Utahraptor (Utahraptor ostrommaysi Kirkland et al., 1993) - Size, Diet & Cretaceous Period Facts

Q: What makes Utahraptor scientifically significant?

Utahraptor provides critical insights into the evolutionary radiation of Theropoda. Holotypes and fossil evidence indicate: Spectacular multi-individual nine-ton sandstone megablock preserving multiple Utahraptors and prey.

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Utahraptor (Utahraptor ostrommaysi Kirkland et al., 1993) - Size, Diet & Cretaceous Period Facts | DinoOrigin

Evolutionary Taxonomy & Cladistics

View Dinosaur Phylogeny

Phylogenetic classification of Utahraptor ostrommaysi Kirkland et al., 1993 based on peer-reviewed cladistic analyses of diagnostic skeletal synapomorphies.

Taxonomic Rank	Taxon / Clade	Diagnostic Context
Kingdom	Animalia	Monophyletic prehistoric clade
Phylum	Chordata	Monophyletic prehistoric clade
Clade	Dinosauria	Monophyletic prehistoric clade
Order	Saurischia (Lizard-Hipped Dinosaurs)	Characterized ancestrally by a triradiate pelvis with an anteriorly pointing pubis.
Suborder	Theropoda	Bipedal saurischian dinosaurs, historically dominated by carnivores and including the avian lineage.
Genus	Utahraptor	Monophyletic prehistoric clade
Species	Utahraptor ostrommaysi Kirkland et al., 1993	Specific authority designation

Anatomy & Physical Characteristics

Utahraptor was the largest known dromaeosaurid in Earth's history, shattering the perception that 'raptors' were exclusively small, lightweight hunters. Inhabiting Early Cretaceous Utah, it grew up to six meters in length and weighed approximately 500 kilograms.

Its formidable second pedal ungual (sickle claw) measured over 24 centimeters in life when covered by a keratinous sheath, functioning as a devastating weapon to pin down large iguanodontids.

Diagnostic Morphological Traits

Heavily muscled dromaeosaur with thick legs, stout torso, massive sickle claws, and plumaged body.

Comparative Scale & Biometrics

Anatomical dimensions relative to an average adult human (1.8 m / 6 ft tall)

Approx. 3.3× human length

Utahraptor (Length)5–6 m (16.4–19.7 ft)

Adult Human1.8 m (6.0 ft)

Length

5–6 m (16.4–19.7 ft)

Height

1.6–1.9 m (5.2–6.2 ft)

Estimated Mass

400–600 kg (882–1,323 lbs)

Diet & Feeding Ecology

All Carnivore Species

Trophic Guild: Carnivore

Iguanodonts (Iguanacolossus) and armored ankylosaurs (Gastonia).

Paleobiology & Behavior

Colossal dromaeosaurid predator reaching up to 5.5 meters in length and weighing over 300 kg, equipped with devastating 24 cm sickle claws. In the Cedar Mountain Formation of Utah, Utahraptor was the apex dromaeosaurid, serving as a massive evolutionary precursor to later Cretaceous relatives like Deinonychus and Velociraptor.

Habitat & Ecological Biome

Prehistoric Depositional Setting

Semi-arid floodplains, scrublands, and open woodlands of the Cedar Mountain Formation.

Fossil Evidence & Specimen Records

Preserved Skeletal Material & Bonebeds

Spectacular multi-individual nine-ton sandstone megablock preserving multiple Utahraptors and prey.

Discovery & Taxonomic Naming History

Year of Discovery / Description1991

Type Specimen Locality & FormationCedar Mountain Formation, Utah, United States

Discovered by Jim Kirkland, Rob Gaston, and Don Burge; described in 1993.

Geological Era & Chronostratigraphy

Explore All Cretaceous Period Fauna

Cretaceous Period PeriodTemporal Interval: 135–130 Ma (million years ago)

The longest and final period of the Mesozoic Era, characterized by the rise of flowering plants, ceratopsians, hadrosaurs, tyrannosaurids, and concluding with the Chicxulub asteroid impact.

Where It Lived & Paleoenvironment

North America Dinosaurs

During the Mesozoic Era, continental drift progressively reconfigured land bridges, atmospheric currents, and regional precipitation regimes. Fossils of Utahraptor evidence its adaptation to the paleoenvironments of North America.

Paleogeographic RealmNorth America (North America)

Home to the fossil-rich Morrison Formation of the Late Jurassic and the Hell Creek and Dinosaur Park Formations of the Late Cretaceous.

Fossil Discovery Locality

Scientific Significance & Evolutionary Impact

The anatomical architecture of Utahraptor serves as a crucial benchmark in vertebrate paleontology, illustrating key adaptive radiations within Theropoda.

Phylogenetic Placement: Informs cladistic debates concerning the divergence, skull biomechanics, and skeletal evolution of Cretaceous Period fauna.
Paleoecological Guild: Documents trophic specialization (Carnivore) and predator-prey dynamics across its regional ecosystem.
Taphonomic Record: Spectacular multi-individual nine-ton sandstone megablock preserving multiple Utahraptors and prey.

Frequently Asked Questions About Utahraptor

Scientifically verified answers based on peer-reviewed paleontological evidence.

Q1.When did Utahraptor live?

Utahraptor lived during the Cretaceous Period Period, approximately 135–130 Ma (million years ago). This places it within the Mesozoic Era.

Q2.How big was Utahraptor?

Paleontological estimates place Utahraptor at a length of 5–6 m (16.4–19.7 ft), a hip/standing height of 1.6–1.9 m (5.2–6.2 ft), and a body mass of 400–600 kg (882–1,323 lbs).

Q3.What was the diet of Utahraptor?

Classified as a carnivore, Utahraptor specialized in consuming Iguanodonts (Iguanacolossus) and armored ankylosaurs (Gastonia)..

Q4.Where were Utahraptor fossils discovered?

Fossil specimens of Utahraptor have been recovered from Cedar Mountain Formation, Utah, United States, with notable historic specimens documented in 1991. Discovered by Jim Kirkland, Rob Gaston, and Don Burge; described in 1993.

What makes Utahraptor scientifically significant?

Academic Literature & Peer-Reviewed References

Authoritative citations establishing the factual taxonomy, biometrics, and anatomy of Utahraptor.

HunteriaView Publication
Kirkland, J. I., Burge, D., & Gaston, R. (1993). A large dromaeosaur [Theropoda] from the Lower Cretaceous of East-Central Utah. Hunteria, 2(10), 1-16.
Curated & Verified: 2026-09-24

Utahraptor

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