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| Chadititan calvoi Agnolin, Motta, Marsá, Rolando, Herrera, Chimento, Rozadilla, Brizzon-Egli, Cerroni, Panzeri, Bogan, Casadio, Sterli, Miquel, Martínez, Perez, Pol & Novas, 2024 Artwork by Gabriel Lio. |
Abstract
Here we describe a new fossil invertebrate and vertebrate assemblage from a previously unknown locality of the Anacleto Formation (Campanian, Upper Cretaceous), near General Roca city, Río Negro Province, Argentina. The specimens were found in a single fossiliferous layer, which yielded bivalves and gastropods, including the first fossil record of the terrestrial clade Megalomastomatidae and the first undoubted record for the terrestrial subulinid Leptinaria. Vertebrates are represented by fishes (lepisosteids, percomorphs, and the dipnoan Metaceratodus kaopen), chelid turtles, a single crocodyliform scute, an indeterminate pterosaur, an incomplete meridiolestidan mammalian jaw, and abelisaurid and rinconsaurian titanosaur dinosaurs. The latter is represented by several individuals of a small and gracile-limbed form. The phylogenetic analysis recovers a monophyletic Rinconsauria including the new taxon, plus Rinconsaurus, Pitekunsaurus, Overosaurus, and Muyelensaurus. The new titanosaur indicates that rinconsaurians were characterized by a body shape that was different from other titanosaurs, with brachiosaur-like posture, gracile limbs, and protonic tail. The faunistic assemblage is characterized by the abundance, but low diversity, of chelid turtles and a very low number of crocodyliforms. This taxonomic composition is reminiscent of other faunal assemblages of the latest Cretaceous of northern Patagonia, but differs markedly from Campanian assemblages known from North America and Europe.
Key words: Campanian, Argentina, Titanosauria, Rinconsauria, Chelidae, Gastropoda
SAUROPODA Marsh, 1878
TITANOSAURIA Bonaparte & Coria, 1993
RINCONSAURIA Calvo, González Riga & Porfiri, 2007
Chadititan calvoi nov. gen. et sp.
Derivation of the name. Chadi, from the Mapundungum, meaning salt; the specific epithet honors the late Jorge O. Calvo (1962–2023) a great colleague that recently passed away, who described several titanosaurs and coined the name Rinconsauria.
Federico Agnolin, Matías Motta, Jordi García Marsá, Mauro Aranciaga Rolando, Gerardo Alvarez Herrera, Nicolás Chimento, Sebastián Rozadilla, Federico Brizzon-Egli, Mauricio Cerroni, Karen Panzeri, Sergio Bogan, Silvio Casadio, Juliana Sterli, Sergio Miquel, Sergio Martínez, Leandro Perez, Diego Pol and Fernando Novas. 2024. New Fossiliferous Locality from the Anacleto Formation (Late Cretaceous, Campanian) from northern Patagonia, with the Description of A New titanosaur. Revista del Museo Argentino de Ciencias Naturales. 26(2); 217–259. DOI: 10.22179/REVMACN.26.885