A newly identified genus and species of titanosaurus, a colossal sauropod dinosaur from the Cretaceous period, has been uncovered from fossils in northern Patagonia, Argentina.
Reconstructing the life of Yenen Hassai. Image credit: Gabriel Rio.
Named Yenen Hassai, this new species roamed Earth approximately 83 million years ago during the Late Cretaceous period.
This ancient creature belongs to the Titanosauridae, a fascinating group of large, long-necked herbivorous dinosaurs that thrived on the Gondwana supercontinent.
“The head of Yenen Hassai was proportionately smaller compared to its massive body,” explained Dr. Leonardo Filippi, a paleontologist from CONICET and the Urquiza Municipal Museum in Argentina.
“This titanosaur measured between 10 to 12 meters (33 to 39 feet) in length and weighed approximately 8 to 10 tons.”
The fossil remains of Yenen Hassai were excavated from the Bajo de la Carpa Formation at a site known as Cerro Obero la Invernada in Neuquén, Patagonia, Argentina.
This material showcases one of the most complete titanosaur skeletons found in the region, preserving six cervical vertebrae, ten dorsal vertebrae with associated ribs, the sacrum, and the first caudal vertebra.
Alongside the holotype, researchers identified remains of at least two additional sauropods at the site, including a juvenile specimen and another adult titanosaur, which may belong to an unclassified species.
“Through phylogenetic analysis, Yenen Hassai is found to be closely related to Nalambuenatitan and Overosaurus, as a basal member of an unnamed clade of derived non-lithostrotians saltasaurids,” they noted.
“Evidence from the titanosaur fauna at Cerro Obero la Invernada indicates that species diversity was relatively high during the Santonian period, suggesting that at least two lineages, colossosaurs and saltasauroids, coexisted.”
“This discovery positions the Cerro Obero-La Invernada region as the area with the highest diversity of titanosaurs during the Santonian of the Neuquén Basin, offering crucial insights into the evolution of dinosaur fauna in this era.”
This significant finding is detailed in a recent article: research paper published in the Journal of Historical Biology on January 12, 2026.
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LS Filippi et al. Yenen Hassai: An Overview of Sauropod Titanosaurs Diversity from the Cerro Overo-La Invernada Region (Bajo de la Carpa Formation of the Santonian), Northern Patagonia, Argentina. Historical Biology published online January 12, 2026. doi: 10.1080/08912963.2025.2584707
Source: www.sci.news
