• Sierra del Carmen

    Big Bend

    National Park Texas

The 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 Big Bend specimen was found in the Javelina formation, which was deposited about 74-66 million years ago. Ms. Dana Biasatti, who is now a graduate student at SMU, discovered this specimen. The fossilized bones are being collected under a Scientific Research and Collecting Permit issued by Big Bend National Park to Dr. Anthony Fiorillo of the Dallas Museum of Natural History. The specimen will remain the property of the National Park Service, but it is loaned to the Dallas Museum of Natural History for cleaning, preparation, study, curation, and possible display.

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.

Did You Know?

Road sign to Big Bend State Park, 1930s

Before its establishment as a National Park in 1944, Big Bend was a Texas state park for eleven years. When established in May of 1933 the park was first designated "Texas Canyons State Park." The name of the new park was changed to Big Bend by the end of that year. More...