Types of Fossils
The word fossil comes from a Latin word meaning “something dug up”. Often the first thing that comes to mind when you hear the word fossils, are dinosaur bones. In reality there are many types of fossils that can be found. They say that fossils can help us learn more about life and evolution. Many fossils that have been found in different parts of the world have been subjected to much study and research. People who study fossils are called Paleontologists.
Main Categories of Fossils
Fossils can generally be classified into two main categories; body fossils and trace fossils. A good example of body fossils are bones, teeth, claws and even skin. Footprints, trackways, nests or toothmarks would fall under trace fossils.
Body fossils reveal what a plant or animal looked like. These are fossilized remains of animals or plants like bones, shells and leaves. Trace fossils on the other hand tell a lot about how an animal lived in its time.
An example of a body fossil. The fossilised animal shown here is Sclerocephalus Haeuseri.
Some Other Different Types of Fossils
Types of fossils can include; mold fossils, cast fossils, trace fossils and true form fossils. Mold fossils are a fossilized impression made in the surface where an organism grows or is attached. Cast fossils are formed when a mold is filled in. Good examples of trace fossils are fossilized nests, burrows and footprints as earlier mentioned. True form fossils are fossils of actual animals, animal parts or plants.
Body fossils like bones have helped shed information about dinosaurs and their existence. Bones and skeletons of dinosaurs have been excavated since 1818. In 1858, an almost complete skeleton was found in New Jersey, USA. Bones of other animals have also been found such as mammoths, ancient fish and other pre historic mammals. It is quite common for fragments of teeth and claws to be found together with the fossilized bones. Some soft tissue such as skin, muscles, tendons, organs and blood vessels have also been found, although these cases are quite rare since soft tissues usually decay before it is fossilized.
Trace fossils have been found in over 1500 sites including coal mines, riverbeds, deserts and mountains. Trackways or set of imprints are usually made in the mud or sand. These fossil footprints have given much information about how many legs an animal had, the bone structure of the foot, their speed and length of stride, the existence of herds and stampedes, their stalking behavior and how they carry their tails. Though many tracks are found, defining the species to which they belong can often be a difficult process. Toothmarks on the other hand were usually found on bones probably from fighting one another or from predators.
Interestingly enough fossilized gizzard rocks have also been found. It is believed that dinosaurs swallowed stones to help break down the food they consumed. These stones are called gastroliths meaning stomach stones and are usually rounded and smooth in texture. Burrows and nests that have been found reveal a lot about behavior and how an animal lived. Even fossilized feces give a lot of information about an animal’s habitat and diet.
Learning about the different kinds of fossils proves advantageous as it has helped in the research of existence and life in pre historic and ancient times.