The Devonian Period






After watching 4.45 billion years of Earth evolution, you might not expect to suddenly meet a turtle-toothed fish the size of a school bus. Introducing Dunkleosteus.

Although microscopic enamel fangs had already evolved among conodonts, chewing teeth were making a new appearance -- on a massive scale. Evolved from dermal plates up to two feet thick, combined with the mechanical power of a true jaw, this animal had a bite that could crush any biological object in the Devonian world. Self-sharpening, scissor-like and anchored by massive muscles, this creature's mandibles ruled the seas.

But Dunkleosteus did not swim alone. The Devonian was the "Age of Fish" -- including kinds whose descendents survive to the present day such as boneless sharks, the lobe-fin coelacanth, and ray-fin fishes that you can find today in Tennessee lakes.

Devonian Earth had created a predator on a ten-thousandth fold scale from Ordovician rivals. But evolution had not stopped on land. Stumbling on thickened fins, one fish had chosen to leave the sea. It would inherit a strange new world of low tropical jungles surrounding a disintegrating supercontinent.

To travel back in time to the Devonian era, visit Parson's Tennessee where you can find exposures of the Birdsong shale, rich in fossils from that time.


Devonian Tennessee
Devonian Tennessee

Devonian Forest
Land plants in the Devonian

Leptaena acuticuspitadaLeptaena acuticuspitada, from Parsons Tennessee