Sphaerotholus is a group of dinosaurs that lived during the Late Cretaceous period, around 76 to 66 million years ago. These dinosaurs fall under a special type called pachycephalosaurs, known for their unique dome-shaped skulls.
**Where They Were Found**
Sphaerotholus dinosaurs were discovered mainly in the western United States and Canada. So far, five different species have been identified.
1. **Sphaerotholus goodwini** was found in New Mexico.
2. **Sphaerotholus buchholtzae** comes from Montana and Saskatchewan.
3. **Sphaerotholus edmontonensis** was located in Alberta, Canada.
4. **Sphaerotholus lyonsi** also comes from Alberta.
5. **Sphaerotholus triregnum** was found in Montana.
The name “Sphaerotholus” comes from Greek. It combines “sphaira,” meaning “ball,” and “tholos,” meaning “dome.” This reflects the distinctive round shape of their skulls.
**Discovery and Learning**
The Sphaerotholus group has been around for millions of years, showing they were widespread and survived various changes in their environment.
When paleontologists first described these dinosaurs, they highlighted specific features that set them apart from others. For example, they identified unique shapes and arrangements of bones in their skulls.
**Different Species**
– **Sphaerotholus goodwini** has a skull that lacks some facial bones. It was named after the paleontologist Mark Goodwin.
– **Sphaerotholus edmontonensis** had notable horns on its dome and was similar in size to a small car.
– **Sphaerotholus buchholtzae** was recognized for a particular bone structure on its skull as well, and it honors a researcher named Emily A. Buchholtz for her work in the field.
– **Sphaerotholus lyonsi**, which was only recently described, features a double row of bony nodes on the back of its skull.
– **Sphaerotholus triregnum** has a triple row of small bony nodes, which gives it a unique appearance and was named for looking like a crown.
**Classification**
Sphaerotholus is classified within the family of pachycephalosaurs, a group known for their thick skulls. Recent studies have shown that all the species in this group share many similarities.
Sphaerotholus gives us a fascinating look at how dinosaurs lived and adapted in their environments millions of years ago. These dinosaurs are special not just for their appearance but also for what they tell us about life on Earth during the age of dinosaurs.