Fishy Hips Show The Transition To Walking On Land Was Simpler Than Thought

It's common knowledge that all land-based animals originated from the primordial sea, but just exactly how still remains a mystery to scientists. According to new research focusing on the some rather fishy hips, the evolution to walking could have started before any of our ancestors even set foot on land.

Scientists taking a look at some of humans' closest fish relatives found some rather strong evidence that the structural integrity needed in the hipbone to walk on dry land began forming while tetrapod ancestors were still swimming.   

"Many of the muscles thought to be 'new' in tetrapods evolved from muscles already present in lungfish. We also found evidence of a new, more simple path by which skeletal structures would have evolved," said study lead author Dr. Catherine Boisvert from the Australian Regenerative Medicine Institute at Monash University.

Tetrapods are believed to have taken their first steps onto dry land around 395 million years ago thanks to two major advancements: strong hipbones to support walking, and a spinal connection through the ilium, the largest and uppermost pelvic bone. After studying the Australian lungfish and the Axolotl, or the Mexican Walking Fish, the team of scientists concluded that the skeletal structures of the fishes could foster the evolutionary change needed to walk on land in fewer steps than was previously thought.

"The transition from ocean-dwelling to land-dwelling animals was a major event in the evolution of terrestrial animals, including humans, and an altered hip was an essential enabling step," Dr Boisvert said.

"Our research shows that what initially appeared to be a large change in morphology could be done with relatively few developmental steps."

You can read the full published study in the journal Evolution and Development.