First preserved dinosaur butthole is 'perfect' and 'unique,' paleontologist says

A well-preserved fossil of the dinosaur Psittacosaurus found in China has paleontologists waxing poetic about its well-preserved cloaca.  

The dinosaur's derrire is so well preserved, researchers could see the remnants of two small bulges by its "back door," which might have housed musky scent glands that the reptile possibly used during courtship an anatomical quirk also seen in living crocodilians, said scientists who studied the specimen.