Measuring 7.5 meters in its length and standing 2.5 meters tall, the Pentaceratops was one of the largest ceratopsid dinosaurs. Unlike the more famous Triceratops, the Pentaceratops had a five-horned skull. All ceratopsids had a powerful frill, which was probably little used to defend themselves. In all likelihood, the Pentaceratops had the largest known skull of all land-living animals. Quite a thick skull.