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The Herrerasaurus is one of the most primitive dinosaurs that walked the earth during the Triassic period, about 228 million years ago, in and around Northwest Argentina. The type species Herrerasaurus ischigualastensis is the sole species belonging to this genus.


Scientific Classification

Kingdom Animalia
Phylum Chordata
Clade Dinosauria
Order Saurischia
Family †Herrerasauridae
Genus Herrerasaurus
Species H. ischigualastensis
Binomial name Herrerasaurus ischigualastensis

Quick Facts

Pronunciation her-AIR-a-SAWR-us
Geological Period Late Triassic period, about 235-230 million years ago
Size 13-15 ft in length
Height 4-7 ft at the hips
Weight 250-500 pounds
Maximum Speed Approximately 25 mph
Location/Distribution & Habitat In and around north-western Argentina, South America
Climate/Environment Warm tropical
Diet Carnivorous
Birth Type (Reproduction) Oviparous
Locomotion Bipedal

History and Discovery

In 1959, the fossils of the creature were first discovered by a goat herder named Victorino Herrera in the Ishigualasto region, San Juan Province, in the north-western part Argentina, where they are thought to have lived. The herder accidentally stepped on the skeletal remains after which he came to understand what it was actually.

Later, in 1963, the biologists named the new reptile ‘Herrerasaurus’ honoring the discovery of Herrera, which in English literally translates to ‘Herrera’s lizard’.

However, for many years, it was not particularly clear to the paleontologists how to classify the creature. The primary reason for this confusion is that there have been several biological theories related to this creature.

One theory suggested that the animal might have been an early Theropod dinosaur, while the other propounded that it was an ancient Sauropodomorph (the suborder that includes Prosauropods and Sauropods), whereas another theory believed that the creature was not a dinosaur at all.

Scientists had to wait for more than two decades before a decent herrerasaurus fossil showed up. In 1988, an almost complete skeleton, including the skull, was unearthed. This discovery threw a much clearer light on the creature, after which the scientists unanimously opined that it was an ancient Theropod dinosaur.

Physical Description

The Herrerasaurus had a medium shaped body and walked on two long hind legs, while their relatively shorter forearms had short arm bones. The arms were about half the length of its back legs, with the fingers bearing sharp claws.

It had an elongated narrow skull with hinged jaws. The creature could open its mouth wide for eating chunks of meat.

The teeth of these animals were perfectly serrated like in a saw. The special joint in its jaw was adapted to hold down its prey better.

Behavior & Diet

Scientists believe that the carnivore Herrerasaurus was probably not the apex predator in its ecosystem. It may have probably survived consuming Hyperodapedon and Ischigualastia, but it was also being hunted itself by the contemporary top predators that included reptiles like Postosuchus, Saurosuchus, and several others.

Herrerasaurus probably feasted upon small- and medium-sized creatures like small dinosaurs, a group of herbivorous reptiles called rhynchosaurs, and herbivorous mammal-like reptiles known as synapsids.

Interesting Facts

  • The Herrerasaurus helped the paleontologists explain the evolution of the modern bird wings.

Published on February 18th 2019 by under Reptiles.
Article was last reviewed on 16th September 2019.

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