Open Paleo

Rinconsauria

Calvo et al., 2007

Its genera lived 100.5–66.0 million years ago Late Cretaceous
Late Cretaceous stages

Rinconsauria is a clade of titanosaurian sauropod dinosaurs from the Late Cretaceous of South America. Its members are all relatively small for titanosaurs, generally less than about 11 meters long. The group is anchored on Rinconsaurus and Muyelensaurus, the two genera used to define it, and most analyses that include both recover it with that original content, though in some it forms a more inclusive group with Lognkosauria nested inside (Carballido and colleagues, 2022). Most recent analyses recover it as the sister group of Lognkosauria within the larger clade Colossosauria (Carballido and colleagues, 2022), though those built on the matrix of Gorscak and O'Connor separate the two, and most place Aeolosaurus close to or within Rinconsauria (Díez Díaz and colleagues, 2025).

Diagnosis

  1. Suboval tooth crowns with labial and lingual faces differentiated by crests
  2. Bony processes supporting the postzygapophyseal facets in the middle caudal vertebrae
  3. Posterior caudal centra depressed posteriorly

Clades within Rinconsauria

Genera placed directly in Rinconsauria

  • Brasilotitan Machado et al., 2013 Campanian–Maastrichtian (83.6–66.0 Ma)Brazil
  • Chadititan Agnolín et al., 2025 Campanian (83.6–72.2 Ma)Argentina
  • Muyelensaurus Calvo et al., 2007 Coniacian–Santonian (89.8–83.6 Ma)Argentina
  • Rinconsaurus Calvo & González Riga, 2003 Santonian (85.7–83.6 Ma)Argentina
  • Uberabatitan Salgado & de Souza Carvalho, 2008 Maastrichtian (72.2–66.0 Ma)Brazil

References

  1. Calvo, J. O.; González Riga, B. J.; Porfiri, J. D. (2007). A new titanosaur sauropod from the Late Cretaceous of Neuquén, Patagonia, Argentina. Arquivos do Museu Nacional, Rio de Janeiro 65(4): 485-504.

    Erected Rinconsauria.

    calvo2007b
  2. Carballido, J. L.; Otero, A.; Mannion, P. D.; Salgado, L.; Pérez Moreno, A. P. (2022). Titanosauria: a critical reappraisal of its systematics and the relevance of the South American record. South American Sauropodomorph Dinosaurs: Record, Diversity and Evolution 269-298. Springer International Publishing. doi:10.1007/978-3-030-95959-3_8

    Found that most analyses recover Rinconsauria with its original content, as the sister lineage of Lognkosauria.

    carballido2022a
  3. Díez Díaz, V.; Mannion, P. D.; Csiki-Sava, Z.; Upchurch, P. (2025). Revision of Romanian sauropod dinosaurs reveals high titanosaur diversity and body-size disparity on the latest Cretaceous Haţeg Island, with implications for titanosaurian biogeography. Journal of Systematic Palaeontology 23(1). Informa UK Limited. doi:10.1080/14772019.2024.2441516

    Reported that analyses on the Gorscak and O'Connor matrix separate Rinconsauria and Lognkosauria, and that most place Aeolosaurus close to or within Rinconsauria.

    díezdíaz2025a