Understanding when and where ancient animals lived provides context for their existence and offers insight into a planet vastly different from our own. Pinpointing a dinosaur’s place in geological time helps unlock details about its environment and the broader evolutionary story of life on Earth.
The Early Jurassic Period
The dinosaur known as Dilophosaurus lived during the Early Jurassic Period, a significant span of time approximately 201.3 to 174.1 million years ago. This epoch marked the beginning of the Jurassic Period, which itself is the middle segment of the Mesozoic Era, often referred to as the “Age of Dinosaurs.” Following a major extinction event at the close of the Triassic Period, the Early Jurassic saw life recover and diversify. Fossil evidence for Dilophosaurus has been primarily unearthed in North America, particularly from the Kayenta Formation in Arizona.
Life During the Early Jurassic
During the Early Jurassic, Earth’s climate was generally warm and humid, lacking polar ice caps and experiencing higher global temperatures than today. The supercontinent Pangaea had begun to rift apart, influencing global geography and creating diverse habitats. While some low-latitude regions experienced vast deserts, overall, the planet supported lush vegetation. Plant life was dominated by gymnosperms such as conifers, cycads, and ginkgoes, alongside various ferns; flowering plants had not yet evolved.
Dinosaurs became the dominant terrestrial vertebrates, recovering from previous extinctions and beginning their widespread diversification. Early forms of large sauropods and other theropods shared the land with smaller, emerging mammals. In the oceans, marine reptiles like ichthyosaurs and plesiosaurs thrived, alongside early modern sharks, rays, and abundant ammonites. The first stem-group birds also made their appearance during this period.
Unraveling Dilophosaurus
Dilophosaurus, whose name means “two-crested lizard,” was a predator, reaching lengths of about 7 meters (23 feet) and weighing around 400 kilograms (880 pounds). It was a bipedal theropod, characterized by a slender and lightly built body adapted for agility. The most distinctive feature of Dilophosaurus was the pair of bony crests on its head, which were likely covered in keratin and may have been used for display. Its skull was proportionally large yet delicate, with a notable gap in its upper jaw.
Despite its portrayal in popular culture, there is no scientific evidence to suggest that Dilophosaurus possessed a neck frill or could spit venom. These traits were fictional additions for dramatic effect in media, not based on fossil records. In reality, Dilophosaurus was considerably larger than its cinematic depiction, making it one of the earliest large carnivorous dinosaurs. Its diet consisted of meat, and it likely hunted smaller dinosaurs, though it may also have scavenged.