Earliest Land Animals Had Fewer Skull Bones Than Fish -- Restricting Their Evolution, Scientists Find
Published:30 Sep.2022 Source:University of Bristol
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.
Lead author James Rawson of Bristol’s School of Earth Sciences said: “Simply counting the number of bones misses some important data. We used a technique called network analysis, where the arrangement of skull bones -- which bones connect to which -- is recorded in addition to bone number.” The authors found that tetrapods having fewer skull bones than fish made the organisation of their skulls more complex. By looking at the variety of skull bone arrangements over time, the authors also discovered that the origin of tetrapods coincides with a drop in the variety of skull bone arrangements.