The Oldest Known Dinosaur

A fossil that’s been lying around in a British museum for years has now pushed back the earliest known existence of dinosaurs by an estimated ten to fifteen million years.
The fossil was originally discovered in the 1930s by Rex Parrington of Cambridge University near Lake Nyasa, now known as Lake Malawi, in Tanzania. It is now being called Nyasasaurus parringtoni in honor of the discovery. It has been kept at London’s Natural History Museum for decades. A study conducted in the 1950s was inconclusive, but advancements in paleongology in the intervening years has allowed researchers to better understand fossils such as this one.

Although the fossil is fragmentary, investigators were able to identify several features that they say are common to dinosaurs. The bones show marks of rapid growth, which is common to dinosaurs, and the upper arm muscles were anchored to the bones by an elongated deltopectoral crest, which is unique in dinosaurs. Its hips also display features only known in dinosaurs.

Researchers believe Nyasaurus probably stood upright and measured 7 to 10 feet (2 to 3 meters) from head to tail. It likely weighed about 45 to 120 pounds (20 to 60 kg). Evidence so far indicates that it sported a long neck and tail.

A similar fossil has since been discovered at the Iziko South African Museum in Cape Town, South Africa. Researchers are planning field work in Tanzania in the hope of finding more fossils. They hope to find more evidence to better understand this animal’s anatomy.

Although dinosaurs are associated with the Jurassic Period, it has long been argued by some theorists that they or their predecessors had to have been living at least as far back as the Middle Triassic period, which ended about 237 million years ago. Nyasaurus has now provided the best evidence for the validity of the theory.

The world of Nyasaurus was very different from that of the later dinosaurs. The world’s continents were still joined together in a great landmass called Pangaea. At that time, what is now Tanzania would have been located in the southern part of the supercontinent. South America, Africa, Antarctica and Australia were all located in the general area at that time.

Nyasaurus was dated based on the age of the rock layer in which it was found, along with the ages of the layers both above and below the location of the find. They also compared the ages of these rock layers with others located around the world which contained similar animal remains.

Perhaps this discovery will encourage researchers to watch for other fossils in their Triassic-age excavations.

For more information, go here