pterodon

This is exhibit is right up our alley. For the next few months, the Pittsburgh Museum of Natural History is displaying strange prehistoric critters as part of its "Bizarre Beasts" series. Descriptions provided by the Museum.Helicoprion A coil of teeth caps the lower jaw of a sculpture of a 13-foot (4-meter) whorl-tooth shark, or Helicoprion, a fish genus that lived about 250 million years ago. Artist Gary Staab depicts the animal's jaw as something of a spiral conveyor belt, in which new teeth would advance to replace old ones (concealed here by skin) . But the true arrangement and…