Bajadasaurus
"Bajada lizard"
- Lived
- 139 to 133 million years ago, Early Cretaceous
- Diet
- Herbivore
- Group
- Sauropods, Dicraeosauridae
- Found in
- Argentina
- Named by
- Gallina et al. 2019
Where its fossils were found
The evidence
Today
135 million years ago
Habitat
It lived beside rivers in the Bajada Colorada Formation of Argentina. Leinkupal and Ninjatitan were other sauropods in this landscape.
Field notes
About Bajadasaurus
What it was like
Bajadasaurus was a long-necked plant eater from the dicraeosaurid family, a group of sauropods with fairly short necks for their kind. Its most striking feature was a row of very long, paired spines rising from the bones of its neck and curving forward over the head.
Nobody knows for sure what the spines were for. They may have carried a covering of horn, helped with display, or made the neck harder for a predator to bite. Its slender skull held thin, pencil-like teeth at the front of the jaws.
Its world
It lived about 139 to 133 million years ago, in the Early Cretaceous, in what is now Argentina. Its bones come from the Bajada Colorada Formation, laid down by rivers, where it shared the land with the sauropods Leinkupal and Ninjatitan.
How it was found
Gallina and colleagues named Bajadasaurus in 2019 from a single find: a skull and part of the neck. Its closest well-known relative is Amargasaurus, which had similar spines.
Field gallery
More views of Bajadasaurus
Scenes reconstructed from the available fossil evidence.
1 of 3
Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Bajadasaurus.
The evidence
The science behind Bajadasaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- A skull and part of the neck preserve slender jaws with pencil-shaped teeth at the front.
- A neck vertebra carries extremely long, paired bony spines that curve forward.
Borrowed from relatives
- The missing trunk, legs and tail are restored by comparison with Amargasaurus and Dicraeosaurus.
- Amargasaurus provides a comparison for the soft tissues around the long neck spines.
Still unknown
- Whether the neck spines carried separate horn coverings or were joined by skin.
- Whether the spines mainly served defense, display or another purpose.
- Its color and the complete arrangement of its neck spines.
Discovery timeline
- 2019Named itGallina et al.
- 2022Close relativeCerda et al.
- 2023SkullGarderes et al.
Key papers
The research behind what we know of Bajadasaurus
Named it
Described the skull and forward-curving neck spines, proposing that the spines helped deter predators.
A new long-spined dinosaur from Patagonia sheds light on sauropod defense system. Scientific Reports 9
Read the paper : A new long-spined dinosaur from Patagonia sheds light on sauropod defense system (opens in a new tab)Close relative
Examined the bone structure of Amargasaurus neck spines to test competing ideas about their soft tissue coverings.
Osteohistology of the hyperelongate hemispinous processes of Amargasaurus cazaui (Dinosauria: Sauropoda): Implications for soft tissue reconstruction and functional significance. Journal of Anatomy 240: 1005-1019
Read the paper : Osteohistology of the hyperelongate hemispinous processes of Amargasaurus cazaui (Dinosauria: Sauropoda): Implications for soft tissue reconstruction and functional significance (opens in a new tab)Skull
Studied the skull in detail and proposed a horny covering over the front of the muzzle.
Cranial osteology of Bajadasaurus pronuspinax (Sauropoda, Dicraeosauridae). Historical Biology 36: 1343-1367
Read the paper : Cranial osteology of Bajadasaurus pronuspinax (Sauropoda, Dicraeosauridae) (opens in a new tab)
Close relatives
Other members of Dicraeosauridae
Sources: Wikidata