Into the Gap: Fossil find stands on its own four legs
By Sid Perkins
A fossil originally misidentified as an ancient fish turns out to be the nearly intact remains of a four-limbed creature, perhaps one of the first to walk on land. The find is particularly important because it dates from an era noted for its dearth of terrestrial fossils that illuminate the evolution of the ancestors of today’s amphibians, reptiles, and mammals.
There’s been plenty of fossil material for studying the evolution of some fish into early four-legged animals, or tetrapods. However, aquatic vertebrates with rudimentary legs disappear from the fossil record about 360 million years ago, says Jennifer A. Clack, a paleontologist at the University Museum of Zoology in Cambridge, England. Well-preserved tetrapod specimens don’t turn up again until about 20 million years later, when many animals with modern-style limbs were strolling the planet.