# Dilophosaurus wetherilli

> A large Early Jurassic theropod from the Kayenta Formation of Arizona with two thin crests on its skull. The neck frill and venom spitting of Jurassic Park are fiction with no fossil support.

- Classification: Dinosauria (clade) > Saurischia (clade) > Theropoda (clade) > Neotheropoda (clade) > Dilophosauridae (family) > Dilophosaurus (genus) > Dilophosaurus wetherilli (species)
- Length: 7 m
- Hip height: 1.3–1.6 m
- Mass: 400 kg
- Age: 199.5–184.2 million years ago (Early Jurassic)
- Fossils found in: Kayenta Formation (Arizona)
- Diet: carnivore
- Described: Samuel P. Welles, 1954
- In films: Jurassic Park (1993), Jurassic World Dominion (2022), Jurassic World Rebirth (2025)

Canonical page: https://dinodex.club/dinosaurs/dilophosaurus-wetherilli
Last updated: 2026-09-27

## Overview

Dilophosaurus wetherilli lived in what is now northern Arizona during the Early Jurassic. Its bones come from the Kayenta Formation, on Navajo Nation land. Samuel Welles described the first skeletons in 1954 as a new species of Megalosaurus and, after a later specimen showed its paired skull crests, gave it its own genus in 1970.

It was one of the largest predators of its time: a slender, long-legged theropod with a pair of thin, arched crests along the top of the skull and a notch between the premaxilla and maxilla in the upper jaw. Marsh and Rowe (2020) redescribed all known specimens and showed that the skull was sturdier than once thought, not weak or fragile.

The Dilophosaurus of the film Jurassic Park is much smaller, has an expandable neck frill and spits venom. None of this is known from fossils: there is no evidence for a frill or for venom, and the real animal was far larger (Marsh & Rowe 2020). The crests were probably for display.

## Name meaning

From Greek di- ("two"), lophos ("crest") and sauros ("lizard"): "two-crested lizard" (Welles 1970); wetherilli honours John Wetherill, a Navajo trader and explorer (Welles 1954).

## Sources

1. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf
2. Marsh, A. D. & Rowe, T. B. (2020). A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona. Journal of Paleontology 94(S78): 1-103. https://doi.org/10.1017/jpa.2020.14
3. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
4. Welles, S. P. (1954). New Jurassic dinosaur from the Kayenta Formation of Arizona. Geological Society of America Bulletin 65(6): 591-598. https://doi.org/10.1130/0016-7606(1954)65[591:NJDFTK]2.0.CO;2
5. Welles, S. P. (1970). Dilophosaurus (Reptilia: Saurischia), a new name for a dinosaur. Journal of Paleontology 44(5): 989.

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Cite as: "Dilophosaurus wetherilli". DinoDex. https://dinodex.club/dinosaurs/dilophosaurus-wetherilli (updated 2026-09-27).