Researchers say they've discovered a walking fish, thanks to fossils unearthed in Canada during the mid-2000s.

The hind fins of a 375-million-year-old Tiktaalik roseae, found in the Canadian Arctic in 2004, offer the scientific community some of the best insight to date of the transition of water creatures to land, according to new research published in the Proceedings of the National Academy of Sciences.

The first fossils found were from the ancient animal's front half, including its skull, shoulders and front fins.

The creature's rear portion stayed somewhat a mystery until recently. Scientists uncovered the creature's pelvis only after a second more recent excavation, described in the latest study, the Washington Post reported.

"This is an amazing pelvis, particularly the hip socket, which is very different from anything that we knew of in the lineage leading up to limbed vertebrates," study co-author Ted Daeschler, associate curator of vertebrate zoology at the Academy of Natural Sciences of Drexel University, told the Post. "Tiktaalik was a combination of primitive and advanced features. Here, not only were the features distinct, but they suggest an advanced function. They appear to have used the fin in a way that's more suggestive of the way a limb gets used."

Current evolutionary theories suggest early animal walkers used their forward limbs for movement while hind limbs were small and were not involved in that function.

The new finding challenges that belief and forwards a more compelling notion: that mobile hind appendages developed even before vertebrates transitioned to land.

"These are four-wheel-drive animals, not just front-wheel-drive only," Daeschler said.

"It looks like this shift actually began to happen in fish, not in limbed animals," research co-author Neil Shubin, a professor at the University of Chicago, also said in the Post story.

It's assumed the Tiktaalik looked like a mix between a crocodile and shark and could grow up to nine feet long. Boasting sharp teeth and a flat head, the creature had gills, scales and fins, a movable neck, a strong ribcage and primitive lungs.

The Tiktaalikt also had strong fore fins, shoulders, elbows and partial wrists to support itself on the ground.