Herrerasaurus ischigualastensis was a small to medium-sized bipedal dinosaur that lived during the Late Triassic period. It was a carnivorous theropod, characterized by its long, slender body, sharp teeth, and strong hind limbs, which suggest it was an agile predator. Herrerasaurus is considered one of the earliest dinosaurs, offering insights into the early evolution of these creatures. It inhabited the lush, prehistoric landscape of what is now Argentina, in an area known as the Ischigualasto Formation.

Herrerasaurus ischigualastensis is native to the Late Triassic period, specifically found in what is now northwestern Argentina, predominantly in the Ischigualasto Formation. This region is part of the Ischigualasto-Villa Unión Basin.

During the Late Triassic, the Ischigualasto region was a volcanically active floodplain with a seasonal climate. The area was characterized by lush vegetation, including ferns, horsetails, and primitive conifers, indicating a humid environment with distinct wet and dry seasons.

Herrerasaurus ischigualastensis was likely a carnivorous predator, occupying a top predator ecological niche within its environment. It preyed on other contemporary vertebrates, including smaller dinosaurs and synapsids. The species was well-adapted to a terrestrial lifestyle, utilizing its bipedal locomotion for hunting and scavenging.