Dino card No. 1696 of 2,027

Sphaerotholus

Say it: sfair-oh-THOH-lus

Name means: “ball dome”1

Ate: PlantsDome-headsLate Cretaceous

Sphaerotholus was a dome-headed dinosaur that lived near the end of the Age of Dinosaurs. It had a thick, bony dome on its skull and probably used it for head-butting contests.1

Lived

84 to 66 million years ago2

Late Cretaceous

Fossils found in

Western United States (Montana, New Mexico) and Canada (Alberta, Saskatchewan)2 1

Food

Plants2

Length

2 m1

for S. edmontonensis, about 2 m (6.6 ft)

Weight

40 kg1

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 10 house cats

as long as 4 house cats nose to tailas long as 11 bananas end to endas heavy as 8 watermelons

How big was Sphaerotholus compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

cool stuff

Fun facts

Sphaerotholus lived for a long time, about 7 to 8 million years, and spread across a wide area from New Mexico to Montana.1

There are five known species of Sphaerotholus, each with slightly different bumps and nodes on the back of their skulls.1

One species, S. triregnum, had a triple row of small bony nodes on its skull, making it look like it wore a triple crown.1

Another species, S. lyonsi, had a double row of small nodes, while others had a single row of large nodes.1

The name Sphaerotholus means 'ball dome', which describes its round, dome-shaped skull.1

Sphaerotholus is considered a highly evolved, or derived, pachycephalosaur.1

AI-made picture of Sphaerotholus — An AI-made picture of how Sphaerotholus might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

you asked

Most asked questions about Sphaerotholus

?How big was Sphaerotholus?

Sphaerotholus edmontonensis reached about 2 metres (6.6 feet) in length and weighed around 40 kilograms (88 pounds). Other species were probably a similar size.1

?What did Sphaerotholus eat?

Sphaerotholus was a plant-eater. Like other pachycephalosaurs, it had teeth suited for eating tough plants.1

?When did Sphaerotholus live?

Sphaerotholus lived during the Late Cretaceous, from about 76 to 66 million years ago.1

?Where did Sphaerotholus live?

Sphaerotholus lived in what is now the western United States and Canada, from New Mexico to Montana and Alberta.1

?How many species of Sphaerotholus are there?

There are five known species: S. goodwini, S. buchholtzae, S. edmontonensis, S. lyonsi, and S. triregnum.1

?Why did Sphaerotholus have a dome?

Sphaerotholus had a thick, bony dome on its skull that it probably used for head-butting contests, like other dome-headed dinosaurs.1

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Myth buster

Myth: Some people think Sphaerotholus used its dome for ramming like a battering ram.

Truth: Scientists are not sure. The dome might have been for head-butting, but it could also have been for showing off to mates or recognizing each other.1

For dino experts

Scientific name: Sphaerotholus
Named by: Williamson and Carr 20032
Group: Dome-heads
Family / clade: Pachycephalosauridae2
Classification: Ornithischia > Pachycephalosauria2
Age of the rocks: 84 to 66 million years (Campanian / Maastrichtian)2
Rock formations: Hell Creek, Kirtland, Frenchman2
Countries: USA, Canada2
Fossil records: 6 in the Paleobiology Database2
Discovery: The first species, Sphaerotholus goodwini, was named by Thomas Williamson and Thomas Carr in 2002 from a partial skull found in New Mexico. The species name honors paleontologist Mark Goodwin.1
Still debated: Scientists still debate whether some species, like S. edmontonensis, are really separate or just the same as others, because their skulls look very similar.1

Where the facts come from

Sphaerotholus (en.wikipedia.org)
Sphaerotholus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.

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