Coahuilasaurus

Coahuilasaurus is an extinct genus of kritosaurin ornithopod dinosaur that roamed the Earth during the Campanian stage of the Late Cretaceous period. Its fossils have been discovered in the Cerro del Pueblo Formation of Coahuila, Mexico, a region known for its rich paleontological finds.

Discovery and Naming

The genus was formally named and described in 2024. The generic name, Coahuilasaurus, directly references the Mexican state of Coahuila, where the fossil remains were unearthed, translating to "Coahuila lizard." The specific epithet, lipani, is a tribute to the Lipan Apache Native American tribe, historically associated with the area of discovery.

Classification and Physical Characteristics

Coahuilasaurus is classified as a member of the Kritosaurini tribe, placing it within the larger group of hadrosaurid, or duck-billed, dinosaurs. Based on the available fossil evidence, which includes jaw and fragmentary skull bones, Coahuilasaurus was a substantial dinosaur. It is estimated to have reached a length of 8 to 9 meters (approximately 26 to 30 feet) and possessed a body mass exceeding 4 metric tons (around 4.4 short tons). As an ornithopod, Coahuilasaurus was a herbivore, adapted to processing plant matter.

Paleoenvironment

The Cerro del Pueblo Formation, where Coahuilasaurus fossils were found, is characterized by alternating layers of siltstones, sandstones, and gray shales. This geological setting indicates a dynamic environment with fluctuating sea levels, preserving evidence of fluvial, lacustrine, coastal, and shallow marine ecosystems. The terrestrial deposits suggest a coastal floodplain adjacent to an estuary, supporting a heavily vegetated riverine ecosystem. This environment was rich in life, evidenced by the abundance of dinosaur teeth and bone fragments, along with a diverse array of crocodiles, turtles, and invertebrates.