Herrerasaurus is the archosaur that arrived even before the popular velociraptor.
This ancient reptile was a vicious predator. But it lacked the dinosaur features of the leg and hip bones. Some scientists suggest that the herrerasaurus is a close relative of the dinosaurs. Others classify them as theropods or saurischian.
What do you need to know about the herrerasaurus? Let us review the following information and understand the way this ancient predator lived and how it may have paved the way for the appearance of the velociraptor.
Physical Characteristics
The herrerasaurus was one of the very first carnivorous dinosaurs. Research shows that these predators lived during the Carnian stage or Late Triassic Period in Argentina. During its time, the herrerasaurus was a monster. It shared the planet with other primitive dinosaurs, such as the Daemonosaurus, Staruikosaurus, and Tawa.
A fossil that represented the earliest known animal predator was identified by UK scientists. The specimen is considered to be 560 million years old. It was found by Charnwood Forest in Leicestershire. This species is closely related to the jellyfish we know today.
This predator was built with a heavy body, with a light gait. Scientists estimate its weight to be 250 pounds to at least 500 pounds. Herrerasaurus also had threatening talons and sharp teeth. These traits made this archosaur a terrible opponent to its enemies, even those who were as big as it was.
Its skin was like that of an early lizard, textured with nodes. This was evidence of avian genetic traits, leaning towards feathering and egg-laying. Herrerasaurus had a flat back, which sped up its movements. Its long feet and short thighs made it a fast runner. It was four to seven feet tall and seven to 15 feet long. This reptilian-avian dinosaur could attack and jump with great force because of its strong hind legs. It even used these legs for defending and propelling itself.
If it were still alive today, the herrerasaurus would have stronger legs than modern horses or dogs. It would also be heavier than most people. This predator’s feet were limber and big. It would have easily overpowered humans and other animals today. Scientists say that its descendants are modern birds.
This archosaur had a small head and a long tail. The function of the tail was to balance the herrerasaurus and adjusted its speed while it ran. It also had a flexible and slender neck. It had five toes on each foot. The middle three toes were larger and weight-bearing. They supported the full weight of the archosaur.
This predator also had long hands. Each one had deadly, curved claws on the first and second digits. Its thumbs also had claws. The smaller fourth and fifth digits did not have any claws at all. Some scientists believe that the lineage developed many features similar to those of dinosaurs. These features include a large hip bone that was strengthened by two sacral bones. These predators also had some apomorphic traits. Their pubic bone pointed backward like what you see in modern birds. The end of the pubis was shaped like a boot.
The neck and skull of the herrerasaurus were rectangular. It also had a narrow snout. The depressions above the temples showed where the adductor muscles stayed. Its adaptive mandible showed how active it was as a predator. Its slender neck vertebrae had prominent epipophyses.
Its skull did not have a postfrontal opening, but it had a tiny post-temporal opening. Scientists compared the skull of the herrerasaurus to other basal saurischian dinosaurs. Their studies show that there were many commonalities between saurischians and theropods. The similar traits it shared with saurischians include the presence of a subnarial foramen between the upper jaw and premaxilla. With theropods, this archosaur shared an intra-mandibular joint. Even so, the general neck and skull anatomy of herrerasaurus were more primitive than other basal dinosaurs.
Movements and Behavior
The herrerasaurus moved and stood on its toes. Its leg and feet muscles gave it a powerful gait. Like any predator, it looked around its territory and waited for the right moment to hunt down its prey. It ran and jumped in the air before it landed on its catch. It was not as big as the T-rex, but it had the power to hold and eat its prey.
This predator had short forelimbs like the velociraptor. Its hips were lizard-like or saurischian. This quality made it easy for this archosaur to move on land. It was cold-blooded. It often conserved energy when it was not hunting or moving around.
Basic Diet
Researchers found proof that the herrerasaurus ate land rodents. It even preyed upon animals that were weaker or smaller than itself. This was proof that this predator was a carnivore. Other scientists suggest that this archosaur also ate plant material and insects.
As years passed, theropods began to have a broader diet range. The herrerasaurus had a special hinge type of joint in its mandible. This joint enabled the mandible to slide to the front and then back. It gave this predator a bite that allowed it to grab hold of its squirming prey. It also gave this archosaur more control when it hunted.
This reptilian-avian predator ate much like a mammal or bird. It was able to lurk and hide in its forest and valley territories when it stalked its prey. If its prey managed to jump up and run, the herrerasaurus was able to chase it down. It used its short forearms to grasp and rip its prey apart. Its forearms had digits that functioned as gripping hands rather than feet.
Some scientists say that the herrerasaurus was not the top predator in its chosen ecosystem. It may have consumed ischigualastia and hyperodapedon. Small dinosaurs like the herbivorous rhynchosaurs and synapsids may have been part of their diet as well. This archosaur may have been hunted as well by the other top predators in the area. These hunters included saurosuchus and postosuchus.
Living Environment
Herrerasaurus lived in what is now South America. This large region used to be part of a much bigger landmass called Pangaea. This huge area gave the herrerasaurus more than enough territory. Experts believe that Pangaea existed 230-300 million years ago. Scientists believe that this agile predator lived in the flood plains and valleys that were always rich with abundant prey and lush vegetation. They added that this predator also lived in the warm volcanic areas.
The Discovery
Experts recognize South America as the main root of all prehistoric dinosaurs. The discovery of herrerasaurus took place in what is Argentina today. Victorio Herrera and Osvaldo A. Reig made the discovery. It took many years before herrerasaurus was decoded in detail. It was only in 1988 that the first skull was discovered. Since then, scientists started to figure out the true appearance of this predator.
The Puzzling Archosaur
The herrerasaurus had traits that were found in different groups of dinosaurs. Some of its characteristics did not even belong to the dinosaur classification. That is why it was classified as a non-dinosaur. It was either a saurischian or an archosaur. This predator’s bloodline had the traits of lizards and birds. The discovery of herrerasaurus paved the way to a deeper understanding of species evolution, biology, and adaptability. This predator was an ideal example of adaptation through difficulty.
Scientists also consider herrerasaurus as an important example of convergent evolution. These archosaurs had their own bloodline. Even so, they also had traits that belonged to saurischian and ornithischian dinosaurs. Their quick evolutionary spread combined species-specific and ecological variety. Then, the species imbibed these traits into their genes in such a short period.
The Classification
Scientists are still debating the true classification of the herrerasaurus. Some experts see it as a basal theropod. Others consider it as a basal saurischian or sauropodomorph. Other experts believe that this archosaur is another type entirely. Their analysis indicates that this predator appeared long before the separation of the saurischian and ornithischian dinosaurs.
The Paleobiology
Many scientists believe that herrerasaurus was a possible carnivore. Because of its size, this archosaur ate insectivores and small to medium herbivores. These archosaurs were probably the prey of larger predators like rhynchosaurs and synapsids as well. Evidence shows that these predators also ate larger predators like rauisuchids and saurosuchus.
The coprolites dug up by scientists showed that the herrerasaurus digested the bones of its prey. Researchers also found proof that these archosaurs were cathemeral. This means that these predators were active for short specific periods in one day. Hunting would have been often for them.
The paleoenvironment of the herrerasaurus was the Ischgualasto formation. It consisted of forests and plains in an area rich in volcanic activity. The area’s paleoclimate was moist and warm, with different seasonal changes. It was also peppered with imposing seasonal rains. Giant conifers, horsetails, and ferns.
Conclusion
The herrerasaur species looked very much like the velociraptor. It had a long tail, short forearms, and ferocious hunting behavior. But if you look at it closely, it possessed characteristics of both lizards and birds. Scientists believe that it appeared during the time before the characteristics of birds and lizards were found in separate primitive animals. This archosaur is believed to be an important link to the evolution of the bird-like and lizard-like dinosaurs.
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