Protylopus is a really old animal that lived a long, long time ago. It was kind of like a horse, but not exactly. It lived about 30 to 40 million years ago, way before people were even around!
You know how horses have really long legs and hooves? Well, protylopus had shorter legs and toes that were more like small hooves. They also had teeth that were good for chewing on tough plants.
Protylopus was one of the first animals that people think might have been related to horses. Over a really, really long time, animals like protylopus changed and evolved to become the horses we know today! Pretty cool, right?