OBJECT DOSSIER · SMITHSONIAN OPEN ACCESS

Stegosaur, plated dinosaur — Stegosaurus stenops

SAGE Museum Deep Time scientific dossier

Artist / Creator

Susannah Maidment et al. & Natural History Museum, London

Date / Period

Late Jurassic — Kimmeridgian · Approximately 152 million years ago in the Smithsonian Deep Time interpretation.

Object Type

composite cast

Medium

composite_mount

About This Object

Geologic period: Late Jurassic — Kimmeridgian

Age: Approximately 152 million years ago in the Smithsonian Deep Time interpretation.

Feeding: Herbivorous.

Locomotion: Terrestrial quadruped.

Body plan: Large quadrupedal herbivore with a small skull, arched back, paired dorsal plates and four prominent tail spikes.

Evidence: Plates, tail spikes, vertebrae and limb bones are direct skeletal evidence. Display posture and soft tissues are reconstructions.

Why it matters: Stegosaurus combines two highly unusual anatomical systems: large dermal plates and a weaponized tail, making it ideal for explaining how paleontologists separate directly preserved anatomy from hypotheses about function.

Plain Language Identity: A Late Jurassic plated dinosaur famous for its paired back plates and defensive tail spikes.

What You Are Looking At: A composite cast representing the skeleton and defensive anatomy of Stegosaurus stenops rather than one complete original fossil individual.

Defense Or Attack: Tail spikes were capable of functioning as defensive weapons. The exact function of the large dorsal plates remains more complex and debated.

Ecosystem: Late Jurassic Morrison Formation ecosystem of western North America.

Preservation: Composite cast.

Open Questions: Do not state a single definitive function for the dorsal plates. Thermoregulation, display and species recognition have all been discussed.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/stegosaurus-stenops-marsh-1887:nmnhpaleobiology_3450470; https://www.si.edu/newsdesk/factsheets/david-h-koch-hall-fossils-deep-time

Enrichment Method: SAGE curated research pass; title + scientific name + source scene matched; historic taxonomy retained where relevant; evidence separated from inference

Scientific name: Stegosaurus stenops

Evidence / representation: comparative_taxon_visual

Why It Is In This SAGE Exhibit

comparative_taxon_visual

Jurassic Giants: Size, Teeth, Armor and Survival.

Provenance

Smithsonian Deep Time source scene: Stegosaurus Spikes vs. Ceratosaurus Claws

Visual source institution: Wikimedia Commons

Exhibition History

Included in the SAGE Museum Dinosaurs & Deep Time staging exhibit.

Collection & Credit

Media license: CC BY 4.0

https://creativecommons.org/licenses/by/4.0

Subjects & Themes

Stegosaurus stenops Late Jurassic — Kimmeridgian composite cast Stegosaurus Spikes vs. Ceratosaurus Claws Jurassic Giants

ORIGINAL COLLECTION SOURCE

This object page stays inside SAGE Museum. The Smithsonian link below is provided only as the original scholarly collection record. It opens separately.

VIEW ORIGINAL SMITHSONIAN RECORD ↗