Pentaceratops was a slightly older relative of Triceratops. This dinosaur was roughly 23 feet long and weighed close to 3 tons. Like most ceratopsians, Pentaceratops had a fantastic arrangement of horns and a very tall frill. In fact, Pentaceratops had one of the tallest frills of any ceratopsian. These dinosaurs lived in North America about 80 million years ago.