Evolution is arguably the most solid theory in modern biology. It has represented the foundation of biological research for centuries now and it’s still the basis over which many present day discoveries are made. Take the human teeth for example: its usefulness is undeniably linked to our evolution as a big, solid food churning species and its appearance is a solid indicator of the evolution of biological processes throughout species. Previous methods of food deconstruction involved a sandpaper like mouth but the Placoderms, a group of fish living some 400 million years ago are believed to be the first to exhibit bony jaw structures. It was thought that these fish had what you’d call “real teeth” but recent analysis from the Australian National University, which employed 3D printing and 3D scanning of a Buchanosteus fish fossil revealed evidence that the group could have represented a transitional link.

This interesting biological breakthrough was conducted by Australian National University (ANU) researchers Gavin Young and Yuzhi Hu, and Dr Carole Burrow from Queensland Museum. The results have already been published in the journal Biology Letters. Entitled ‘Placoderms and the evolutionary origin of teeth: a comment on Rücklin & Donoghue (2015)’, the paper is disputing the real teeth conclusions of an article published in that same journal a year ago. The study itself was funded by the Australian Research Council.

The scanning and reconstruction were based on very rare skull and braincase fossils of the Buchanosteus which have been found in the area surrounding Lake Burrinjuck in southeast Australia. Dating back to the Early Devonian period, the species has been compared numerous to the earlier placoderms and also the jawed fish of more distant relationship.The samples retrieved from the excavation site were unfortunately too badly preserved to provide a full picture to the researchers. Nonetheless, by means of CT 3D microscanning techniques and subsequent 3D printing of the missing parts, researchers were able to prove that the Buchanosteus had a more primitive set of teeth than was assessed in previous studies.

“It's great that we are able to use recent technology, such as micro-CT scanning and 3D printing, to examine some of the earliest known evidence of tooth-like structures in the most primitive jawed fishes,” told Carole Burrow. 3D printing enabled the researchers to model the jaw structures of exceptionally intact fish samples, enlarge the system six fold and study how the whole mechanism moved and functioned.

Putting the breakthrough into perspective, the real value of these new notions resides in the larger scope question of how teeth structures came to be in all vertebrate species, including humans. “We are conducting further research on the internal tissue structure of tooth-like denticles in the mouth of the fish fossil, to determine whether they represent a transitional stage in the evolution of teeth,” says Gavin Young, paleontologist at the ANU Department of Applied Mathematics.

You can read more about the study in the detailed press release.