Diplocaulus, aka "Boomerang Head"

The weirdest species the team has found in the Red Beds is the “Boomerang Head,” or, as it's officially known, the species Diplocaulus, meaning "two tailed," a reference to its double-spined tail bones.

It has an extrememly odd-looking body, with a flattened body and legs. The head, however, is pulled out to the sides in the shape of a boomerang - so extremely that by adulthood, the head could be 4 to 6 times wider than it was long. It was armor plated as well, with extremely strong jaws.

Some scientists contend that this shape may have helped Diplocaulus glide through the water - but the flattened lower body could not have contained the muscles of a strong swimmer. It's much more likely that this was an ambush predator, who waited unseen on the bottom of a murky river until unwary prey came along.

It's also possible that the skull served as a defensive mechanism - in which Diplocaulus may have used the points of its head as sideways horns to punch with - or as an aid for mating. Since Diplocaulus' eyes were on the top of its head, finding and impressing a mate by sight would be near impossible. So, a larger skull makes a love connection much more likely.

In any case, it's hard to imagine a predator - even the mighty Dimetrodon - swallowing this easily.

(c) Robert T. Bakker

After Dimetrodon, Diplocaulus fossils are the next most common find at the team's site. They've found pieces of skull - which has a unique shiny, pitted surface that feels very much like it came from a living thing - everywhere they look. They've also found leg fossils and pieces of backbone that show how incredibly strong this species was - perhaps the strongest example of sideways locomotion that's ever evolved.

A piece of Diplocaulus skull discovered at the HMNS site.