Ancient fish fossil sheds details on human hand evolution

Scientists from Flinders University in Australia working with a University from Canada have discovered what they say is the first fish specimen that has shined a light on what they term as a missing evolutionary link in the fish to tetrapod transition. The fossil is from an ancient species of fish called Elpistostege, and it was discovered in Miguasha, Canada. The team says that it yields insights into how the human hand evolved from fish fins.

Fish first began to move on to land during the late Devonian period millions of years ago. The complete fish fossil is 1.57 meters long and shows a complete pectoral fin skeleton for the first time in this fish species. The team used high-energy CT-scans to look closely at the skeleton of the pectoral fin.

The skins revealed the presence of a humorous, radius, and ulna. The team also found rows of carpus (wrist) and phalanges (fingers) and scan. Scientists say that this is the first time that there has been an unequivocal discovery of fingers like to fin with fin-raise in any known fish.

The team says that the articulating digits in the fin are like the finger bones found in the hands of most animals. The discovery pushes the originals of digits in vertebrates to the fish level and tells us that the patterning for the vertebrate hand was first developed this before fishes left the water.

Similar study in the past was based on incomplete skeletal specimens. The complete specimen sheds much more light on the fish species. Scientists say that while Elpistostege is the closest, we can get to a true "transitional fossil" of an intermediate between fishes and tetrapods.