An international team of scientists led by Stephanie E. Pierce from The Royal Veterinary College in London and Jennifer A. Clack from the University of Cambridge including scientists from Uppsala University (Sweden) and the European Synchrotron Radiation Facility (ESRF) in Grenoble (France) reported new x-ray examinations of early tetrapod fossils that rewrites present theory of how animals first ventured on to land in the Jan. 13, 2013, issue of the journal Nature.
The majority of tetrapod fossils are in very dense rock. Until now examination of the exact bone structure of the first sea creatures that ventured on to land was limited and produced a variety of arguments among paleontologists and evolutionary biologists.
The high-resolution x-ray images produced by this research revealed that the first tetrapods that made short excursions on land 400 million years ago had vertebrae composed of three sets of bones that were exactly the reverse of the commonly accepted theories.
The first known bony sternum was also identified in the rib cage of Ichthyostega. A bony sternum allowed for added support of the animal's chest and body as it crawled about on land for the first time.
The research was reviewed at the Eureka Alert website the date of publication.