Fossil fish discovery reveals origins of limbs

A recently discovered prehistoric fish is believed to exhibit an early precursor to modern arms and legs.

The 375-million-year-old Tiktaalik roseae fossil was discovered by three palaeontologists in the Canadian Arctic and possesses skeletal features, including limb-like fins and large pelvic bones, that are remarkably similar to those found in modern land animals.

This prehistoric crocodile-like fish is likely to have been a transitional species, bridging the gap between animals that lived in the water and animals that lived on the land. Its fins even possess primitive elbow and wrist-type joints.

"That wrist you use to write with, the neck you use to move your head around with, the lungs you’re using to breathe... all derive from parts in the bodies of fish," said Prof Neil Shubin. "Your hands and arms derive from parts of the fins."

It isn't clear at exactly what point Tiktaalik would have been able to emerge from the water and move about on land, but it is thought that it would have been capable of squirming across shallow water, a bit like a mudskipper.

"What the fossil record tells us is how deeply we are connected to life on the rest of the planet. In this case, this tells us how closely we are related to fish," said Prof Shubin.