Dilophosaurus wetherilli

Dilophosaurus wetherilli is a primitive theropod dinosaur that lived during the Early Jurassic , approximately 193 million years ago, in what is now North America. Its fossils were discovered in the Kayenta Formation, in Arizona, and first described in 1954. This dinosaur is distinguished by having a pair of elongated bony crests on its skull, giving it its name, which means "double-crested lizard". For a long time, Dilophosaurus was wrongly represented in popular culture as a venomous dinosaur with an extendable frill, although there is no scientific evidence to support these characteristics.

The skull of Dilophosaurus is long and narrow, with an estimated length of up to 60 cm . Its thin, arched bony crests were not strong enough to serve as weapons, so they probably had a role in visual display, possibly to attract mates or intimidate rivals. Its jaws were relatively weak compared to those of more advanced theropods, but did feature a series of curved, serrated teeth, ideal for shearing meat. A notable feature of its skull is the presence of a flexible joint in the upper jaw, which may have allowed it a more efficient bite when catching prey.

The postcranial skeleton of Dilophosaurus wetherilli reveals that it was a slender and agile carnivore, with a total length of 6–7 metres and a weight of approximately 400 kg . Its hind limbs were long and slender, adapted for speed, suggesting that it was an efficient runner capable of chasing small prey or moving quickly to avoid confrontations with larger predators.

Its arms were relatively long and robust , with three fingers ending in sharp claws, indicating that it may have used its forelimbs to hold onto prey. Unlike later large theropods, which relied primarily on their jaws, Dilophosaurus probably used a combination of claws and bites to hunt.

Its spine and pelvis showed a light but strong structure, with vertebrae that had cavities to lighten the weight of the body. Its long, flexible tail provided balance while running, allowing it to maneuver with agility in its environment.

The habitat of Dilophosaurus in the Early Jurassic was composed of alluvial plains, rivers and open forests, where it coexisted with other primitive dinosaurs, crocodiles and large amphibians. It is thought to have been an opportunistic hunter , feeding on small vertebrates and possibly scavenging when it had the opportunity.

Recent anatomical studies have corrected many of the previously held ideas about Dilophosaurus , revealing that it was a more robust and developed theropod than initially thought. Its combination of speed, functional claws and a specialized skull make it one of the first large predators of the Jurassic, marking a key stage in the evolution of later theropods.

Approximate measurements of Dilophosaurus:

• Complete 1:35 scale
  • Length 111 mm
  • Height 121 mm
  • Width 37 mm
  • Snout-tail length 200 mm

• Complete 1:20 scale
  • Length 195 mm
  • Height 213 mm
  • Width 65 mm
  • Snout-tail length 350 mm