Austroraptor cabazai

Austroraptor cabazai was a large feathered paravian from the latest Cretaceous Allen Formation of northern Patagonia. At roughly five to six metres long, it was far larger than most close relatives. Its proportions were equally unusual: the skull was elongate and low, the teeth were conical and mostly lacked the coarse serrations common in predatory theropods, and the forelimbs were less than half the length of the femur. Two partial skeletons document complementary parts of the animal. These fossils show that the southern unenlagiine radiation included not only small, lightly built forms but also a distinctive large-bodied predator.

Its fossils occur between approximately 70.1 and 66 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The reconstructed skull approached eighty centimetres in length and had an especially long maxilla. Numerous small, conical teeth occupied the narrow jaws; their form differs from the laterally compressed, strongly serrated teeth of many dromaeosaurids. The humerus was extremely short relative to the femur, and the second specimen added the radius, ulna, parts of the hand and further foot bones. The hind foot retained the specialized second toe associated with paravians, although its claw was less strongly curved than in Velociraptor. Feathers are not preserved with Austroraptor itself but are inferred from extensive evidence across Paraves.

• Exceptionally long, low skull reconstructed at about eighty centimetres
• Numerous small, conical teeth with greatly reduced serrations
• Forelimbs less than half the length of the femur
• Large body size compared with other unenlagiines
• Specialized second toe with a moderately curved claw
• Long hind limbs and an elongated balancing tail

Marcelo Isasi discovered the holotype MML-195 at Bajo de Santa Rosa, about ninety kilometres southwest of Lamarque in Río Negro Province. Fernando Novas, Diego Pol, Juan Canale, Juan Porfiri and Jorge Calvo named the species in a paper published in 2009. A second, slightly smaller skeleton, MML-220, was recovered during a 2008 expedition and described by Philip Currie and Ariana Paulina Carabajal in 2012. The genus name combines the Latin auster, south wind, with raptor, thief. The species honours Alberto 'Tito' Cabaza, founder of Lamarque's municipal museum.

Naming authors: Fernando E. Novas, Diego Pol, Juan I. Canale and 2 coauthors.

The Allen Formation records a low-relief landscape of rivers, shallow lakes, floodplains and coastal-influenced environments near the end of the Cretaceous. Austroraptor shared northern Patagonia with titanosaurs, hadrosaurids, ankylosaurs, abelisaurids, birds, turtles and crocodyliforms. Its narrow snout and tooth form have prompted suggestions of feeding in or around water, but the formation alone does not establish a specialized aquatic lifestyle.

Austroraptor was a bipedal carnivore, yet the exact prey it targeted is unknown. Its long jaws and conical, weakly serrated teeth differ from the slicing dentition of many land predators and may have been useful for gripping small or slippery prey. A fish-rich diet is therefore a testable hypothesis, not a directly preserved fact. The shortened arms make forelimb-assisted prey capture less likely than in some smaller dromaeosaurids. No fossil evidence establishes pack hunting.

• At roughly five to six metres long, it was among the largest raptor-like dinosaurs yet discovered.
• Its arms were proportionally shorter than those of most other dromaeosaurids.
• A second skeleton preserved forelimb and foot bones missing from the holotype.
• Its narrow jaws and conical teeth have inspired, but do not prove, a fish-eating interpretation.

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1. 01
   A bizarre large-bodied dromaeosaurid theropod from the latest Cretaceous of Patagonia

   Fernando E. Novas, Diego Pol, Juan I. Canale and 2 coauthors · Proceedings of the Royal Society B 276(1659), 1101–1107 · 2009

   Open source
2. 02
   A new specimen of Austroraptor cabazai from the latest Cretaceous of Río Negro, Argentina

   Philip J. Currie, Ariana Paulina Carabajal · Ameghiniana 49(4), 662–667 · 2012

   Open source
3. 03
   Osteology of Austroraptor cabazai (Paraves: Theropoda): a southern gigantic unenlagiid from the Late Cretaceous of Patagonia

   Matías J. Motta, Fernando E. Novas · Historical Biology 38(6) · 2025

   Open source