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Theropods

Dilophosaurus

Say it: die-LOAF-oh-SORE-us  ·  Name means: “Two-crested lizard”

Scientific life reconstruction of Dilophosaurus: Restoration of Dilophosaurus wetherilli. Matches diagrams in Paul, G. S. (2010). The Princeton Field Guide to Dinosaurs.
⏳ Lived196–183 million years ago
Early Jurassic
🥩 DietCarnivore (meat-eater)
📏 Length6–7 m (20–23 ft)
↕️ Height1.5–2 m (5–7 ft)
⚖️ Weight300–450 kg (660–990 lb)
📍 Found inNorth America
🔎 Discovered1942 by Jesse Williams (Navajo) with Samuel Welles and the University of California team

About Dilophosaurus

Dilophosaurus was a big meat-eater with two thin bony crests on top of its head. It lived long before most famous dinosaurs.

Dilophosaurus wetherilli was one of the largest land predators of the Early Jurassic, known from fossils in Arizona's Kayenta Formation. A 2020 restudy showed it was a strongly built hunter, not the weak-jawed scavenger once imagined, with a pair of delicate head crests probably used for display.

How big was it?

Dilophosaurus: ~6.5 m longPerson 1.7 m · School bus 12 m
Compare with other dinosaurs →

Drawn to scale next to a 1.7 m adult and a 12 m school bus.

Did you know?

  1. Dilophosaurus had two thin, rounded crests on its head, like a pair of fancy fins.
  2. It was about as long as a big car and could run fast on two legs.
  3. It lived more than 180 million years ago, in what is now Arizona.
  4. It did NOT spit poison or have a frill around its neck. That was made up for a movie!
  1. A detailed 2020 study by Adam Marsh and Timothy Rowe found that Dilophosaurus had air sacs in its bones and strong muscle attachments, overturning the old idea that its jaws were too weak to tackle large prey.
  2. Its crests were thin plates of bone, too fragile for fighting, so most scientists think they were used for display to rivals or mates.
  3. The first skeletons were found in 1942 on Navajo land after Jesse Williams, a Navajo man, showed palaeontologists where bones had been spotted.
  4. It was first named as a species of Megalosaurus in 1954, and given its own genus, Dilophosaurus, in 1970 once its crests were recognised.
  5. Fossil footprints from the Early Jurassic, including a resting trace from Utah, are often linked to Dilophosaurus-like animals.
DinoVerse · Dilophosaurus fact sheet
Theropods

🥩 What did it eat?

Food: Scutellosaurus, Sarahsaurus, small reptiles, early mammal relatives, fish.

Grabbed prey with clawed hands and strong jaws, slicing with long serrated teeth; a notch near the front of its upper jaw may have helped it grip wriggling animals.

Clues scientists use: curved, serrated tooth shape; strong grasping hands with large claws; remains of small plant-eaters in the same rocks.

🗺️ Where fossils were found

  • Kayenta Formation, Navajo Nation, Arizona, USA (North America)
Skeleton / museum mount of Dilophosaurus: Dilophosaurus on display at the Royal Ontario Museum
Skeleton / museum mount of Dilophosaurus: Dilophosaurus on display at the Royal Ontario Museum

Myth or fact?

✗ Myth: Dilophosaurus spat venom and had a frill that opened around its neck.

✓ Fact: There is no evidence for either. No living dinosaur relatives spit venom, and its fossils show no bones that could support a frill. Both ideas came from the Jurassic Park film.

✗ Myth: Dilophosaurus was only as big as a dog.

✓ Fact: It was about 6 to 7 metres long, one of the biggest predators of its time.

✏️ Quick quiz

Circle the right answer. Name: ______________________

  1. What did Dilophosaurus have on top of its head?

    • A One big horn
    • B Two thin crests
    • C A bony dome
    • D A sail

  2. Could Dilophosaurus really spit venom?

    • A Yes, very far
    • B Only when babies
    • C No, that was made up for a movie
    • D Only at night

  3. In which US state were Dilophosaurus fossils found?

    • A Arizona
    • B Florida
    • C Alaska
    • D New York

Answers: 1–B 2–C 3–A

Sources and picture credits