# Herrerasaurus ischigualastensis

> One of the earliest known dinosaurs, a two-legged predator from the Late Triassic of north-west Argentina, about 230 million years old. A complete skull found in 1988 showed it was an agile hunter with grasping hands.

- Classification: Dinosauria (clade) > Saurischia (clade) > Herrerasauridae (family) > Herrerasaurus (genus) > Herrerasaurus ischigualastensis (species)
- Length: 4.5–6 m
- Hip height: 1–1.3 m
- Mass: 200–350 kg
- Age: 237–227.3 million years ago (Late Triassic)
- Fossils found in: Ischigualasto Formation (San Juan Province); Argentina
- Diet: carnivore
- Described: Osvaldo A. Reig, 1963

Canonical page: https://dinodex.club/dinosaurs/herrerasaurus-ischigualastensis
Last updated: 2026-09-27

## Overview

Herrerasaurus ischigualastensis lived about 230 million years ago in the Late Triassic, in the river valleys of what is now San Juan Province, Argentina. The goatherd Victorino Herrera noticed its bones in the Ischigualasto Valley in 1959, and Osvaldo Reig named it after him in 1963.

For decades it was known only from partial skeletons, and its place in the family tree was unclear. In 1988 a team led by Paul Sereno found a complete skull and skeleton; Sereno and Fernando Novas (1992) showed it was an agile, two-legged predator with short, grasping and raking forelimbs.

It lived at a time when dinosaurs were still rare. The Ischigualasto Formation records the first dinosaurs as dominant carnivores and small herbivores, alongside rhynchosaurs, cynodonts and large crocodile-line reptiles (Martinez et al. 2011).

## Name meaning

"Herrera's lizard", after Victorino Herrera, who found the first remains; ischigualastensis for the Ischigualasto Valley (Reig 1963).

## Sources

1. (2026). Paleobiology Database: Herrerasaurus occurrences. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/occs/list.txt?base_name=Herrerasaurus&show=coords,paleoloc,strat,loc,ref&pgm=gplates
2. (2026). Wikipedia: Herrerasaurus. Wikipedia (English), accessed 2026-09-23. https://en.wikipedia.org/wiki/Herrerasaurus
3. Martinez, R. N., Sereno, P. C., Alcober, O. A., Colombi, C. E., Renne, P. R., Montañez, I. P. & Currie, B. S. (2011). A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea. Science 331: 206-210. https://doi.org/10.1126/science.1198467
4. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
5. Reig, O. A. (1963). La presencia de dinosaurios saurisquios en los "Estratos de Ischigualasto" (Mesotriásico Superior) de las provincias de San Juan y La Rioja (República Argentina). Ameghiniana.
6. Sereno, P. C. & Novas, F. E. (1992). The complete skull and skeleton of an early dinosaur. Science 258: 1137-1140. https://doi.org/10.1126/science.258.5085.1137

---

Cite as: "Herrerasaurus ischigualastensis". DinoDex. https://dinodex.club/dinosaurs/herrerasaurus-ischigualastensis (updated 2026-09-27).