Twenty-three isolated tooth whorls, including holotype IVPP V26641, provide approximately 439 Ma direct evidence of jawed-vertebrate dentition while remaining disarticulated stem-chondrichthyan material rather than a crown-shark body or a global first-appearance datum.
Represented range439–439 Ma
RegionsRongxi Formation, Leijiatun, Guizhou, China
Twenty-three isolated Qianodus duplicis tooth whorls, including holotype IVPP V26641, occur in the late Aeronian Ozarkodina guizhouensis biozone of the Rongxi Formation at approximately 439 Ma and provide direct evidence of jawed-vertebrate dentition; they support a stem-chondrichthyan occurrence, not a crown-shark body, the origin of jaws or a global FAD.
claim:event:early-silurian-qianodus-tooth-whorls
References
The oldest gnathostome teethAndreev, P.S.; Sansom, I.J.; Li, Q.; Zhao, W.; Wang, J.; Wang, C.-C.; Peng, L.; Jia, L.; Qiao, T.; Zhu, M. · 2022 · DOI 10.1038/s41586-022-05166-2