Developmental biology. Lungfish dental pattern conserved for 360 Myr.

Lungfish, the closest living relatives of four-limbed animals, are unique in that adults lack marginal teeth and have to rely on palatal dental plates for crushing food. We have discovered that an identical pattern of tooth development is used to shape these plates in the hatchlings of fossil and living lungfish species that are separated by 360 million years (Myr) of evolution, even though the adults have very different dental forms; the same pattern is also evident in the transient marginal dentition, despite being functional only until the juvenile stage. This remarkable finding indicates that developmental programming for dentition in lungfish is uniform, unique and conserved for all tooth fields.