Appalachiosaurus: The Fierce Predator of the Late Cretaceous Period

Appalachiosaurus: The Fierce Predator of the Late Cretaceous Period

Millions of years ago was a time when the continents were not as we know them today. North America was not a vast, unbroken landmass–split into two by a large inland sea. This was a time when creatures roamed the earth, so different from anything we see today that they almost defy belief. One such creature was the Appalachiosaurus, a dinosaur that lived during the Late Cretaceous period. This formidable predator was a sight to behold, and its story is as fascinating as it is ancient.

Appalachiosaurus Key Facts

Appalachiosaurus pronunciationAh-Pah-Lay-Chee-Oh-Sore-Us
Meaning of nameAppalachian Lizard
Type SpeciesAppalachiosaurus montgomeriensis
When it Lived83.5 to 66.0 MYA
PeriodLate Cretaceous
EpochMiddle Campanian to Late/Upper Maastrichtian
Length21.0 to 23.0 ft
Height8.2 ft
Weight1200-1500 lbs
MobilityMoved on two legs
First Discovery1982 by David King
Location of first findAlabama, USA
First Described by2005 by Thomas Carr, Thomas Williamson & David Schwimmer
HolotypeRMM 6670
Also Found InSouth Carolina, USA

Appalachiosaurus Origins, Taxonomy and Timeline

Digital illustration of an Appalachiosaurus dinosaur, characterized by its robust build and powerful limbs. The dinosaur is depicted in a dynamic running pose, with a slightly open mouth revealing sharp teeth.

The name, meaning “Appalachian Lizard,” is derived from the region where it was first discovered. In the Late Cretaceous, North America was still divided into the western paleocontinent Laramidia and the eastern paleocontinent Appalachia. This is paired with the Greek word ‘sauros’, meaning lizard. This name pays homage to its place of origin and its reptilian nature.

This dinosaur belongs to the group known as theropods. These were primarily carnivorous dinosaurs that moved on two legs. More specifically, it is part of the Tyrannosauroidae family, a group of dinosaurs that includes the infamous Tyrannosaurus rex. The type species of this genus is Appalachiosaurus montgomeriansis, named after Montgomery County in Alabama where the first specimen was found.

The timeline spans from the Middle Campanian to the top of the Late/Upper Maastrichtian, which is part of the Late Cretaceous period. This places the existence of Appalachiosaurus in a time when dinosaurs were the dominant terrestrial vertebrates of North America.

Discovery & Fossil Evidence

The first discovery was made in 1982 by geologist David King in Alabama, USA. The specimen, designated as RMM 6670, was later described in detail by Thomas Carr, Thomas Williamson, and David Schwimmer in 2005. The discovery was somewhat serendipitous. While mapping and sampling sediment in central Alabama for a project, Auburn University professor David King came across numerous bones and bone fragments. Among these was a small foot bone, which he identified as a significant fossil. To prevent potential damage, he buried it and returned a few days later to retrieve it. Upon examination, it was clear that the bone was from a dinosaur. This initial discovery was significant as it provided the first evidence of this previously unknown dinosaur. 

A mounted skeleton of an Appalachiosaurus on display in a museum. The skeleton is positioned in a dynamic, running pose, showcasing the dinosaur's large skull, sharp teeth, and robust limbs. The background features a mural of a prehistoric landscape with trees and vegetation, enhancing the exhibit's immersive experience
Jonathan Chen, CC BY-SA 4.0, via Wikimedia Commons

Since the initial discovery, further finds have been made in the United States, specifically in Alabama as well as North and South Carolina. These additional finds have helped to build a more complete picture of this dinosaur, although there is still much to learn.

The fossils found include parts of the skull, vertebrae, and limbs, providing valuable insight into the physical characteristics and potential behaviors of this carnivore. The degree of preservation varies among the fossils, but overall they have provided a wealth of information about this dinosaur.

Appalachiosaurus Size and Description

This was a formidable creature, as evidenced by the fossil evidence we have. But what did it look like, and how big was it?

Short Description of Appalachiosaurus

Like many of its theropod relatives, it was a bipedal predator that moved on two legs. Its body was built for hunting with a large head, powerful jaws, and sharp teeth. Its long tail helped it maintain balance while running and its strong, muscular legs suggest that it was a fast runner. The skin is not well known but it is believed to have been covered in scales like other theropods.

Size and Weight of Type Species

A scale comparison chart featuring the type species Appalachiosaurus montgomeriensis. The chart shows the silhouette of the dinosaur, which is about 5 meters long, compared to the silhouette of an average human.
Slate Weasel, CC0, via Wikimedia Commons

The size is a topic of ongoing research. Because the type specimen belongs to a juvenile individual, the adult size is unknown. Current estimates suggest that it was a medium-sized theropod but the exact dimensions are still under investigation. As more fossils are discovered and studied, we will gain a clearer understanding of the size and weight of this fascinating dinosaur.

The Dinosaur in Detail

The Appalachiosaurus was a unique dinosaur with features that set it apart from other theropods. Its strong jaws and sharp teeth suggest that it was a formidable predator. The structure of its vertebrae and limbs suggest that it was a fast and agile runner capable of chasing down prey. These features, along with its size and probable hunting strategies, make it a fascinating subject of study.

The Appalachiosaurus in its Natural Habitat

The world of the Late Cretaceous period was a very different place from the world we know today. The climate was warmer, the continents were in different positions, and the landscape was dominated by a variety of vegetation. In this world, the Appalachiosaurus was a top predator.

As a carnivore, it would have hunted other Appalachian dinosaurs and possibly smaller animals. Its strong jaws and sharp teeth would have been well suited for this task. Speed and agility would have allowed it to chase down and capture its prey.

Its social behavior is not well known but it is possible that it was a solitary hunter, relying on its own skills and instincts to survive. However, this is a topic of ongoing research and as more fossils are discovered and studied, we may gain a better understanding of the social behavior of this fascinating dinosaur.

Interesting Points about Appalachiosaurus

  1. Appalachiosaurus was a dinosaur that inhabited an area known as Appalachia. This region, stretching from what is now northern Canada to Alabama, was isolated from the rest of North America for nearly 30 million years, leading to the development of unique flora and fauna.
  2. The name is a reference to the paleocontinent Appalachia, which is in turn named after the Appalachian Mountains found there.
  3. This carnivorous dinosaur existed through the end of the Late Cretaceous period, approximately  83.5 to 66.0 million years ago. 
  4. To date, paleontologists have found only four different specimens of this dinosaur.
  5. The most complete specimen, the type specimen, is a juvenile. This makes size estimates difficult but it was likely a medium-sized predator.

Contemporary Dinosaurs

In the late Cretaceous period, this formidable predator roamed the lush, verdant landscapes of Appalachia with other North American dinosaurs. These include the Tyrannosaurus, Edmontosaurus, Triceratops, and Ankylosaurus.

The competition for food was fierce, with both the Appalachiosaurus and Tyrannosaurus setting their sights on the same prey. It is not unlikely that these two carnivores would have been locked in a lifelong battle over resources. The Edmontosaurus, an herbivorous dinosaur, would likely often be the target of these predators. The Edmontosaurus, though larger than the Appalachiosaurus, was no match for the cunning and speed of this predator. The Appalachiosaurus could use its agility to outmaneuver the Edmontosaurus–highlighting the predator-prey relationship that existed in this prehistoric ecosystem.

Yet, the Appalachiosaurus didn’t only interact with its prey. The Triceratops, with its three formidable horns and large frill, was a contemporary that the Appalachiosaurus would have been wise to avoid. Similarly, the Ankylosaurus, a dinosaur roughly the same size as the Appalachiosaurus, was a walking fortress. Its body was covered in hard, bony plates. These dinosaurs were not direct competitors for food but were still part of the complex web of relationships that defined the Appalachiosaurus’s environment.

In this vivid tapestry of prehistoric life, the Appalachiosaurus was a central figure and its life intertwined with those of its contemporaries. Each interaction, each competition, each chase, shaped the world of the Appalachiosaurus. Through this lens, we gain a deeper understanding of the Appalachiosaurus–not just as an individual dinosaur but as a part of an interconnected prehistoric world.

List of All Dinosaurs

We have created a list of all dinosaurs we have covered here, sorted across the seven main groups of dinosaurs. We also include information about their type of diet, (omnivore, herbivore or carnivore) and the time they lived.

Frequently Asked Questions

What does the name mean?

The name means “Appalachian Lizard,” named after the region where it was first discovered, the paleocontinent Appalachia.

What did this dinosaur eat?

As a carnivore, Appalachiosaurus would have hunted other dinosaurs and possibly smaller animals.

When did it live? 

It lived during the Late Cretaceous period, between 83.5 to 66.0 million years ago.

Where was it found?

The first discovery was made in Alabama, USA. Further finds have been made in Alabama, North Carolina, and South Carolina.

How big was Appalachiosaurus?

The exact size is still under investigation but it is believed to have been a medium-sized theropod with length from 21.0 to 23.0 ft and weighed around 0.69 tons.

How did this dinosaur move?

Like most theropods, it was a bipedal dinosaur–meaning it moved on two legs.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of the Appalachiosaurus. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

This article was last fact checked: Joey Arboleda, 07-24-2023

Featured Image Credit: FunkMonk, CC BY 3.0, via Wikimedia Commons