Archive for March, 2010

Velociraptor vs Protoceratops: part II

Dinner time! Image courtesy of Brett Booth.

Most people who have read even a little on dinosaurs at some point will have seen a photo, cast, model or reconstruction of the famous fighting dinosaurs (and if not, then follow the link to see them). However, while this fascinating fossil certainly tells us that at least one Velociraptor took on a Protoceratops this is pretty much the limit of our knowledge of their interaction from the fossil record. Protoceratops is by far the most common herbivore in the fossil record in which it is found (and of course close relativels like Magnirostris) and Velociraptor (or perhaps rather these days velociraptorines thank to thinks like Tsaagan and Linheraptor turning up) the most common predator. Although the two are quite similar in size, the abundance of both and the abundance of fossils would suggest that the two would have some sort of trophic relationship. i.e. the carnivore would be eating the herbivore in some way at some point.

Naturally one would expect a small predator like Velociraptor to target small prey (like juvenile Protoceratops perhaps) but that hardly rules out their taking the odd swipe at elderly or ill individuals or of scavenging from carcasses. If that was the case, then were is the evidence? Tantalisingly the famous CCDP (Chinese-Canadian Dinosaur Project) team reported often finding velociraptorine teeth with the bones of ornithischian dinosaurs, but without saying which ones they were, so while Protoceratops is the most obvious candidate we can’t say for sure. However, my new paper (you saw this coming, right?) describes a better association – velociraptorine teeth in association with a Protoceratops skeleton and feeding traces to boot.

I’m quite pleased with this work if only because it’s the first paper based on something I found and then wrote up which is rather nice. Credit must go to coauthors Jonah Choiniere and Mike Pittman who originally found the teeth and brought them back to camp. I had the bit of info on the CCDP report in my head and had been thinking about bite marks at the time, so after some pestering they took me to the site and together with Corwin Sullivan we started to sort through all the bone fragments to look for any with bite marks on them. Despite the intensive weathering of the bones, there were some pieces with drag marks from small teeth so we collected what we could and took it back to Beijing.

This paper reports on these finds and as noted above it consists of a couple of dromaeosaur teeth found in association with various bones with some of those bones bearing trace marks. I won’t labour the details, since it’s all in the paper, but I would like to talk about the implications here – are the fighting dinosaurs a one off, or did Velociraptor regularly go after Protoceratops.

As noted above the two animals are similar in length though of course in terms of build and body mass, the Protoceratops would have been the far bigger animal. That suggests that the dromaeosaurs would be unlikely to want to tackle something that big. Those who immediately want to leap and cite the fighting dinosaurs will hit two problems, first and most obviously, this is a single record of a single incident and it’s hard to say if it’s unique or not. Perhaps the Proto was already ill or injured, or the dromaeosaur was desperate, or who knows what. Secondly, big though the Protoceratops is in the fighting dinos pair, it’s actually probably not an adult and is only about 2/3rd adult size, so may have been a more tempting target for a predator (if obviously not a small juvenile).

Protoceratops teeth recovered at the site of our new record are pretty big and there were some fragments of big bones and over a big area suggesting these were the remains of a hefty animal. This would have been quite a challenge for a dromaeosaur to try and bring down. Even if it had, how much could it eat? The bite marks we found were on areas of bone associated with the jaws, hardly the most flesh-rich of areas, and there were multiple repeated bites. Why was this happening?

Velociraptor gets scavenging. Image courtesy of Brett Booth.

The conclusion we offer is that this is the result of scavenging. It’s unlikely a dromaeosaur could bring down such a big Protoceratops. Even if it did, there’d be tons of meat available on the legs and belly and the tail – there’s no need to go and scrape off what little lies on the jaws. Hell, even a whole group would probably get enough food from an animal that big without having to start chewing on the scraps on the face to the degree that they leave so many small marks on the bones. In short, this really looks like a dromaeosaur came across a corpse and scraped off it what it could (a meal is a meal) losing a couple of teeth and making some scrapes on the bones in the process. While this doesn’t support the idea of dromaeosaurs tacking big protoceratopsians for food, it does provide evidence that the former were probably feeding on the latter, even if that largely consisted of scavenging. Still, while such a relationship might be expected, it’s always good to find new information to support ideas and further understanding of the problems.

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Astute readers will have noted that the paper is not actually out yet. However, the journal in question released the proofs version early and the media have picked up on it. I did check with the journal and as far as they are concerned there’s no embargo on it. Since the press have already picked up on it, it would be silly for me not to mention my own research. However, please don’t ask me for a copy of the paper, I don’t have the final version yet and there are things being added to the proofs. My hand is therefore rather forced by others.

Finally a huge thank you to Brett Booth of the Carnosauria blog for producing the images above at short notice and in colour too. The artwork is Brett’s and should not be used without his permission.

Theropod feeding traces

One of the most read posts on the Musings is that on my paper on theropod predatory ecology in which Oli Rauhut and I suggest that most big theropod predators probably targeted juvenile dinosaurs rather than adults. We covered a bunch of lines of evidence but one of those was the oft under reported area of dinosaur feeding traces. Quite literally bite marks left on bones by theropods.

There seem to be quite a few of these around according to some surveys, but they don’t get much attention. There’s a small (but growing) list of papers that describe individual bites or small sets of bites in some detail, and there’s a couple of review papers that talk about very large numbers of bites with little detail and not much in between. Thus while there are therefore at least several hundred documented bite marks, and probably quite a few more, only a dozen or so are actually described and illustrated in the literature. That makes it pretty hard to say much about them, since we don’t know what the distribution is like in terms of sizes, numbers, or any other obvious patterns.

I can see why this might often get overlooked, bites aren’t always obvious and nor can they always be easily distinguished from other forms of damage (though quite a few are very obvious). The obvious reason though, for not taking the time out to describe these, is that there is often only very little to say. It’s not at all clear, or even possible to tell most of the time, if the marks were made by an animal just biting another, that actually killed the other, or was merely scavenging a carcass. It’s not always even obvious which animal was bitten (if the marks are on an isolated bone) and it’s very hard to narrow down what the biting animal may have been too. Package all of this together and tooth marks are sadly, if understandably, relegated to being a ‘novelty’ rather than necessarily having anything interesting to say about predatory behaviour or trophic relationships.

However exceptions do exist, like the macerated Triceratops pelvis that’s full of deep T. rex tooth shaped holes, or the pterosaur bone with a dromaeosaur tooth wedged into it surrounded by score marks as the teeth scraped across the bones. These two examples actually demonstrate the two stereotypical bite marks with others usually falling somewhere between the two (obviously this means a dingle trace, there can be multiple kinds present on a bone or skeleton that has suffered bites). Either one will see deep punctures (or even ‘bite-through’ of the whole bone) that are tooth shaped – that is the tooth has penetrated the bone, or there will be scrape marks where the tooth has hit the bone surface and then been drawn across it. The latter is more common since few theropods probably had the power, or even desire to try and crack through big bones and of course we suggest that they probably weren’t even encountering them that often in any case.

Still, for all the problems that are associated with trying to pick out the details of feeding traces they can, on occasion, offer some illumination on the living habits of various dinosaurs. Like the example I’ll cover tomorrow with this shameless cliffhanger and obvious plug…

Xixianykus zhangi – a new alvarezsaur

Xixianykus life reconstruction. Image courtesy of Matt van Rooijen.

Xixianykus life reconstruction. Image courtesy of Matt van Rooijen.

Around the time Haplocheirus hit the journals I commented that this would likely be a good year for Chinese alvarezsaurs. Obviously I rather had some insider knowledge and here’s part of that reason – Xixianykus zhangi. This is a new and really rather small alvarezsaur from Xixa county in Henan, China – a place far more famous for its fossil eggs and isolated baryonychine tooth.

Aside from being the latest taxon in a rather small clade, and having a fair amount of the skeleton intact, Xixinykus has some more interesting things going for it. For a start it does seem to be especially cursorial (that is, adapted for running) which can be seen by a number of anatomical specialisations especially (unsurprisingly) in the legs but also in the body. Despite likely only being likely around half a metre long, the legs on this thing are about 20 cm long. Being fast requires both a long stride length and / or as high stride frequency and Xixianykus as the former in spades at least. This is also combined with proportionally increasing distal parts of the limb (a short femur and a long tibia / metatarsus) which is another good indicator of cursoriality and is higher for Xixianykus than almost all other theropods. Whether or not is did run much is another question entirely, but when it did, it was probably quick. It was also efficient – there are structural adaptations in the body that would have reduced swaying, cutting down energy loss and the short femur also draws muscle mass up the legs making them more efficient (you don’t have to move all that heavy leg muscualture so far than if it was, to take an extreme example, on the foot say).

This is also a fairly old taxon, among the derived alvarezsaurs (the parvicrusorines) this is phylogenetically one of the most basal and the oldest. It’s dated to Santonian-Conacian as opposed to the others which are either Campanian or Maastrichtian. Based on the available material this suggests the possibility of an Asian origin for the group that later dispersed to North America.

Finally, I should add a quick, but large, ‘thank you’ to Matt Van Rooijen author of the Optimistic Painting blog for his reconstruction of the animal. Please don’t rip it off, it’s his artwork, on loan (if you like) to the Musings. If you want to use it, ask him, even if you do see it on various media sites.

A basal parvicursorine (Theropoda: Alvarezsauridae) from the Upper Cretaceous of China
XING XU, DE-YOU WANG, CORWIN SULLIVAN, DAVID W. E. HONE, FENG-LU HAN, RONG-HAO YAN & FU-MING DU (P.R. China). Zootaxa, 2413 1-19.

Taxonomy of the kind I still see too much of

Abstract:
Here we report a new dinosaur Nomen dubium (gen. et. sp. nov.) based on a very incomplete specimen with most of the important parts missing and the rest badly prepared, preserved, damaged or all three, including all the parts that have critical characters for the placement of this taxon in the clade we say it belongs to. It comes from the very vaguely defined beds of uncertain age of some incredibly large and unspecific region which we clearly got from a fossil dealer but won’t admit to. Nomen dubium can be diagnosed by the following characters that we will repeat in full in the paper but we want to put here to flesh out the abstract: absence of a key element that could easily just be missing given how incomplete the fossil is, the absence of a key character that is equally probably just broken because the bone is so badly damaged, and some ridiculously unhelpful and non-diagnostic character like the length of the femur and the number of gastralia, we do include one proper character but it’s not diagnostic of the taxon so much as saurischians / reptiles / tetrapods so is useless. This new genus is placed in the family Wastebasketoidea because it is really poorly defined so we can cram anything we want in there even though all the other members are from a different continent and are 50 million years younger. Finally we conclude with some pretty meaningless statement like the fact that this adds to the diversity of the area (like it could do anything else, though of course that point is dripping with irony given the appalling definition presented here that clearly means this isn’t new) or that it was an important part of the terrestrial ecosystem or some other pointlessly obvious and uninformative sentence.

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I’m not the only one who keeps seeing these am I? And I’m not the only one who is worried he’s actually produced something like this either, right?

Relative relatives

The subject of relatives has been bouncing around my brain of late. The statements, ‘the gorilla, a relative of modern humans’ and ‘the salmon, a relative of modern humans’ are both true, but one is perhaps more true than the other. Obviously all things alive today are relatives at some very deep and very ancient level. As far as we know and can tell, life only originated once on Earth and if you go back far enough fungi, trees, people, dinosaurs, bacteria and viruses have some form of common ancestor somewhere, not to mention all the things in between. However, there are of course, relatives and then there are relatives – relativity is all relative.

It’s clear that humans are more closely related to gorillas than they are to deer, closer to deer than to salmon, and closer to salmon than spiders, but they are still all related. Move in though, or move to an unfamiliar group and that becomes trickier – are beetles closer to flies or mantids, are spiders closer to weevils or centipedes? Unless you have a pretty good grasp of the detailed phylogeny to hand or some clear qualifiers any statements about relationships rapidly, or even instantly, become fuzzy to the point of being irrelevant.

You do see this at its worst in the media (big surprise) but I am sympathetic here. When trying to communicate the idea that some groups or species are closely related to others, aimed at an uninformed audience and avoiding technicalities and illustrations it becomes very tricky very fast. =I’ve also seen a fair amount of tired internet discussions along the lines of ‘Velociraptor isn’t related to Tyrannosaurs at all’. OK the ‘at all’ we can allow as conversational hyperbole, and of course tyrannosaurs and dromaeosaurs (within the theropods) are quite well separated, but they are also related. Compared to say, Dilophosaurus, they are quite close, compared to a crocodile, very close, compared to Troodon, not close. That statement is as true as it is false.

But is it really so hard to use a qualifier or two? Something like ‘Linheraptor is not a particularly close relative of Velociraptor’ is potentially confusing and in a sense no more accurate than ‘Linheraptor is a particularly close relative of Velociraptor’ – just how ‘not close’ or ‘close’ is it? But add just a few extra words and the distinction is obvious, accurate, succinct and informative: ‘Linheraptor belongs to a small group of dinosaurs called dromaeosaurs that includes Velociraptor, but within the group the two are not especially close relatives”. There’s really quite a lot of information in that 20-odd word sentence. It puts the two in context with each other, and the wider group of dinosaurs or theropods as a whole (since this sentence should obviously not stand in isolation in an article). So stick in a few qualifiers and make things more clear, it really will help and it might stop a few discussions were both people are right but arguing pointlessly from different perspectives.

Guest Post: The tyrants head south

Today Roger Benson guests on the Musings as he brings us news of the first tyrannosaur from Australia, or indeed any southern hemisphere continent. Take it away:

Continue reading ‘Guest Post: The tyrants head south’

Jaded and cynical, moi?

I’ve just had the rather singular experience of being told that an article on my work is unlikely to be published because apparently I wasn’t overly enthusiastic about the paper it was based on. I can see the logic, but equally it’s a bit of a surprise. Obviously I really like my job and I like working on dinosaurs and talking about dinosaurs (and pterosaurs too). However, I do this all day every day. The paper in question is based on some pretty poor material that I found two years ago and went through several rather delayed bits of review to get into the journal.

Is it really much of a wonder that I can’t necessarily motivate much interest in an e-mail conversation on something that for me has all but passed by? Sure I’m interested in it and I think it will interest me, but if the magazine has gone to the trouble of writing the article, one rather assumes that they think their readers will be interested in it. Surely my apparent lack of enthusiasm need not prevent them saying it’s interesting if they think it is? In any case, it’s not like I think it’s bad, I think it’s quite cool, but it’s not rendered uninteresting because I don’t say it’s the most fantabulous amazing discovery ever.

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On a not unrelated note, any budding palaeoartists out there who want some exposure, other journos are bugging me about this paper and want some graphics. If you have artwork of a Velociraptor or Protoceratops or something similar (Tsaagan, Bagaceratops etc.) and are willing for it to be used please let me know. I cannot, of course, promise the story will be published or even the images will be used and you are very unlikely to get paid, but it might well bring you a bit of exposure to your work. E-mails to the usual address please.
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The Musings have been a bit quiet of late as I’ve been very busy with various visitors and having internet troubles, but hopefully that’s behind now. More proper posts soon.

Guest Post: How to collect a skeleton from a cliff face with 200 meters of sandstone as overburden

Reconstruction of Seitaad ruessi. Image courtesy of Mark Loewen.

Some of you may have already spotted the new paper out covering the delightful little Seitaad ruessi – a brand new sauropodomorph from the Middle Jurassic of Utah. (Some coverage is here if you have missed it, and the paper is freely available here).  Mark Loewen, one of the authors of the new paper, tells of how the material was found and then how they got the specimen out of the quarry:

Continue reading ‘Guest Post: How to collect a skeleton from a cliff face with 200 meters of sandstone as overburden’

Don’t understand something? Ask, don’t criticise.

The title of this post is not directed to the average Musings reader but what seems to be a significant minority of people posting comments on news items regarding science. It’s an odd mentality, but seems common enough to warrant comment, and with Linheraptor inevitably stirring up a few things, it rather brings it to the fore in my mind. The short version is that when they read something they don’t understand (either what it means or how it was derived) they assume it must be made up or incorrect.

What is infuriating about this is that these things are often easy to discover. Wikipedia isn’t half bad at simplifying quite complex bits of science, and there are all manner of websites devoted to explaining concepts and providing online tutorials, if something is big in the news there will often be quite a bit of commentary from various sources with some details about the research, and of course many papers are available on line, and resources like Ask A Biologist. If you actually want to actually know how some conclusion was reached, look it up or ask. This however, rather assumes that you genuinely want to know. What I suspect (and certainly the impression it always gives me to see these comments) is that the person in question thinks they have got one over on those dim scientists and wants to publicly point out how smart they are and the scientists aren’t. What this actually typically shows however is that they don’t understand the process and can’t be bothered to find out. Doubly frustrating is the fact that most people seem to side with ‘Mr Picky’ and not the actual scientists (you know, the ones who do the science).

This of course fits in with the other issue here, that any mistake made in an article is near inevitably attributed to the researcher and not the journalist. Why, I simply cannot fathom, but it is incredibly common. Why is the blame put on the highly trained and experienced scientist and not on the not-scientifically-trained-and-rushed-summarising-non-expert? I really can’t see why the benefit of the doubt does not fall to the researcher though it rather suggests that people trust them over the word of a scientist which in itself is rather a worry. When you combine this with the apparent attitude of over inflated personal ability over assumed incompetence on behalf of the researcher (which as ever, brings this paper to mind), then you can see how this happens.

All of which brings me back to the importance of good science communication. Getting the right and accurate message across to as many people as possible in the right way. Providing resource for those who want to learn, to learn, and gently correcting those who don’t want to learn or don’t realise they don’t know. It’s incredibly rewarding to get positive feedback from people who have gained knowledge or understanding that they didn’t have before from your work, but equally it’s rather dispiriting to see people claiming your ineptitude (and that of your colleagues) though their own ignorance. Still, that’s why we keep going, we might bring them round yet.

Linheraptor vs the international media

I was not too involved in the PR stuff done for Linheraptor, but after previous experiences with the press (and in the light of this recent, and superb, article) I am interested and intrigued as to just how these stories get circulated and written up to appear in the media. As before, there seemed to be several errors that were introduced early on (and it’s really not clear how) by some newsies which were then replicated and / or added to in subsequent generations of stories. Muller’s ratchet seems to apply to science journalism.

For example:

- The main photo of the cast of Linheraptor was said to be the original specimen by just about everyone, even by those who I e-mailed the photo to directly, telling them it was a cast, and not the original.

- Similarly, this photo was credited to the Journal Zootaxa in which the paper appeared and not me who took the image. This is odd, since again, I sent out the image saying I took it, and with a copy of the paper in which said photo obviously does not appear.

- While losing out here, happily I was credited with creating the life reconstruction that Matt van Rooijen did for us despite him having signed it, and his name appearing in all the source information sent out the media.

- The American Jonah Choiniere and British (admittedly via Hong Kong) Mike Pittman were credited as being Chinese students in at least one source too.

- The new taxon was described as being the nearest relative of Velociraptor, despite the fact that this is explicitly not what the paper says and several people even lifted quotes directly from the paper saying this was not the case.

- Finally (of the things I have spotted and am bothering to list here, I can’t help but rather suspect there are a few more out there) apparently we were able to tell this was a new dromaeosaur because of the shape of the raptorial claw which is nonsense.

You do wonder how some of these people continue to keep hold of a job. All they seem to do is recycle each others words incorrectly and somehow make a career of it. Nice work if you can get it, but since no one else seems to realise they are doing it badly, it carries on. Really how hard is it to copy someone’s name from an e-mail into an article, or check all of 2 figures in the paper to see that they are different from the photo in front of you. And when the correct information is available in the paper, in the press release and as an online resource, why are you copying from third and fourth hand sources in the first place? Really, I want to know. How are they doing this? ‘Pushed for time’ doesn’t really cut as an excuse when you are only writing 200 words or are 3 days behind everyone else on the story.

Quirks of palaeontology

It can be an odd job working as a palaeontologist. There are probably few professions that combine the academia of research and teaching with physicality of fieldwork (except perhaps, chessboxing). Even so, some things that are commonplace in the world of palaeo would probably be considered really quite odd by anyone else, even those within the sciences. Last week I was out at the IVPP’s storage facility with Pauls Upchurch and Barrett (hence the post on traveling crates) and there are a few sights there that might phase the inexperienced. Like finding a lifesize fiberglass pterosaur resting in a window to dray, a tool rack supporting a hadrosaur vertebral column, a tricycle with a pile of bones in the back, and a life size plaster cast of an elephant sitting under plastic sheeting. You probably couldn’t make it up. Does generate fun pictures though…

Continue reading ‘Quirks of palaeontology’

Quick update on Flugsaurier 2010

Two minor updates have come through on <a href=”http://pterosaur-net.blogspot.com/2010/02/details-for-2010-flugsaurier-meeting.html”>this meeting</a> from Lu Jungchang so I thought I should put them here:

“Hello everyone, please pay attention to the following two changes about the pterosaur symposium:

1. Abstract deadline (May 15):

We have just received news that abstracts for Flugsaurier 2010 will be published in the Journal Acta Geoscientica Sinica. In order to ensure that everyone has enough time to prepare and submit abstracts we have decided to postpone the deadline for abstract submission to May 15. Please note that the page limit is now set at 4 pages. All other details remain as in the second circular.

2. Invitation letter.

If you need an invitation letter in order to secure a visa please make sure that you send us your passport details”.

And finally since people don’t seem to have quite picked up on this. DO NOT E-MAIL ME WITH YOUR QUESTIONS. I am helping out with the organisation of the meeting, but any questions should go to Dave Unwin or Lu Jungchang, not me.


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