Australasian Science: Australia's authority on science since 1938

Fish Fossil May Reveal Origin of Human Teeth

Three-dimensional prints of a 400-million-year-old fish fossil from around Lake Burrinjuck 50 km north-west of Canberra reveal the possible evolutionary origins of human teeth, new research has found.

Researchers at The Australian National University and Queensland Museum digitally dissected the jaws of Buchanosteus – an armoured fish from the extinct placoderm group – and used the 3D prints to learn how the jaws moved and whether the fish had teeth.

Dr Gavin Young of the ANU’s Department of Applied Mathematics said the study helped determine when and how teeth had originated in evolutionary history.

“We have used CT scanning facilities at ANU to investigate the internal structure of very fragile fossil skulls and braincases that have been acid-etched from limestone rock,” he said. “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.”

The research, published in Biology Letters, contradicts research published last year suggesting that the extinct placoderms had real teeth.

“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,” said Dr Carole Burrow of Queensland Museum.

“Placoderms have been a common focus in the question of tooth origins. Our team has been able to examine the gnathal plates of placoderms from the Early Devonian period, and compare their internal and external structure with those of younger placoderms as well as with the true teeth in other jawed fishes.”