Feather Origins

Epidexipteryx at the IVPP with feathers used for something or other

We have a weekly discussion group here at the IVPP for the various students as ‘hosted’ by myself, Musings regular Corwin Sullivan and Xu Xing. Last week we ended up in an entrenched debate over the various hypotheses for flight origins in birds (you know, the usual ‘ground-up’, ‘tree down’, ‘WAIR’ and so on – and yes I will say more about these and others one day) but one offshoot was a discussion on the origin of feathers. Perhaps understandably the debate has been largely fixed on the insulation / display aspects of putative uses of feathers, but this is a far from complete list of feather or protofeather functions that may have led to their initial evolution and development. While I would agree that these are likely to have been the two most important factors the others should at least be considered and not left out of the discussion.

Extant vs Extinct

One significantly underappreciated aspect of palaeontological research is just how hard it can be to make reasonable statements about extinct animals in comparison to, or in analogy to living animals. Not for the obvious reason that fossils (of vertebrates at least) are generally just collections of bones (and often not even much of a skeleton) with the occasional splatter of half preserved skin but for the fact that often we can say a lot about an extinct organism, but not much about living ones.

The short version of that is that we actually know far more about many extinct species than extant ones. It’s all very well producing a huge monograph of some fossil lizard that has a close relative among the living, but then you can be frustrated by a lack of a similar level of detail in the live animal. This is, I image, due to two different but related reasons.

Firstly the average biological researcher presented with a livign animal (new to science or one that has known for centuries) has a huge wealth of things he can study – development, soft tissues, behaviour, genetics, natural variation and sexual dimorphism, bony anaomy, biogeography, evolutionary relationships, physiology, ecology and more. In contrast most vertebrate palaeontologists at least dabble in systematics, taxonomy and anatomical descriptions and a great many base their research around it and in consequence do it in far greater detail and is only therefore are able to make only superficial comparisons in terms of something like the shape of the femur because the biologists never got around to describing it in as detailed a manner.

Secondly, while there are obviously far more biologists than palaeontologists out there, they also have a hell of a lot more species to work on. I know a couple of entomologists and I can barely understand how they even vaguely keep track of things. Some small *families* of beetles have thousands of species in them and I can’t keep all of the theropods straight in my head. It should not be a surprise then that archosaur workers have described some fossil birds say in more detail than have the ornithologists who have 10 000+ species to work on, not a few hundred.

Ornithocheiroid jaws

This is just the anterior part of a skull of the ornithocheiroid pterosaur Coloborhynchus. I wanted to show it here for a few reasons as though it’s a fairly unremarkable fossil, it does illustrate a few points well. First off, not all pterosaurs are compressed 2-D fossils – I’m sure many of you know that already, but this does show the quality of the three dimensional preservation here, it is in fantastic condition, with no signs of breaks, distortions or wear (well apart from 95% of the skeleton being missing, obviously). Secondly, it shows the prominent (even procumbent) front teeth that stick forwards out of the front of the jaws that appear in some ornithocheiroids. We really don’t know what they were for, if they even had a special purpose. Finally, this specimen is actually fairly typical of many ornithocheroid specimens – or at least the early ones. The taxonomy of this clade is really a bit of a mess as in the late 1800s a great many names were attached to very fragmentary specimens with various bits of crests and different tooth arrangements. As a result when more complete material started to appear (most notably from Brazil) it rapidly became apparent that features of some isolated bits that had previously been named as separate entities could be found together on a single more complete skull or skeleton, and often multiple times on specimens that were themselves clearly different. Various efforts have been made to sort all of this out with some successes, but of course new finds keep coming out and some of those names just won’t die. Expect to be wading through a quite a few genus and species names of these guys for some time to come.

Bonus rhynchosaur skeleton

One of the really nice little surprises hiding in the basement of the Stuttgart museum was this mount of a skeleton of the rhynchosaur Scaphonyx. We have met a life reconstruction before being devoured by Herrerasaurus at the Beijing Natural History Museum, but here is a skeleton of the beast. OK, so it’s a composite of cast copies and sculpted elements, but it does give you a pretty good idea of the rhynchosaur skeleton, most notably of the course the huge and somewhat triangular skull. The mount was stuck on the top of a large cabinet hence the odd angles of the photos. For more on rhynchosaurs check out the write up of Fodonyx here on the Musings, and Darren Naish’s series of rhynchosaur articles on Tetrapod Zoology.

Karlsruhe living collections

Time for some more ‘not necessarily quite archosaurs’ photos. I mentioned in my post about the Staatliches Museum für Naturkunde in Karlsruhe that they have some fairly extensive live collections as part of their displays and having taken a bunch of photos of them, I should put a few up on here.

When desperation strikes

Pretty much any researcher will be able to tell you of their ‘dream’ find. The one fossil they would love to discover and describe, or at least would love to have available so they could work on it as it would help their research so much. A whole Deinocheirus, a Tyrannosaurus with feathers preserved, a pterosaur with a 20 m wingspan, an allosaur with a stegosaur spike wedged in its braincase, a trackway of a sauropod walking bipedally – you get the general idea.

However, on our recent trip to Japan when given the opportunity to potentially obtain any one fossil in the world, my good friend and colleague Corwin Sullivan asked for something a little different.

Rhamphorhynchus and Pterodactylus

Two classics here brought to us in a nice slice of palaeoart courtesy of Luis Rey. There really is not much I can say about these two which is not repeated elsewhere add infinitum (including on here). Both of course come from the extensive Solnhofen limestones of Bavaria, both are known from around 100 specimens each (at a rough count, we don’t know how many might be lurking in private collections, the numbers could be much higher), both have gone through frustrating periods of taxonomoic splitting and subsequent lumping, and both are incredibly important for our understanding of pterosaur evolution and biology. I mean, come on, if you have not worked out which genera spawned the names pterodactyloids and rhamphorhynchoids by now, you are probably reading the wrong blog.

Once more into the, errr, field, dear friends

Yes this week I am heading back into the field to go and find some more dinosaur bones in the Chinese wilderness. Last summer we were in Inner Mongolia to the north west and this time out we’ll be going down south to Henan province. I have actually been to Henan before a few years back, but the ‘fieldwork’ was limited to a procession of vists to old quarries without actually getting ‘down and dirty’ to look for specimens beyond collecting a few eggshell pieces on the surface. As a result I am looking forward to getting out again and seeing more of another part of China.

The obvious flipside is that getting any posting done is likely to be tricky. Bar the odd trip into town I doubt I’ll have too much internet access for the next three weeks or so. As a result don’t expect much to come up here for a bit and do remember that I can’t approve comments or reply to others in that time. Don’t abandon me though – I’ll try and make sure a few things appear here when I can and my access might be much greater thjan I fear in which case I’ll be posting fairly normally. See you in May!

Guest post: How did pterosaurs extend their wing finger?

There are all kinds of aspects of palaeontology that in some ways we can only guess at how these things might have lived, functioned and behaved as living organisms. However one of the key aspects of science is the ability to make predictions and with careful use of analogy and homology (and of course the fossil record), we can try to work out some of those complexities that otherwise might leave us stumped. My former student Edina Prondvai and I have a new paper coming out in Historical Biology discussing how pterosaurs might have been able to extend that massive fourth finger and keep it stead during flight while minimizing energy expenditure. Edina takes us through it in this guest post:

A 3-D Dorygnathus skeleton

Another from the vaults of the Stuttgart museum. This is a modelled skeleton of the rhamphorhynchoid Doryganthus. Perhaps unsurprisingly you don’t often see rhamphorhynchoid pterosaurs reconstructed in this way in museums for the simple reason that they are small and fiddly and have to be meticulously sculpted by hand since the few 3-D bones of rhamphorhynchoids that are out there are generally too fragile to cast, or have not been fully prepared from the matrix for the same reason. I’m not surprised if it’s a popularity issue either – why go to the trouble of making something like this when you can just stick up a 3 or 4 metre Pteranodon for the same cost and less effort? Getting a cast of a 2-D Rhamphorhynchus or Dimorphodon is easy enough so just stick that on the wall and don’t bother to show off how the animal might actually have looked.

It is therefore nice to see something like this being made to show the animal as more than Mesozoic road-kill in a rock. I don’t know why it was being stored in the basement and not on display but clearly a few bits are in need of repair, and it certainly is something that was once on show. Hmmmm, kinda run out of things to say here. The end.

Staatliches Museum für Naturkunde, Stuttgart

Continuing with my reviews of various museums around the world I recently got to go to the State Museum for Natural History in Stuttgart (link goes to their site) for the first time. It was a place I had managed to avoid for two years while I was based in Munich despite the extensive pterosaur collection they have there and also the huge number of Plateosaurus specimens. The timing and opportunities were never quite right, so I made a special effort when I had cause to travel from Karlsruhe to Munich, so Ross Elgin, Dino Frey and I made the trip.

Where is the pterosaurian 5th finger?

Anyone who has breezed their way through the more pterosaurian sections of this blog (or browsed much pterosaur stuff at all) will know that the huge finger on the pterosaur hand that supports the main wing is the fourth (ring) finger. What you may not have asked yourself is how we *know* it’s the fourth finger. Since pterosaur ancestors presumably had the more normal five fingers like all but the most basal or derived tetrapods, how do we know that the remaining fingers and 1-4 and not 2-5?