Gaps in fossil records are one of the most frustrating aspects of paleontological and genetic sciences and cause myriad disputes in the field, most notably with regards to human evolution. An oft used rebuke from creationists that deplore the notion that we descended from apes is that there are not sufficient intermediates. Unfortunately, it is only since the enlightenment period of the 18th century that western science started taking the concept of the usefulness of fossil excavation seriously. Combined with the difficulty and expense of the art of digging up bones from the ground, it is easy to see why such gaps exist. When these gaps are filled though, it creates a palpable sense of excitement in the field as it often leads to vexed questions being finally answered conclusively. This is especially so when it concerns one of the most celebrated creatures of all: The Tyrannosaurus Rex.
This month has seen the publication of the discovery of the first distinct species found in the Kyzlkum Desert of Uzbekistan, one of the driest in the world, which plugs a 20-million-year gap in the fossil records at the early cretaceous period. Tyrannosaurus Rex is probably the world’s most iconic dinosaur, finding a special place in popular culture in films such as Jurassic Park and King Kong and the subject of exhibitions in New York and London’s most prestigious natural history museums. Its fearsome reputation as being one of the largest predators to have ever lived has made it recognisable around the world, one who could crunch through the very bones of its prey. It’s likely that its keen senses also aided its evolutionary progress.
T. Rex belongs to the family of animals known as Tyrannosaurids which also contain the carnivorous Albertosaurus. This family evolved from the smaller bodied Tyrannosauroids (taxonomy can get confusing when only one letter changes) from the mid-Jurassic period, ca. 170 million B.C. This work is particularly interesting as it suggests that the T. Rex evolved to be intelligent before it got large. The reason for this hypothesis is the inner ear cavity and brain derivation from the fossil, discovered in 2004 are similar to that seen in their later Cretaceous form. They were able to determine this using computer tomography. This technique was used to take X-ray cross-section images of the braincase, before combining them into three dimensional images.
This new work from a team comprised of scientists from Edinburgh, St Petersburg and Chicago has christened the new discovery the aphoristic Timurlengia euotica. Timurlengia was likely to be 3-4 metres in length (a quarter of the size of T. Rex) and roughly the size of a large horse. It also had longer arms than the short stumps that have so often been ridiculed in its younger sibling. The teeth were a third of the size, far less intimidating. However, its keen senses and neurosensory features were already evolved such that if they were given the opportunity to, they could take the place of the top predators.
From primitive scavenger to the king of the dinosaurs in just a few tens of millions of years. Just when we thought the world’s most feared predator couldn’t get more intriguing.
Image by Erik Drost via Flickr