| [ Summary ] |
Aspidin, the most primitive vertebrate calcified tissue, had acullular structures without any cell inclusion inside the tissue. More evolved advanced forms of aspidin included aspidinocyte (osteocyte-like cells) in the calcified tissue. These advanced types had osteon-like structures and cement lines, suggesting remodeling of aspidins. This suggests that osteocytes in present vertebrates originated from aspidinocytes. Recently, several reports have demonstrated that dinosaur fossils are available to protein and genomic analyses, and their osteocytes are important targets for further study. |