Before I count down I want to mention those groups which narrowly missed out on making the list. The fauna of the Zechstein sea, particularly fossils found in South Yorkshire, interest me a lot as they are my local fossils. I have blogged about them a few times and hope to do something more academic with them too. I also briefly considered adding crocodiles to the list, as their past threw up many interesting variations which look nothing like our modern crocs, but I know little about them (I would say that if you want to be a vertebrate palaeontologist then crocodiles may be a great area to study). I also considered adding jawless, armoured fish from the Silurian, as I had a lecture on them today and found them very interesting, but they just missed out to some groups which I have liked for longer. So, onto the list...
|A crinoid fossil from Doncaster Museum.|
9: The Dinosaur to Bird Transition
It is well established now that birds evolved from dinosaurs, which is testament to the hard work of many palaeontologists. Laboriously comparing traits on fragmented fossils, they had to rely completely on a few rare transitional fossils to come to their conclusions. No genetic testing was available, only comparison of fossils. If we had no Archaeopteryx then our understanding might have been rather different. We are fortunate now to have quite a range of fossils spanning this transition, with feathered dinosaurs on one side, primitive birds on the other, and a spectrum in between, where individual traits can be seen to gradually change. It also allows me to include a group I like but have not included in this list - dromaeosaurs. Those swift, vicious hunters were closely related to the ancestor of birds, possessing many key skeletal precursors and covered in many feathers. This group of fossils speaks of my childhood love of dinosaurs (which still exists in a non-academic sense, enough to get a tattoo of one) and of my love of evolution. I do not intend to study them academically, though I would not turn down a good look at Archaeopteryx and will undoubtedly write about them in future.
7: Fossils of the Hunsrück-Schiefer
|A beautiful pyrite-preserved brittle star Ophinurina lymani.|
6: The Fish to Amphibian Transition
Another fascinating evolutionary transition which is documented well by the fossils, yet manages to keep astonishing us. The "fishibian" Tiktaalik is becoming one of the main transitional forms mentioned, though it would need a lot more publicity to surpass Archaeopteryx in fame. One of the reasons this group of fossils makes my list is because Neil Shubin's book Your Inner Fish had a big impact on me, informing my understanding of evolution and helping reignite my passion for palaeontology. A good portion of the book is dedicated to Tiktaalik, which the author was instrumental in finding.
4: The Transition from Reptiles to Mammals
This is arguably the most beautiful transition in the fossil record. We are exceptionally lucky to have numerous well-preserved fossils documenting this pivotal change in our history. It is most famous for the fact that we can see the changes from the reptilian jaw, which contains around seven bones, to the mammalian condition where there is one main jaw bone. What is incredible about this is that the fossils show the other jaw bones becoming reduced and migrating to the ear, where they have become the inner ear bones of all mammals. There are even some fossils with double hinges on their jaws, caught in the act in a way. The changes in the jaw and ear are alongside changes from reptilian motion (side to side) to the up-down undulation of mammalian movement; changes in dentition and the development of a secondary palate, allowing them to chew; the development of fur and warm blood, and a whole host of other changes which are intimately linked (usually metabolism and consumption) and documented by the fossils. Astonishing!
3: The Cambrian "Explosion" Fauna
1: Small Shelly Fauna
So there you go, my top ten. While I was writing it I felt like swapping around the order, but this list is meant to be transient, so I thought I would stick to it how I originally order it rather than constantly shuffling them around. I can possibly guess what you are currently thinking and I bet the words "nerd" or "geek" pop up at least once.