Name means: Double Cowl
Species: salamandroides, magnicornis, brevirostris, minimus, recurvatus
Range: Permian (Asselian-Wuchiapingian ,303-254 MYA) from the United States and possibly Morocco
Size estimate: 1-3 ft length, 20-60 lbs
Discovery: Edward Drinker Cope, 1877
Classification: tetrapoda, batrachomorpha, lepospondyli, nectridea, diplocaulidae
The Salamander-like Diplocaulus lived during the same epoch as Dimetrodon, in many of the same areas. It seems to have kept to the water for most of its life, so it likely did not cross paths often with the land-living Dimetrodon. Diplocaulus may have been the last surviving member of a primitive group of amphibians known as lepospondyls. Spool-shaped backbones characterized this group. In Diplocaulus' case its spine design may have made it an agile swimmer, though its small limbs may have made it clumsy on land. Some early reconstructions even omitted the limbs altogether.
Diplocaulus' arrow-shaped head has inspired a few theories on its purpose. Some suggest its head acted as a defense. Many predators of the time could not tear prey to pieces, so the width of Diplocaulus' head would have prevented larger animals from swallowing it. Even so, the backwards-facing points could catch in a predator's throat, putting both animals in mortal danger. Other theories describe it as a hydrofoil to help the animal swim in an up-and-down motion like whales and dolphins. Tests in wind tunnels confirm that Diplocaulus could open its mouth to catch prey while swimming without slowing down. A third possibility suggests it helped the animal flush prey out of mud, and may have helped it hide in the mud itself. One controversial fossil described in 1998 suggests a flap of skin attached to the ends of the skull and ran down its body. This flap perhaps helped it swim, or it could have hidden its legs when the animal rested in the mud. Few scientists currently accept this interpretation.