A Blog of Two Parts: Hard to Explain/Reptilia pt. 1

This blog comes in two parts: Part 1 is boring and part 2 is a bit more interesting.

Let’s get the boring out the way first. First of all, I’d like to issue a small disclaimer. My idea for this blog was to introduce people outside of the world of research into what I’m doing, whilst simultaneously providing a decent record of my work for those within it. However, this isn’t going to be easy, and some things are going to prove to be problematic along the way:

1. These two worlds are pretty damn different, and the way that research is presented between them even more so. Let’s take an example. These two articles report on the same research presented for these audiences. One is from a reputable journal, the other from a less than reputable paper (I feel bad just linking to it…). I’m going to be honest; if you can make it through the journal entry and understand it clearly without having seeing one before, you’re a greater person than I. The point of a jounral is to contain all the possible information a scientist would need to know if they were to carry out the same research for themselves, and as such can be very dry to read. This is fairly different from the usual journalistic style that most people are used to. Finding a solution that fits between these isn’t going to be an easy path, and it’s likely it’ll get a bit rocky along the way. My initial aim is to discuss things first in a more technical manner, before following up with a paragraph of explanation, but this may change in time as I get more used to this whole blogging phenomenon.

2. In order to discuss the research I’m doing, I’m going to have to do a lot of catching up for those who haven’t covered the subjects involved before. Science, by and large, is viewed as a tricky subject. Now I don’t necessarily believe that it is. However, there’s no denying that there’s a lot of theory, formulae and names to remember before you can even begin to discuss things in a wider context, and that’s often just for one tiny section of a subject. My aim is to provide a blog where anyone can begin to pick this stuff up and run with it. Some of this catching up will be from my own writing, but if I spend all my time doing this I won’t be able to cover anything else! For this reason, with some things I’ll be chatting about I’ll give a link to a place which I think can explain it in a better way than I could.

3. I’m pretty new to this stuff. Let’s face it, I’m still an undergraduate. I’m in my fourth year and I’m doing alright in terms of grades, but I’ve only really scratched the surface on most topics related to palaeontology. And because of this, somewhere along the way, I’m going to undoubtedly make some mistakes. I’ll try and reduce it as much as possible by showing my work to my supervisor, but if anyone sees anything suspect, please let me know!

So basically, I’m human, I’m not perfect and if I make mistakes please let me know and I’ll get them sorted as soon as possible!

Now that’s out the way, onto the interesting stuff. So by now I’ve introduced myself, and what I intend to show with this blog. However, I’ve so far failed to talk about the most important thing in all this: what my work actually is.

So without further ado, I present my title for my MSci project…

“The completeness of the fossil record of pterosaurs: implications for their origin and diversity through the Mesozoic.”

Not the snappiest title, I have to admit. But what does it mean? To understand what’s going on, I’m going to break it down into three key points – Pterosaurs, Completeness, and Implications.

Pterosaurs

I’ll start with the most straightforward bit. Pterosaurs are one of the most recognisable prehistoric creatures, and have featured in popular culture for years. An excellent introduction to them is given at Pterosaur.net, a hub for pterosaur research, and I thoroughly suggest checking it out. In the meantime, I’ll give a quick rundown on all the things we need to know about Pterosaurs.

Pterosaurs are extinct flying reptiles, which lived between the late Triassic (225 million years ago) and Cretaceous (65 million years ago), dying out alongside the dinosaurs. Contrary to popular belief though, they are not flying dinosaurs. In fact, they are close relatives to dinosaurs and crocodylomorphs, as can be shown by something known as a cladogram:

Cladogram showing how Pterosaurs fit in with the evolution of Reptillia. Source

A cladogram is produced by cladistics, which is a method for determining the evolutionary relationship between different organisms. All species on earth today evolved from a single shared common ancestor, and thus a shared evolutionary history to some degree. How similar an organism is to another can be used to assess how closely related they are. If we use hundreds of small characteristics that are subtly vary between species, we can construct a “tree”, or cladogram, which organises organisms based on their evolutionary history. But what’s really clever is that key evolutionary changes can be tracked along this tree so we can observe where they first appeared. With this, we can see where species diverged and where a specific feature (such as hair) first originated. This is an incredibly powerful tool, which when combined with stratigraphy can be used to form a pretty respectably history of any organism you can think of.

Cladogram showing a very basic depiction of vertebrate evolution. Source

A good example for this is above; this is a cladogram representing a highly simplified version of vertebrate evolution. You can see where the different organisms branch off to the left hand side, and where features appear as the red bars on the main “limb”. You can also see groups appearing: for instance, the mammals are grouped with an additional branch. As I mentioned before, this cladogram is preeeetty basic. But add in numerous species and they can get complex pretty fast…

A cladogram showing archosaur evolution. Pterosaurs are a group within Archosaurs, and you can see them branch off just before Dinosaurs appear. Source

If I’ve been a bit cack handed in this description, this is once again handled beautifully by Pterosaur.net, as well as numerous sites across the web!

Pterosaurs are interesting from a cladistics point of view, in the fact that they’re pretty odd as far as things go. As I mentioned before, cladistics works by comparison between species, looking for numerous small changes and differences which allow a cladogram to be generated. Whilst this works well between pterosaur species, when trying to understand the group’s origins, the radical difference from the rest of the archosaurs (part of the larger group that dinosaurs, pterosaurs, birds and crocodiles are included within) makes them really tough to compare as the details we’d normally look for just aren’t there. However, we can tell that they branched off the main tree before dinosaurs first appeared, making them close relations but not part of the group. Pterosaurs can also be divided into two key groups with large differences in anatomy – the Rhamporhynchoids, or long tailed pterosaurs; and the pterodactyloids, or short tailed dinosaurs. These are shown below in red and blue respectively, with the diagram on the right showing the evolution between the two groups. The middle specimen is a really interesting species known as Darwinopterus modularis, a “transition species” (God, I hate that phrase…) showing unique traits of each the Rhamporhynchoidea (long tail, similar body and limbs) and the Pterodactyloidea (neck and head).

A diagram of Pterosaur evolution using a cladogram on the left, and a progressive series of models to the right highlighting key changes in the Pterosaur body plan. Source

This is partly why pterosaurs are really interesting to study, but it’s mostly just that they’re really cool. They’re the first vertebrates to evolve manually powered flight, have a huge range of appearance, and thanks to new fossil sites in Asia, new and exciting species are being discovered all the time. I’ll go into detail with their evolution and anatomy a bit more detail later on, but hopefully this has provided a good introduction to these flying reptiles.

In the next part of this blog I’ll be going over completeness and the implications of my work. Keep an eye out, it should be up in the next few days!

P.S. One final note… I’m going to try and continue to name my blog entries after songs (vaguely) related to the post, in keeping with the title of this blog. First person to post the band will a shout out, and thus fame and infamy, in the next blog. This is until my creative edge completely runs dry, which is likely to be after about three more posts.

Today’s post titles comes from these two great songs.

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