Acrocanthosaurus | Coffee And Coelophysis

Exploring the Houston Museum’s Dinosaur Treasures

Posted on November 20, 2024 by Noelle K. Moser

Email: noellemoser@charter.net

**Image Credit:** *Noelle K. Moser****. Stan and I, positioned at the intersection of popular culture and science. Like Stan, Tyrannosaurus Rex is a silent witness to a world we can only experience through bone.*** *Houston Museum of Natural Science*.

Disclaimer: This article reflects my independent observations and insights gained during my research at the Houston Museum of Natural Science. I want to clarify that I am not affiliated with the HMNS in any capacity and have not received any compensation for writing this piece. The views and opinions expressed are solely my own. I am a professional writer and researcher specializing in dinosaurs. I travel to museums across the country to gather information and insights for my blog, where I explore the fascinating world of theropods and Mesozoic life.

The study of the Mesozoic era presents intriguing opportunities for exploration, particularly through its remarkable dinosaurs that once roamed the Earth. After thorough planning, which involved securing airline tickets and hotel accommodations, I recently visited the esteemed Houston Museum of Natural Science in Houston, Texas. This destination is celebrated for its exceptional paleontology exhibits, notably featuring three impressive specimens of Tyrannosaurus rex. The museum serves as a valuable resource for anyone interested in the fascinating history of dinosaurs and their environments during the Mesozoic era.

**Image Credit:** *Mary Haggard.* Houston Museum of Natural Science.

During my visit, I was truly moved by the incredible fossil collection on display. Multiple specimens of Tyrannosaurus rex, Acrocanthosaurus, Allosaurus, and Gorgosaurus brought a sense of excitement and connection to the past. As I explored the exhibits of herbivores—Diplodocus, Triceratops, Hadrosaurs, Ankylosaurus, and even a rare pair of Quetzalcoatlus—I couldn’t help but feel a deep sense of wonder. It reminded me of the rich history these magnificent creatures represent and the awe they evoke, connecting us to a world we can only experience through bone.

As someone profoundly captivated by Tyrannosaurus Rex, I dedicate my work to exploring its evolution, adaptations, and the mysteries of its lifestyle, making this visit truly meaningful. Houston is home to specimens of Stan, Bucky, and Wyrex—famous T-rex individuals that each tell a unique story about the life and evolution of this apex predator. Studying these fossils up close allowed me to dive deeper into their adaptations, pathologies, and mysteries.

Beginning with The Morian Hall of Paleontology, visitors are offered an engaging exploration of prehistoric life through a diverse collection of fossils and visual displays. This innovative exhibition presents the concept of deep time in a way that accommodates various learning styles, making it an informative experience for a wide range of audiences.

Immersed in a journey through deep time, visitors will encounter a variety of familiar prehistoric creatures. Notable among these are trilobites, which were marine arthropods, and ammonites, known for their coiled shells. The path also features early tetrapods, the four-legged ancestors of amphibians, reptiles, and mammals. Additionally, one might come across impressive Devonian giant fishes such as Dunkleosteus, as well as the Permian period’s Dimetrodon. Another significant creature to observe is the notable Triassic archosaur Postosuchus, an ancient reptilian predator.

Dimetrodon: Houston Museum of Natural Science

Entering the dinosaur hall, visitors are welcomed by the impressive cast of “Big Al,” the renowned Allosaurus that represents the pinnacle of Jurassic predators. Discovered in 1991 at the Howe Quarry in the Morrison Formation of Wyoming, “Big Al” is not only the most complete and well-preserved specimen of its kind but also a symbol of resilience. The pathologies revealed in this remarkable skeleton tell a powerful story of survival, showcasing evidence of injuries, diseases, broken bones, and the remarkable bone growths that came in response to adversity. “Big Al” inspires us to appreciate the strength and tenacity found in nature’s history.

**Image Credit:** *Noelle K. Moser.* ***Cast of “big Al”.*** Houston Museum of Natural Science

Stepping into the Paula and Rusty Walter Mesozoic Gallery, one is in awe of the vastness of space and the magnificent creatures that once roamed the Earth. Towering at the center is a Diplodocus rearing on its hind legs, long neck, and head stretching to the ceiling.

**Image Credit:** *Noelle K. Moser*. ***Diplodocus reared on its hind legs towering over theropods in various life-like poses.*** Houston Museum of Natural Science. Houston, Texas.

In various life-like poses stand a variety of large theropods and herbivores, each telling a story of the past. Most notable, and the reason for my venture to the Houston Museum of Natural Science, is BHI 3033, “Stan.”

Stan: The Tyrant Lizard King with Multiple Injuries

**Image Credit:** *Mary Haggard.* ***Stan and I, standing at the intersection of science and popular culture. Tyrannosaurus Rex is a silent witness to a world we can only experience through bone.*** Houston Museum of Natural Science. Houston, Texas.

Stan, a remarkable specimen found in 1987 in the Hell Creek Formation of Montana, serves as a beacon of discovery for paleontology and the biology of Tyrannosaurus rex. His fossil includes the most complete T. rex skull, a testament to the wonders of the natural world. Beyond the skull, Stan’s remains consist of 190 bones, representing about 63% of the entire skeleton, offering invaluable insights into the anatomy, lifestyle, and pathologies of one of the most intriguing Tyrannosaurus rex specimens in history. (Larson, 2008)

**Image Credit:** *Noelle K. Moser.* ***The impressive dental battery of Stan comprised of 60 conical serrated teeth.*** Houston Museum of Natural Science. Houston, Texas

An examination of Stan’s bones reveals multiple pathologies and healed injuries sustained throughout his life. Puncture wounds on the back of his skull and ribs suggest he was at one time bitten by another Tyrannosaurus Rex. Bite marks at the base of his skull indicate a significant neck injury, leading to the fusion of two vertebrae, likely causing him pain for the remainder of his life. Holes on the side of his skull suggest more healed wounds and possible infections from bone-eating parasites. Stan’s pathologies show that life in the Cretaceous was challenging, even for a Tyrannosaurus Rex.

**Image Credit:** *Noelle K. Moser.* ***Holes on the side of Stan’s skull show pathology of healed injuries and possibly bone-eating parasitic infections.*** Houston Museum of Natural Science. Houston, Texas.

In a poised stalking stance with jaws gracefully agape, Stan proudly displays his formidable set of 60 teeth. Like all Tyrannosaurus rex specimens, he embodies extraordinary evolutionary development in dentation, demonstrating the power to overcome even the most daunting challenges in his quest for survival.

**Image Credit:** *Noelle K. Moser*. ***Stan proudly displays his formidable set of 60 teeth***. Houston Museum of Natural Science. Houston, Texas.

Examining Stan in such an accessible manner has given me a deeper insight into his life through his skeletal remains. Despite suffering severe injuries and pain, Stan’s capacity for healing and survival is a testament to the extraordinary resilience and robustness of this theropod. While the bone analysis of Stan shows healing, another T-Rex was not as lucky.

Wyrex: The Bob-tailed T-Rex.

**Image Credit**: *Noelle K. Moser.* ***Wyrex, the bobtail T-rex.*** Houston Museum of Natural Science.

Discovered in 2002 within the Hell Creek Formation of Montana and transferred to the Houston Museum of Natural Science (HMNS) in 2009, the fossil known as “Wyrex” is an extraordinary Tyrannosaurus rex specimen. This groundbreaking discovery unveils a remarkable partial braincase and two nearly complete legs and feet, providing exhilarating new insights into the foot anatomy of the legendary Tyrannosaurus rex! (Larson, 2008)

**Image Credit:** *Noelle K. Moser*. ***Complete foot preserved with Wyrex providing exhilarating new insights into the foot anatomy of the legendary Tyrannosaurus rex.*** Houston Museum of Natural Science.

Mounted in an attack stance adjacent to an Ankylosaurus, it is readily apparent that one-third of the tail is absent. As a critical component of Tyrannosaurus rex anatomy, the tail serves as a counterbalance to the skull and accommodates powerful musculature necessary for locomotion.

**Image Credit:** *Noelle K. Moser*. ***The tail serves as a counterbalance to the skull and accommodates powerful musculature necessary for locomotion***. Houston Museum of Natural Science. Houston, Texas.

Analysis of the bone indicates no evidence of healing, suggesting that the tail may have been severed post-mortem, or that this injury ultimately unalived Wyrex. Had Wyrex survived this injury, the T-rex would have required a significant period of rehabilitation to regain the ability to walk effectively.

**Image Credit:** *Noelle K. Moser.* ***Wyrex, positioned in an imposing attack pose, offers visitors the opportunity to examine the remarkable dentition and distinctive anatomical characteristics of the formidable Tyrannosaurus Rex.*** Houston Museum of Natural Science.

Presented in an assertive attack stance, Wyrex offers visitors an exceptional opportunity for a detailed examination of its distinctive conical, serrated teeth. This close-up perspective not only showcases the impressive anatomy of this prehistoric predator but also fosters a deeper appreciation for the evolutionary traits that contributed to its role in the prehistoric ecosystem.

In addition to its other remarkable features, Wyrex has yielded another significant discovery: several patches of fossilized skin from the Tyrannosaurus rex. This finding marks the first time that such skin has been uncovered for this iconic dinosaur, providing new insights into its biology and appearance. (Larson, 2008).

***Patch of fossilized skin associated with Wyrex.*** Houston Museum of Natural Science. Houston, Texas

Bucky: A Female Teenage T-Rex.

**Image Credit**: *Mary Haggard.* ***Bucky plays a significant role in our understanding of Tyrannosaurus rex, as this remarkable fossil includes one of the most complete T-rex tails to date.*** Houston Museum of Natural Science. Houston, Texas.

The final Tyrannosaurus Rex showcased in the Paula and Rusty Walter Mesozoic Gallery is a sub-adult female TCM 2001.90.1 “Bucky”. Discovered in 2001 in the Hell Creek Formation by a rancher who, while breaking in a young horse, spotted the bones that led to this remarkable find, just 8 miles from where another robust female T-rex, Sue, was unearthed. (Larson, 2008)

**Image Credit:** *Noelle K. Moser*. ***Tyrannosaurus Rex Bucky and Wyrex present complementary highlights, drawing attention to the devastating tail injury that Wyrex sustained.*** Houston Museum of Natural Science. Houston, Texas.

Bucky plays a significant role in our understanding of Tyrannosaurus rex, as this remarkable fossil includes one of three most complete T-rex tails. It serves as a poignant reminder of the devastating injury that Wyrex endured, allowing us to reflect on the challenges a Tyrannosaurus rex faced in their lifetime.

As a sub-adult, juvenile teenage T. rex, Bucky provides valuable insights into the growth rates and different stages of maturity in the morphology of this iconic theropod. Bucky’s development illustrates the physical changes that occur as T. rexes progress from juveniles to adults, helping us understand their life cycle better.

Acrocanthrosaurus:

**Image Credit:** *Noelle K. Moser*. ***Acrocanthosaurus, the high-spined lizard of the Early Cretaceous.*** Houston Museum of Natural Science. Houston, Texas.

My journey to the Houston Museum of Natural Science would be incomplete without highlighting one last impressive theropod: Acrocanthosaurus. Most likely belonging to the Carcharodontosaur clade, a group of formidable predatory dinosaurs that thrived during the Aptian stage of the Early Cretaceous period.

**Image Credit:** *Mary Haggard*. ***Acrocanthosaurus***. Houston Museum of Natural Science. Houston, Texas.

Acrocanthosaurus stands out for its remarkably high neural spines, believed to have formed a striking sail along its back during its time on Earth. This formidable theropod once roamed ancient landscapes alongside colossal titanosaurs, majestic giants among the largest creatures ever to grace the Earth. Imagining these giant beasts sharing the same world ignites a sense of wonder and inspiration!

**Image Credit**: *Noelle K. Moser*. ***Stan viewed from the second-floor observation platform showcasing the immense size of this Cretaceous Apex Predator.*** Houston Museum of Natural Science.

Studying dinosaurs is not just a passion; it’s a profound calling to uncover the mysteries of their world and our planet. My research leads me to natural history museums across the nation, with each destination unveiling new insights into the fascinating realm of dinosaurs and deepening my admiration for these incredible creatures.

This visit highlighted the fascinating aspects of Tyrannosaurus Rex and reinforced the reasons behind their enduring appeal. It’s not merely their impressive size and strength; rather, the complex details of their existence contribute significantly to their allure. The experience provided an exceptional opportunity to observe a diverse array of theropod evolution and variety all in one location. Most importantly, the Houston Museum of Natural Science offers tangible access to the wonders of prehistoric Earth, connecting us to a lost world we can only experience through bone.

Image Credit: *Mary Haggard*. ***Studying dinosaurs connects us to a lost world we can only experience through bone.*** Houston Museum of Natural Science. Houston, Texas.

To watch a video of my trip to HMNS please visit my YouTube Channel.

I am a multi-disciplinary writer, paleontology blogger, and content creator. If you found this post engaging, be sure to check out my online writing portfolio to explore my extensive body of work.

Resources:

Larson, Peter and Carpenter, Kenneth. Tyrannosaurus Rex: The Tyrant King. Indiana University Press. Bloomington, Indiana. 2008.

Pim, Keiron. Dinosaurs the Grand Tour: Everything Worth Knowing About Dinosaurs from Aardonys to Zuniceratops. The Experiment. New York, NY. 2019.

My Visit to Houston Museum of Natural Science in Houston, Texas.

Unveiling Giganotosaurus: The Prehistoric Rival of Tyrannosaurus Rex

Posted on September 17, 2024 by Noelle K. Moser

email: noellemoser@charter.net

Image Credit: **Giganotosaurus** ***skeleton.*** *Fernbank Museum of Natural History in Atlanta, Georgia.*

Boasting a skull as long as a man and a body the length of a bus, Giganotosaurus is among the largest predatory theropods ever discovered. Before Tyrannosaurus Rex reigned as the King of the Dinosaurs, a larger theropods dominated the prehistoric landscape. His name Giganotosaurus Carolinii.

**Image Credit: Noelle K. Moser**. **Tyrannosaurus Rex MOR 555 and I.**

Known as the “Giant Southern Lizard”, Giganotosaurus was a formidable predator that dominated the Southern Hemisphere. This massive theropod, a member of the Carcharodontosauridae family, hunted titanosaurs and other herbivores, establishing itself as one of the largest carnivorous dinosaurs, surpassing the mighty T-rex by 2.2 tons.

Image Credit: Noelle K. Moser. Tyrannosaurus Rex MOR 555. Weight 6 tons. Length 39 ft.

Image Credit: *Comparison of the largest theropods that walked the Earth. Giganotosaurus (Green), Tyrannosaurus Rex (Blue), and Spinosaurus (Red).*

The tale of Giganotosaurus began in 1993 with the discovery of a tibia jutting from the earth in Patagonia. In 1994, paleontologists revealed the unearthing of a massive new theropod. The fossilized remains comprised a partial skull, a large portion of the vertebral column, elements of the pelvis, and fragments of limb bones.

Image Credit: ***Giganotosaurus holotype (first Giganotosaurus skeleton found) laid in the dirt.*** *Natural Science Museum at El Chocón, in the northwestern Argentine Patagonia*.

The discovery of Giganotosaurus is important because it deepened our understanding of the Carcharodontosaurid clade. Producing some of the largest theropods to ever live such as the newly discovered Meraxes Gigas, Acrocanthrosaurus, Carcharodontosaurus, and Giganotosaurus. This clade is of further interest to dinosaur enthusiasts because it allows us to explore the upper limit of theropod size.

**Image Credit:** *Noelle K. Moser.* ***Alamosaurus (Titanosaur) and Tyrannosaurus Rex. Giganotosaurus preyed upon Titanosaurs*** ***during the Cretaceous.*** *Perot Natural History Museum. Dallas, Texas.*

Nature maintains a delicate balance between predators and prey. Large herbivores require equally formidable carnivores to sustain this balance. Giganotosaurus, a giant theropod, played a crucial role in the ecosystem where it lived. The real question is not whether Giganotosaurus hunted these massive herbivores, but how it did so. This article will explore the origins of the Giganotosaurus, its hunting strategies, and ultimately why it faced extinction.

Origins of Giganotosaurus:

**Image Credit:** *Noelle K. Moser. **Giganotosaurus and I.** Knoxville Zoo. Knoxville, TN.*

During the Mesozoic, an evolutionary arms race between herbivores and carnivores ensued. As herbivores grew larger to gain a competitive advantage, the theropods also increased in size. The Jurassic period, marking the middle era of the age of dinosaurs, witnessed a remarkable diversification in dinosaur body plans. Herbivores grew larger, and thundering across the landscape were the sauropods, the giants of the Mesozoic era, including species such as Diplodocus and titanosaurs.

**Noelle K. Moser.** ***Neck of Diplodocus***. *National Museum of Natural History. Washington, D.C.*

Giganotosaurus belongs to the Carcharodontosauridae family, a group of theropod dinosaurs known for producing some of the largest carnivores ever to walk the earth. Besides their massive size, a distinctive characteristic of this group is streamlined narrow skulls with shark-like teeth.

Image Credit: **Carchardontosaurus skull.** ***The Carcharodontosauridae family possessed shark-like serrated teeth perfect for tearing the flesh off bones.***

Teeth reveal much about a creature. By examining dinosaur teeth, we can determine their diet, hunting methods, and how they consumed their prey.

During the Jurassic, the middle period of the Mesozoic Era, there was a significant increase in size among species as a result of an evolutionary arms race between predators and prey. As herbivores grew larger, carnivores also evolved to match their size.

The Jurassic saw some of the largest and most famous herbivores – the sauropods. Species such as Diplodocus, Brachiosaurus, Supersaurus, and Camarasaurus.

Image Credit: ***Comparison Graphic of some of the longest Sauropods that lived during the Jurassic***.

Counterparts to these lumbering giants, were the carnivores of the Jurassic, relatives of Giganotosaurus such as Tyrannotitan, Lusovenator, Siamraptor, and Acrocanthrosaurus.

Image Credit: An overview of the paleofauna that inhabited the Southern Hemisphere during the Mesozoic era includes theropods such as Mapusaurus (red) and Meraxes gigas (dark blue), which are carcharodontosaurs and related to Giganotosaurus.

Inhabiting the Southern Hemisphere, the relatives of Giganotosaurus, known as primitive Carcharodontosaurs, evolved into increasingly larger theropods in response to the growing size of the herbivores they preyed upon. By the end of the Jurassic and into the Early Cretaceous, the Carcharodontosauridae family comprised some of the largest carnivorous dinosaurs to have ever walked the Earth.

**Image Credit: Noelle K. Moser**. ***Life-size reconstruction of Giganotosaurus.*** *Knoxville Zoo. Knoxville, Tennessee.*

Giganotosaurus represented the culmination of an evolutionary arms race, standing as the pinnacle of the Carcharodontosauria clade.

How Giganotosaurus Hunted and Killed Prey:

Analysis of the leg bones of Giganotosaurus shows that this theropod was not built for speed, but it didn’t need to be. Although it was slower than the swift herbivores, Giganotosaurus preyed on the more ponderous sauropods, known as titanosaurs.

The titanosaurs were the last surviving group of long-necked sauropods, thriving at the time of the Chicxulub Impact at the end of the Cretaceous that ended the age of the dinosaurs. This group includes some of the largest land animals known to have ever existed, such as Argentinosaurus.

Image Credit: ***Argentinasaurus and Giganotosaurus displayed together.*** *Fernbank Museum of Natural History. Atlanta, Georgia.*

Titanosaurs lived by one rule, get big and get big fast. From the moment of hatching, sauropods like Argentinasaurus were eating machines. Dining on leaves and hard fibrous vegetation, a herd of titanosaurs could defoliate an area in a few days.

Large guts and hard-to-digest food allowed for a slow release of energy over time. This superpower aided in the ability of these sauropods to reach full size in less than ten years. Once fully grown, an adult Argentinasaurus was 128 ft long, 65 ft tall, and weighed 65 to 82 tons. This sheer size alone was enough to detour many theropods from making a meal out of these massive herbivores. Traveling in herds combined with size officially removed them from the menu.

Hunting a herd of titanosaurs was perilous. A single misstep can result in one of these colossal herbivores crushing an overzealous theropod, leading to instant death. Considering this risk, the question is not whether Giganotosaurus hunted titanosaurs, but rather how they accomplished such a feat.

Much like the enigmas posed by extinct species, the most effective way to address these questions is by examining the present. Observing lions as they hunt a herd of wildebeests, we see the predators collaborate to disperse the group, targeting the smaller, ill, or weakest members for an easier kill. A lion understands that to attack the largest, strongest, or healthiest would be, at best, a perilous endeavor. This logic can be similarly applied to Giganotosaurus.

Traveling herds exhibit remarkable organization. The young and subadults are positioned centrally, while the robust and healthy adults encircle them, forming a protective barrier. Typically, the elderly or injured members trail behind, comprising the rear guard as the herd moves across the terrain.

Understanding herd dynamics, a hunting Giganotosaurus would likely approach the herd from behind, targeting the weaker Argentinasaurus individuals. Despite not being in their prime, these titanosaurs remained formidable, capable of inflicting fatal injuries. It is probable that for these reasons, Giganotosauruses would hunt in packs, coordinating their efforts to take down one of these colossal creatures.

Evidence from the teeth of Giganotosaurus suggests that, unlike the bone-crushing bite of Tyrannosaurus Rex, Giganotosaurus had teeth better suited for slicing off flesh from its prey. Packs of Giganotosaurus would alternate in biting and slashing their prey, aiming to keep it moving and bleeding. The hunting strategy was to exhaust the prey through blood loss, fatigue, and infections caused by the theropods attacks, leading to the titanosaur’s eventual collapse under its own weight.

Trace fossils provide definitive evidence of theropod hunting strategies located along the Paluxy River near Glen Rose, Texas, USA. Here, a dramatic narrative of a dinosaur hunt is etched into the stone.

Image Credit: ***Peluxe River in Glenn Rose, Texas. Footprints from a Cretaceous hunt involving Acrocanthrosaurus and Saurposeidon recorded in stone.***

120 million years ago, on a muddy Cretaceous floodplain, the dynamics of dinosaur relationships were immortalized in stone. A herd of colossal sauropods lumbered along a waterway, stalked closely by a large carnivore. The pursuing theropod was focused, intent on the hunt.

Following behind the herd, slightly to the left, the theropod’s tracks indicate that the hunter rhythmically trailed the lumbering sauropods. Then the theropod’s footprints show that the hunter suddenly skipped a few steps, meaning only one thing, an attack.

Most of the trackway was removed. It is now preserved and displayed at The American Museum of Natural History in New York. Some of the trackway still remains submerged under the Paluxy River near Glen Rose, Texas.

Image Credit: ***Trackway from the Peluxy River on display at The American Museum of Natural History in New York***.

Giganotosaurus Extinction:

Giganotosaurus lived during the Late Cretaceous period, specifically in the Cenomanian stage, approximately 99.6 to 97 million years ago. The reasons for its extinction are not definitive, but fossil records suggest several plausible scenarios. During the latter part of the Cretaceous, environmental changes due to plate tectonics posed survival challenges for Giganotosaurus and other Carcharodontosaurids.

Additionally, around 30 million years ago, Tyrannosaurs emerged as the dominant carnivores, with Abelisaurs prevailing in the Southern Hemisphere and Tyrannosaurus Rex in the northern. It is conceivable that Giganotosaurus was outcompeted by these more adaptable theropods, leading to a gradual decline and eventual extinction.

After the extinction of the last of the Carcharodontosaurs, Giganotosaurus lost its dominance, allowing the Tyrannosaurus and the formidable Tyrannosaurus Rex to rise as the King of the Dinosaurs until 66 million years ago when the age of the dinosaurs came to an end.

I am a multi-disciplinary writer, published author and web content creator. If you like this post, visit my other sites and online writing portfolio.

The Kuntry Klucker – A Blog about Backyard Chickens.

The Introvert Cafe – A Mental Health Blog.

**Image Credit: Noelle K. Moser.** ***Me peering through the fenestra of Tyrannosaurus Rex MOR 555.*** *Cincinnati Natural History Museum. Cincinnati, Ohio.*

Resources:

Johnson-Ransom, Evan. Dinosaur World: Over 1,200 Amazing Dinosaurs, Famous Fossils, and the Latest Discoveries from the Prehistoric Era. Applesauce Press. Kennebunkport, Maine. 2023.

Keiron, Pim. Dinosaurs The Grand Tour: Everything Worth Knowing About Dinosaurs from Aardonysx to Zuniceratops. The Experiment. New York, NY. 2019.

My visit to Natural History Museums across the nation.

Carcharodontosaurus Saharicus: Shark-Like Teeth and Massive Size

Posted on August 19, 2024 by Noelle K. Moser

email: noellemoser@charter.net

Image Credit: ***Carchrodontosaurus Skull.***

Millions of years before Tyrannosaurus Rex roamed the earth, another group of gigantic meat-eaters ruled the land. This group of dinosaurs produced some of the largest carnivores, Giganotosaurus, Mapusaurus, Acrocanthrosaurus, and Tyrannotitan.

Roaming North Africa 99 to 94 million years ago, Carchrodontosaurus (CAR-car-oh-DONT-oh-SORE-us) reached massive sizes, some outweighing Tyrannosaurus Rex by a ton. While size alone places this theropod in the Dinosaur Hall of Fame, the most remarkable characteristic of this massive meat-eating machine is the teeth of this carnivore.

Image Credit: ***Chacharodontosaurus Life Restoration.***

Shark-Like Teeth of Charcharodontosaurus.

Image Credit: ***Carcharodontosaurus Blade-Like Tooth.***

Weighing seven metric tons, Carcharodontosaurus had a ferocious apatite, armed with 60 sharp recurved, serrated teeth that bear a striking resemblance to that of a great white shark – and inspiration for the name – this massive meat-eater effortlessly sliced and diced large titanosaurs which it hunted in family groups. Even more captivating was the discovery of Carcharodontosaurus.

Discovery of Carchrodontosaurus:

In 1699, Edward Lhuyd found a tooth thought to have belonged to a large extinct carnivorous fish. Subsequent studies showed that the tooth belonged to an unknown species of Megalosaurus. In 1824, William Buckland, an English Theologian, geologist, and paleontologist, discovered the first dinosaur fossil, Megalosaurus (meaning “great lizard”). The fossil recovered contained the lower mandible (jawbone) and teeth of a large theropod from the Middle Jurassic about 166 million years ago. William Buckland described the teeth as sharp, serrated, and jagged, similar to the shark tooth found by Edward Lhuyd nearly 100 years earli

Tracking across Egypt in 1914, German paleontologist Ernest Stromer and his expedition team excavated a partial skeleton of a large theropod with shark-like serrated jagged teeth described as Megalosaurus saharicus, belonging to a group of theropods called Megalosauridae.

Image Credit: ***Jawbone of Megalosaurus described and illustrated by William Buckland in 1824.***

After careful study, in 1931, Stromer announced that the tooth belonged to a new species of carnivorous theropod dinosaur he called C. saharicus (Carcharodontosaurus Saharicus). Unfortunately, the skeleton was destroyed by Allied bombing raids during the Second World War. C. saharicus was lost to science until 1995 when a complete skull was excavated from the Kem Kem Beds in Morocco.

Size:

Stromer hypothesized that C. saharicus was around the same size as the tyrannosaurid Gorgosaurus, which was 26–30 ft long, 39–41 ft head to tail, and weighed approximately 5–7 metric tons. Carcharodontosaurus saharicus is one of the largest known theropod dinosaurs and terrestrial carnivores.

Feeding and Diet:

Bite forces of Carcharodontosaurus and other giant theropods Acrocanthosaurus and Tyrannosaurus were analyzed showing that carcharodontosaurids had much lower bite forces than Tyrannosaurus despite being similar in size. A 2022 study estimated that the anterior (front teeth) bite force of Carcharodontosaurus was 11,312 newtons while the posterior (back teeth) bite force was 25,449 newtons, suggesting that it did not eat bones.

The shark-like teeth of Carcharodontosaurus acted like a meat slicer, while the conical-shaped teeth of Tyrannosaurus Rex crushed bone. Acrocanthosaurus (another carcharodontosaurid) relied on pack cooperation with a slice-and-dice approach to hunting. The theropods trailing behind a large herd of sauropods would take turns biting and slashing at the target; the objective was to keep the prey moving and bleeding. The lumbering prey, weakened through blood loss, exhaustion, and infections, would collapse under its weight. Like Acrocanthosaurus, this suggests that Carcharodontosaurus used this same hunting method.

Paleoenvironment:

Image Credit: ***The Tethys Ocean during the Mesozoic when the super content of Pangea began to break apart.***

Carcharodontosaurus fossils reside in Cretaceous-age formations across North Africa. During the Cretaceous, North Africa, bordered by the Tethys Ocean, occasionally flooded and created an environment of tidal flats and lush waterways. The seasonal monsoons created sub-tropical environments supporting diverse fauna. Unlike other regions, Cretaceous North Africa is an anomaly as several groups of meat-eating dinosaurs lived nearby. Fossil records show that niche diets allowed the habitat to support fewer herbivores per carnivore ratio. Fish-eating dinosaurs such as Spinosaurus hunted in the water while land-dwelling theropods hunted on land. Simply put, the carnivorous dinosaurs did to compete for food.

Image Credit: ***Life restoration of life during the Cretaceous. Carcharodontosaurus Saharicus at the center right.***

Extinction:

For unknown reasons, the tyrannosaurs (Abelisaurs in the Northern Hemisphere, Tyrannosaurs Rex in the Southern Hemisphere) replaced Carcharodontosaurus and the other predatory theropods Giganotosaurus, Mapusaurus, and Acrocanthosaurus. The remaining tyrannosaurs ruled the land for 3.6 million years until that fateful day 66 million years ago.

I am a multi-disciplinary writer, blogger and web content creator. If you liked this post, please visit my online writing portfolio and other sites.

The Kuntry Klucker – A blog about raising backyard chickens

The Introvert Cafe – A Mental Health Blog

~ Noelle K. Moser ~

Resources:

Natural History Museum Carcharodontosaurus

Ransom-Johnson, Evan & Csotonyi, Julius. Dinosaur World. Kennebunkport, Maine, Applesauce Press, 2023.

Wikipedia: Charcharodontosaurus

My visits to Natural History Museums across the country.

Acrocanthosaurus: The T-Rex of Texas and Its Prehistoric Hunt

Posted on June 29, 2023 by Noelle K. Moser

email: noellemoser@charter.net

Acrocanthosaurus: *Noelle K. Moser.* *Houston Museum of Natual Science*.

120 million years ago, along a muddy cretaceous flood plain, the relationship between dinosaurs was laid out in stone. A herd of massive sauropods slowly trudged alongside a waterway stocking, and following closely behind was a large carnivore. The trailing theropod had an objective; the carnivore was on a hunt.

Laid out in the sediment along a muddly flood plain. It is along the Paluxy River near Glen Rose, Texas, USA. There is an epic tale of a dinosaur hunt. It is recorded in stone. The footprints only tell part of the story. It is unclear if the theropod’s efforts were successful. What we do know is that Acrocanthosaurus (AK-ro- CANTH-oh-SORE-us) Atokensis was the hunter. Sauroposeidon (SORE-oh-puh-SY-don) Protheles were the prey.

First discovered in the 20th century, a complete examination of the prints was conducted in 1935 by Roland T. Bird. Bird was the first to recognize the tracks as a “chase sequence” between the herbivore herd and the theropod. Exhaustive studies by many paleontologists and recent computer analysis concur with Bird; the tracks are a prehistoric early cretaceous hunt.

**Paluxy River Dinosaur Footprints of Acanthrosaurus and herbivore.** Image Credit

Acrocanthosaurus Atokensis: The T-Rex of Texas

To fully appreciate the “chase sequence” discovered by Roland T. Bird, we need to understand the participants in this epic early cretaceous tale. Known as the T-Rex of Texas, Acrocanthosaurus is one of the largest Cretaceous theropods known to exist. It is second only to Giganotosaurus, Carcharodontosaurus, and Tyrannosaurus Rex, respectively.

**Theropod Size Comparison Chart:** Image Credit

Acrocanthosaurus meaning “high-spined lizard,” is a genus of carchondontosaurid. It is known for high neural spines on the vertebrae. It is one of the most spectacular hunters of the Cretaceous. Acrocanthosaurus has jaws packed with 68 serrated teeth. It has a body length of 36 to 38 feet. It weighs 4-6 metric tons. It is native to North America. Fossil remains are only found in Oklahoma, Texas, and Wyoming. A few teeth found as far away as Maryland suggest a continent-wide presence.

Despite its gigantic size, an examination of the skeleton shows that the thigh bone is longer than its lower leg bones. This means that Acrocanthosaurus was not a fast runner. Outpaced by many of the swifter hadrosaurs like tentosaurus and other herbivores, Acrocanthosaurus would target massive slower-moving prey. Such prey included Sauroposeidon. This is evidenced by the Peluxy River trackway.

**Tentosaurus a swift hadrosaur that roamed in the same area as Acrocanthosaurus:** Image Credit

Unable to run down its prey, Acrocanthosaurus relied on pack cooperation with a slice-and-dice approach to hunting. Outweighed by the immense size of the Sauropods, it would be foolish for Acrocanthosaurus to attack the lumbering sauropods. Rather than risk injury, the theropods would take turns biting and slashing. Their objective was to keep the prey moving and bleeding. Weakened through blood loss, exhaustion, and infections inflicted by Acrocanthosaurus, the Sauroposeidon would eventually collapse under its weight. It would feed the local ecosystem, including Acrocanthosaurus, for days.

***Acrocanthosaurus Brain Structure***. Image Credit.

Like other Cretaceous theropods, Acrocathosaurus had a large complex brain. In 2005, scientists created an endocast of the braincase of Acrocanthosaurus. They found that while the brain is similar to many theropods, it is most similar to that of allosauroids. Specifically, it is similar to Carcharodontosaurus and Giganotosaurus. This provides further support for the hypothesis that Acrocanthosaurus was indeed a carcharodontosaurid.

***Carcharodontosaurus Skull***. Image Credit

Like carchodontosaurus, Acrocanthosaurus had an enhanced optic nerve. This indicates that these theropods had stereoscopic binocular vision. Therefore, they could accurately discern depth and distance. A large auditory bulb supports impeccable hearing capabilities. Overall brain size suggests advanced intelligence. This includes planning and social interaction behaviors.

Sauroposeidon: “The Earth Shaker”

Every ecosystem must sustain a never-ending balancing act to survive, a delicate relationship between predator and prey. Where there are large carnivores, large herbivores are needed to preserve this balance. While they may seem defenseless, titanosaurs like Saurposeidon were well-defended and not easy meals to obtain by local predators.

Named after Poseidon, the Greek god of the sea and the god of earthquakes. Sauroposeidon made the ground tremble. It literally shook the earth as it walked. These titanosaurs were one of the largest animals the planet has ever seen. They were outclassed only by Argentinosaurus. Argentinosaurus was only slightly longer and heavier.

Titanosaurs lived by one rule, get big and get big fast. From the moment of hatching, sauropods like Saurposiedon were eating machines. Dining on leaves and hard fibrous vegetation, a herd of titanosaurs could defoliate an area in a few days. Large guts and hard-to-digest food allowed for a slow release of energy over time. This superpower aided in the ability of these sauropods to reach full size in less than ten years. Once fully grown, an adult Sauroposiedon was 100 ft long, 65 ft tall, and weighed 60 to 66 tons. This sheer size alone was enough to detour many theropods from making a meal out of these massive herbivores. Traveling in herds combined with size officially removed them from the menu.

**Sauroposeidon size compared to a human.** Image Credit

Hunting a herd of Sauroposeidon was very dangerous. One wrong move and one of these massive herbivores could easily crush, instantly killing an over-eager theropod. Given this danger, the question becomes not did Acrcanthosaurus hunt one of the titanosaurs but how.

Like many questions left by extinct creatures, the best way to answer these questions is to look at the present. When we observe lions hunting a herd of wilder beasts, the predators will work together to break up the herd. They single out the small, sick, or weakest members. This makes for an easy kill. A lion knows that attacking the largest, strongest, or healthiest individual would be a dangerous mission at best. We can apply this same reasoning to Acrocanthosaurus.

Traveling herds are very organized. Babies and subadults are in the middle. The large and healthy adults assemble around them as hedges of protection. Elderly or injured individuals typically follow behind the main herd forming the rear as the herd marches across the land.

The hunting Acrocanthosaurus is stalking the herd from behind slightly to the left. It is clear that the predator is aware of this herd dynamic. This Sauroposeidon is not in the prime of its life. It is still a dangerous animal and can inflict injury or death on the theropod. It is most likely for this reason that the Acrocanthosaurus rhythmically steps with the herd. When the time is right, it lunges toward the individual and makes a calculated attack.

The soft mud of the Texas floodplain records this dance between predator and prey several times. Then the tracks disappear, lost in time. This leaves the end of this Cretaceous tale a mystery for paleontologists to solve 120 million years later.

It is unclear if Acrocanthosaurus ate dinner that day 120 million years ago. However, the titanosaur eventually succumbed to the injuries. It provided enough meat to feed an ecosystem for days.

Acrocanthosaurus and Sauroposeidon tracks. Image Credit.

Many people visit this site every year and behold the immense size of the footprints left in the mud. What they may fail to realize is the importance of these tracks. This trackway is more than impressive prints from creatures of the past. These prints show the interaction and relationship between two kinds of dinosaurs, predator and prey. They roamed Texas millions of years ago. Their interactions are recorded in stone.