Elasmosaurus
Long-necked plesiosaur from the Late Cretaceous of North America.
Elasmosaurus is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.6 to 77 million years ago. The genus is the namesake of the family Elasmosauridae, a group of long-necked plesiosaurs, and is notable for its extremely long neck, which measured about 7.1 meters (23 ft) out of a total length of 10.3 meters (34 ft).
- lived
- Late Cretaceous (Campanian), about 80.6–77 million years ago
- length
- 10.3 meters (34 ft)
- neck_length
- about 7.1 meters (23 ft)
- neck_vertebrae
- 72
- known_for
- One of the longest-necked animals; subject of Cope's famous skull-on-tail reconstruction error
Lore & Background
Cope recognized them as plesiosaur remains and arranged for the rest of the specimen to be shipped to Philadelphia. Cope attempted to recall all copies of the preprint and issued a corrected version, but rival paleontologist Othniel Charles Marsh publicized the mistake, contributing to the 'Bone Wars' rivalry between Cope and Marsh. Only one incomplete skeleton is definitely known, consisting of a fragmentary skull, spine, and now-lost girdles; other species have been moved to other genera or deemed invalid.
Reader's Guide
Elasmosaurus holds a significant place in paleontological history as the first recognized member of the Elasmosauridae, a family of long-necked plesiosaurs. Its discovery in Kansas marked the beginning of a fossil-collecting rush that sent thousands of fossils from the region to East Coast museums. The genus is also famous for Cope's embarrassing error of placing the skull on the tail, a mistake that became a well-known episode in the 'Bone Wars' and is frequently cited in discussions of scientific error and rivalry. Despite its fame, much about Elasmosaurus remains uncertain. Its long neck—among the longest of any animal, with 72 vertebrae—was not very flexible and could not be held high above water, contrary to earlier depictions. Its function is unknown but may have been related to feeding. Elasmosaurids likely ate small fish and marine invertebrates, using gastroliths to aid digestion. The genus is known from the Pierre Shale formation, representing marine deposits of the Western Interior Seaway. A fragmentary specimen from Germany may also belong to this genus.
Did You Know?
- Elasmosaurus had 72 neck vertebrae, at least 3 fewer than its relative Albertonectes.
- Elasmosaurus was the first major fossil discovery in Kansas and the largest from there at the time.
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