Alamosaurus

Alamosaurus was named after Ojo Alamo (Cottonwood Spring) in New Mexico, where the first specimens were found early in 1922. Other Alamosaurus fossils have been found in Utah, Wyoming, and the Big Bend region of Texas. Adults were probably about 70 feet long.

Alamosaurus is the only known sauropod in North America from this time period (Upper Cretaceous). All North American sauropods died out about 105 million years ago. Then, after a 35-40 million year gap, Alamosaurus appeared in North America about 70 million years ago. (All dinosaurs became extinct about 65 million years ago.) Some scientists believe that Alamosaurus migrated into North America from South America after the two continents were joined together by the Isthmus of Panama. This view is supported by the fact that Alamosaurus belongs to the titanosaurid family of sauropods, and titanosaurids were common in South America during the Cretaceous time period.

The discovery consists of 10 fossilized neck bones (cervical vertebrae). Three of the smaller vertebrae were carried out of the park's wilderness area by hand, and the seven larger vertebrae will be transported by helicopter. The larger fossilized bones are estimated to weigh over 1000 pounds apiece. The fossils have been covered with plaster casts to protect them during transportation to the paleontology laboratory at the Dallas Museum of Natural History.

The fossil was probably deposited in an ancient river floodplain about 100-200 miles west of the ancient coastline. Fossilized wood suggests that trees at least 90 feet tall grew on the ancient landscape. The climate was probably warm and probably did not have strong seasonal variations.