An Ultimate Guide to Austroraptor: The Southern Seizer

Leave a comment / / Updated on: 23rd September 2023

NameAustroraptorDietCarnivorous
Name MeaningSouthern thief / Southern seizerHeight1.5 to 2 meters (5 to 6.5 feet)
Pronunciationaw-stroh-RAP-torLength5 meters – 6 meters (16 feet — 20 feet)
EraMesozoicLate CretaceousWeight91 – 300 kg (200-660 lbs)
ClassificationDinosauria,‭ Saurischia & TheropodaLocationArgentina (South America)

Austroraptor Pictures

Austroraptor dinosaur walking isolated in white background -3D render
Austroraptor | CoreyFord via iStock

The Austroraptor

Gage Beasley Prehistoric's Austroraptor Concept
Gage Beasley Prehistoric’s Austroraptor Concept

Austroraptor is a genus of carnivorous dinosaurs that lived in South America during the Late Cretaceous period about 70 million years ago.

This theropod dinosaur belonged to the family Dromaeosauridae, a group that includes several small-to-medium-sized feathery carnivores commonly found in North and South America.

The Velociraptor is the most popular member of this group. Fossils of this dinosaur were first discovered in rocks of the Allen Formation, Río Negro, Argentina.

The name Austroraptor means “southern thief,” a reference to the dinosaur’s Southern Hemisphere origin.

Austroraptor shared many similarities with the other dromaeosaurids both in terms of their anatomy and general behavior.

Maxilla and dentary of the holotype of Austroraptor cabazai
Maxilla and dentary of the holotype of Austroraptor cabazai | Photo via Wikipedia (CC BY 4.0)

However, it was also unique in a lot of ways, which makes it quite an interesting dinosaur to study.

Although many parts of its skeleton are still missing, paleontologists have already learned a lot about this dinosaur from studying the remains found so far.

Being among the last generation of non-avian dinosaurs that existed before they all got wiped out, studying this dinosaur has provided a glimpse into the evolution of the dinosaurs.

In this post, we’ll cover some of the fascinating facts about this.

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

Austroraptor 3D Render
Austroraptor | CoreyFord via iStock

Austroraptor was a large, moderately built bipedal dinosaur, that is often compared to the popular depiction of the Velociraptor in terms of its body proportion and physical characteristics.

Although Austroraptor is not as big as many North American dromaeosaurid dinosaurs like the Utahraptor,‭ ‬ it is the largest member of the family known from South America.‭

This dinosaur is only known from two incomplete specimens.

Estimates project that it may have measured up to five to six meters (16 feet to 20 feet) in length from its head to tail.

Gage Beasley Prehistoric's Austroraptor Size Comparison
Gage Beasley Prehistoric’s Austroraptor Size Comparison

Weight estimates for this dinosaur vary from 91 kilograms on the low end to about 300 kilograms at the maximum (200–660 pounds).

These estimates put this dinosaur in the same weight category as a modern lion.

Austroraptor had an elongated but narrow skull (much narrower than that of other South American dromaeosaurids).

The low skull measured about 80 centimeters (31 inches) in length and had sharp, non-serrated teeth.

This dinosaur had a muscular body with strong, slender legs that seemed well-adapted for agile movements.

This dinosaur had three disproportionate toes on each foot. It had a long tail made up of a collection of bones and ossified tendons.

One of the most distinctive features of the Austrorapor is its relatively short forearms.

Although other members of the Dromaeosauridae family (including velociraptors) are known for their short forearms, the Austroraptor’s arm was even shorter.

Austroraptor in PNE Vancouver Fair
Austroraptor in PNE Vancouver Fair | Linda Crampton via Owlcation

The forelimbs are less than half the length of the dinosaur’s hind legs.

Because of the relative length of this dinosaur’s arms, it is often compared to the Tyrannosaurus, even though both dinosaurs are not close relatives.

Like many of its relatives, the Austoraptor had feathers which most likely helped with insulation and display but was probably not for flight.

It is one of the few large theropod dinosaurs known to have feathers.

Habitat and Distribution

Austroraptor fossils have been discovered in terrestrial sediments of the Allen Formation in Argentina.

The formation dates back to the Late Cretaceous period between 78 and 66 million years ago.

This dinosaur went extinct along with the rest of the non-avian dinosaurs at the end of the Mesozoic era.

Fossils of these dinosaurs were recovered specifically from the province of Rio Negro, located in the southern region of Argentina.

This area was part of the larger landmass known as Gondwana during the Late Cretaceous.

At that time, the region was situated much closer to the South Pole than its present location.

The supercontinent was home to large titanosaurs and theropods like the Austroraptor that inhabited the interior ecosystems in contrast to the hadrosaurids that lived in the coastal lowlands.

Paleontologists believe Austroraptor lived near bodies of water such as rivers, lakes, or coastal areas.

Austroraptor dinosaurs watch as Amargasaurus drink from a Cretaceous swamp
Austroraptor dinosaurs watch as Amargasaurus drink from a Cretaceous swamp | CoreyFord via iStock

The nature of the sedimentary deposits containing this dinosaur’s fossils suggests that it lived in wetlands and floodplains.

These areas would have provided abundant opportunities for hunting and scavenging.

During the Late Cretaceous, the climate of the Gondwana supercontinent, where the Austroraptor lived, was relatively warm and temperate.

The area experienced mild winters and warm summers. The presence of large water bodies may have influenced the local climate.

It was a lush continent with conditions that supported a wide array of plant and animal life.

As a result, the ecosystem was characterized by a rich diversity of dinosaurs and other reptiles.

Behavior and Diet

Austroraptor (left) attacks a juvenile sauropod dinosaur in an artist's interpretation
Austroraptor (left) attacks a juvenile sauropod dinosaur in an artist’s interpretation | hedwig_the_owl via Flickr

Austroraptor was a bipedal dinosaur that moved on its long and slender hind legs.

Scientists believe this dinosaur was quite agile and capable of moving at very high speeds.

Not a lot is known about the Austroraptor’s social behavior. However, Austroraptor may have lived and hunted in small groups, similar to some modern predatory species.

One of the unique features of this dinosaur is its proportionately small forearms, equipped with sharp sickle-shaped claws.

This is a feature that is typically well-developed in other dromaeosaurid dinosaurs as they tend to use their claws to hold on to prey and make a kill.

The smaller size of the Austroraptor suggests that it was probably adapted to a different diet even though it was a carnivore.

Another evidence that this dinosaur had a unique diet is the shape of its skull.

It had a narrow jaw, indicative of poorly developed biting muscles and proportionately weak bite force.

It also had conical, non-serrated teeth, which are not well-suited for holding and tearing into prey.

Skeletal reconstruction and body shape of Austroraptor
Skeletal reconstruction and body shape of Austroraptor | Diego Pol via ResearchGate

Based on this evidence, scientists have suggested that this dinosaur was a niche predator incapable of hunting large prey actively.

The short arms would have been incapable of holding on to prey, and the lack of specialized teeth meant this dinosaur may have preferred hunting small animals.

This may have included small to medium-sized dinosaurs and other small animals like reptiles and mammals that shared its environment.

Despite its large size, the Austroraptor’s dentition was more similar to that of smaller piscivorous dinosaurs like the spinosaurids.

Because of this, many scientists have suggested that this dinosaur was a fish-eater instead of a terrestrial predator.

There’s also a chance it was a scavenger, using its large size to chase off smaller predators and steal their kill.

The absence of serrated teeth suggests that this dinosaur probably swallowed its prey whole.

Life Cycle

Austroraptor dinosaur walking isolated in white background -3D render
Austroraptor | Elenarts108 via iStock

Our knowledge of the Austroraptor’s lifecycle is limited since the available fossil records provide very limited information about the dinosaur’s reproduction and sexual behavior.

Drawing a comparison from other related dinosaurs, female Austroraptors would likely have laid a clutch of eggs.

The eggs were likely incubated and protected by the parents or left in a suitable environment until they hatched.

Once hatched, Austroraptor may have undergone rapid growth within the early stages of life, reaching sexual maturity very quickly.

This is the typical growth pattern observed in several dinosaur groups, particularly large theropods like the Austroraptor, sauropods, and hadrosaurs.

Evolution and History

Austroraptor was a carnivorous theropod dinosaur that lived in Argentina in the Cretaceous Period.
Austroraptor | CoreyFord via iStock

The evolution of the dromaeosaurs dates back to the Jurassic Period.

During this time, all the continents were closer together, forming a continuous landmass known as Pangea.

Scientists think the oldest members of the Dromaeosauridae family emerged up to 180 million years before Pangea broke up.

Although all members of the Dromaeosauridae family began their evolution on Lauresia, the northern landmass of Pangea, the southern species, like the Austoraptor, migrated to Southern Gondwana sometime during the Cretaceous.

The species that evolved on the southern continents are grouped in the subfamily Unenlagiinae.

Apart from the Austroraptor, other South-American dromaeosaurs in this subfamily include Neuquenraptor, Unenlagia and Buitreraptor.

They all show similarities in terms of their skull bones, teeth shape, and vertebral elements.

But the most notable adaptation observed in this group is their improved speed and agility, which would have made them more efficient at pursuing prey compared to other dromaeosaurids in the Northern Hemisphere.

Austroraptor cabazai mount, as seen at an exhibition in Copiapó
Austroraptor cabazai mount, as seen at an exhibition in Copiapó | By PaleoNeolitic via Wikipedia CC BY-SA 4.0

They were less stocky and had longer legs. They also had modified metatarsals.

These adaptations suggest that the Unenlagiines preyed on smaller and quicker animals.

Their unique diet is also supported by the absence of serrated teeth, as seen in other dromaeosaurid dinosaurs.

Austroraptor underwent several other adaptations and modifications throughout their evolutionary history.

For instance, the early dromaeosaurids had more primitive features, such as long, bony tails, and fewer specialized features.

But as their lineage evolved, many members of the group developed unique traits like reduced tail lengths and increased specialization in their limbs and skulls.

Austroraptor is particularly notable because it represents one of the largest known dromaeosaurids.

Its large size distinguishes it from other members of the Unenlagiinae subfamily, which were generally smaller.

Interactions With Other Species 

Austroraptor walking in the desert
Austroraptor walking in the desert | Elena Duvernay via GettyImages

Austroraptor was a mid-sized predator within its ecosystem.

Back in the Late Cretaceous, when this dinosaur was alive, the South-American continent had several large, herbivorous dinosaurs like Argentinosaurus and smaller ones like Saltasaurus and Lapampasaurus.

The diversity of the local ecosystem suggests a fairly complex food web in the Late Cretaceous of South America.

However, Austroraptor was probably not an active predator of their terrestrial dinosaur neighbors.

The unique nature of this dinosaur’s dentition suggests that it was better equipped to hunt fishes, small mammals, and reptiles.

Reconstruction of Austroraptor preying on fish, depicting a piscivorous diet
Reconstruction of Austroraptor preying on fish, depicting a piscivorous diet | By Fred Wierum via Wikipedia CC BY-SA 4.0

But potential prey could have also included small to medium-sized herbivorous dinosaurs, such as juveniles or individuals of smaller species.

Austroraptor may have also interacted with other large predators within the same ecosystem, such as abelisaurids like Quilmesaurus.

The different carnivore species may have competed for resources like water, food, and space.

This competition would have influenced the distribution, abundance, and behavior of these predators.

For instance, some experts believe Austroraptors were scavengers.

If this were true, this dinosaur would have used its massive size to intimidate smaller dinosaurs to steal their prey.

Cultural Significance 

Austroraptor walking in the desert
Austroraptor | Elena Duvernay via GettyImages

Although only a few fragmentary remains of this dinosaur have been discovered so far.

Austroraptor has played a crucial role in expanding our knowledge of dinosaur diversity, evolution, and paleobiology.

The discovery of this dinosaur has provided valuable insights into the evolution and behavior of dromaeosaurid dinosaurs, a unique group of dinosaurs that occupied a vital ecological niche during the Late Cretaceous.

Austroraptor represents a unique branch of dromaeosaurid dinosaur that shows remarkable adaptations that sets it apart from other members of the Dromaeosauridae family.

Although many of the Austroraptor’s skeleton is still missing, the skull, leg, arm, and vertebrae bones recovered so far have helped us learn a lot about this group of narrow-snouted predators and their relatives.

Austroraptor is not very popular in pop culture and science fiction.

However, relatives like the popular velociraptors have made it to the big screen, including a cameo in the Jurassic Park movies.

Many experts have opined that the on-screen depiction of the Velociraptor is closer in size and proportion to an Austroraptor or any of the larger members of the dromaeosaurid family.

Austroraptor is also well-featured in museum exhibitions, educational materials, and scientific literature aimed at engaging and inspiring the public, especially young learners, to be more interested in dinosaurs.

Conclusion 

Austroraptor is a medium-large-sized carnivorous dinosaur that lived in Argentina about 70 million years ago.

It was a member of a dromaeosaurid family of feathered theropod dinosaurs that flourished in North and South America during the Cretaceous period.

Austroraptor was the largest dromaeosaurid dinosaur from South America.

In addition to the size, Austroraptor also showed many distinct traits that set them apart from other dromaeosaurs, including shorter arms, longer legs, and different skull structures and dentitions.

Although there’s still much to be learned about this dinosaur and its relatives, the discovery of the Austroraptor has shown that the South-American continent was an important center of dinosaur diversification during the Cretaceous.

It adds to a long list of dromaeosaurs that lived on the South-American continent and showed that these dinosaurs grew even bigger than earlier thought.

FAQs 

What does the name “Austroraptor” mean?

The name “Austroraptor” is derived from Latin roots. “Austrum” means “south,” referring to the region where the fossil remains were discovered in South America, and “raptor” means “thief” or “plunderer,” indicating its carnivorous nature.

Where were the fossil remains of the Austroraptor found?

Fossils of Austroraptor have been discovered in the Patagonia region of southern Argentina. The specific locality is the Allen Formation, known for its rich fossil deposits from the Late Cretaceous.

Did the Austroraptor have feathers?

While direct evidence of feathers in Austroraptor has not been found on fossils recovered so far, its close relatives within the dromaeosaurid family and many other related dinosaurs had fossilized feathers.

Therefore, it is likely that Austroraptor had some form of feathers or feather-like structures, possibly for insulation and display.

Is Austroraptor related to Velociraptor?

Austroraptor and Velociraptor are both members of the broader dromaeosaurid family of dinosaurs. However, they belong to different subfamilies and are not closely related.

Austroraptor belongs to the Unenlagiinae subfamily, while Velociraptor is part of the Velociraptorinae subfamily.

Sources 

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