Amphibious Ancestors
Vertebrates' transition to dry land took some fancy footwork
By Sid Perkins
Imagine a scale-covered fish that uses fleshy limbs that end in fins to haul itself out of the water. Its mosaic of body features also includes sturdy ribs, the first vertebrate neck, and both gills and lungs. Paleontologists recently unearthed fossils of such a creature, which met their expectations for a proposed missing link between fish and the earliest land vertebrates. These relics derive from an era that corresponds to a 9-million-year gap in the vertebrate fossil record.
The new fossils turned up in an Arctic region decades ago pinpointed as a likely location for a transitional creature that would be well adapted to life in the shallows but also mobile on land. Some paleontologists are predicting that the species will become an evolutionary icon as important as Archaeopteryx, the first bird.