Tiktaalik roseae Fossils Reveals Key Link in Evolution of Hind Limbs (video) University of Chicago Medical Center Share Print E-Mail Loading video... Caption Neil Shubin of the University of Chicago presents his latest discovery: The rear portion of Tiktaalik roseae, a 375 million-year-old transitional species between fish and the first legged animals. This finding reveals that the evolution of hind legs actually began as enhanced hind fins and challenges existing theory that large, mobile hind appendages were developed only after vertebrates transitioned to land. The fossils are described online Jan 13 in the Proceedings of the National Academy of Sciences. Credit University of Chicago, Kevin Jiang Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.