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Description
Acrocanthosaurus atokensis

Allosaurs and, in this profile’s case, carcharodontosaurs are among the most iconic of all flesh-eating dinosaurs. They filled the apex predator niche for nearly 90,000,000 years of the Mesozoic. From the type species of the entire family, Allosaurus from the Late Jurassic to the giant Giganotosaurus of the Mid-Cretaceous. However, among the last and largest carnosaurs that ruled North America arose during the Early Cretaceous. Some 57,000,000 years before the arrival of T.rex, another titan ruled the floodplains of the American West, Acrocanthosaurus atokensis.

History of Discovery:

In 1947, in Southern Oklahoma, specifically Atoka County, material from a theropod dinosaur was uncovered. It was a very fragmentary skeleton, consisting of ribs, tail vertebra, part of the pelvis, and most notably, fragments of neural spines. After three years, American paleontologists J. Willis Stovall and Wann Langston Jr. originally described the fossil material, and Langston was the one who coined the name of the specimen. While describing the specimen, originally, Langston wanted to call it “Acracanthus atokaensis”; however, while preparing the fossil, deciding to make it more formal, he coined the name Acrocanthosaurus atokensis. The generic word is derived from the Greek meaning “High-Spine Lizard,” and the specific name is a Latinized word for Atoka County. The entire name means High-Spined Lizard from Atoka County.

More fragmentary bones and specimens were discovered in the intervening years, but it was not until 1982 that a very complete specimen was uncovered from Wyoming. They pulled out a pristine skull and a complete forelimb, and a decent portion of the rest of the skeleton was preserved. This was also during the height of the Dinosaur Renaissance and allowed for the most accurate reconstruction of this awe-inspiring dinosaur.

Moreover, footprints from the Paluxy River show what is likely to be an Acrocanthosaurus walking along a beach. Among the footprints include a theropod (Acrocanthosaurus), an ornithopod, possibly Tenontosaurus or related kin, and a massive Sauropod dubbed “Paluxysaurus jonesi” now believed to be Sauroposeidon. These animals were the dominant apex predators across the mid-Cretaceous American West.

However, in 2023, Acrocanthosaurus was found to be not limited to the west. In Maryland, they found material consisting of various bone fragments and a nearly complete tibia. Dr.Thomas Holtz identified this as Acrocanthosaurus. These fossils confirm that these dinosaurs dominated from coast to coast of the United States.

Classification:

When it was described, it was placed in the order of Carnosauria. This was when many theropod dinosaurs unearthed were just lumped into this order which included a multitude of theropods from tyrannosaurs to allosaurs. Today, the order, while still in use, is primarily used to describe animals like animals like Allosaurus, Giganotosaurus, Torvosaurus, Megalosaurus, Spinosaurus, and Carcharodontosaurus. However, a more apt term to describe them is allosaurs or, in Acrocanthosaurus’ case, carcharodontosaurs.

In 2013, it was determined through phylogenetic studies led by Dr.Fernando Novas that Acrocanthosaurus was an allosaur, specifically a basal carcharodontosaurid. These theropods exploded in diversity at the dawn of the Cretaceous. From China, Europe, and the two continents most prevalent, Africa and South America, where dinosaurs like Meraxes, Giganotosaurus, Mapusaurus, and Carcharodontosaurus have been uncovered. However, the only carcharodontosaur to be definitively named and described in North America is Acrocanthosaurus. Future fossil discoveries may shed light on other species in North America.

In 1988, Gregory S. Paul described what he considered a second species of Acrocanthosaurus from the United Kingdom—reclassifying the taxon known as Altispinax dunkeri to Acrocanthosaurus altispinax. Most paleontologists believe this dinosaur is too fragmentary to be identified beyond being a carnosaur. So, while it could be an animal similar to Acrocanthosaurus, calling it a second species is highly unlikely.

Description:

Acrocanthosaurus was a massive theropod. It ranged in size from 35-38ft long to 9-10.5ft tall, weighing around 5.5-6 tons. The skull was four feet long and had serrated, blade-shaped teeth designed to cut through flesh.

The forelimbs of this dinosaur were robustly built as well, tipped with menacing talons designed to pierce flesh and likely grapple onto prey (as will be discussed later).

As its name suggests, it did have “high spines” but not as high as its distant cousins, the Spinosaurus. The neural spines protruded from the base over half a foot tall, giving it a distinct outline from other Allosaurs. However, these spines likely didn’t produce a pronounced spine on the animal. More likely, the spines functioned as muscle attachment points for its back and legs. Furthermore, the animal’s “spines” being so low would probably result in a humped-back silhouette.

Habitat:

Acrocanthosaurus ruled North America 115,000,000 years ago, from as far east as Maryland to as far west as Texas and Montana. The most complete specimens, however. The two formations where the most material was uncovered would be the Antler’s Formation of Oklahoma and the Cloverly Formation of Wyoming and Montana. The formations were highly different from today's temperate Rockies and Great Plains. It would have been a swampy environment populated with ferns, tree ferns, conifer forests, and rivers that would have flowed through this palustrine environment. River systems would’ve been dominated not by cypress trees or mangroves but rather by fern-like cypress analog called Weichselia. There would have been plains, but these would not have been grasslands but rather ferns and horsetail prairies.

Dinosaurs of this environment included species like the giant sauropod Sauroposeidon, which was the largest dinosaur in the region and one of the tallest dinosaurs that ever walked the planet. The most common herbivore, Tenontosaurus, would have lived alongside this theropod, grazing upon the fern prairies and forests of the Cloverly Formation, and the armored nodosaur Sauropelta lived in the environment as well, just to name a few species.

Deinonychus, the archetypal raptor, was also from the Cloverly and Antler’s Formation and would have competed with Acrocanthosaurus for prey. However, adult Acrocanthosaurus would have been the undisputed apex predator in this region. Being such a powerful predator, North America would have been its oyster.

Predation Habits:

While it was an apex predator, paleontologists debate to what extent this was a hunter of sauropods.

A rather infamous documentary, “Monsters Resurrected,” shows the Paluxy River tracks as evidence of an Acrocanthosaurus hunting a sauropod. However, that was based on a single section of the Paluxy trackway interpreted as an Acrocanthosaurus clinging onto the side of the sauropod dinosaur. As fanciful and awesome as this seems, there is no evidence that the Paluxy tracks show a hunt as it is impossible to determine what time these tracks were made.

As with many predators, it is improbable that even a fully grown Acrocanthosaurus would go after adult Sauroposeidon. They could have taken them down by hunting in packs or unorganized mobs. However, the evidence for this is open for debate.

In 1998, a sauropod called Sonorasaurus was found in Arizona. This dinosaur lived around the same time as Acrocanthosaurus, and some of the fossil material had scraping bite marks on the bones of the dinosaur, showing that these dinosaurs did prey upon sauropods. However, whether or not this was a predation event is unknown as the bones show no sign of healing.

The forelimbs have been subject to many areas of study. The Acrocanthosaurus found in 1982 preserved the forelimb, and studies indicate it could not have swung as far out to the side or forward compared to other carnosaurs. However, there are indications that these were still usable weapons for smaller prey like Tenontosaurus and perhaps other iguanodontids. Most paleontologists who research the limbs suggested it used its skull to capture the prey and, when brought in close, inflicted more damage to its quarry by hooking into the flesh and pulling back, perhaps doing this multiple times.

Extinction:

As formidable it was, this excellent apex predator vanished from North America some 110,000,000 years ago. The cause of extinction is unknown, but probably due to climate change. The animal could not adapt as the environment changed and succumbed to extinction.

As of 2024, it is unknown if other large 30ft+ Carnosaurs were present in North America after the Jurassic. There have been some suggestions that Siats meekerorum may be a candidate, but whether or not it’s an allosaur is unknown, but that is a story for a different profile. However, papers detailing the analysis of the Cedar Mountain Formation, where the infamous Utahraptor hails from, show there was a large apex predator in the region some 20,000,000 years before Acrocanthosaurus evolved. Whether this was an allosaur or a carcharodontosaurids is unknown. Hopefully, future fossil finds will clear this up.

Until then, Acrocanthosaurus remains one of the last well-known Allosaurs that dominated the North American continent until the mighty tyrannosaurs arrived on the scene. With its menagerie of features, this is an animal that holds a special place in the study of these awesome theropod dinosaurs.
___________________________________________________________________________________________
Yep, another redux of a PMP staple. The skull, the jaws, the claws and the bulk of the animal was really off. Especially the claws and jaws, I had to re-mesh and redo them. Mainly because the mandible was off, as well as the claws which were just straight as rails not the meat-hook talons.

Old Profile

I'm mainly redoing ep4 of PMP and all scenes with it and plan to post them here. So look forward to that.

Also, thanks to WDGHK for informing me of the teeth in Cedar Mountain. More info, please visit the blogpost below or his art.

The Cedar Mountain Allosaur – DINOSAURS AND BARBARIANS

For Past Meets Present
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original model and skin by Tyranachu, modified by me:
Tenontosaurus (Tyranachu) | ZT2 Download Library Wiki | Fandom

Original model by DinosaurManZT2 skin and mesh modified by me.
Giganotosaurus (HENDRIX) | ZT2 Download Library Wiki | Fandom

Description
Acrocanthosaurus atokensis

Allosaurs and, in this profile’s case, carcharodontosaurs are among the most iconic of all flesh-eating dinosaurs. They filled the apex predator niche for nearly 90,000,000 years of the Mesozoic. From the type species of the entire family, Allosaurus from the Late Jurassic to the giant Giganotosaurus of the Mid-Cretaceous. However, among the last and largest carnosaurs that ruled North America arose during the Early Cretaceous. Some 57,000,000 years before the arrival of T.rex, another titan ruled the floodplains of the American West, Acrocanthosaurus atokensis.

History of Discovery:

In 1947, in Southern Oklahoma, specifically Atoka County, material from a theropod dinosaur was uncovered. It was a very fragmentary skeleton, consisting of ribs, tail vertebra, part of the pelvis, and most notably, fragments of neural spines. After three years, American paleontologists J. Willis Stovall and Wann Langston Jr. originally described the fossil material, and Langston was the one who coined the name of the specimen. While describing the specimen, originally, Langston wanted to call it “Acracanthus atokaensis”; however, while preparing the fossil, deciding to make it more formal, he coined the name Acrocanthosaurus atokensis. The generic word is derived from the Greek meaning “High-Spine Lizard,” and the specific name is a Latinized word for Atoka County. The entire name means High-Spined Lizard from Atoka County.

More fragmentary bones and specimens were discovered in the intervening years, but it was not until 1982 that a very complete specimen was uncovered from Wyoming. They pulled out a pristine skull and a complete forelimb, and a decent portion of the rest of the skeleton was preserved. This was also during the height of the Dinosaur Renaissance and allowed for the most accurate reconstruction of this awe-inspiring dinosaur.

Moreover, footprints from the Paluxy River show what is likely to be an Acrocanthosaurus walking along a beach. Among the footprints include a theropod (Acrocanthosaurus), an ornithopod, possibly Tenontosaurus or related kin, and a massive Sauropod dubbed “Paluxysaurus jonesi” now believed to be Sauroposeidon. These animals were the dominant apex predators across the mid-Cretaceous American West.

However, in 2023, Acrocanthosaurus was found to be not limited to the west. In Maryland, they found material consisting of various bone fragments and a nearly complete tibia. Dr.Thomas Holtz identified this as Acrocanthosaurus. These fossils confirm that these dinosaurs dominated from coast to coast of the United States.

Classification:

When it was described, it was placed in the order of Carnosauria. This was when many theropod dinosaurs unearthed were just lumped into this order which included a multitude of theropods from tyrannosaurs to allosaurs. Today, the order, while still in use, is primarily used to describe animals like animals like Allosaurus, Giganotosaurus, Torvosaurus, Megalosaurus, Spinosaurus, and Carcharodontosaurus. However, a more apt term to describe them is allosaurs or, in Acrocanthosaurus’ case, carcharodontosaurs.

In 2013, it was determined through phylogenetic studies led by Dr.Fernando Novas that Acrocanthosaurus was an allosaur, specifically a basal carcharodontosaurid. These theropods exploded in diversity at the dawn of the Cretaceous. From China, Europe, and the two continents most prevalent, Africa and South America, where dinosaurs like Meraxes, Giganotosaurus, Mapusaurus, and Carcharodontosaurus have been uncovered. However, the only carcharodontosaur to be definitively named and described in North America is Acrocanthosaurus. Future fossil discoveries may shed light on other species in North America.

In 1988, Gregory S. Paul described what he considered a second species of Acrocanthosaurus from the United Kingdom—reclassifying the taxon known as Altispinax dunkeri to Acrocanthosaurus altispinax. Most paleontologists believe this dinosaur is too fragmentary to be identified beyond being a carnosaur. So, while it could be an animal similar to Acrocanthosaurus, calling it a second species is highly unlikely.

Description:

Acrocanthosaurus was a massive theropod. It ranged in size from 35-38ft long to 9-10.5ft tall, weighing around 5.5-6 tons. The skull was four feet long and had serrated, blade-shaped teeth designed to cut through flesh.

The forelimbs of this dinosaur were robustly built as well, tipped with menacing talons designed to pierce flesh and likely grapple onto prey (as will be discussed later).

As its name suggests, it did have “high spines” but not as high as its distant cousins, the Spinosaurus. The neural spines protruded from the base over half a foot tall, giving it a distinct outline from other Allosaurs. However, these spines likely didn’t produce a pronounced spine on the animal. More likely, the spines functioned as muscle attachment points for its back and legs. Furthermore, the animal’s “spines” being so low would probably result in a humped-back silhouette.

Habitat:

Acrocanthosaurus ruled North America 115,000,000 years ago, from as far east as Maryland to as far west as Texas and Montana. The most complete specimens, however. The two formations where the most material was uncovered would be the Antler’s Formation of Oklahoma and the Cloverly Formation of Wyoming and Montana. The formations were highly different from today's temperate Rockies and Great Plains. It would have been a swampy environment populated with ferns, tree ferns, conifer forests, and rivers that would have flowed through this palustrine environment. River systems would’ve been dominated not by cypress trees or mangroves but rather by fern-like cypress analog called Weichselia. There would have been plains, but these would not have been grasslands but rather ferns and horsetail prairies.

Dinosaurs of this environment included species like the giant sauropod Sauroposeidon, which was the largest dinosaur in the region and one of the tallest dinosaurs that ever walked the planet. The most common herbivore, Tenontosaurus, would have lived alongside this theropod, grazing upon the fern prairies and forests of the Cloverly Formation, and the armored nodosaur Sauropelta lived in the environment as well, just to name a few species.

Deinonychus, the archetypal raptor, was also from the Cloverly and Antler’s Formation and would have competed with Acrocanthosaurus for prey. However, adult Acrocanthosaurus would have been the undisputed apex predator in this region. Being such a powerful predator, North America would have been its oyster.

Predation Habits:

While it was an apex predator, paleontologists debate to what extent this was a hunter of sauropods.

A rather infamous documentary, “Monsters Resurrected,” shows the Paluxy River tracks as evidence of an Acrocanthosaurus hunting a sauropod. However, that was based on a single section of the Paluxy trackway interpreted as an Acrocanthosaurus clinging onto the side of the sauropod dinosaur. As fanciful and awesome as this seems, there is no evidence that the Paluxy tracks show a hunt as it is impossible to determine what time these tracks were made.

As with many predators, it is improbable that even a fully grown Acrocanthosaurus would go after adult Sauroposeidon. They could have taken them down by hunting in packs or unorganized mobs. However, the evidence for this is open for debate.

In 1998, a sauropod called Sonorasaurus was found in Arizona. This dinosaur lived around the same time as Acrocanthosaurus, and some of the fossil material had scraping bite marks on the bones of the dinosaur, showing that these dinosaurs did prey upon sauropods. However, whether or not this was a predation event is unknown as the bones show no sign of healing.

The forelimbs have been subject to many areas of study. The Acrocanthosaurus found in 1982 preserved the forelimb, and studies indicate it could not have swung as far out to the side or forward compared to other carnosaurs. However, there are indications that these were still usable weapons for smaller prey like Tenontosaurus and perhaps other iguanodontids. Most paleontologists who research the limbs suggested it used its skull to capture the prey and, when brought in close, inflicted more damage to its quarry by hooking into the flesh and pulling back, perhaps doing this multiple times.

Extinction:

As formidable it was, this excellent apex predator vanished from North America some 110,000,000 years ago. The cause of extinction is unknown, but probably due to climate change. The animal could not adapt as the environment changed and succumbed to extinction.

As of 2024, it is unknown if other large 30ft+ Carnosaurs were present in North America after the Jurassic. There have been some suggestions that Siats meekerorum may be a candidate, but whether or not it’s an allosaur is unknown, but that is a story for a different profile. However, papers detailing the analysis of the Cedar Mountain Formation, where the infamous Utahraptor hails from, show there was a large apex predator in the region some 20,000,000 years before Acrocanthosaurus evolved. Whether this was an allosaur or a carcharodontosaurids is unknown. Hopefully, future fossil finds will clear this up.

Until then, Acrocanthosaurus remains one of the last well-known Allosaurs that dominated the North American continent until the mighty tyrannosaurs arrived on the scene. With its menagerie of features, this is an animal that holds a special place in the study of these awesome theropod dinosaurs.
___________________________________________________________________________________________
Yep, another redux of a PMP staple. The skull, the jaws, the claws and the bulk of the animal was really off. Especially the claws and jaws, I had to re-mesh and redo them. Mainly because the mandible was off, as well as the claws which were just straight as rails not the meat-hook talons.

Old Profile

I'm mainly redoing ep4 of PMP and all scenes with it and plan to post them here. So look forward to that.

Also, thanks to WDGHK for informing me of the teeth in Cedar Mountain. More info, please visit the blogpost below or his art.

The Cedar Mountain Allosaur – DINOSAURS AND BARBARIANS

For Past Meets Present
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original model and skin by Tyranachu, modified by me:
Tenontosaurus (Tyranachu) | ZT2 Download Library Wiki | Fandom

Original model by DinosaurManZT2 skin and mesh modified by me.
Giganotosaurus (HENDRIX) | ZT2 Download Library Wiki | Fandom