Dino Discovery: An Amazing, All-Purpose Body Part

It’s one of the most amazing dinosaur body parts that scientists have ever found. No, we’re not talking about the giant, dagger-like teeth of T. rex, the mighty clubbed tail of Ankylosaurus, or the super-long neck of Apatasaurus.

We’re talking about a little dinosaur called Psittacosaurus and its remarkable rear.

Amazing discovery

Decades ago, paleontologists — the scientists who study life long ago — unearthed the special Psittacosaurus (SIT-eh-keh-SOR-us). The beaked leaf-eater lived 120 million years ago in an area that is now northeastern China. It was about the size of a golden retriever, had horns on the sides of its head, and sported a bristly tail.

Most of the time, paleontologists find only the fossilized skeletons of dinosaurs. Bones and teeth take longer to decay, so they have a better chance of becoming fossils than an animal’s soft parts. But on rare occasions, scientists find a dinosaur body that still has bits of soft tissues, such as blood vessels, feathers, or skin.

This Psittacosaurus was one of those rare finds. It was in incredibly good shape and even had bits of scaly, reddish-brown skin on it. It also had an intact tush.

OK, if you want to get all scientific about it, the proper term is “cloacal vent.” The vent is the opening under the animal’s tail, and the cloaca (kloh-EY-kuh) is the muscular chamber, or space, behind it. Early scientists didn’t seem to be too impressed with the body part; the word “cloaca” is Latin for “sewer.” But the paleontologists who recently studied the Psittacosaurus were excited to find it. As far as anyone knows, it’s the only dino rear ever discovered.

Multitasker

And, wow, is it amazing! It did lots of things for the little dino. That has helped scientists learn about how the dinosaur lived and how similar or different it was to other animals.

For example, most mammals — including humans — have separate holes for going Number 1 and Number 2. That’s not the case for other animals, like birds, reptiles, and amphibians. Like other reptiles, Psittacosaurus’s cloaca did everything the dino needed to do: peeing, pooping, laying eggs, you name it. (But, no, not eating or breathing. It had a mouth and nostrils for that.)

Paleontologist Jakob Vinther, who studied the rear, used an analogy to explain its multipurpose wonders to Popular Science magazine: “It’s the Swiss army knife of back ends.”

Even among the other animals that have a one-hole-for-everything body part, Psittacosaurus’s cloaca still stands out.

Singular style

The little dino’s backside was not shaped like any other animal’s — and the researchers checked. Biologist Diane A. Kelly, a member of the research team and an expert on animals’ rear ends, told the New York Times that most cloacal vents just look like slits or rounded holes, sometimes with wrinkly skin or scales around them.

Psittacosaurus’s rear was more of a V-shape and darker colored than the rest of its body. Scientists think the color probably helped get the attention of possible mates—much like the bright-red rears of baboons.

Crocodiles, whose rears are a bit similar to Psittacosaurus’s, also have special scent glands used to woo a mate. The researchers think Psittacosaurus may have been able to release its own dino-pleasing perfume, too.

The researchers were so delighted with the discovery of the dinosaur derrière that they were even happy to find a little piece of poop in it. (No worries. It was fossilized and as hard as a rock.) They asked artist Robert Nicholls, who specializes in dinosaurs, to draw Psittacosaurus and reconstruct a 3D model of the dino.

If you’re ever in Frankfurt, Germany, you can check out the dino’s brilliant body part yourself. It’s on display at the Senckenberg Natural History Museum with other amazing discoveries.