Primer registro de estromatolitos en el Maastrichtiano tardío del Grupo Chubut, Cuenca del Golfo San Jorge, Patagonia central, Argentina

Abstract

The presence of stromatolites from Cretaceous outcrops at the headwaters of the río Chico locality in the Golfo San Jorge Basin is reported for the first time. They are present in the uppermost part of the Lago Colhué Huapi Formation (Coniacian-Maastrichtian) of the Chubut Group. The presence of, up to now, four structures interpreted as stromatolites in this locality are not only important because it is the first record in the basin, but because it contributes to the knowledge of these bioconstructions in continental environments. The stromatolite called E1, which is characterized and discussed in detail, is associated with an abundant and diverse fossil record represented by palynomorphs, fragments of silicified trunks, dinosaur remains and eggshells. The study, integrated mainly with the recorded pollen and spores, is important for paleoenvironmental interpretations of the site and contributes to the paleoecological and paleoclimatic understanding of the most modern stratigraphic interval of the Chubut Group.

Reconstruction of the pectoral girdle and forelimb musculature of Megaraptora (Dinosauria: Theropoda)

“…More derived megaraptorans-that is, members of Megaraptoridae-have been found in the mid-Cretaceous of Australia (Australovenator wintonensis, "Rapator ornitholestoides," Megaraptoridae cf. A. wintonensis, and other, indeterminate materials; Bell et al, 2016;Benson et al, 2012;Brougham et al, 2019;Hocknull et al, 2009;Kotevski & Poropat, 2022;Poropat et al, 2019;White et al, 2012White et al, , 2016White et al, , 2020White, Benson, et al, 2013;White, Falkingham, et al, 2013;White, Bell, Cook, Poropat, & Elliott, 2015;White, Bell, Cook, Barnes, et al, 2015) and the mid-and Late Cretaceous of South America (Megaraptor namunhuaiquii, Orkoraptor burkei, Aerosteon riocoloradensis, Murusraptor barrosaensis, Tratayenia rosalesi, Maip macrothorax, and other, generically unassigned specimens; Aranciaga Rolando et al, 2015Rolando et al, , 2021Rolando et al, , 2022Calvo et al, 2004;Casal et al, 2016Casal et al, , 2019Coria & Currie, 2016;Ibiricu et al, 2020;Lamanna et al, 2020;Méndez et al, 2019;Novas, 1998;Novas et al, 2008Novas et al, , 2019Paulina-Carabajal & Currie, 2017;Porfiri et al, 2007Porfiri et al, , 2011Porfiri et al, , 2014Porfiri et al, , 2018Sereno et al, 2008). Several megaraptorans, from early diverging taxa such as Phuwiangvenator and Fukuiraptor to megaraptorids such as Australovenator and Megaraptor, preserve all or part of the humerus, antebrachium, and/or manus, which has allowed for the recognition and description of progressive modifications of the forelimb skeleton through the evolution of the clade, culminating in the highly ...…”