Middle Permian pareiasaurs (IMAGE) California Academy of Sciences Caption The plant-eating pareiasaurs were preyed on by sabre-toothed gorgonopsians. Both groups died out during the end-Permian mass extinction, or "The Great Dying." Credit © Xiaochong Guo Usage Restrictions Photos available for editorial use only. Credits mandatory. License Licensed content 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.