Temporal range: Late Cretaceous
|Restoration of two individuals|
Simón, Salgado & Calvo, 2018
Simón, Salgado & Calvo, 2017
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.
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. The holotype might have been the same holotype as the one assigned to Sauropodus.
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.