A new species of duck-billed dinosaur, Ahshislesaurus wimani, has been identified from fossil evidence found in New Mexico. This species is estimated to have lived approximately 75 million years ago during the late Cretaceous period.
Characteristics and Size
Ahshislesaurus wimani is believed to have possessed a flat head and a bony crest positioned low on its snout. This herbivorous dinosaur could reach lengths of up to 40 feet (12 meters). Hadrosaurids, the group to which A. wimani belongs, were large plant-eating dinosaurs that were prevalent during the final 24 million years of the Cretaceous period.
Re-evaluation of Fossils
Fossils initially discovered in 1916, including an incomplete skull, a lower jawbone, and several vertebrae from the Kirtland Formation in New Mexico, had previously been classified under the hadrosaurid genus Kritosaurus. Researchers revisited these specimens, which are housed at the Smithsonian National Museum of Natural History.
Analysis of the skull's shape and features revealed distinctions sufficient to classify it as a separate genus and species. Paleontologists emphasized that skull morphology is a primary basis for differentiating animal species. This re-evaluation indicates that Ahshislesaurus wimani is closely related to Kritosaurus, suggesting their evolutionary lines diverged relatively recently. Kritosaurus remains a valid genus with its own species.
Implications for Dinosaur Diversity
The identification of Ahshislesaurus wimani indicates that duck-billed dinosaurs, or hadrosaurids, exhibited greater diversity and more overlapping populations during the last 20 million years of the Cretaceous period than previously understood. While the exact mechanisms of co-existence for related species in the same environment are not yet fully understood, tracing the history and extent of different species contributes to the understanding of their ancient environments and the evolutionary history of duck-billed dinosaurs. This group demonstrated significant diversity across the continent and contributed to their global distribution in the Late Cretaceous.