Metriacanthosaurus
- Pronunciation: met-rih-ah-KANTH-uh-SAWR-us
- Translation: Moderately-Spined Lizard
- Order: Saurischia
- Suborder: Theropoda
- Infraorder: Ceratosauria
- Family: Megalosauridae (not confirmed)
- Height: 12 feet (3.7 meters)
- Length: 26 feet (7.9 meters)
- Period: Late Jurassic
- Description: Carnivore, Bipedal
- Notes: Found in southern England, Metriacanthosaurus had vertebraewith spines up to 10 inches (25.4 cm) long, perhaps supporting a skin sail. It has been speculated that the purpose of such skin sailswas to aid in regulating body temperature.