MEANING: Herrera's lizard
PERIOD: Late Triassic
CONTINENT: South America
Herrerasaurus is a basal saurischian dinosaur from the Late Triassic period of what is now Argentina. It was one of the earliest dinosaurs from the fossil record, and for many years the classification of Herrerasaurus was unclear because it was known from very fragmentary remains. It was a lightly built bipedal carnivore with a long tail and a relatively small head. Adults had skulls up to 56 cm long and grew to 6 m in total length and 350 kg in weight, making Herrerasaurus the largest known carnivorous dinosaur of its time.
Herrerasaurus is from the Triassic. The Triassic is a geologic period which spans from the end of the Permian Period 251 million years ago to the beginning of the Jurassic Period 201 million years ago. Both the start and end of the period are marked by major extinction events. The global climate during the Triassic was mostly hot and dry, with deserts spanning much of Pangea's interior. However, the climate shifted and became more humid as Pangea began to drift apart. Though it is the first period of the Mesozoic Era, the age of the dinosaurs, true dinosaurs didn't exist through most of it, finally evolving only in the Late Triassic.
Herrerasaurus is a theropod. Theropods are dinosaurs that are characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Theropods first appeared during the Carnian age of the late Triassic period and included all the large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous. In the Jurassic, birds evolved from small specialized theropods, and are today represented by about 10,500 living species.