Img: Artist's impression of panderichthys. Credit: D.Bogdanov.
Swedish scientists studying a fish that lived 385 million years ago have made a remarkable discovery that pushes back knowledge as to when fingers and toes first evolved.
It has been long-believed that the first creatures to develop fingers were tetrapods as they made their way from sea to living on land around 10 to 20 million years later.
However, a study by scientists from Uppsala University in Sweden, which has been published in the journal Nature, has shown an early form of finger structure was already present inside the fins of an ancient fish called Panderichthys, which lived mostly in mud pools and rivers and grew to around four feet (130 cms) in length.
"For a long time, we thought that fingers were a novelty for tetrapods," said lead researcher Catherine Boisvert, an evolutionary biologist at Uppsala University.
"In the past two years, some evidence has come forward to make us doubt. It's really the last piece of evidence to say fingers are not new. They were really present in fish," she added.
The precursor to fingers was hidden behind the skin and scales of the fish, which probably used them for support rather than all-out swimming, claimed the team.
"It was probably using its front fins as supports to be able to look up, kind of doing push-ups at the bottom of the river looking outside with its eyes," Boisvert said.
The study is a landmark in evolutionary biology, with its confirmation that fingers were already developing in fish prior to their move to land.
"It is an important piece of evidence for the evolution of fish to tetrapods and how 'we' transformed from fish to land animals," said Boisvert.