Pareisactus
"intruder"
Type species Pareisactus evrostos
- Lived
- 72 to 66 million years ago, Late Cretaceous
- Diet
- Herbivore
- Group
- Ornithopods
- Found in
- Spain
- Named by
- Párraga and Prieto-Márquez 2019
Where its fossils were found
The evidence
Today
70 million years ago
Habitat
It lived on the island landmasses of Late Cretaceous Europe, in what is now Spain. Abditosaurus, Adynomosaurus and Pararhabdodon are also recorded from the Conques rocks.
Field notes
About Pareisactus
What it was like
Pareisactus was named from a single shoulder blade thought to belong to a rhabdodontid, one of the plant-eating ornithopods of Late Cretaceous Europe. Its identity is uncertain: one later study suggested the distorted bone may belong to a duckbill instead.
Its world
It lived about 72 to 66 million years ago, at the end of the Late Cretaceous, in what is now Spain. Its bone comes from the Conques Formation, where the titanosaur Abditosaurus and the duckbill Pararhabdodon also lived.
How it was found
Párraga and Prieto-Márquez named it in 2019. The type species is Pareisactus evrostos. Its name refers to how it was the one odd bone among many duckbill bones at the site.
Field gallery
More views of Pareisactus
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 Pareisactus.
The evidence
The science behind Pareisactus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- A single, nearly complete shoulder blade is the only bone assigned to Pareisactus.
- The naming study described a deep hollow for a shoulder muscle with a thick bony roof, a long point at the shoulder joint, and a well-marked ridge like that of Rhabdodon.
Borrowed from relatives
- The head, limbs and tail are restored by comparison with Rhabdodon and Zalmoxes, rhabdodontids known from more complete remains.
Still unknown
- Its full body size and proportions.
- What the bone really shows. One later study of the specimen argues that it comes from the right side rather than the left, that flattening and distortion may have produced its hollow and ridge, and that it may belong to a duckbill instead.
- Its place in the family tree. A later study calls it a probable rhabdodontid, while one large analysis found it too incomplete to place reliably.
Discovery timeline
- 2019Named itPÁRRAGA & PRIETO-MÁRQUEZ
- 2023Family treeAugustin, Ősi & Csiki-Sava
- 2025Family treeCzepiński & Madzia
Key papers
The research behind what we know of Pareisactus
Named it
Described a distinctive shoulder blade and identified Pareisactus as a relative of Rhabdodon.
Pareisactus evrostos, a new basal iguanodontian (Dinosauria: Ornithopoda) from the Upper Cretaceous of southwestern Europe. Zootaxa 4555
Read the paper : Pareisactus evrostos, a new basal iguanodontian (Dinosauria: Ornithopoda) from the Upper Cretaceous of southwestern Europe (opens in a new tab)Family tree
Reviewed the island-dwelling rhabdodontids, including Pareisactus, and their anatomy, feeding and evolutionary history.
The Rhabdodontidae (Dinosauria, Ornithischia), an enigmatic dinosaur group endemic to the Late Cretaceous European Archipelago. Fossil Record 26: 171-189
Read the paper : The Rhabdodontidae (Dinosauria, Ornithischia), an enigmatic dinosaur group endemic to the Late Cretaceous European Archipelago (opens in a new tab)Family tree
Compared the group's members and treated Pareisactus as a probable rhabdodontid whose single bone limits how firmly it can be placed.
Exploring the diversity and disparity of rhabdodontomorph ornithopods from the Late Cretaceous European archipelago. Scientific Reports 15
Read the paper : Exploring the diversity and disparity of rhabdodontomorph ornithopods from the Late Cretaceous European archipelago (opens in a new tab)
Close relatives
Other members of Rhabdodontoidea
Sources: Wikidata