Restoration diagram of early ceratosaurus (left) and triceratops (right) and comparison diagram of mandibular teeth morphology. (Photo provided by the interviewee)
Skull, tooth perspective and maxillary tooth reconstruction of early ceratosaurus. (Photo provided by the interviewee)
The researchers found that the tooth characteristics of the early Ceratosaurus were completely different from that of Triceratops: the early Ceratosaurus had very few replacement teeth, which indicated that the tooth changing speed of the early Ceratosaurus was much slower than that of the late Triceratops. The position of new teeth growth in early ceratosaurus was also different from that in Triceratops. Triceratops' new teeth grew from the bottom of the old teeth, while the early ceratosaurus' new teeth grew from the inside of the old teeth.
Why are the tooth systems of early Ceratosaurus and Triceratops so different? Han believes that the early Ceratosaurus was small in size. For example, the body length of Cryptosaurus tanguticus was only about 1.2 meters, while that of Triceratops was about 9 meters. The increase in size led to a greater demand for food and higher requirements for teeth in Triceratops.
"Triceratops' teeth are very complex, which enables them to fully chew food in their mouths, while the teeth of early ceratosaurus are very simple and may only have the function of cutting plants. Different functions also lead to different dental systems. " Han Lufeng added that gastroliths were also found in cryptosaurus Downs and another early ceratosaurus, which indicated that they probably swallowed pebbles into their stomachs to aid digestion like modern birds, which made their teeth bear less pressure and wear more slowly.