About half of the dinosaurs in the Late Triassic may have never existed. Paleontologists have announced the discovery of an approximately 210-million-year-old skull belonging to a creature known previously only by scattered teeth in the American Southwest. The skull casts doubts on the early history of one of the two main branches of the dino family tree. If the doubts prove true, it would make the Late Triassic sort of like the Hatfields without the McCoys or the Montagues without the Capulets. Revueltosaurus callenderi was thought to be the only confirmed North American member of the early ornithischian (pronounced "OR-nith-ISH-ee-in," and meaning "bird-hipped") dino group. Its existence had implied that ornithischians were evolving right alongside the other big branch in the dino family: the saurischians ("SOAR-ish-ee-ins," meaning "lizard-hipped").

One was probably often prey to the other, in fact. The ornithischians gave rise to stegosaurs and triceratops, while the saurischians evolved into long-neck plant eaters, tyrannosaurs and modern birds. But the newfound Revueltosaur skull has revealed that all those scattered teeth lied: Revueltosaur isn't even a dinosaur. It's a sort of crocodile. "We're definitely going back to square one," said William Parker, paleontologist for Petrified Forest National Park's in Arizona. "We know this material can't be assigned to ornithischian dinos."

View: Full Article | Source: Discovery Channel

I just want to point out a couple of things before somebody tries to use this post in the usual Evolution Vs Creation argument that typically arises when the fossil record is in question.


1) First of all the statement "About half of the dinosaurs in the Late Triassic may have never existed" is not exactly accurate.

A more accurate statement would have been that they "may have been misidentified" the creatures obviously existed or else we wouldn't have their teeth

Also, we are talking about only North American Late Triassic ornithischians,
which are all classified exclusively on teeth. There are 2 other reasonably well-confirmed Late Triassic ornithischians that have been found in other parts of the world.

2) This only goes to point out the fact that as of yet, we are far from having a complete fossil record to work with.

As a result, when new discoveries are made, additional knowledge is gained, examined, tested, and the previous information is reevaluated to ensure that our interpretation of the fossil record is as accurate as possible.

The Late Triassic pseudosuchian Revueltosaurus callenderi

Thank you Shaftsbury