"By analysing fossil skulls of animals across the transition from an aquatic to terrestrial environment, researchers from the University of Bristol, Barcelona's Universitat Pompeu Fabra and University College London discovered that tetrapods had more complex connections between their skull bones than fish. And, rather than promoting the diversification of life on land, these changes to skull anatomy actually restricted the evolution of tetrapod skulls.<p>Tetrapods evolved from fish and were the earliest land animals with limbs and digits; the ancestors of everything from amphibians to humans."