Named By: White - 1939.
Classification: Chordata, Tetrapoda, Amphibia, Labyrinthodontia, Reptiliomorpha, Seymouriamorpha, Seymouriidae.
Species: S. baylorensis, S. sanjuanensis, S. graandis.
Size: 60 centimetres long.
Known locations: USA, Texas, Utah. Germany.
Time period: Early Permian.
Fossil representation: Numerous well preserved specimens, including two laying side by side.
Although it had several reptilian features, Seymouria was actually an amphibian. This creature displays a strong backbone and muscle growth for movement on land, and hearing adapted for use out of water. It’s possible that its preferred form of locomotion would have been a side to side undulating motion like modern lizards, this action would increase the reach of the limbs. Despite these adaptations it has been hypothesised that Seymouria still had to return to the water for spawning. There appears to be some sexual dimorphism in that males had thicker skulls.