Carnotaurus sastrei

Carnotaurus sastrei was a specialised large predator from latest Cretaceous Patagonia. Its deep, short skull carried a stout horn core above each eye, while the forelimbs were reduced even beyond the condition in tyrannosaurids. The only known skeleton, MACN-PV-CH 894, is substantially complete and preserves skin impressions from several regions of the body. That combination makes Carnotaurus one of the best documented southern-hemisphere theropods, while also imposing a major limitation: variation, growth and differences between sexes cannot be tested from a sample of one.

Its fossils occur between approximately 72 and 69 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The holotype preserves most of the skull and skeleton, both forelimbs and extensive patches of integument. Crushing and sideways deformation altered parts of the skull, so modern studies separate original anatomy from distortion. The horns were bony cores that probably carried keratin in life, but their external shape and use cannot be reconstructed exactly.

• Short, deep skull with a robust horn core above each eye
• Rough facial bones indicating extensive keratinous or scaly coverings
• Small blade-like teeth and a flexible lower-jaw construction
• Extremely shortened but robust forelimbs with four metacarpals
• Long, gracile hind limbs relative to other large theropods
• Deep tail-base musculature reconstructed from specialised vertebrae and ribs
• Non-overlapping basement scales with larger conical feature scales

Members of the Sastre family guided José Bonaparte's eighth Patagonian expedition to the fossil site near Bajada Moreno, Chubut Province, in 1984. The nearly articulated skeleton was enclosed in an exceptionally hard hematite concretion, making preparation slow. Bonaparte named Carnotaurus sastrei in 1985; Carnotaurus means 'meat-eating bull' and sastrei honours Ángel Sastre. Bonaparte, Fernando Novas and Rodolfo Coria published the full skeletal description in 1990.

Discovery credit: Sastre family, José Bonaparte-led Patagonian expedition.

Naming authors: José F. Bonaparte.

The La Colonia Formation records low-relief coastal plains with rivers, ponds, estuaries and marine influence. Carnotaurus shared this landscape with turtles, crocodyliforms, snakes, mammals and herbivorous dinosaurs. Exact dates within the formation continue to be refined, so the displayed range is approximate.

Carnotaurus was a terrestrial carnivore, but preferred prey and hunting technique are unknown. Its long hind limbs and expanded tail musculature suggest strong forward locomotion, not a measured top speed. The horns may have had display or combat roles, and the skull and neck could resist some loading, but head-butting scenarios remain hypotheses. The preserved skin confirms scales; it does not establish colour or the absence of every filament on unpreserved body regions.

• MACN-PV-CH 894 remains the only scientifically described Carnotaurus individual.
• Its skin is the most comprehensively preserved scaly covering known for a non-avian theropod.
• A 2021 reanalysis found that the large conical scales were scattered irregularly, not arranged in tidy rows as older art often showed.
• The hands retained four metacarpals even though the arms were extremely short and probably had little reach.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   The Paleobiology Database

   Open source
2. 02
   A horned Cretaceous carnosaur from Patagonia

   José F. Bonaparte · National Geographic Research · 1985

3. 03
   Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Middle Cretaceous of Patagonia

   José F. Bonaparte, Fernando E. Novas, Rodolfo A. Coria · Contributions in Science · 1990

   Open source
4. 04
   The hand structure of Carnotaurus sastrei: implications for hand diversity and evolution in abelisaurids

   Javier Ruiz, Angélica Torices, Humberto Serrano, Valentín López · Palaeontology · 2011

   Open source
5. 05
   Dinosaur Speed Demon: The Caudal Musculature of Carnotaurus sastrei and Implications for the Evolution of South American Abelisaurids

   W. Scott Persons, Philip J. Currie · PLOS ONE · 2011

   Open source
6. 06
   The skull of Carnotaurus sastrei Bonaparte 1985 revisited: insights from craniofacial bones, palate and lower jaw

   Mauricio A. Cerroni, Juan I. Canale, Fernando E. Novas · Historical Biology · 2020

   Open source
7. 07
   The scaly skin of the abelisaurid Carnotaurus sastrei from the Upper Cretaceous of Patagonia

   Christophe Hendrickx, Phil R. Bell · Cretaceous Research · 2021

   Open source
8. 08
   Carnotaurus sastrei: original skull and collection record

   Museo Argentino de Ciencias Naturales Bernardino Rivadavia

   Open source