Richardoestesia
- Lived
- 86 to 66 million years ago, Late Cretaceous
- Diet
- Carnivore
- Group
- Theropods, Dromaeosauridae
- Found in
- Canada, United States, Uzbekistan and Romania
- Named by
- Currie et al. 1990
Where its fossils were found
The evidence
Today
75 million years ago
Also reported from Russia.
Habitat
Its original jaws come from the Dinosaur Park Formation in Alberta, a coastal plain crossed by winding rivers. Other dinosaurs from these rocks include Saurornitholestes, Dromaeosaurus and Ornithomimus.
Field notes
About Richardoestesia
What it was like
Richardoestesia is known mostly from teeth: small, narrow and finely serrated. The teeth belonged to a small theropod with a slender jaw. They may have suited catching fish or small prey, but the animal's body is unknown.
Its world
Its teeth come from many Late Cretaceous rock layers in western North America, from Alberta to Texas, over millions of years. That means the name may cover several different animals. Teeth like them have also been reported from Asia and Europe.
How it was found
Currie and colleagues named Richardoestesia in 1990, from a pair of lower jaws. Since then, 155 finds have been listed, almost all of them teeth.
Field gallery
More views of Richardoestesia
Scenes reconstructed from the available fossil evidence.
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 Richardoestesia.
The evidence
The science behind Richardoestesia
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The original specimen is a pair of slender lower jaws with developing teeth.
- Isolated teeth assigned to Richardoestesia have narrow crowns with tiny serrations along their edges.
Borrowed from relatives
- A whole-body restoration borrows the legs, arms and tail of better-known small theropods, such as Saurornitholestes.
Still unknown
- Its body shape, size and covering.
- Which animals it ate.
- How many different animals the widely scattered teeth represent.
Discovery timeline
- 1990Named itCurrie, Rigby & Sloan
- 2013Fossil sitesLarson & Currie
- 2019New findAverianov & Sues
Key papers
The research behind what we know of Richardoestesia
Named it
Named Richardoestesia while comparing the teeth of small theropods from Alberta.
Theropod teeth from the Judith River Formation of southern Alberta, Canada. Dinosaur Systematics: 107-126
Read the paper : Theropod teeth from the Judith River Formation of southern Alberta, Canada (opens in a new tab)Fossil sites
Compared tooth measurements across rock layers and found that similar-looking small theropod teeth can represent different animals.
Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time. PLoS ONE 8: e54329
Read the paper : Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time (opens in a new tab)New find
Compared teeth from Uzbekistan with North American samples and questioned whether isosceles is a distinct species.
Morphometric analysis of the teeth and taxonomy of the enigmatic theropodRichardoestesiafrom the Upper Cretaceous of Uzbekistan. Journal of Vertebrate Paleontology 39: e1614941
Read the paper : Morphometric analysis of the teeth and taxonomy of the enigmatic theropodRichardoestesiafrom the Upper Cretaceous of Uzbekistan (opens in a new tab)
Close relatives
Other members of Dromaeosauridae
Sources: Wikidata