Another fish to tetrapod transitional

Tiktaalik, found exactly where a tetrapod transitional was predicted in the fossil record, in exactly the geological formation predicted, was a spectacular find of a fish to tetrapod transitional.

Now comes another earlier find and the first of a tetrapod transitional in Australia. Dated to 380 million years ago, Gogonasus is fantastically well preserved in 3-D, and the team have used X-ray tomography and other new techniques to reveal fine detail of the skeletal anatomy. While still a fish, it shows some characters that begin to show a transition to the tetrapod form, particularly in the ears and in the limbs.

Gogonasus lies quite early in the fish to tetrapod transition. Fish that are more derived, ie closer to tetrapods are known from Europe and America (Pandericthys and Tiktaalik) but none are known from the Godwana supercontinent. However, early tetrapods are known from Godwana. The authors therefore predict that fossils of fish closer to tetrapods than Gogonasus will be found in Australia to parallel Tiktaalik from Eurasia. They have set off to test this prediction by exploring Devonian formations – who said that palaeontology makes no predictions?