Choconsaurus baileywillisi
Restoration of two individuals
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Dinosauria
Order: Saurischia
Infraorder: Sauropodomorpha
Family: Titanosauria
Genus: Choconsaurus
Simón, Salgado & Calvo, 2018
Type species
Choconsaurus baileywilisi
Simón, Salgado & Calvo, 2017

Choconsaurus is an extinct genus of herbivorous sauropod dinosaur belonging to the group Titanosauriformes, which lived in the area of present-day Argentina at the end of the Cretaceous.[1]

The fossil remains were found in Villa El Chocón in the Neuquén province, where the skeleton of a sauropod was reported. In 2017, the species type Choconsaurus baileywillisi was named and described by Edith Simón, Leonardo Salgado and Jorge Orlando Calvo. The genus name refers to its discovery in El Chocón. For its part, the name of the species is in homage to the American geologist Bailey Willis, who traced the stratigraphy of the area between 1910 and 1914.[1]

The holotype specimen was found in a layer of the Huincul Formation dating to the end of the Cenomanian epoch. It consists of a partial skeleton lacking a skull. The vertebrae of the neck, back and tail and parts of the limbs were preserved. This constitutes the most complete skeleton known of a basal titanosaur in 2017.[1] The holotype might have been the same holotype as the one assigned to Sauropodus.[2]

The describing authors have identified some distinctive features. In the cervical vertebrae, the upper edge of the face of the posterior joint was hardly developed. In the first vertebrae there are very large secondary protuberances on both sides of the hyposphene. The central and posterior vertebrae have an additional crest located between the posterior crest that extends from the lateral protrusion to the vertebral body and the secondary crest running parallel to the main crest. The frontal vertebrae of the tail have a protrusion in the posterior hyposphenic secondary joint.[1]

Choconsaurus was classified in its description article of 2017 within the clade Titanosauria in a basal position, outside the clade Eutitanosauria.[1]


  1. 1.0 1.1 1.2 1.3 1.4 (2017) "A new titanosaur sauropod from the Upper Cretaceous of Patagonia, Neuquén Province, Argentina". Ameghiniana in press: 1–29. DOI:10.5710/AMGH.01.08.2017.3051. 
  2. "Argentine Find May Be Previously Unknown Herbivore" (February 8, 2001). The New York Times.