There is a parallel here with the hadrosaur and ceratopsian dinosaurs of the Late Cretaceous. Nasutoceratops is an extinct genus of ceratopsian dinosaur. The upper assemblage also has a tyrannosaurid, a ceratopsian, and a pachycephalosaur. Horner stressed that the frill of ceratopsian skulls consisted of metaplastic bone. In ceratopsian dinosaurs, it opposed the rostral bone. This closure distinguishes "Protoceratops" from other ceratopsian dinosaurs. Some researchers even suggested that the talon was used to disembowel large ceratopsian dinosaurs. Adams (1987) suggested that the talon was used to disembowel large ceratopsian dinosaurs. "Triceratops" is by far the best-known ceratopsian to the general public. Early members of the ceratopsian group, such as "Psittacosaurus", were small bipedal animals. "Protoceratops", a type of ceratopsian, also shows signs of sexual dimorphism. Teeth of an unidentified ceratopsian species are known from the same stratigraphic level. The earliest known ceratopsian, "Yinlong downsi", lived between 161.2 and 155.7 million years ago. The spiky ceratopsian/thyreophoran-like, Virtuous Beast who is the god of life. A nocturnal lifestyle has been suggested for the primitive ceratopsian "Protoceratops".