Rocasaurus

Rocasaurus; Temporal range: Campanian-Maastrichtian, 75–70 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Femur and pelvis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	†Sauropodomorpha
Clade:	†Sauropoda
Clade:	†Macronaria
Clade:	†Titanosauria
Family:	†Saltasauridae
Tribe:	†Saltasaurini
Genus:	†Rocasaurus
Species:	†R. muniozi
Binomial name
	†Rocasaurus muniozi; Salgado & Azpilicueta, 2000

Rocasaurus (meaning "General Roca lizard") is a genus of titanosaurian sauropod that lived in South America. Rocasaurus was discovered in Argentina in 2000, within the Allen Formation which is dated to be middle Campanian to early Maastrichtian in age (75 to 70 million years ago in the Late Cretaceous). This genus grew up to 8 metres (26 ft) long, making it one of the smaller sauropods. It seems to be closely related to saltasaurid dinosaurs, like Saltasaurus and Neuquensaurus.

The type species, Rocasaurus muniozi, was formally described by Leonardo Salgado and Azpilicueta in 2000.^[1] New specimens were described in 2021.^[2]

Discovery and naming

Between 1989 and 1994, expeditions of the National University of Comahue and the Carlos Ameghino Provincial Museum collected titanosaur fossils from the locality of Salitral Moreno, 25 km south of the city of General Roca in Río Negro Province, Argentina.^[3] In 2000, Leonardo Salgado and Claudia Azpilicueta described some of these remains as representing a new genus and species, Rocasaurus muniozi. The genus name refers to its discovery near General Roca and the species name honors Juan Carlos Muñoz, director of paleontology at the Carlos Ameghino Provincial Museum, for his support of paleontological research in the region.^[4]

Fossil record

The holotype of Rocasaurus muniozi, MPCA-Pv 46, is a partial skeleton of a juvenile individual including partial cervical vertebrae, partial dorsal vertebrae, caudal vertebrae, both ilia, ischia, and pubes, and the left femur. Other elements of R. muniozi found at Salitral Moreno include three cervical vertebrae and several caudal vertebrae.^[3] Additional remains of R. muniozi are known from another locality, Salitral Ojo del Agua, and include partial cervical vertebrae, a partial dorsal vertebra, and a fragmentary ischium.^[5]

Phylogeny

Rocasaurus in a cladogram after Navarro et al., 2022:^[6]

Saltasauridae

Opisthocoelicaudiinae

	Opisthocoelicaudia

	Nemegtosaurus

Saltasaurinae

	Alamosaurus

	Baurutitan

Ibirania

	Bonatitan

	Rocasaurus

Saltasaurini

Neuquensaurus

	MACN-PV-RN 233

	Saltasaurus

References

^ Salgado, L. and C. Azpilicueta. (2000). Un nuevo saltasaurino (Sauropoda, Titanosauridae) de la provincia de Río Negro (Formacíon Allen, Cretácico Superior), Patagonia, Argentina. Ameghiniana 37 (3):259-264.
^ Rolando MA, Garcia Marsà JA, Agnolín FL, Motta MJ, Rodazilla S, Novas FE (2021-09-20). "The sauropod record of salitral ojo del agua: An upper cretaceous (Allen formation) fossiliferous locality from northern patagonia, Argentina". Cretaceous Research. 129: 105029. Bibcode:2022CrRes.12905029R. doi:10.1016/j.cretres.2021.105029. ISSN 0195-6671. S2CID 240577726.
^ ^a ^b Garcia, Rodolfo; Salgado, Leonardo (2013). "The titanosaur sauropods from the Allen Formation (late Campanian-early Maastrichtian) of Salitral Moreno (Patagonia, Río Negro, Argentina)". Acta Palaeontologica Polonica. 58 (2): 269–284. doi:10.4202/app.2011.0055. hdl:11336/9015. ISSN 0567-7920.
^ Salgado, Leonardo; Azpilicueta, Claudia (2000-09-30). "Un nuevo saltasaurino (Sauropoda, Titanosauridae) de la provincia de Río Negro (Formación Allen, Cretácico Superior), Patagonia, Argentina". Ameghiniana. 37 (3): 259–264. ISSN 0002-7014.
^ Rolando, Mauro Aranciaga; Marsà, Jordi A. García; Agnolín, Federico L.; Motta, Matías J.; Rozadilla, Sebastián; Novas, Fernando E. (2022). "The sauropod record of Salitral Ojo del Agua: An Upper Cretaceous (Allen Formation) fossiliferous locality from northern Patagonia, Argentina". Cretaceous Research. 129: 105029. Bibcode:2022CrRes.12905029R. doi:10.1016/j.cretres.2021.105029. ISSN 0195-6671.
^ Navarro, Bruno A.; Ghilardi, Aline M.; Aureliano, Tito; Díaz, Verónica Díez; Bandeira, Kamila L. N.; Cattaruzzi, André G. S.; Iori, Fabiano V.; Martine, Ariel M.; Carvalho, Alberto B.; Anelli, Luiz E.; Fernandes, Marcelo A.; Zaher, Hussam (2022-09-15). "A new nanoid titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of Brazil". Ameghiniana. 59 (5): 317–354. doi:10.5710/AMGH.25.08.2022.3477. ISSN 1851-8044. S2CID 251875979.