Overview
- The peer‑reviewed study, published in the Swiss Journal of Palaeontology by Kate Trinajstic, John Long and Vincent Dupret, identifies the deep-time onset of tooth root resorption.
- High‑resolution imaging at the Australian Synchrotron (ANSTO) shows vascular canals and spongy bone invading dentine inside older teeth, consistent with internal resorption.
- A growth series of Bullerichthys fossils documents increasing tooth-row counts through life, linking developmental changes to inferred replacement mechanisms.
- Shallow pits beneath each oblique tooth row contain newly formed teeth, interpreted as sites of a dental lamina comparable to that in modern bony fishes.
- The authors conclude placoderm dental development aligns more closely with living bony fishes than previously thought, reshaping models of early vertebrate dentition.