RIGA - Swedish scientists based in Latvia have discovered the most primitive four-legged animal in world history. Part fish, part land creature, this 365 million year old tetrapod fossil gives scientists new information about pre-historic animals and sheds new light on evolution as we know it.
Professor Per Ahlberg of Uppsala University who led the project told The Baltic Times about the importance of the discovery.
"The transition from fish to land animal is relatively unknown, and examples like this represent the earliest kinds of land animals and gives us a broader picture of our own evolutionary transformation."
The discovery was named Ventastega Curonica after the Venta river and the old name for the Latvian province Kurzeme, Courland.
Ventastega would have looked like a small alligator with fins. It was able to survive in water as well as crawl over land, probably living in shallow waters. The creature would have existed about 100 million years before the dinosaurs.
Scientists think it is unlikely that other creatures evolved from the Ventastega. Ahlberg stated that they "believe that the species just died out on its own. It's only a short side branch that leads to an even bigger part of the evolutionary scale," he said.
Ahlberg and his team didn't find limbs intact on the fossil, but deduced that the creature must have had them due to certain pelvic and shoulder placements. Scientists are still trying to determine why fish began to develop legs, and hopefully the Ventastega will be able to help them answer those questions.
Scientist believe that the Ventastega is important not just for basic evolutionary theory but for dispelling the idea that animals descended linearly. The discovery shows that animals develop independently of each other and at varying rates branching off into subspecies.
The quality of the Latvian fossils pleased the scientists as they were extremely well preserved. Ahlberg believed that the quality of the fossils is due to the geological characteristics of the area.
"This region has had a very quiet geological history since that time, and as a result the rocks have not been folded or squashed up to form mountains.
"We still find sediments not yet properly turned to rock. These fossils were found in compact, wet sand. It's not sandstone, it's sand; you dig it with a bread knife," Ahlberg said.
Tetrapods were thought to have evolved from shallow fresh water habitats near the end of the Devonian period, 365 million years ago. Tetrapods have four feet and a vertebra. Snakes, amphibians and mammals including man are all tetrapods by descent. Tetrapods evolved at different times all over the world as proved by the famous Tiktaalik fossil found in Canada.
Regarding further research, Ahlberg said: "together with colleagues in July we are going into the field again to a different location in Latvia to try and find older rocks and even more primitive species to support our research."
