# Stegosaurus stenops

> A plated thyreophoran from the Late Jurassic Morrison Formation of the western United States, with two rows of tall bony plates along its back and four tail spikes. Known from the exceptionally complete specimen "Sophie".

- Classification: Dinosauria (clade) > Ornithischia (clade) > Thyreophora (clade) > Stegosauridae (family) > Stegosaurus (genus) > Stegosaurus stenops (species)
- Length: 6.5 m
- Hip height: 2–2.6 m
- Mass: 1.1–2.3 t
- Age: 154.8–145 million years ago (Late Jurassic)
- Fossils found in: Morrison Formation (Colorado); Wyoming
- Diet: herbivore
- Described: Othniel Charles Marsh, 1887
- In films: The Lost World: Jurassic Park (1997), Jurassic Park III (2001), Jurassic World (2015), Jurassic World: Fallen Kingdom (2018), Jurassic World Dominion (2022)

Canonical page: https://dinodex.club/dinosaurs/stegosaurus-stenops
Last updated: 2026-09-27

## Overview

Stegosaurus stenops lived in western North America in the Late Jurassic, and its fossils come from the Morrison Formation. O. C. Marsh named the species in 1887 from a nearly complete, articulated skeleton (USNM 4934) collected at Garden Park, Colorado.

It was a four-legged plant eater with a small, narrow head, two alternating rows of large plates along its back and two pairs of spikes at the end of the tail. The best-known individual, NHMUK PV R36730 ("Sophie"), from Red Canyon Ranch in Wyoming, is about 85 percent complete; Maidment et al. (2015) found it was not fully grown.

Brassey et al. (2015) modelled Sophie's volume and estimated about 1.6 tonnes, noting that equations based on limb bones give much higher values. Full-grown animals were larger.

## Name meaning

From Greek stegos ("roof") and sauros ("lizard"), as Marsh first thought the plates lay flat like roof tiles; stenops means "narrow face" (Marsh 1887).

## Sources

1. Brassey, C. A., Maidment, S. C. R. & Barrett, P. M. (2015). Body mass estimates of an exceptionally complete Stegosaurus (Ornithischia: Thyreophora): comparing volumetric and linear bivariate mass estimation methods. Biology Letters 11(3): 20140984. https://doi.org/10.1098/rsbl.2014.0984
2. 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
3. Maidment, S. C. R., Brassey, C. & Barrett, P. M. (2015). The postcranial skeleton of an exceptionally complete individual of the plated dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming, U.S.A.. PLoS ONE 10(10): e0138352. https://doi.org/10.1371/journal.pone.0138352
4. Marsh, O. C. (1887). Principal characters of American Jurassic dinosaurs. Part IX. The skull and dermal armor of Stegosaurus. American Journal of Science (series 3) 34: 413-417.
5. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.

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Cite as: "Stegosaurus stenops". DinoDex. https://dinodex.club/dinosaurs/stegosaurus-stenops (updated 2026-09-27).