Dilophosaurus

MEANING: Two crested lizard

PERIOD: Early Jurassic

CONTINENT: North America

Dilophosaurus was one of the earliest large predatory dinosaurs. It grew to about 7 m in length, and weighed around 400 kg. Dilophosaurus was lightly built, with a proportionally large, but delicate skull, featuring a pair of arched crests on the top. These crests were likely used in visual display, such as species recognition and sexual selection.

Dilophosaurus is from the Early Jurassic. The Jurassic Period, the second period of the Mesozoic Era, spanned from about 201 to 145 million years ago. It followed the Triassic-Jurassic extinction event, which cleared the way for new groups of organisms to rise and diversify - especially the dinosaurs. This extinction, likely caused by massive volcanic activity related to the breakup of the supercontinent Pangea, triggered climate shifts and widespread ecological upheaval. In the aftermath, the Early Jurassic began as a time of recovery and opportunity, where surviving lineages began to spread into newly vacated ecological roles.

During the Early Jurassic, Pangea was still largely intact, but rifting had begun in earnest, especially in the northern hemisphere. This led to the formation of new coastlines and the early stages of the Atlantic Ocean. Global climates were warm and relatively stable, with no evidence of polar ice. In many regions, lush forests of ferns, cycads, ginkgoes, and conifers flourished. These plants formed the backbone of early Jurassic ecosystems and provided food for a growing diversity of herbivorous dinosaurs.

Dinosaurs, which had first appeared in the Late Triassic, truly began to establish dominance during this time. Early sauropods like began evolving larger body sizes and more efficient quadrupedal locomotion, paving the way for the giants of the Late Jurassic. Theropods such filled the role of medium-to-large predators, while small ornithischians scurried below the forest canopy. Although these groups were still relatively primitive compared to their later descendants, the foundations of major Mesozoic lineages were already being laid in the Early Jurassic. The period set the stage for an explosion of diversity and gigantism that would characterize the rest of the Jurassic world.

Dilophosaurus is a basal theropod. Theropods are a lineage of bipedal saurischian dinosaurs that first appeared in the Late Triassic. The earliest forms were generally slender, lightly built predators with long legs, grasping hands, and serrated teeth. These basal theropods represent the first major radiation of carnivorous dinosaurs, establishing many of the anatomical traits that would define the group for the rest of the Mesozoic. Their adaptations for speed, agility, and active predation helped make them some of the most successful dinosaurs of the early Jurassic landscapes.

From these beginnings, theropods went on to diversify into a remarkable variety of forms. Later lineages produced the giant allosauroids and tyrannosaurs, as well as smaller, feathered maniraptorans including modern birds - the only theropods still alive today. While most theropods remained carnivores, some later groups evolved herbivorous or omnivorous diets, reflecting their evolutionary flexibility. Basal theropods stand at the root of this history, providing an important window into how the earliest meat-eating dinosaurs set the stage for one of the most dynamic and enduring dinosaur lineages.