Open Paleo

Rinconsaurus

Calvo & González Riga, 2003 RIN-con-SOR-us

Named for Rincón de los Sauces, the locality in Neuquén Province, Argentina where it was discovered, combined with Greek '-saurus' meaning 'lizard'.

85.7–83.6 million years ago Santonian, Late Cretaceous
Late Cretaceous stages

Rinconsaurus is a genus of titanosaur sauropod dinosaur from the Late Cretaceous in what is now Argentina. The type species, Rinconsaurus caudamirus, was described by Calvo and Riga in 2003, and is based on three partial skeletons.

Diagnosis

  1. Neural spines in mid-anterior dorsal vertebrae inclined posteriorly more than 60 degrees with respect to vertical
  2. Middle caudal vertebrae with bony processes supporting articular surfaces of postzygapophyses
  3. Procoelous posterior caudal centra with intercalation of amphicoelous-biconvex or amphicoelous-opisthocoelous-biconvex centra

Species

Rinconsaurus caudamirus Calvo & González Riga, 2003

Type species

From Latin 'cauda' meaning 'tail' and 'mirus' meaning 'amazing' or 'wonderful', referring to the unusual shape of the tail vertebrae.

Holotype
MAU-Pv-CRS-26 , Museo Argentino Urquiza, Rincón de los Sauces
Material
Eight articulated anterior and middle caudal vertebrae, six articulated posterior caudal vertebrae, and a right ilium
Notes
The right ilium was relabeled MAU-Pv-CRS-275/2 after publication and now carries both numbers, and a left ilium labeled MAU-Pv-CRS-275/1 was added to the material, neither change reported in print. Pérez-Moreno and colleagues (2023) cite the right ilium under its original number and keep it as the holotype's only ilium, treating the left one as a paratype, the original left ilium being unaccounted for. They present this as provisional until the history of the ilia is established.
Horizon
Bajo de la Carpa Formation, Santonian, Late Cretaceous , 85.7–83.6 million years ago
Locality
Cañadón Río Seco, Neuquén, Argentina The site's bearing from Rincón de los Sauces reverses between sources, two kilometers north in Calvo and González Riga (2003) and two kilometers south in Pérez-Moreno and colleagues (2023).

References

  1. Calvo, J. O.; González Riga, B. J. (2003). Rinconsaurus caudamirus gen. et sp. nov., a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina. Revista geológica de Chile 30(2). SciELO Agencia Nacional de Investigacion y Desarrollo (ANID). doi:10.4067/s0716-02082003000200011

    Erects the species and assigns the type locality to the Río Neuquén Formation of the Neuquén Group.

    calvo2003a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b
  3. Pérez-Moreno, A.; Otero, A.; Carballido, J. L.; Salgado, L.; Calvo, J. O. (2023). The appendicular skeleton of Rinconsaurus caudamirus (Sauropoda: Titanosauria) from the Upper Cretaceous of Patagonia, Argentina. Cretaceous Research 142: 105389. Elsevier BV. doi:10.1016/j.cretres.2022.105389

    Reports the horizon as the base of the Bajo de la Carpa Formation, and revises the type series, excluding the supposed prefrontal as a notosuchian ilium.

    pérez-moreno2023a