Dinosaur species and six-year-old humour

Like many children nowadays, our Theresa grew up watching Barney and Friends on video and television. Given that preschoolers are the targeted demographic of this programme, Theresa hasn't watched it for some time. However, yesterday she tried, with only partial success, to identify which species of dinosaur three of the characters might be. She postulated that Barney is a tyrannosaurus rex, which is confirmed here. She couldn't quite manage to identify BJ and Baby Bop, although BJ is generally said to be a protoceratops. Baby Bop is variously identified as a protoceratops or a triceratops (even though she is ostensibly sister to BJ).

By the way, what was the ugliest dinosaur of all?

Answer: The eyesaur.