Camptosaurus

MEANING: Flexible lizard

PERIOD: Late Jurassic

CONTINENT: North America

Camptosaurus is an early member of the iguanodontia - the group of herbivorous dinosaurs that contains the more derived hadrosaurs. It was robust and bipedal, growing to around 6 m in total body length, and weighing approximately 1 t. Camptosaurus had a beaked snout and tightly packed teeth to process its diet of tough vegetation.

Camptosaurus is from the Late Jurassic. The Late Jurassic was a dynamic period, spanning from about 162 to 143 million years ago. The continents were continuing to drift apart, and the supercontinent Pangaea had fully split into Laurasia in the north and Gondwana in the south. This continental rearrangement led to the formation of large inland seas and shallow coastlines that fostered diverse ecosystems. The climate during the Late Jurassic was warm and humid, with lush forests of conifers and ferns that stretched across much of the continents, creating a rich ecosystem where dinosaurs flourished the dominant land animals.

Dinosaurs continued to diversify through the Late Jurassic, with some of the most famous species evolving in this time. Many well-known sauropods, such as Brachiosaurus and Apatosaurus roamed the land, exhibiting niche partitioning with their selectively distinct neck positions. Alongside them, stegosaurs became widespread, their plates and spikes making them one of the era's most recognizable groups. Theropods like Allosaurus and Ceratosaurus were the apex predators, evolving large, powerful bodies and sharp teeth that allowed them to hunt the gigantic herbivores. The early evolution of birds was taking place, setting the stage for the numerous species that would fill the skies in the eras to come.

Unlike the dramatic mass extinctions that marked the beginning and end of the Mesozoic, the Jurassic Period ended without a sharp boundary. As the continents continued to drift, ecosystems gradually transformed into unique habitats that supported the more specialized dinosaur species of the Cretaceous.

Camptosaurus is an iguanodontian. Iguanodontia was an important branch of the ornithopoda, a group of herbivorous dinosaurs that would become one of the most successful clades of the Cretaceous. These dinosaurs first appeared in the Late Jurassic as small bipedal grazers, but diversified through the Early Cretaceous, gradually increasing into larger more robust forms. While the more derived hadrosaurs of the Late Cretaceous became highly specialized for chewing tough plant material, basal iguanodontians retained a mix of primitive and advanced traits. They were among the first large-bodied ornithopods to spread widely across the Northern Hemisphere, with fossils found in Europe, North Africa, and Asia.

Early iguanodontians possessed powerful hind limbs for efficient bipedal movement but could also walk on all fours when foraging. One of their most distinctive features was their unique hand structure, which included a stiff, spike-like thumb that may have been used for defense or breaking apart tough vegetation. Although they lacked the fully developed dental batteries of later hadrosaurs, their teeth were already adapted for efficient plant processing, giving them an evolutionary advantage as herbivores. These adaptations laid the groundwork for the eventual dominance of hadrosaurs, which would expand into even more diverse habitats and continue to thrive until the end of the Cretaceous.