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.
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