Unaysaurus
"black water lizard"
- Lived
- 227 to 206 million years ago, Late Triassic
- Length
- about 2.5 m (8 ft)
- Group
- Early sauropodomorphs, Plateosauridae
- Found in
- Brazil
- Named by
- Leal et al. 2004
Size comparison
To scale
Scale in metersOutline: typical early sauropodomorph shape
Where its fossils were found
The evidence
Today
220 million years ago
Habitat
It lived on the river plains preserved in the Caturrita Formation of southern Brazil, where conifer wood has been found. Other dinosaurs from the formation include Guaibasaurus and Macrocollum.
Field notes
About Unaysaurus
What it was like
Unaysaurus was a small plant eater about 2.5 meters (8 feet) long, an early member of the long-necked line that later produced the giant sauropods. It walked on its hind legs and had a long neck and a small head.
It was closely related to Plateosaurus from Germany, which suggests animals could move easily across the joined continents of the time.
Its world
It lived in the Late Triassic in what is now southern Brazil. Its bones come from the Caturrita Formation, where it shared the land with Guaibasaurus and the long-necked Macrocollum.
How it was found
Leal and colleagues named Unaysaurus in 2004, from a single skeleton with a skull, one of the most complete early dinosaurs from Brazil.
Field gallery
More views of Unaysaurus
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 Unaysaurus.
The evidence
The science behind Unaysaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The original partial skeleton preserves a skull and parts of the backbone and limbs.
- A smaller individual is known from isolated vertebrae and bones of the foot.
Borrowed from relatives
- Missing parts of the body are restored by comparison with early sauropodomorphs such as Plateosaurus.
Still unknown
- Its skin color and pattern.
- Exactly which plants it ate.
- Whether adults cared for their young.
Discovery timeline
- 2004Named itLEAL et al.
- 2019Full descriptionMcPhee et al.
- 2023Growing upMüller et al.
Key papers
The research behind what we know of Unaysaurus
Named it
Named a small early sauropodomorph from Brazil and identified similarities to Plateosaurus.
A new early dinosaur (Sauropodomorpha) from the Caturrita Formation (Late Triassic), Paran Basin, Brazil. Zootaxa 690
Read the paper : A new early dinosaur (Sauropodomorpha) from the Caturrita Formation (Late Triassic), Paran Basin, Brazil (opens in a new tab)Full description
Restudied the bones and recovered a close relationship with Plateosaurus, although support for that pairing was weak.
Reassessment ofUnaysaurus tolentinoi(Dinosauria: Sauropodomorpha) from the Late Triassic (early Norian) of Brazil, with a consideration of the evidence for monophyly within non-sauropodan sauropodomorphs. Journal of Systematic Palaeontology 18: 259-293
Read the paper : Reassessment ofUnaysaurus tolentinoi(Dinosauria: Sauropodomorpha) from the Late Triassic (early Norian) of Brazil, with a consideration of the evidence for monophyly within non-sauropodan sauropodomorphs (opens in a new tab)Growing up
Recognized a smaller, still-growing individual among the original fossil material, expanding the record of young Unaysaurus.
On a skeletally immature individual of Unaysaurus tolentinoi (Dinosauria: Sauropodomorpha) from the upper Triassic of southern Brazil. The Anatomical Record 307: 1071-1083
Read the paper : On a skeletally immature individual of Unaysaurus tolentinoi (Dinosauria: Sauropodomorpha) from the upper Triassic of southern Brazil (opens in a new tab)
Close relatives
Other members of Plateosauridae
Sources: Wikidata