Nevada, known for its vast desert landscapes, also holds a record of dinosaur life. While marine reptiles like the ichthyosaur are commonly associated with its ancient past, terrestrial dinosaurs also left their mark.
Unearthing Nevada’s Dinosaurs
Evidence of dinosaurs in Nevada primarily comes from fragmentary remains and trace fossils like footprints. Paleontologists have identified various dinosaur groups from these finds, including duck-billed hadrosaurs, iguanodons, titanosaur sauropods, allosaurs, tyrannosauroids, raptors, ankylosaurs, and small bipedal plant-eaters known as hypsilophodonts.
Nevadadromeus schmitti is the first dinosaur species formally named from Nevada. This small, bipedal herbivore, a thescelosaurine, was equipped with a beak and long, slender hind legs, suggesting it was swift and agile. Its remains, found in 2008 and published in 2022, added to the state’s dinosaur record. Beyond body fossils, numerous dinosaur tracks, particularly from theropods, offer insights into their behavior and movement.
Ancient Environments and Geological Clues
Nevada’s dinosaur record is shaped by the ancient environments of the Mesozoic Era. During much of the Triassic Period (252 to 201 million years ago), northern and central Nevada were covered by shallow tropical seaways. These marine conditions were ideal for preserving marine life.
Extensive shallow seas limited terrestrial dinosaur habitats during the early Mesozoic. By the Jurassic and Cretaceous periods, significant portions of Nevada became dry land, with the entire state largely mountainous and above sea level by the Cretaceous Period (145 to 66 million years ago), allowing dinosaurs to roam. Tectonic activity and mountain-building events contributed to the fragmentary nature of dinosaur fossil discoveries by compressing and sometimes destroying potential fossil-bearing sediments.
Key Discovery Sites and Evidence
Valley of Fire State Park, near Las Vegas, is a notable site for dinosaur tracks, specifically tridactyl (three-toed) grallatoroid tracks attributed to small, bipedal theropod dinosaurs. This park is also where the bones of Nevadadromeus schmitti were discovered, along with remains of a new type of hadrosaur, or duck-billed dinosaur.
Other significant trackway localities include the Red Rock Canyon National Conservation Area and Springs Preserve, both near Las Vegas, where Jurassic dinosaur footprints have been identified in the Aztec Sandstone. In the Lake Mead National Recreation Area, the earliest known Triassic vertebrate tracks in Nevada have been found, providing a glimpse into the animals that walked the land before dinosaurs became dominant. Unexcavated dinosaur remains have also been noted in areas like Eureka, Nevada.