Bone histology and growth curve of the earliest ceratopsian <i>Yinlong downsi</i> from the Upper Jurassic of Junggar Basin, Northwest China.

ABSTRACT: Yinlong downsi, the earliest known ceratopsian, is represented by dozens of specimens of different sizes collected from the Upper Jurassic of the Junggar Basin, northwestern China. Here, we present the first comprehensive study on the bone histology of Yinlong downsi based on ten specimens varying in size. Four ontogenetic stages are recognized: early juvenile, late juvenile, subadult, and adult. The reconstructed growth curve suggests that Yinlong may reach sexual maturity at 6 years old, which is earlier than that of the well-studied early-diverging ceratopsian Psittacosaurus (9 years old) but later than ceratopsids (about 3 to 5 years old). This may indicate that sexual maturity begins earlier during the evolution of ceratopsians, and that the giant size of c

SUBMITTER: Han F 

PROVIDER: S-EPMC11663408 | biostudies-literature | 2024

REPOSITORIES: biostudies-literature