Herrerasaurus
Early saurischian dinosaur from the Late Triassic of Argentina.
Herrerasaurus is a genus of saurischian dinosaur from the Late Triassic period, known from fossils discovered in the Ischigualasto Formation of northwestern Argentina. Measuring up to 6 meters long and weighing around 350 kilograms, it is one of the earliest dinosaurs in the fossil record and has been central to debates on dinosaur origins and classification.
- length
- 6 m (20 ft)
- weight
- 350 kg (770 lb)
- period
- Late Triassic (Carnian, ~231.4 million years ago)
- diet
- Carnivore
- discovery_location
- Ischigualasto Formation, northwestern Argentina
- type_species
- Herrerasaurus ischigualastensis
- named_by
- Osvaldo Reig (1963)
Lore & Background
For many years, Herrerasaurus was known only from fragmentary remains, leading to varied classifications: it was hypothesized to be a basal theropod, a basal sauropodomorph, a basal saurischian, or even not a dinosaur. The discovery of an almost complete skeleton and skull in 1988 by a team led by Paul Sereno clarified its anatomy, and it has since been classified as an early saurischian in most phylogenies, though some researchers still consider it a primitive theropod. It is a member of the Herrerasauridae family.
Reader's Guide
Herrerasaurus holds significant importance in understanding the early evolution of dinosaurs. Its fossils, found in the Ischigualasto Formation alongside Eoraptor, provide key evidence for the timing and diversification of major dinosaur lineages. The ongoing debate over whether Herrerasaurus is a basal saurischian or a primitive theropod has implications for the monophyly of dinosaurs and the sequence of character acquisition. Sereno's 1992 study of Herrerasaurus suggested that only a few proposed dinosaurian synapomorphies were actually derived from a common ancestor, with others resulting from convergent evolution. The study of Herrerasaurus thus continues to inform hypotheses about the origin and early radiation of dinosaurs, including the divergence of theropods, sauropodomorphs, and ornithischians.
Did You Know?
- Herrerasaurus means 'Herrera's lizard,' after the rancher who discovered the first specimen in 1958.
- Its skull could reach up to 56 cm (22 in) in length.
- The foot had five toes, but only the middle three bore weight.
- Herrerasaurus had a flexible joint in the lower jaw that could slide back and forth for a grasping bite.
More in Extinct Archosaurs 1-24
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