As reported last week a new tyrannosaur from Asia has just been identified by palaeontologists; following hot on its heels was a paper on identifying the sex of individual tyrannosaur skeletons based on the chemical signatures for pregancy in their bones. These are just the latest in an apparently endless series of discoveries of these dinosaurs, but there are some interesting and interlocking reasons for why there is so much research into this group.
Not all fossils or groups are equals, and tyrannosaurs were particularly common at the end of the Cretaceous Period that marked the end of the non-avian dinosaurs’ reign. As a result of being relatively young animals by geological standards, there tend to be more specimens of them, since they have had less time to be destroyed by various geological processes.
This is then further exaggerated by the fact that a lot of work has been carried out by palaeontologists in the US and Canada, where tyrannosaurs were the dominant carnivores, so a lot of tyrannosaur fossils have been found. After all, if you put in more effort you will find more things, and people will tend to dig in (relatively) local fossil sites. The rich history of North American palaeontology therefore helps give us more tyrannosaur skeletons to work on.
On top of that, tyrannosaurs are popular animals with the public and with scientists too. Museums want tyrannosaur skeletons to exhibit, so they are something that both scientific and commercial collectors will try to find and bring back; again this increases the number of specimens available.
Having lots of fossils means that we have a lot of grist for the mill of science. Palaeontology is rather a difficult field to work in without fossils, so we can only find out a lot about tyrannosaurs if we have lots of specimens. More material generally helps of course, but it also means you are more likely to recover exceptional or unusual animals like those preserved showing injuries, marks from being fed on by other tyrannosaurs, or with preservation of unusual tissues like cartilage or skin and feathers (as opposed to just teeth and bones).
Finally, and critically, there is an inevitable positive feedback loop on all of this. The more we know about tyrannosaurs, the easier it becomes to learn more about them. As we discover things like the new discoveries highlighted above, we fill in more and more of the jigsaw of our knowledge of these animals. That picture has a huge number of pieces missing for sure, but each new fossil or study can help link together areas (hey this piece has water and tree on it, it must go in this area) or even open up new avenues of research (a piece with a colour different all of the bits we have so far) or show us when we have gone as far as we can (to possibly stretch the jigsaw analogy too far, an edge). As such, tyrannosaurs are disproportionately covered in research as there is far more context for new research to fit into because of all the other existing tyrannosaur studies.
The fact that detailed studies have provided us with an excellent idea of which tyrannosaur species evolved when and where and with what features, makes it relatively easy to see where a new animal fits in and how and when certain traits appeared and evolved. Or the fact that we already have a method for identifying female dinosaurs based on their bone structure means that a corroborating result from chemical traces gives us great confidence in our interpretations. Even so, it’s not all to the benefit of the tyrannosaurs.
Just as fruit flies are a model for genetics in many animals and mice used as a lab animal for learning more about mammals (including humans), tyrannosaurs are something of a model for our work on other dinosaurs and more distantly related reptiles. They provide us with a platform to build on since we have worked out how to use certain methods or make certain inferences using out tyrannosaur data. Major areas of research like growth rates, skull function, and speed and turning have first been calculated on tyrannosaurs and then later applied to other dinosaurs.
As such, the tyrannosaurs represent our best known, and arguably most important, group of dinosaurs. Our knowledge of them is far greater than any other set of species, but while this can sometimes lead to hype in the media thanks to the public’s fondness for these impressive animals, it does mean that they form a foundation of much of our understanding of the dinosaurs. Public interest or scientific research into the tyrannosaurs is not likely to drop away soon, but there is more to them than their reputation as just huge carnivores but they underpin far more science than most would realise.
