Glowing Dinosaursby Firoiu Dan Nicolae Reserve a copy
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Stegosaurus with blue plates and pink muscles, seen from the side

N° 079 · IV. Horns and Armour

Stegosaurus

The Plated Giant

Say it: STEG-oh-SORE-us

Species
Stegosaurus stenops, Marsh 1887
Name means
Roof lizard
Lived
Late Jurassic, about 152 to 145 million years ago
Found
United States
Length
Up to about 9 m
Weight
About 1.6 tonnes for a young adult
Diet
Herbivore

Three things to know

A roof lizard, by mistake

Its name means roof lizard: its plates were thought to lie flat like tiles. A later skeleton showed they stood upright in two alternating rows.

Nobody knows what the plates did

They may have warned off hunters, helped animals recognise their own kind, or controlled body heat.

Lighter than it looks

The most complete skeleton, from Wyoming, is 5.6 m long. A 2015 study put that young adult at about 1,560 kg. Its brain was about the size of a plum.

Every fact on this page is traced to a published source, listed at the back of the book.

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When and where Stegosaurus lived

Stegosaurus lived about 152 to 145 million years ago, in the Late Jurassic, in what is now the western United States, with related forms in Portugal. Its fossils come from the Morrison Formation, where it lived alongside Diplodocus, Brachiosaurus and the hunter Allosaurus, on wide river plains with a warm, seasonal climate.

How Stegosaurus was discovered and named

Othniel Charles Marsh named the first Stegosaurus in 1877, during the fierce fossil rivalry of the American West known as the Bone Wars. The species shown here, Stegosaurus stenops, followed in 1887. The most complete skeleton yet found, a young adult nicknamed Sophie, was dug up in Wyoming and is now displayed at the Natural History Museum in London.

How Stegosaurus lived

Stegosaurus was a slow, four-legged plant-eater with a small head held low to the ground, ideal for feeding on ferns and low shrubs. Its back carried two rows of tall bony plates, and its tail ended in four long spikes, often called a thagomizer, a word that began as a joke in a cartoon. Those spikes were a real weapon: an Allosaurus tail bone has been found with a wound that matches a Stegosaurus spike.

Stegosaurus in Glowing Dinosaurs

Stegosaurus is entry N° 079 of the atlas, in the chapter IV. Horns and Armour. Its spread follows the same layout as every other dinosaur in the book: on the left, its name and how to say it, the epithet The Plated Giant, the three facts above, field notes and the six signs that show when it lived, how big it was, how dangerous it would have been, where it was found, what it ate and how it fought. On the right is the full glowing plate: stegosaurus with blue plates and pink muscles, seen from the side. Two more plates of Stegosaurus appear elsewhere in the book, and each can also be ordered as a signed work for the wall, printed on wood or acrylic under glass. In the same chapter you will also find Triceratops.

Why Stegosaurus glows

No dinosaur is known to have glowed, and the book says so plainly. The light is the artist’s way of seeing inside the animal: in the plate of Stegosaurus, bones, muscles and outline shine through a dark ground, so the shape of the skull, the length of the neck and tail and the build of the legs can be read at once, the way a fossil skeleton is read in a museum hall. The colours are chosen to separate bone from muscle and to make each animal recognisable across the whole atlas, while every fact printed beside the picture is checked against published research.

Questions about Stegosaurus

How big was Stegosaurus?

Stegosaurus measured up to about 9 m from nose to tail and weighed about 1.6 tonnes for a young adult. The size panel on its spread in the book draws it beside a person, so its scale can be seen at a glance.

When did Stegosaurus live?

It lived in the Late Jurassic, about 152 to 145 million years ago. On the timeline in the book, its place is marked between the first dinosaurs, about 230 million years ago, and the end of the age of dinosaurs, 66 million years ago.

Where have Stegosaurus fossils been found?

Its fossils have been found in United States. The map on its spread in the book marks the places where its bones were dug up.

What did Stegosaurus eat?

Its diet: herbivore. The diet sign in the book shows this with a simple symbol, so young readers can sort the plant-eaters from the meat-eaters.

What does the name Stegosaurus mean?

The name means “roof lizard”. The full scientific name is Stegosaurus stenops, Marsh 1887: the genus, the species and the scientist who named it, with the year. It is pronounced STEG-oh-SORE-us.

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