Science / Medicine : Gills Found in Ancient Land Animal

British researchers have found evidence of fish-like gills in a 360-million-year-old salamander-like creature, suggesting that the first backboned animals to walk on land lived more like fish than scientists thought. The discovery, reported last week in the British journal Nature, will force a re-examination of ideas about the evolution and ecology of the earliest four-limbed vertebrates, one expert said.

It shows that those creatures, although looking like regular land-dwellers, actually were “fish with legs,� said paleontologist John Bolt of Chicago’s Field Museum.

Michael Coates and Jennifer Clack of the Cambridge University Zoology Museum said they found evidence of the gills while examining anatomical features of Acanthostega gunnari, a creature that is one of the earliest known four-limbed vertebrates.

Although the creature probably also had lungs for use on land, the evidence of gills suggests it was “primarily aquatic,� the researchers wrote. Bolt said four-legged animals with gills had never been observed before.