Are there any fossils of dinosaur skin?

The rarest types of dinosaur fossils are those showing skin texture but not the actual skin itself. This is because of the fossilization process: the body of the dinosaur needs to be in a dry environment and some soft parts mummify; then the mummified parts leave an impression on the rock, and this is very rare.

The few fossils of dinosaur skin uncovered to date show that most dinosaur skin was tough and scaly, like modern reptiles. For example, there was the tough, wrinkled skin with bony plates of the Cretaceous period hadrosaur Edmontosaurus. Similar to the hadrosaurs, ornithopods had thick, wrinkled skin with embedded bony knobs of various sizes. Some small theropods, like the recently discovered Sinosauropteryx, may have had feather-like features on its skin for heat regulation.

What dinosaur skins have recently been found?

There have been several discoveries of dinosaur skin in recent years. One was discovered several years ago by a teenager on his family ranch in North Dakota: a 67 million-year-old hadrosaur (duck-billed dinosaur) with actual fossilized skin, complete with scales and a suggestion of stripes. The dinosaur mummy was found in southwestern North Dakota in 2004; to date, it is one of only about four dinosaurs ever found with fossilized skin. Another one was found in China, complete with a tear caused by a predator. It also shows that below the scales of this Psittacosaurus was a thick hide comprised of 25 layers of collagen, which is thought to be similar to modern shark skin.

Because it decays quickly, there are very few examples of dinosaur skin that have been fossilized. The impression samples that survive have provided dues, such as the possibility that some dinosaurs had feathers (iStock).

Did all dinosaurs have the same type of skin?

The amount of fossilized skin uncovered to date is extremely small, and most of our ideas of dinosaur skin come from extrapolation from modern reptiles. The chances of all dinosaurs having the same skin is probably small, since, over millions of years, these animals adapted to their environment and specialized needs.

Todays reptiles do not have the same types of skin, either. Reptilian skins vary from a lizards protective covering of scales or plates to the hard bony shell of turtles all different adaptations to their specific needs and environments.

Have any dinosaur embryo skin impressions been found?

Yes, for the first time ever, the skin impressions of dinosaur embryos have been discovered at a large nesting site in the Patagonian badlands of Argentina, South America. The eggs at the site nicknamed Auca Mahuevo (huevo meaning egg) by paleontologists because of the large number of dinosaur eggs found there are approximately 70 to 90 million years old, placing them in the Late Cretaceous period. Some of the eggs contained embryos, with patches of fossilized baby dinosaur skin. The skin had a scaly surface, similar to that of modern lizards. One skin impression had a distinct stripe of larger scales near its center, a section that probably ran down the dinosaurs back.

Have any other soft parts of dinosaurs been found?

Yes, some soft parts impressions of dinosaurs have been found in the past, but they are rare. Plus, some fossils display the outlines of internal organs; and some animals have fossilized remains inside them of what the dinosaur had just eaten. One of the most exciting discoveries is housed in the North Carolina Museum of Natural Science: the first-ever discovery of traces of a dinosaur heart in a fossil nicknamed Willo. This dinosaur was a member of the group known as Tescelosaurus (marvelous lizard, living about 66 million years ago), a 600 pound, hog-like plant eater about the size of a pony. Its long, bony tail gave it a total length of about 13 feet (4 meters).

Using special equipment to see inside the dinosaurs body, researchers developed a three-dimensional view of the heart. The organ had four highly developed chambers and a single arched aorta. This one discovery found in North Dakota changed the way many scientists look at dinosaurs. In particular, it provided evidence that some of the long-extinct beasts were quick and possibly warm-blooded like birds (a complex heart is usually indicative of a high metabolism), not slow and plodding like some contemporary reptiles.

What dinosaur fossil found in Italy showed the remnants of soft parts?

The fossil of a small, baby carnivorous dinosaur hardly more than a hatchling was announced in Italy in the 1990s. The dinosaur was actually found by an amateur collector in the southern part of the country in 1981, but he thought it was just the fossil of a bird. In 1993, the fossil collector saw the movie Jurassic Park and realized his fossil looked very similar to the movies Velociraptor (in reality, true Velociraptors were smaller). In 1998, after the fossil was examined by paleontologists, it was determined to be the bones of a young dinosaur; it was also the first dinosaur ever discovered in Italy.

This dinosaur, called Scipionyx samniticus, is about 113 million years old. Although it is a distant cousin of both the Tyrannosaurus rex and Velociraptor, it is considered to belong to an entirely new family. The fossil also shows something that usually does not survive millions of years of fossilization: soft parts, including a fossilized digestive tract running through the skeleton, from the throat to the base of the tail. Even the wrinkles in the dinosaurs intestines were preserved.

Is there any evidence of sickness in dinosaurs?

Yes, there has been a great deal of evidence of dinosaur illnesses. For example, fossils of a dinosaur called Gilmoreosaurus showed, in 2003, evidence of a tumor, as well as hemangiomas, metastatic cancer, and osteoblastoma all major illnesses in organisms. Several other hadrosaurids, including Brachylophosaurus, Edmontosaurus, and Bactrosaurus, also showed many of these diseases in various studies.

Scientists are still speculating on why the dinosaurs had such problems. They could have stemmed from anything from environmental factors to a genetic propensity toward the diseases.

What color or colors were the dinosaurs?

No one, as yet, has been able to tell anything about the color of a dinosaurs skin. The skin fades as it is mummified, and the rocks eventually lend their own color to the fossil. But paleontologists theorize that dinosaurs, like some modern animals, used color and patterns to camouflage and identify themselves. Therefore, dinosaurs skin colors probably ranged from light and dark browns to greens in various patterns all earth colors, allowing them to hide or blend in with their environment.

But there may have also been brightly colored, smaller dinosaurs. After all, todays birds thought to be directly related to the dinosaurs by many paleontologists are often brightly colored in order to attract a mate or warn other birds (and even predators) away from their territory. Many scientists believe the dinosaur fossils being found with feathers some with traces of feather pigment may one day lead to knowledge about dinosaur colors.

There is also some evidence that crocodiles and birds, the closest living relatives of dinosaurs, may have color vision. This suggests that dinosaurs may have responded to colors in their environment, especially bright colors for territorial or mating displays or for identifying prey more easily. Its also interesting to note that crocodiles with color vision are themselves not brightly colored at all.

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