Dino card No. 1686 of 2,015

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

Artist's life restoration of Sphaerotholus — How Sphaerotholus may have looked, by ABelov2014 (https://abelov2014.deviantart.com/). CC BY-SA 3.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

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

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 to 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 hello@dinowiki.app and we will fix it.