuquén and the Río Colorado subgroups. Malarguesaurus florenciae is a somphospondylian titanosauriform (Dinosauria, Sauropoda) from the Río Neuquén subgroup (Portezuelo Formation), Neuquén Basin, Argentina. This specimen was found at Quebrada Norte site, Paso de las Bardas area, 190 km south of Malargüe City, Mendoza Province. The aim of this study is to analyse the Malarguesaurus bone microstructure to elucidate the histological features and growth patterns. Histological thin sections made in skeletal elements reveal a presence of fibrolamellar bone tissue, suggesting an overall fast growth, however, the absence of growth marks advice for a sustained growth. The lack of growth marks can be interpreted as a product of the intense remodelling of the bone matrix. This contribution offers new insights into the bone microstructure and growth trajectory of Malarguesaurus titanosauriform from the Neuquén Basin during the Upper Cretaceous span.