- Length
- 21 m
- Diet
- Plant-eater
- When
- Late Cretaceous70 to 66 million years ago
- Fossils found in
- USA
- Named by
- Gilmore (1922)
- Family tree
- Dinosauria › Saurischia › Sauropodomorpha › Sauropoda › Macronaria › Titanosauriformes › Titanosauria › Lithostrotia
Sauropods. Long-necked, four-legged plant-eaters, the biggest animals ever to walk on land. See all 59
Lived at the same time
- Dryptosaurus · same country
- Ornithomimus · same country
- Thescelosaurus · same country
- Torosaurus · same country
- Pachycephalosaurus · same country
- Ankylosaurus · same country
- Pachyrhinosaurus · same country
- Triceratops · same country
Other sauropods
- Saltasaurus Late Cretaceous
- Ampelosaurus Late Cretaceous
- Isisaurus Late Cretaceous
- Magyarosaurus Late Cretaceous
- Neuquensaurus Late Cretaceous
- Nemegtosaurus Late Cretaceous
- Opisthocoelicaudia Late Cretaceous
- Dreadnoughtus Late Cretaceous
Source: Alamosaurus 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.