Ceratosaurus nasicornis seh-RAT-oh-SOR-us
"Horned lizard"
You 1.8 m (5.9 ft) tall
Ceratosaurus 6 m (19.7 ft) long
4 people holding hands
- Length
- 6 m (19.7 ft) — About 6 m long, ~700 kg — smaller than Allosaurus but distinctive.
- Period
- Late Jurassic (155–145 Mya)
- Place
- North America · Western United States · Tanzania · Portugal
- Food
- Carnivore — Smaller prey, possibly including fish — long flexible body and tall teeth suggest river hunting.
Ceratosaurus had a short horn on its nose and small horns over its eyes — features that made it stand out from the other big Jurassic predators it shared turf with. It was smaller and rarer than Allosaurus in the Morrison Formation, with a more flexible body and an unusual row of bony plates running down its back.
What we know
- Single nasal horn and two small brow horns — display structures, not weapons.
- Row of small bony plates (osteoderms) along the back.
- Four-fingered hand — primitive compared to allosaurs and tyrannosaurs.
- Lived alongside Allosaurus in the Morrison Formation but was less common.
What we guess
- Whether it competed with Allosaurus or specialized in different prey.
- Whether the unusually long, blade-like teeth indicate fish-catching like Spinosaurus.
- The exact purpose of the back osteoderms — armor, display, or thermoregulation.