Camptosaurus

Camptosaurus, meaning 'flexible lizard,' is an extinct genus of plant-eating, beaked ornithischian dinosaurs that roamed western North America during the Late Jurassic period. The name was chosen by Professor Othniel Charles Marsh in 1885 to reflect the presumed flexibility of its sacral vertebrae, although the original name he proposed in 1879, Camptonotus, meaning 'flexible back,' had to be changed as it was already in use.

Discovery and Classification

The first remains were found in Albany County, Wyoming, in 1879. Over the following decades, numerous specimens were unearthed from the Morrison Formation, leading Marsh and later paleontologists like Charles W. Gilmore to describe several species. However, modern analyses have revised the taxonomy, with many species once assigned to Camptosaurus now placed in different genera like Uteodon, Osmakasaurus, and Planicoxa. Current understanding suggests that Camptosaurus is a basal member of the Ankylopollexia clade, placing it as a close relative to the ancestors of later iguanodontids and hadrosaurids.

Physical Characteristics and Paleobiology

Camptosaurus is described as a relatively heavily built dinosaur with robust hindlimbs and broad feet, still possessing four toes. While earlier reconstructions were inaccurate due to the use of incorrect skull material, current understanding depicts a triangular skull with a pointed snout and a beak. Its teeth were densely packed and featured thick median ridges and denticles, indicative of a diet consisting of tough vegetation. While specific locomotion is debated, it is considered a facultative biped. Studies on related iguanodonts suggest Camptosaurus may have been capable of running speeds up to 25 km/h (15 mph). Fossilized embryos attributed to Camptosaurus have also been discovered, offering insights into its reproductive biology. Estimated adult lengths range from 5 to 6 meters, with some individuals reaching up to 6.79 meters, and weights between 500 to 1,000 kilograms.