Utahraptor
“Utah's thief”The largest raptor, with a 24-centimetre killing claw
Overview
Utahraptor is a genus of large dromaeosaurid dinosaur that lived during the Early Cretaceous period from around 139 to 135 million years ago in what is now the United States. The genus was described in 1993 by American paleontologist James Kirkland and colleagues with the type species Utahraptor ostrommaysi, based on fossils that had been unearthed earlier from the Cedar Mountain Formation of Utah. Later, many additional specimens were described including those from the skull and postcranium in addition to those of younger individuals.
Source: Wikipedia
Why it matters
- Named in 1993, the same year Jurassic Park's oversized 'Velociraptors' hit cinemas, and conveniently about their size.
- A nine-tonne block from Utah holds several individuals that may have died together in quicksand.
- Heavily built for its kind, it probably ambushed prey rather than chasing it.
Classification & discovery
- Group
- Dinosaur · Theropod · Dromaeosauridae
- Parent taxon
- Eudromaeosauria
- Diet
- carnivore
- Environment
- terrestrial
- Life habit
- ground-dwelling
- Named
- by Kirkland et al. in 1993
When it lived
137.1 – 132.6 million years ago · Cretaceous
Where it was found
Utah · Countries with fossils: US
4 fossil occurrences in the Paleobiology Database · Rock formations: Cedar Mountain
Size

Length 6 m · Mass 400 kg · Size estimates are editorial, from the literature; silhouettes from PhyloPic.
- Length
- 6 m
- Height
- 1.8 m
- Mass
- 400 kg
- First appearance
- 137.1 MaValanginian
- Last appearance
- 132.6 Ma
- Span of the fossil record
- 4.5 million years
- Fossil occurrences
- 4US
- Year named
- 1993Kirkland et al.
Sources
Image: Jaren Wilkey, CC BY-SA 4.0 · CC BY-SA 4.0 · image page
Life restoration: Fred Wierum, CC BY-SA 4.0 · CC BY-SA 4.0 · image page
Silhouette: Emily Willoughby (PhyloPic) · license
Text: Wikipedia (CC BY-SA 4.0). Taglines, highlights and size estimates are editorial.