Remains of what was probably the most primitive four-legged creature in Earth’s history were discovered by Swedish scientist. The 370-million-year-old skull, shoulder and pelvis bones of the creature which seems to have been a walking fish shed light on the times and the way our ancestors began a new life on terra firma.

The discovery will very probably help scientists better understand the evolution process and more precisely the period when the fish slowly transformed into advanced animals that walk on land.

The bones of the water-dweller, Ventastega curonica, were found in Latvia and the findings were published in Thursday's issue of the journal Nature. The fossilized bones belong to a creature which had the head of a tetrapod and the body and fins of a fish-like animal - Panderichthys scientists said.

In the study, Ventastega curonica was described as a creature with an ample jaw and razor-like teeth, body parts which show that it was a ferocious predator the size of an adult crocodile. The creature was perfectly adapted for a predator. It also had primitive flippers, which allowed it to explore shallow marshes for prey.

"I imagine this is an animal that could haul itself over sand banks without any difficulty. Maybe it's poking around in semi-tidal creeks picking up fish that got stranded," said lead author Per Ahlberg, a professor of evolutionary biology at Uppsala University in Sweden.

The discovery suggests the fact that the early amphibious animals of the Late Devonian period didn’t evolve in a simple linear fashion but diversified along differing branches.

"It is tempting to interpret Ventastega as a straightforward evolutionary intermediate. However, this simple picture should be approached with a degree of caution," the authors of the study said.

Ventastega's remains were unearthed by a team of paleontologists of Uppsala University led by Per Ahlberg. Latvia is located in a region which once was part of a swampy, semi-tropical continent straddling the equator.