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long-neck giant
Sidersaura
Say it like this: “SID-er-SAWR-uh”
Sidersaura marae
Sidersaura ate plants and walked on four legs. It lived in the Late Cretaceous. Bones have been found in Argentina.
- When
- Late Cretaceous (Cenomanian · Turonian) · roughly 100.5 to 89.8 million years ago
- Named in
- 2025 · Lerzo, L. N.; Gallina, P. A.; Canale, J. I.; Otero, A.; Carballido, J. L.; Apesteguía, S.; Makovicky, P. J.
- Hip height
- Not established
- Length
- 18–20 m · 59–66 ft
- Weight
- 15 tonnes
- Found in
- Argentina · Huincul
- Food and walking
- Herbivore · Four legs
- Kind
- long-neck giant · Sauropod
- Family branch
- Rebbachisauridae
The story in short
In 2025, L. N. Lerzo and colleagues published the name Sidersaura. The name means “star lizard.”
It lived in the Late Cretaceous (Cenomanian · Turonian), roughly 100.5 to 89.8 million years ago. Finds come from Argentina, including the Huincul Formation. It was a herbivore and walked on four legs.
Published estimates put Sidersaura at a length near 18–20 m and a body mass around 15 tonnes.
On the family tree it sits in Rebbachisauridae, among the sauropod dinosaurs.
Close relatives
Agustinia
Agustinia ligabuei
Early Cretaceous (Albian) · roughly 113.2 to 100.5 million years ago
Amazonsaurus
Amazonsaurus maranhensis
Early Cretaceous (Aptian · Albian) · roughly 121.4 to 100.5 million years ago
Astigmasaura
Astigmasaura genuflexa
Late Cretaceous (Cenomanian · Turonian) · roughly 100.5 to 89.8 million years ago