Dinosaurs · Large theropod

Marshosaurus

Say it marsh-oh-sore-us. The name means ‘[Othniel Charles] Marsh lizard’.

Marshosaurus beside a person 1.75 m tall. Ticks mark every metre.Body shape drawn for this site, showing the general build of large theropods

Length: 6 m
Diet: Meat-eater
When: Late Jurassic154 to 142 million years ago
Fossils found in: USA
Named by: Madsen (1976)
Family tree: Dinosauria › Saurischia › Theropoda › Neotheropoda › Tetanurae › Avetheropoda

Where Marshosaurus sits in the age of dinosaurs.Periods from the ICS chart; dinosaur dates from the Natural History Museum

Large theropods. Big two-legged meat-eaters, such as Tyrannosaurus. See all 63

Lived at the same time

Dryosaurus · same country
Gargoyleosaurus · same country
Haplocanthosaurus · same country
Hesperosaurus · same country
Othnielia · same country
Saurophaganax · same country
Supersaurus · same country
Barosaurus · same country

Other large theropods

Elaphrosaurus Late Jurassic
Saurophaganax Late Jurassic
Allosaurus Late Jurassic
Ceratosaurus Late Jurassic
Metriacanthosaurus Late Jurassic
Yangchuanosaurus Late Jurassic
Piatnitzkysaurus Late Jurassic
Eustreptospondylus Mid Jurassic

Source: Marshosaurus in the Natural History Museum Dino Directory, read 12 November 2026. Sizes are the museum's estimates for a typical adult. "Lived at the same time" lists dinosaurs whose dates overlap, which does not always mean they met.