Baby dinosaur found near ancient sea.

Seventy-four million years ago, young dinosaurs may have frolicked beside an ancient sea in what is now the landlocked state of New Mexico, according to Donald L. Wolberg, a paleontologist with the New Mexico Bureau of Mines and Mineral Resources in Socorro.

Wolberg and his colleagues found pieces of the lower jaw and teeth of a baby duckbilled dinosaur in the Cretaceous rocks of northwestern New Mexico. "The teeth showed no wear or breakage," indicating that the animal died within a few weeks of its hatching, Wolberg says. He discovered the jaw, which stretches less than 3 inches long, buried beneath the larger rib of an adult dinosaur.

This infant dinosaur, the first reported from the region, probably hatched nearby. Previous excavations in the area have unearthed dinosaur eggshells and structures thought to be dinosaur nests.

These rocks formed along the shore of an inland sea that covered the middle part of the continent in the Cretaceous period, Wolberg says. Fossils such as marine clams and sharks' teeth have been found within a few meters of dinosaur remains, indicating that these duckbilled dinosaurs "lived and bred right next to the seashore," says Wolberg.

He calls these findings "surprising," noting that previous reports of dinosaur nests come from drier, inland habitats: "We never expected to find dinosaurs nesting in this setting." The new results suggest, however, that dinosaurs were more adaptable to a broader range of environments than previously thought, Wolberg says.