Archaeopteryx

It was suggested to me not too long ago that I might well have the best and most extensive collection of images of Archaeopteryx specimens online. Between having seen quite a few of these on display and having taken photos myself, plus the near endless collection generously sent on by Helmut Tischlinger of his UV works, nearly every specimen is on here and most with multiple views, close-ups and in UV. I am still missing a couple, but I’d have to agree that I’ve yet to see any online collection that can rival mine. Still, they are scatted around all manner of posts and so aren’t necessarily that easy to find. No more, here’s they are all are for convenience.

Cast of the London specimen

The Berlin specimen

The Berlin specimen returns

The Munich specimen

Mayr with the Eichstaett specimen

Eichstaett, Thermopolis and Berlin in UV

Solnhofen, Eichstaett and ‘chicken-wing’ specimens

Close-ups of the Solnhofen specimen

Solnhofen specimen in black and white

The Thermopolis specimen

The Daiting specimen (and in UV)

The most recent (11th) specimen (and in UV)

If you have others you are happy to share and have permission to distribute, do please let me know and send them on. This is simply there as a reference collection for people to learn and work with, but obviously more (or better, not all of these are great) would be lovely to have and make this still more useful. I know there are some scans and images out there and it’d be great to round this out as a clearing-house for people who want to see and compare these specimens.

Sciurumimus

Readers will remember a beautiful fossil from the Solnhofen being shown on here back in November of last year. People who have access to the internet will probably now now that yesterday the first formal publication on this animal came out. It’s now named Sciurumimus – the squirrel mimic – on account of the rather bushy tail. There’s already a ton of discussion on this online and quite some hefty coverage so I’m not going to dive into the ins and outs of feather distribution in theropods or the phylogenetic position of it. It is worth comparing it to Juraventor of course – sister-taxon to Sciurumimus in the analysis and from the same beds. Despite the obvious gross similarities, the authors do note a ton of small differences between the two that suggest they are genuinely distinct.

Of much more interest to the readers though will be the fact that once more Helmut Tischlinger has been generous enough to send me a variety of nice images with permission to publish them here. At least one of these isn’t in the paper and the res is pretty good so even those of you who’ve been able to peruse the PNAS paper might do well here, so enjoy. As usual my thanks to him for this very generous act and a reminder that these are his images and should not be reproduced without permission etc.

 

 

 

 

The giant, feathered tyrannosaur Yutyrannus huali

So perhaps inevitably the fossil beds of Liaoning in China have coughed up yet another fascinating feathered dinosaur. Yutyrannus huali (which translates as the ‘beautiful feathered tyrant’) is big – as big as some of the Late Cretaceous tyrannosaurines with the largest specimen being around 9 m long and estimated to have weighted close to 1.5 tons. In short, this was big. And feathered. While they are not brilliantly preserved, they are clearly present in places and directly associated with the skeleton as should be expected.

There are a few interesting things about this and I’ll go over them in turn, though as ever the first port of call should really be the paper for the real nitty gritty. First off, the specimens themselves – there are three of them, so this is already a well known animal, and two are basically complete. There’s a lot of anatomy right there and yes, I have to confess, rather more than some other tyrannosaurs I could mention. Indeed two of them are preserved together, as a pair, which nicely hints at least (well, I’m going to say so) at the possibility of sociality (theropods being more social than previously suggested, how interesting?).  Multiple specimens are always great and animals this size being preserved at all are quite rare in the Jehol, so it’s pretty impressive we have three of them. They are also preserved in that psuedo-3D manner I mentioned the other day so there’s really quite a bit of detail there and they are not badly crushed or mashed (as you can see in the pictures below).

Now it is of course already known that tyrannosaurs were feathered, with the basal Dilong being preserved with feathers. The question is of course, did the bigger ones like T. rex have them? There’s been suggestions that they didn’t as they could overheat and there are hints of scaly, feather-less skin from impressions refereed to Tyrannosaurus. So while at least some tyrannosaurs certainly had feathers, and large ones certainly could have done, this is definitive evidence that they genuinely did. The size issue is of course interesting since indeed, very large animals tend to reduce insulation to avoid overheating (elephants, rhinos, hippos etc. are not that hairy and indeed elephants can struggle to keep cool). The obvious exception being animals that live(d) in cold climates like mammoths, and the researchers note that actually the environment Yutyrannus lived in was likely rather cooler on average than that occupied by a number of later tyrannosaurs, so this may indeed have helped them stay warm.

Below are some pictures of the various fossils. While you’ve probably seen a number of these before on all the other sides my insider contacts means I’ve been sent a few to use which were neither in the paper nor press release. So there’s something novel here for everyone, even if it’s not in the text.

Top image by Brian Choo (used with permission) and the rest courtesy of Xu Xing and colleagues.

Xu, X. et al. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature. doi:10.1038/nature10906

Heads and tails – Microraptor feathers

From Li et al., 2012

Much has been said about the recent Science paper reporting on the possibility, or perhaps rather probability, that Microraptor had iridescent feathers. So much so awesome, but there are, for me, other interesting things that are buried in the supplementary data to the paper that I’ve not seen mentioned so far (not that I have widely read coverage of the paper, I mostly just read the paper).

First off, as seen above, the idea that things like Microraptor and others (Anchiornis being the most obvious candidate) had some little crest of feathers on the head. As shown by the X-ray, pigeons have a very similar arrangement of feathers and yet it’s simply part of the natural contours of the feathers and their position. Basically the feathers really are preserved as they were in life, and that this isn’t anything odd or expanded but that the shape of the head (with feathers) would be very modern bird-like.

Secondly, the tail was noted to have two rather elongate streamers in the midline and this looked familiar but I couldn’t place my finger on it. Now I have it, it is, for me, really quite similar to what you see in European magpies. There’s an obvious tail fan there, but in the middle, the feathers are rather longer, though not *that* exaggerated. Given the implications for signalling advocated in the paper, I’d be intrigued to know if people have looked at these feathers alone in magpies and how they are used or if birds are affected socially when they are trimmed or absent – could be something there to look at one day.

From Li et al., 2012

Li, et al. Reconstruction of Microraptor and the Evolution of Iridescent Plumage. Science 9 March 2012: 1215-1219.DOI:10.1126/science.1213780

Psittacosaurus again

Psittacosaurus is a genus that has had much coverage on the Musings if only becuase there are so many specimens floating around. However, while I’ve at least made mention of it, the most important specimen had not really featured here before and so here it is (well a cast). This is the famous / infamous ‘filamentous’ specimen that was purported to show an ornithischian with something close to protofeathers. It caused a storm of controversy, partly because of the apparently illegal acquisition of the specimen and also because it was far from clear if these were filaments or not. Obviously the appearance of Tianyulong went a very long way to convincing people that this was likely for real and not just the remnants of a plant, what with that being an ornithischian covered in them. This remains then a most important and much understudied specimen – would kinda help if it turned up – anyone know where it is?

Tianyulong

Although I have seen this specimen before (and indeed others) this is the first time it’s been ‘out’ and available. Like many things published in Nature and Science and similar journals, the specimens might be very interesting and important, but the restrictions of space means you may only get a small photo of the material and a couple of close-ups: no lavish 10 colour plates or multiple views of important elements for you (though the supplementary data increasingly helps out).

Not that I can do much more here as the damned thing was quite some way from the glass and at an odd angle, but hey, at least it’s a couple of new images of this interesting and potentially profoundly important specimen.

Anchiornis & Microraptor

As noted on here before, an increasing number of dinosaur species from China are known from multiple good specimens, but have yet to enter the literature. When there is a mountain of new species to describe, new material of well (and not so well) established taxa tends to fall to the bottom of the to-do list.

It was then pleasing to see a new specimen each of Microraptor (above) and Anchiornis (well, the two were labelled as such) on display at the Dino Expo. Both species are apparently very well represented in collections but only when they start being described and catalogued and their identities confirmed can we start to work on major areas of their biology that are limited to taxa with large pools of specimens – sexual dimorphism, ontogeny, intraspecific variation. Still, at least I have some photos….

Wing decay

This is a photo from last summer’s fieldwork in Xinjiang in western China and it makes rather a nice point about taphonomy and preservation. Obviously the preservation of feathers is a rather important aspect of dinosaur palaeontology so an understanding of how they act in living (well, dead) birds is a great source of data for us. As noted in the past, feathers can and do both articulate and even attach to the bones of both birds and dinosaurs and this can be seen in a few fossils and very clearly in living taxa.

You can see this rather well here. Whatever bird these wings came from is long gone, as has the skin and muscles, but the feathers, while a bit tatty, are still there. Not only are they still there, but they’re also still articulated on the bones in a pretty natural position. So feathers are structures that are remarkably resistant to decay and resistant to moving from their natural positions. This of course tells us two things about fossils.

First this tells us that we can reasonably assume that fossils like Microraptor maintain their feathers in a natural position when fossilised. Even in such a heavily weathered and battered specimen like the one shown here the wing feathers at least suck it all up without any real trouble. So a near complete and articulated specimen with all manner of small feathers etc. in situ really is about as natural as you can reasonably expect.

Secondly, this also explains why you often get fossils with feathers and not much else in the way of soft tissues. Things like muscles and skin are exceptionally rare as specimens (as indeed are other things like pterosaur wings or amphibian gills) and even in the kinds of localities that preserve such things, feathers are still more common. Look at Archaeopteryx for example – several specimens have beautiful arrays of feathers but no other soft tissues at all – not even necessarily good claws or bits of cartilage which are pretty robust as non-bony things go. Well that’s not quite true as most of the feathers preserved in these are as impressions, though some original bits remain, though this is very much true of various Liaoning specimens for example.

Still this does show you what can be learned from just a few scraps of dead animal lying in the dirt. Obviously what I’m talking about here is based on papers published on the subject of bird decay, but this lone bit of bird is a good example of how this goes and what it can tell us about fossils 150 million years in the ground.

Juravenator

Getting to Eichstaett was really rather good timing given that the new and long description of Juravenator is finally out. This little theropod caused quite a stir when it first appeared in 2006, though of course as a specimen it had been around for a while before then. I did have a bunch of photos of this from previous trips, but nothing digital, and now the slab is out in display this was too good an opportunity to miss.

Juravenator is generally considered to be a compsognathid of some kind and the specimen is wonderfully complete. Partly prepared using UV light this meant that even very small details are preserved and not lost through cleaning the bones. In addition to the scales around the tail (see below) there is the possibility of some feather-like fibers amongst the scales. If there is a ‘problem’ as such with the material it is that this is another juvenile. This seems to be a common theme with compsognathids with the ‘classic’ Compsognathus holoype also obviously being a young animal as well. It would be nice to have a really good adult compsognathid turn up and give us a bit more insight into this group. While several taxa are now known, they don’t get anything like the attention of other even ‘minor’ theropods groups and its about time someone really got to grips with them (or if they have, I’ve clearly missed it).

Chiappe, L.M. and Göhlich, U.B. (2010). “Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany.Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen, 258(3): 257-296. doi:10.1127/0077-7749/2010/012

What colour was Anchiornis?

If you have been keeping up with recent research on feathered dinosaurs (or even if you haven’t, this was everywhere for a while) you will know that several teams have published papers describing the colours of the feathers of various dinosaurs. Those with good memories or a strong interest will probably know that Anchiornis was revealed to have been predominantly back (or at least, very dark) with splashes of orange (or reddy colours).

However, it would I think be premature to assume that this is necessarily the right, or perhaps better, only answer. What we really know is that one Anchiornis specimen was black and orange at the time it died (assuming there are no taphonomic or other issues). Even people exceptionally unfamiliar with the basics of ecology or ornithology should be able to recognise this potential problem. There are lots of reasons to think that not all Anchiornis were this colour, and not all of the time.

At the bare minimum we might expect differences within the species as there will always be some differences in colour and patterning. The morphology of the bones might be identical between different species that were otherwise distinguished by their feather patterns or behaviour (as with the pheasants example I gave recently) that and thus are effectively invisible in the fossil record. There could always be local differences across the range of the species (some might live in forests and others in open areas or have different predators etc.). Far more simply though, it would be a surprise if males and females were truly identical in plumage, if juveniles had the same patterns as adults or if there were no changes over the seasons with moults.

In short, the research is exciting and interesting and the wealth of new ‘accurate’ reconstructions of Anchiornis are great. But for this and other feathered dinosaurs, this really not rule out other variations and combinations of colours from being wrong or being suggested. I’d be most surprised if future work didn;t reveal other patterns and colours for other specimens of the same fossil taxon. Equally, I’d be wary of inferring too much from one specimen – the present pattern can;t be used to infer much about the beahviour of the animal when we don’t know if it was male or female, in breeding season or not, in a summer or winter coat or even midway between them.

Why Microraptor should never be drawn the same way again

One thing worth bringing up on the wrists front never quite made it into the paper (or even the supplementary material) in quite the way I would have liked. It gets a mention but not the emphasis required at least in terms of palaeoart but also in terms of the actual biology of the animal in hand (since there is only limited space and you can’t really go off on a tangent for a few hundred words even if you want to).

Microraptor, as we know, has very long arm feathers, far longer than anything else we looked at in fact. Those keeping up will also note that it has really rather strongly rooted feathers and thus, what you see in the holotype is what you get. Take another look at that and you can see that the big flight feathers on the hand are stick out at a fair angle from the hand, but still act as a kind of angled extension to the arm. They were also probably rooted firmly in place and could not move much, even if the animal wanted to move them. But what does this mean?

Well, if you take a look at most palaeoart of Microraptor and even academic reconstructions and drawings of the animal in published papers, people seem to have been cheating. Not in a dishonest sense I hasten to add, more that, whether they meant to or not, the image just does not match the anatomy of the specimen. I’ve even checked a few of these and the feathers are either not at the right angle to the hand (which would be fixed), or are much shorter than as are preserved. The feathers are so long, and indeed the arms are so long that, [important note looming] assuming the arms are held such that the palms face inwards (the ‘clapper’ position) the feathers will be stuck in the ground. They can’t not be, they are just too long and can’t be moved out of the way. Microraptor has a serious feather issue.

Even with a flexed wrist, Microraptor's feathers would be stuck in the ground. Even if the arm were held out straight and parallel to the ground, the problem would remain. Image from Sullivan et al., 2010.

There are of course solutions to this problem and we illustrate and describe them. First of all, if you pronate the hands a little (i.e. rotate the hands inwards towards a ‘slapper’ position) then of course the feathers will now point at least partially to the side rather than down, and while this makes them stick out awkwardly, they won’t drag on the ground. Secondly, if you raise the arm right back so that the humerus is parallel to the spine, and then crook the elbow and / or the wrist a lot, you can get the feathers to point backwards or even up. The arm is in an odd looking position and might even get in the way of the legs (though of course birds, with an ever more abducted wrist, pull this off quite neatly) but again the feathers are at least clear of the ground.

Bringing the humerus back to be subparallel to the spine and then bending the elbow and the wrist finally brings the feathers free of the ground. Image from Sullivan et al., 2010.

Now Microraptor has some really big feather and clearly led a rather unusual life. Most, if not all of these things would be unnecessary for pretty much every other feathered dinosaur, but the general point is important. Feathers (whatever their purpose) were very important for the animals that had them, and as we can see from the fossils, they evolved to have lots of them and big one, and were kept in good condition. You don’t see dromaeosaurs or oviraptorosaurs with frayed feather tips and ragged edges, they looked after them and this includes not scragging them on vegetation or abrading them on the ground. Whatever else Microraptor was doing, it was looking after its feathers. This means it did not hold its arms in a way that would have led to profound damage to the feathers (or may just have even been physically impossible if those feather shafts were especially inflexible), and thus one of these, admittedly unusual, postures must have been adopted. You can’t manipulate the anatomy and you can’t contradict the evidence, so anyone thinking of drawing Microraptor in an old-style ‘Velociraptor’ pose with the hands held in front of the animal below the head needs to think again.

Biologically this is also interesting and potentially important. After all if the hands of Microraptor (or any similarly feathered dinosaur) tried to bring its hands to its mouth while holding something or to strike at prey in front of it, then it won’t be able to without dragging its feathers across the floor. This puts rather a limit on what the arms can actually do, especially when brought forwards. This isn’t necessarily and issue for the animal, such a penalty would clearly be a trade off against having those enormous flight feathers. But it does mean that if we are to successfully consider and test ideas about how the hands and arms of maniraptorans evolved and were used, we have to take such issues into account and not consider the bones in isolation – those feathers were important too.

(A few extra caveats / details. Yes, feather shafts are at least a bit flexible, and could probably be crushed against the ground without breaking them or doing too much damage, and yes lots of preening would help keep them in good shape. However, doing this every time the animal wanted to bring the arms forwards would in the long term risk damaging them, especially if done often, and preening also brings its own costs in terms of time and effort. On balance, it is far easier to just keep the feathers off the ground the bend shafts, ‘unzip’ barbs, and break tips that it is to go through that rigmarole and risk constantly. It’s also possible that the feathers were less firmly fixed / more motile than in modern birds, but they do have to take the forces of flight [presumably] and we do see things like quill knobs that argues for a very secure and fixed attachment).

I guess I should add, in the best traditions of SV-POW! and Tet Zoo, massive ‘Musings bonus points’ will be available to anyone who can find a ‘correct’ Microraptor online or produce one themselves.

Microraptor and the feathered dinosaurs are not fakes

Whether by accident or design it’s hard to say, but the Musings has largely been free of creationist madness and incompetence over the (already) years (OK, only two) I’ve been writing. I tend not to delve into that side of things simply because more people do it better than I could, and I have no interest in engaging with people who don’t understand, or want to learn, the first thing about science. Even so, making the odd statement or correcting the more egregious public errors are hardly out of my realm and obviously the title of this post is rather relevant. Both the new UV paper and other recent papers on feather colour add to the general pattern of observations that Microraptor and other Lianoning feathered dinos are not fake so it is perhaps worth collating a few of them here.

Most obviously, these things look exactly like feathers and they appear in places we’d expect feathers to be and arrayed in the same way. This is no chance association. It would be easy to scoff and say that a good faker would go for this pattern, but that’s not actually necessarily true. The presence of different feather types in phylogenetically consistent and meaningful patterns is not the kid of thing one could fake easily, if at all without huge coordination of all those farmers and fossil dealers collecting and selling specimens. Not to mention you know, the actual researchers who go out and collect fossils firsthand themselves. We’re getting into ‘evolution ninja’ levels of conspiracy here to account for protofeathers being found only in earlier taxa and then more specialised and more derived feathers in more derived taxa, so best move on.

Secondly, the feathers are pretty much indistinguishable between the various birds and the feathered dinosaurs. If the dinosaurs truly are faked, then how come the feathers are apparently identical to the supposedly non-faked birds. The feathers are also pretty much identical to the apparently uncontroversial feathers preserved in the Solnhofen of Germany and the Crato of Brazil. And actually, more recent feathers that don’t date from the Mesozoic look the same too, again confounding the supposed difference between bird and dinosaur feathers.

Incidentally, none of these feathers form any of these formations look fake. Stick them under a microscope and they are (in most cases, obviously not all of them are perfectly preserved) very highly detailed (down to the sub-millimeter scale) and could hardly have been painted on. Of course, go a fair bit further with an SEM kit and we can see that these are indeed preserved in incredibly detail. They have the structure of composition of feathers (right down to identifiable melanosomes of different kinds) and are not fakes, the remains of bacteria, or for that matter, degraded collagen fibres.

Finally of course (though less critical than several of these points, but hell, it’s my research) we also see that under UV there is still so signs of fakery or other shenanigans, and of course there are now more feathers (or more accurately more bits of feathers) that could not seen before. Few people would go to the trouble of faking things that cannot be seen or even perhaps even detected using a technology they don’t even know about. These are not faked and there is no possible evidence or reason to suggest that they are or even could be or how on Earth this could be done.

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