A Body for Terrible Hands

It was a whirlwind year for dinosaur palaeontology, yet again. This week I'm writing about what I consider the most important news in my science field for 2014, for the Science Borealis blog carnival. There are so many great stories to choose from! Kulindadromeus and feather-like structures in ornithischians? The bizarro new reconstruction of a short-legged Spinosaurus? Both of those stories were pretty interesting, but my choice has to be the description of multiple skeletons of the Mongolian ornithomimosaur Deinocheirus.

If you like dinosaurs, there's a good chance you've heard about Deinocheirus before, even if it's not quite a household name like Stegosaurus or Triceratops. Deinocheirus (which means "Terrible Hands") was found during the Polish-Mongolian expeditions in the 1960s, and up until very recently has only been known by this single specimen, a pair of tremendous arms. And I do mean tremendous!

Me, in 2007, mimicking the 'zombie arms' of Deinocheirus, rather convincingly if I do say so myself.

A few years ago, the quarry for this holotype specimen was relocated and some gastralia (belly ribs) were found and described, but besides that this has been it. What on earth did the rest of this dinosaur look like? Was it a carnivore, herbivore, or something else? Where did it fit in the Cretaceous Gobi ecosystem?

While the exact evolutionary relationships of Deinocheirus have been enigmatic, there's been a general consensus that it was some kind of ornithomimosaur, or ostrich-mimic dinosaur. Even if you're not a dino-buff, you'll recognize ornithomimids as the stampeding dinosaurs in Jurassic Park – Gallimimus was the one 'flocking this way', and, conveniently, Gallimimus is a commonly encountered fossil in the Upper Cretaceous rocks of the Gobi Desert and would have lived alongside Deinocheirus. Where Gallimimus is an elegant, sprightly kind of dinosaur, Deinocheirus, it turns out, is not at all, not even a little bit.

It turns out that Deinocheirus is even more surprising than we would have ever guessed; the giant arms are nothing compared to the weirdness of the rest of its skeleton. Deinocheirus looks like a cross between a therizinosaur and a hadrosaur. It's a big, broad-bellied ornithomimosaur with a 'sail' of heightened neural spines on its vertebrae, and a widened, shovel-like snout with a deep jaw and tiny eyes. It looks like it was adapted for eating vegetation and had gastroliths preserved in its stomach region, but also had fish scales in there as well, prompting the authors to describe it as a megaomnivore, which is among my new favourite words of the year. Given that its close relatives the ornithomimids are known to have had feathers, as well as many other theropod dinosaurs, it is most likely that Deinocheirus had at least some feathers.

Deinocheirus, by the always-incredible Michael Skrepnick.

I will forever be jealous of my colleague Derek Larson, who was on the 2009 Korea-Mongolia International Dinosaur Project expedition that found the new skeletons of Deinocheirus (I was there just a year later, and it was a great year...but no Deinocheirus). I'm so thrilled that I've been able to see the original bones in person, and they really are quite something to see – I hope that the specimen will eventually be mounted and put on display so everyone can see it for themselves, too!

The "Canadian contingent" (which actually includes at least one American and one Australian, but let's not be too picky) at the 2013 Hwaseong International Dinosaurs Expedition Symposium last December, gawking away at Deinocheirus.

Deinocheirus is also an important reminder that Mongolian fossils are under threat. Sadly, many probably excellent skeletons are removed illegally from Mongolia every year – no fossils are allowed to leave the country without a permit, and none can be sold, so any fossils from "Central Asia" on the auction blocks are almost certainly stolen goods. The Deinocheirus skull had made its way out of Mongolia some years ago, and was, thankfully, repatriated to Mongolia when word of the new skeletons began to circulate throughout the palaeontological community. Incredibly, the skull actually belonged to one of the newly collected skeletons! This is a story that could have ended very differently – we might not have known about the strange skull of Deinocheirus because of fossil poaching.

Poached fossils make everybody sad! Here Phil Currie is showing the remains of a tyrannosaur skull that was improperly collected by poachers and destroyed in the process.

So why choose Deinocheirus over Kulindadromeus or Spinosaurus? Like I said, all three are top contenders for the most surprising finds of 2014. In some ways, the fuzz of Kulindadromeus is less surprising, and its significance lies in the fact that it lends support to the hypothesis that fuzz was present in most dinosaurian clades. Spinosaurus has also long been considered a specialist in aquatic foods, so while the new skeletal revision is certainly weird, it's not quite a fundamental re-envisioning of this beast. But Deinocheirus is way beyond what anyone would have ever predicted the rest of the skeleton would have looked like, and just goes to show that there are surprises waiting around every corner for us when it comes to dinosaur diversity. And, in my opinion, Deinocheirus leads to even more questions than it answered: what was it doing with that sail; why is its jaw so deep and its eyes so small; what kind of environment produces a megaomnivore like that; are any of the bits and pieces of what we thought was Gallimimus actually parts of juvenile Deinocheirus? I could go on and on.

Congratulations to my colleagues in Korea and Mongolia for organizing the Korea-Mongolia International Dinosaur Project expeditions – I'm sure this is just the first of many wonderful projects that will result from those years of fieldwork.

Know Your Ankylosaurs: Mongolia Edition!

After a whirlwind couple of weeks with a bunch of international travel, I've finally had a chance to sit down and write about my most recent paper on the ankylosaurs of the Baruungoyot and Nemegt formations of Mongolia. I've been interested in these ankylosaurs for a long time now, both because of their interesting cranial anatomy and their relationships to the ankylosaurs of North America (especially Alberta). So, here's a plain-language summary of some complicated taxonomy! Hooray!

Part the first: Dyoplosaurus giganteus

A toe!

We need to start here because Dyoplosaurus giganteus is the first of the ankylosaurs in this manuscript to have been named. Based on a fragmentary postcranium, Dyoplosaurus giganteus was considered similar to the North American Dyoplosaurus acutosquameus (pre-dating the synonymy of Dyoplosaurus with Euoplocephalus), but larger. Unfortunately, the holotype lacks any diagnostic characters that can differentiate it from specimens discovered since its original description, and so D. giganteus must be considered a nomen dubium. Which is important because...

Part the second: Tarchia

...it was partly synonymized with the newly-named genus Tarchia, based on similarities between the osteoderms, which then included Tarchia gigantea and Tarchia kielanae. Most people picture the beautifully preserved skull in the PIN collections as 'the' Tarchia, but in fact it is not the holotype of either D. giganteus or Tarchia kielanae. T. kielanae's holotype is a partial skull roof. Later, Tarchia kielanae was considered a junior synonym of Tarchia gigantea because it's quite fragmentary and there weren't any obvious differences between the two skulls. But here's the catch: the holotype skull of Tarchia kielanae does indeed preserve a diagnostic character that is not present in the PIN 'Tarchia' skull – a weird little ossification that sits on/in front of the squamosal horn, but isn't the squamosal horn. This feature is found only in one other described specimen – the holotype of Minotaurasaurus ramachandrani.

On the left, a sketch of T. kielanae's holotype from Maryanska's 1977 paper; on the right, a cast of the holotype of Minotaurasaurus.

The end result is that:

1.  Tarchia kielanae is valid

2. Minotaurasaurus is a junior synonym of T. kielanae

3. There are no diagnostic features in D. giganteus and no reason to refer the PIN skull to Tarchia, so T. gigantea is redundant.

4.  I'm sorry other ankylosaur workers, this really messes things up.

The Minotaurasaurus holotype is much more complete than the T. kielanae holotype and provides most of the anatomical information for Tarchia kielanae. Tarchia kielanae has extremely narrow squamosal horns, a prominent prefrontal caputegulum, four internarial caputegulum, a huge mandibular caputegulum, and that distinctive ossification above the squamosal horn.

Part the third: What about Saichania?

The Museum of Evolution in Warsaw has a cast of Saichania with the elements in situ.

Saichania is safe! This is an easily diagnosed taxon based on a GREAT holotype which includes a skull and front half of the postcrania and osteoderms that were articulated at the time of discovery (a cast of the in situ specimen shows the original arrangement). But, Saichania is probably not what you think it is – most people (well, at least those who think about such things) will probably visualize the mounted skeleton found in several museums/traveling exhibits. In one of my previous papers I argued that this skeleton should not be referred to Saichania based on several differences of the postcranial anatomy, and its provenance from the Djadokhta Formation rather than the Baruungoyot Formation. (The skull on this mounted skeleton is a cast of the holotype Saichania skull, and so unfortunately there isn't a lot of overlapping material.) Instead, that skeleton is possibly a relatively mature Pinacosaurus, or something different entirely.

Not Saichania, unfortunately! (Except for the head.) But maybe a big Pinacosaurus?

What about the PIN 'Tarchia' skull? 

So amazing!

Although it has a few small differences compared to the holotype Saichania skull, my best assessment right now is that this skull should also be referred to Saichania, not Tarchia. Both skulls have robust squamosal horns compared to the rediagnosed Tarchia, a small prefrontal caputegulum and large loreal caputeglae, and only a single internarial caputegulum. Eventually, as more specimens are found and described, it might be worth creating a new species of Saichania for the PIN skull, especially given that it was found in the Nemegt Formation and the holotype of S. chulsanensis is from the Baruungoyot Formation. Alternately, there might just be a single species of Saichania in both formations – a better understanding of the dinosaur biostratigraphy of Mongolia is much needed!

Part the fourth: A new kid on the block!

Meet Zaraapelta nomadis, a new ankylosaurid from the Baruungoyot Formation! This specimen was collected during the 2000 Dinosaurs of the Gobi expedition organized by Phil Currie and Nomadic Expeditions. 

Please enjoy this beautiful life restoration of Zaraapelta by my lovely and talented friend Danielle Dufault!

Zaraapelta has some features that indicate it's relatively closely related to Tarchia, including prominent prefrontal ornamentation. However, it has a couple of unique features that show that it is distinct – the squamosal horns are deep, like in Saichania, and there is extensive ornamentation behind the orbit. The squamosal horn also has a weird double-layered texture that I haven't encountered in any other ankylosaurid. At the moment we only have a skull for Zaraapelta, but I'm hoping that with the revision of ankylosaurid taxa I've proposed in this manuscript, future workers will be able to identify more specimens for these taxa as well!

And many thanks to Jessica Tansey, who did the technical illustrations of the skull for me while she was an undergrad at the UofA!

Part the fifth: Tail club conundrums

A cast of the ZPAL MgD I/113 tail club in the UALVP collections.

One really neat thing that I've mentioned in a couple of previous papers is that one specimen collected by the Polish-Mongolian expeditions in the 70s has a weird and unique tail club morphology. In pretty much all ankylosaurids, the tail club handle vertebrae look like a nested series of Vs in dorsal view, and the angle formed by the point is about 20-22 degrees. Ankylosaurus is the odd one out because it has distinctive U-shaped vertebrae. And ZPAL MgD I/113 has a morphology that's in between these two – not quite U-shaped, but not as sharply pointed as the V-shaped morphology in other ankylosaurids. There are also specimens from Mongolia with the V-shaped morphology, so we've got at least two species represented by tail club handles. But here's the problem: although we've got some really great skulls, partial skeletons, and skeletons with in situ osteoderms, there actually aren't any skeletons with both a skull and a tail club from these formations in Mongolia! Do either of the tail club morphotypes belong to the named species from Mongolia? Or does the unusual tail club handle represent a new species in the Nemegt Formation? We'll only be able to figure this out if we find a skull and tail club in the same specimen, but it would be pretty exciting if we were able to name another new ankylosaur from the Gobi.

So, that's a brief overview of the taxonomic stuff from the new paper. But before we finish, I want to pause for a moment to acknowledge one of my coauthors who couldn't see the paper in its final published form. Very sadly, our friend Badam passed away suddenly last December, which came as a shock to those of us who've benefited from her kindness and generosity while we've visited Mongolia. I wish I had had more time to spend with Badam, but I'm extremely grateful for the times I got to spend with her in Mongolia and when she visited Edmonton a few years ago. She is a presence that will be missed.

Miriam, Badam and I at Nemegt in 2007. A happy time. We miss you, Badam.

I'm glad to see this paper finally published - it was another one of those multi-year projects to visit lots of museums in order to see all of the necessary specimens - and it was a nice send-off for my time at the University of Alberta. Last weekend I moved down to Raleigh, North Carolina to begin a postdoc with Lindsay Zanno at the North Carolina Museum of Natural Sciences/North Carolina State University. I had an amazing time in Edmonton and I'm sure that's not the last Alberta will see of me, and I'm hoping to accomplish some fun things here in Raleigh. To new adventures!

If you want to learn more about Zaraapelta and friends, try:

Arbour VM, Currie PJ, Badamgarav D. 2014. The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia. Zoological Journal of the Linnean Society 172:631-652.

Watch my awkward face on Global TV! (Also with footage from the Discovering Dinosaurs exhibit!)

Scaling Up

Let's turn our attention from hadrosaur skin to ankylosaur skin, a topic which has received surprisingly less attention in the published literature than I would have thought. I should qualify that statement, however, by saying that by 'ankylosaur skin' I mean ankylosaur skin impressions, because ankylosaur dermal elements are well known and the focus of many a paper – I refer of course to osteoderms, which form within the dermis of the skin and which give ankylosaurs their spiky and armoured appearance.

For a couple of years now I've been keeping notes about occurrences of skin impressions in ankylosaurs, which eventually lead to a paper by myself, Mike Burns, Phil Bell, and Phil Currie. We reviewed the morphology of scale patterns in the few specimens that preserve skin, and found that there were some intriguing differences in scalation between different ankylosaurs.

The holotype of Scolosaurus cutleri, NHMUK R5161, has the best preserved integument for any North American ankylosaur, and has loads  of scale impressions lying overtop of the in situ osteoderms. In Scolosaurus, the scales form rosettes around the osteoderms. The largest scales are generally found closest to the osteoderms, but some large scales are scattered in between the osteoderms as well. Underneath the scales, small ossicles (little osteoderms less than 1 cm in diameter, but usually only 2-4 mm wide) fill the spaces between the larger osteoderms.

Scolosaurus is hard to photograph well, sorry!

In contrast, a very unusual specimen (ROM 813) has a completely different morphology. This specimen includes unusual long, rectangular osteoderms that aren't present in NHMUK R5161. The scales are on average much smaller, don't form much of a rosette pattern around any of the osteoderms, and are more uniform in size overall. ROM 813 is a little bit difficult to interpret because it is partially disarticulated (which is also intriguing given that such large portions of the integument are intact), but our best guess for the preserved portions is shown here.

Another super cool thing about ROM 813 is that it preserves the epidermal covering of an osteoderm, and it is the only example of this in an ankylosaur that I know about. In the photo below, the smooth side of the osteoderm is the epidermal scale, and the rough side of the osteoderm is the true bony part of the osteoderm.

Moving over to Mongolia, a specimen referred to Tarchiagigantea lacks the small pavement of ossicles seen in the Albertan ankylosaurs, and the epidermal scales are huge and more rectangular. In the portion of the integument preserved, osteoderms are separated by only one row of scales.

There's enough overlapping material between these specimens to allow us to compare scale patterns among different ankylosaurs, and the differences support the hypothesis that these are different taxa. Unfortunately, right now we can't assign ROM 813 to any known ankylosaurid taxon from Alberta – this could represent the postcrania of Euoplocephalus tutus, or Dyoplosaurus acutosquameus, or (less likely) a new taxon of ankylosaurid from the Dinosaur Park Formation. I think it's safe to say that the differences between Scolosaurus and ROM 813 represent true taxonomic differences, a finding that is in line with previous work by Phil Bell on scalation differences between Saurolophus angustirostris and Saurolophus osborni.

Illustrations by Lida Xing and via PLOS ONE.

One more comment about ankylosaur skin: In 2010 I had the opportunity to study the holotype of Liaoningosaurus paradoxus, and very interesting little ankylosaur from the Liaoning Formation of China. The original authors described Liaoningosaurus as possessing a ventral plastron (bony shield, like that found in turtles), which would have been a highly unusual anatomical feature given that no other ankylosaurs possess a plastron. Having looked at this specimen, I think a better interpretation for the plastron is that this is a segment of skin impressions from the belly region – there didn't seem to be any bony texture around the edges of this area, and the pattern is more consistent with scales than any osteoderms in other ankylosaurs.

Belly scales for Liaoningosaurus. The scale bar is in millimetres.

Papers!

Arbour VM, Burns ME, Bell PR, Currie PJ. 2014. Epidermal and dermal integumentary structures of ankylosaurian dinosaurs. Journal of Morphology 275:39-50.

Arbour VM, Lech-Hernes NL, Guldberg TE, Hurum JH, Currie PJ. 2013. An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions. Acta Palaeontologica Polonica 58:55-64. Many thanks to Dr. Hurum for inviting me to help describe this specimen!

Bell PR. 2012. Standardized terminology and potential taxonomic utility for hadrosaurid skin impressions: a case study for Saurolophus from Canada and Mongolia. PLOS ONE 7:e31295.

Xu X, Wang X-L, You H-L. 2001. A juvenile ankylosaur from China. Naturwissenschaften 88:297-300.

Thoughts on Tarbosaurus, part 4

Well, a lot has happened since the auction of a nearly complete Tarbosaurus was halted last May. At the end of December, Eric Prokopi surrendered his claim to the Tarbosaurus and other Mongolian and Chinese dinosaur fossils in his possession, and pleaded guilty to several charges surrounding the Tarbosaurus case. The Mongolian government is renewing its commitment to preserving its outstanding natural history heritage by creating a new dinosaur museum in capital city Ulaanbaatar, and several museums elsewhere in the countryside.

I hope the awesome leather Tarbosaurus makes the trip to the new digs.

Most recently, Paige Williams wrote an excellent article for the New Yorker interviewing many of the people involved in the Tarbosaurus case, including Prokopi. "Bones of Contention: A Florida man's curious trade in Mongolian dinosaurs" was an illuminating read for me, despite having followed the case closely. A few things struck a chord with me, because I was surprised by some of the attitudes displayed by people who are otherwise portrayed as 'passionate' about paleontology.

Prokopi started out as what seems like a pretty avid rockhounder and fossil buff growing up in Florida. Indeed, several previous news stories have portrayed Prokopi as simply doing what he loves. After university, he began selling fossils full time. He cleaned fossils, and sold small items to museums and nature centres. For the most part, this seems like pretty legit stuff. But then Paige quotes Prokopi: "One thing I was wondering is if any of these paleontologists you've talked to have given their argument of why paleontology is important...[fossils are] just basically rocks...It's not like antiquities, where it's somebody's heritage and culture and all that."

You can't have it both ways. You can't call yourself a 'commercial palaeontologist', co-opting the name of a scientific discipline, and then turn around and question the purpose or validity of palaeontology.

Later, Paige quotes Prokopi's wife Amanda: "And for what? For bones? No one's been murdered. We restored a dinosaur."

Tarbosaurus on display at the Mongolian Natural History Museum, in 2007.

So look, I get it. Stealing a dinosaur isn't as bad as murdering someone. And no, palaeontology isn't curing cancer or finding renewable energy or solving world conflict or any of those big-ticket items. But I'd like to think we live in a world where we don't have to funnel all of our resources into just the absolute bare minimum required to survive. I'd like to think that we have it in our hearts and our minds (and our pocketbooks) that we can study things that do not have immediate, direct, tangible, GIGANTIC benefits. I'd like to think that we live in a world where understanding nature and evolution and animals and biodiversity and our planet are TOTALLY OK things to spend one's time thinking about. Stealing a dinosaur doesn't have to be as bad as murder to still be a crime, and palaeontology doesn't have to cure cancer in order to have value.

I don't know what the take-away message from this post is, but I guess all of us in palaeontology and other sciences need to keep talking to the public, keep talking to policy makers, and keep trying to inject some enthusiasm for curiosity, exploration, and critical thinking into our everyday worlds. That's not too big a task, right?


For previous rants about this whole affair, see:
Thoughts on Tarbosaurus, part 1: in which I discuss the role of museums in conserving fossils.
Thoughts on Tarbosaurus, part 2: in which I discuss the identity of Tarbosaurus and how we know it's from Mongolia.
Thoughts on Tarbosaurus, part 3: in which I discuss why fossil poaching is a bad thing.

Thoughts on Tarbosaurus, Part 3

Previously in this series on the poached Tarbosaurus skeleton, I've discussed the role of museums in fossil collecting, how the specimen was identified as Tarbosaurus, and how we know the skeleton came from Mongolia. Today, I'll discuss one final question: Why is fossil poaching such a big deal, anyway?

(Various museum trips, manuscript deadlines, and fieldwork in Dinosaur Provincial Park have kept me from returning to the blog as quickly as I had hoped, and much has transpired in the Tarbosaurus case in the last few weeks; in particular, see Phil Currie's article in New Scientist. Hopefully, posting will become a bit more frequent, and optimistic, in the next little while.)

To me, it seems obvious why fossil poaching is a big deal (in a bad way) - it reduces or removes access to fossil specimens, and reduces or removes important information about that fossil. First, let's talk about access to fossils. As I discussed in part 1 of this series, the role of museums is to conserve artifacts for present and future generations; additional responsibilities include facilitating research and education, and usually involve displaying objects to the public. Private owners of fossils have no such responsibilities. Some private collectors may choose to display some of their fossils to friends and family, or may even open their private residence to visitors. But they don't have to, and most fossils held by private collectors are probably only ever seen by a handful of people. For really common, super-abundant fossils, perhaps this is not a terrible thing. Vertebrate fossils are rarely common and abundant, and each specimen often has important information to contribute to the study of any particular organism.

A second point about access that is probably not widely known is that palaeontologists cannot really study or publish on privately-held fossils. This is because other palaeontologists may not be able to access those specimens to verify the original palaeontologist's findings, and so therefore the science would not be reproduceable. There are probably lots of instances where private collectors have made substantial contributions to museum collections by donating their discoveries or purchases, but while the specimen is privately held, it is, for all intents and purposes, 'invisible' to the scientific community. A specimen that cannot be published in the scientific literature does not contribute to our understanding of the fossil record, and represents lost knowledge. This is why it is important for fossils to be in recognized institutions like museums or university collections, so that palaeontologists (and the public!) can study the material and use it to better understand our world.

Next, let's talk about how poaching reduces the information content of fossils. Fossils do not exist in a vacuum. The sediments encasing a fossil are nearly as important as the fossil itself, as these provide at least two crucial pieces of information about the fossil: 1) how old it is, and 2) what the depositional environment was. Interpreting the age and depositional environment of a rock is not always easy, and requires specialized training in geology in order to be done properly. When a fossil is yanked out of the rock with no attention paid to where or how it was found, important information is lost.

Pop quiz! Is that the Nemegt or Baruungoyot Formation?

Finally, and most obviously, poaching can damage the fossils themselves, if the poachers do not have the appropriate tools or training to properly excavate the fossils. The more a fossil is broken, the more information is lost. Collecting fossils is tricky, difficult work that requires a lot of patience and strength. Without the right tools and people, fossils get broken. Amateur or commercial collectors may be excellent record-keepers and skilled excavators, and so this may not be a problem - but from my experience at least in Mongolia, poachers don't seem to be really good at collecting the dinosaurs they aim to sell.

 See those white bone fragments there? Those used to be a Tarbosaurus skull.

I hope the attention given to the Tarbosaurus auction marks the beginning of the end of fossil poaching in Mongolia, although I suspect I may be being overly optimistic with that sentiment. But fossil poaching and destruction is not limited to Mongolia, as evidenced by a tragic story that happened basically in my backyard this week. A few weeks ago, the University of Alberta and Pipestone Creek Dinosaur Initiative field crews found a beautiful hadrosaur skeleton, with skin impressions, along the Red Willow River near Grande Prairie. The PCDI team was excited because this would make for a great display specimen (not to mention it being a scientifically important specimen) for the museum they are working very hard to get funded and built. Earlier last week while in Dinosaur Park, we received the terrible news that the partially-excavated, plaster-jacketed specimen had been vandalized and severely broken. We're not sure who did it or why. Even earlier in the summer, an in situ display of the Pipestone Creek Pachyrhinosaurus bonebed had been smashed and vandalized as well.

In Alberta, excavating fossils without a permit, or damaging fossils, can get you a $40 000 fine and/or a year in prison. Nowhere else in Canada has fossil protection laws as good as Alberta's, and in no other province is the general public as widely educated about fossils. Fossils are everywhere in Alberta, we have an abundance of museums and public outreach, several universities conduct palaeontological research, and there's an active amateur society. And STILL people feel the need to wreck our fossils - no, scratch that, THEIR fossils. I find this intensely discouraging, and I don't have a good solution.

Given the recent international attention on the Tarbosaurus case, I hope Alberta sets a good example by prosecuting the fossil vandals to the fullest extent possible, if they are able to catch them. At the very least, I hope that this provokes a renewed interest in protecting our amazing fossil resources. Wherever you're from, support your local museums and universities, and be interested in the natural world around you. It will take all of us working together to protect it.

Thoughts on Tarbosaurus, Part 2

In my last post I talked about the role of museums in conserving fossil resources, with regards to the recent news about the Tarbosaurus auction. I wanted to address some of the other frequent comments I have seen on blogs and news articles. So, we’re now on to:

Comment 2: How do we know the tyrannosaur came from Mongolia? (and the related question, which I’ve decided to lump with this one: Why does the auction company, and subsequent news stories, refer to the specimen as Tyrannosaurus bataar while palaeontologists call it Tarbosaurus?

The first thing we need to address with these questions is the concept of ‘species’. In high school, most of us will have learned that a species is defined as a group of interbreeding individuals that can produce fertile offspring. This is called the Biological Species Concept. What many people may not know is that this is just one of many species concepts. Palaeontologists can’t go back in time to check on which dinosaurs were interbreeding, so the biological species concept can’t really be used in palaeontology. Instead, we generally use the Morphological Species Concept, which essentially boils down to ‘a species is a group of individuals that look like each other and not like others’.

Much of the arguing and debate in palaeontology results from the problems associated with the morphological species concept, and that is because individuals from the same species can look different from each other, and individuals from different species can look similar to each other. Biologists working on still living (‘extant’) animals need to worry about three main sources of morphological variation:

1.      Changes that occur during growth: An older individual of the same species can look different from a younger one.

2.      Sexual dimorphism: Males and females of the same species may look different.

3.      Normal individual variation: Individuals within a species can look different from each other because of normal variation resulting from small genetic differences and environmental differences. As an example, think about all the different dog breeds there are today. All dogs can interbreed (theoretically, although surely a Great Dane crossed with a Chihuahua must be pushing the limits of what is practical...) and produce fertile offspring, and belong to the same species, Canis familiaris. On top of that, all dogs are descended from domesticated grey wolves, and so many scientists regard them as a subset of the species Canis lupus. In taxonomic terms, this is called a subspecies, and we would write it as Canis lupus familiaris.

 Via Wikimedia Commons.

Palaeontologists need to add one more source of variation because we work with fossils, and that is:

4.     Changes that occur during fossilization (‘taphonomy’): Most fossils preserve only the skeleton, and so information from soft tissues like colour, integument, and muscles is lost. Skeletons become disarticulated, and individual bones get broken. All of this reduces the amount of information we have to work with. Finally, the remaining bones can become squished and distorted because of the extreme forces that occur as rocks form.

 Disarticulated Argali sheep skeleton in Mongolia, 2010.

Finally, it is important to remember that the natural world doesn’t always fit into discrete categories, and that the concept of species, genus, etc. is something that humans have created to help sort living things into workable categories. How many differences do two populations need to have in order to call them different species? How many differences until we split things into different genera? There isn’t really an answer to those questions, and so deciding on what are ‘species-level’ differences vs. ‘genus-level’ differences is the source of much debate.

But that’s ok, because that is a big part of what is fun about taxonomy and palaeontology!

So, moving on to Tyrannosaurus rex vs. Tyrannosaurus bataar vs. Tarbosaurus bataar. Tarbosaurus bataar and Tyrannosaurus rex have several morphological differences in the skull, but these are not necessarily obvious if you’re not accustomed to anatomical terminology or used to looking at skulls. Nevertheless, they are present, and there is an excellent, free to access paper in Acta Palaeontologica Polonica that you can go download right now to see for yourself. In a nutshell, the skull of Tarbosaurus is narrower than Tyrannosaurus when you look at it front on, and the nasal bones (the bones along the top of the snout) are domed near the front of the eyes. Additionally, the arms of Tarbosaurus are proportionately even shorter relative to the rest of the body than those of Tyrannosaurus, which are already pretty short.

Tarbosaurus bataar partial skull at the Palaeontological Institute in Moscow.

Tyrannosaurus rex skull at the Royal Tyrrell Museum in Drumheller, Alberta.

It’s pretty clear that Tarbosaurus bataar and Tyrannosaurus rex represent different species, because these differences are geographically separated. Small-armed, narrow-skull tyrannosaurs are only found in Mongolia, and longer-armed, wider-skull tyrannosaurs are found only in North America. You could make an argument that perhaps the differences are insufficient to warrant having two genera, in which case the genus Tyrannosaurus has priority over Tarbosaurus because it was named first. However, most palaeontologists accept both the genus Tarbosaurus and the genus Tyrannosaurus as being valid. So why did the auction house consistently call their skeleton Tyrannosaurus bataar? I can’t say for sure, but I suspect it is because Tyrannosaurus is much more a household name than Tarbosaurus, and this makes the skeleton more recognizable and interesting. It’s easier to tell someone your skeleton is a Tyrannosaurus than to do what I’ve just done here and explain how there is a similar, but different, tyrannosaur in Mongolia called Tarbosaurus.

So, we can look for anatomical features in the skull and skeleton that indicate whether or not the tyrannosaur was a Tarbosaurus or a Tyrannosaurus. But how do we know that the skeleton came from Mongolia? Well, much like certain animals today are found only in certain places, some dinosaurs were found only in some places and not others. Tarbosaurus has so far only been recovered from the Nemegt Formation, a set of rocks that are only known in the Gobi Desert of Mongolia. If the skeleton is shown to be a Tarbosaurus, and not some other species of tyrannosaur, then the conclusion we must come to without any additional information is that the specimen comes from Mongolia. We can also use the colour and preservation of the bones to identify where the skeleton came from, because different rock units will produce differently coloured fossils (in Alberta, dinosaur bones are often brown or black, and in Mongolia, they are often white or reddish).

If for some reason there was good evidence that the skeleton did not, in fact, come from Mongolia, that would only make the specimen more scientifically important, as it would extend the geographic or stratigraphic range of the genus Tarbosaurus and would give us important new information about that genus.

I had originally hoped to post this second part much sooner, and so much has transpired since my original Tarbosaurus post. I’m particularly pleased to see that a delegation of Mongolians and palaeontologists examined the auctioned Tarbosaurus this week as part of the investigation into the specimen. You can read their report at the Painter Law Firm's website. I also highly recommend this article at the Guardian by palaeontologist Dave Hone, and many thanks to Brian Switek at Dinosaur Tracking for his kind words about my first post in this series.

Literature!

Hurum JH, Sabath K. 2003. Giant theropod dinosaurs from Asia and North America: skulls of Tarbosaurus bataar and Tyrannosaurus rex compared. Acta Palaeontologica Polonica 48:161-190.

Thoughts on Tarbosaurus, Part 1.

Last time I promised photos of our fieldwork here in Edmonton, but then over the weekend the palaeoverse kind of erupted (in a good way) over the auction of a Tarbosaurus skeleton. Go read Brian Switek’s articlefirst if you’re not acquainted with the story.

Because I am insane, I often read the comments sections on news articles about palaeontology. There are a lot of weird and misguided statements in the comments sections of some of the Tarbosaurus auction news articles (e.g. at CNN, USAToday, Wired). Some of these comments make me frustrated, so I figured I’d try to write down my thoughts on some of the most common recurring themes: 1) Paleontologists are just as bad as fossil poachers and/or private collectors because we hoard the dinosaurs all to ourselves and lock them away in cabinets where the public can’t see them; 2) How do we know the tyrannosaur came from Mongolia?; 3) Why does the auction company call it Tyrannosaurus bataar while palaeontologists call it Tarbosaurus?; and 4) Why is fossil poaching such a big deal, anyway? I’m going to address these over a couple of blog posts because for some reason on these topics I am unusually longwinded and the answer to the first question was getting kind of gigantic.

So, to start with: “Paleontologists are just as bad as fossil poachers and/or private collectors because we hoard the dinosaurs all to ourselves and lock them away in cabinets where the public can’t see them.”

I sort of understand where this sentiment is coming from, but unfortunately it is wholly incorrect, and it saddens me that there folks who have become disenfranchised with science in this way. The role of museums is to conserve artifacts for the long haul – not just a few years, not just this generation, but theoretically for hundreds and hundreds and hundreds of years. Museums also facilitate scientific research (thus contributing new knowledge to society), and education (passing new and old knowledge to members of society). Although there are privately-run museums, many museums in Canada are at least partially supported by the government – ie. the Royal Tyrrell Museum in Alberta, the Canadian Museum of Nature in Ottawa, and the Royal Ontario Museum in Toronto. Because these are publicly-supported institutions, their role is to conserve cultural and natural history artifacts for the people, and so the whole concept of fossils being locked away from the public in museums is largely incorrect.

But let’s dig a little deeper (har har). Yes, a lot of specimens are stored in cabinets and rarely seen by the public. This is not because palaeontologists are trying to ‘hide’ specimens, but because at any museum there is limited space and funding for exhibiting specimens. Choosing which specimens go on display involves a lot of factors: is the specimen sturdy enough to be mounted or displayed, does the specimen need to be easily accessible for research, is there enough space to display the specimen, will it require special new cabinetry and lighting, will it require an entire overhaul of the existing displays or can it be slotted into an existing gallery, how much new interpretive material needs to be created, and more. Not all fossils make great display specimens, but that does not mean they are ‘worthless’ or have little scientific value. For example, many studies require the identification and measurement of THOUSANDS of teeth and bone fragments. How else can you know if a particular fossil is rare unless you have a large, unbiased sample? Yes, we could display these tiny fossils, and I actually think that would be a great way to teach the value of large collections of otherwise mundane fossils. BUT given the option of displaying 1000 Paronychodon teeth in a glass cabinet, or one really excellent Albertosaurus skull, it makes sense that the museum would display the showier, more easily relatable object (sorry, Derek). In a perfect world we would not need to make that choice, but in reality there are constraints on what can be displayed based on time, money, and space.

A lot of commenters on the news articles have mentioned that a lot of museums offer ‘backstage tours’ to the collections areas. While this is true, it is also true that many museums require visiting researchers to be professional palaeontologists associated with either a museum or university (or to be a student studying towards that profession). I can’t speak for all museums here, but I suspect that the main reason for limiting visitors to the backstage areas comes back to conservation of the material. A lot of fossils don’t do well with repeated handling, and even gentle handling by careful scientists (or contact with things like metal calipers!) can gradually erode and damage specimens. As such, limiting access to the collections is not really because we want to hoard the fossils and keep them to ourselves, but out of concern for the long-term safety of irreplaceable objects. The flip side of this is that some museums have dedicated teaching and outreach collections of sturdier specimens that can be handled often.

But a lot of these comments seem to come back to a sense of distrust of professional palaeontologists, and perhaps a distrust of the ‘scientific establishment’ as a whole. I don’t really know what to say to this – yeah, there are probably some really awful people who are also palaeontologists, who don’t look kindly on amateur palaeontologists or private collectors, and who may be generally unpleasant people to be around. But there are awful people in every profession. It doesn’t excuse their behaviour, but there’s not necessarily a lot any one of us can do about it. From my experience, the vast majority of professional palaeontologists are just that – professional. They are excited to learn more about life on earth, to contribute to the scientific record, and to educate the public about those findings. They like dinosaurs (or brachiopods, or trilobites, or sabre-toothed cats) SO MUCH that they literally want to spend their entire career thinking about them ALL THE TIME. (There is no escape.) Many of them would love to display more of their fossils, but are unable to because of lack of funding or space. So, if you are really and truly concerned about the lack of public access to fossils, the best thing you can do is go out and support your local museum. Petition your local or provincial or federal government to make museum funding a priority. Participate in fundraisers or organize your own. Donate your time by volunteering as a fossil preparator, or go out into your community and teach others about palaeontology. The worst thing you can do is support the illicit trade of poached, illegally-acquired specimens. And we’ll talk about why in the next post.

(And if you want to help out re: the Tarbosaurus auction, there's a Change.org petition you can sign.)

Gobi Desert Diaries: Nemegtomaia Edition

Today I've got five questions for Federico Fanti, the lead author on a paper published a few weeks ago in PLoS ONE on a nesting oviraptorosaur. I first met Federico during the 2007 Nomadic Expeditions Dinosaurs of the Gobi expedition, in which we all had a grand time prospecting for dinosaurs and during which we celebrated a fine discovery indeed.

1. What inspired you to conduct this study?

Well, the fossil itself! I grew up with incredible pictures taken somewhere in the Gobi Desert of Mongolia, with spectacular fossil remains literally emerging from the vermillion sand. When Phil Currie and I realized that we were looking at a nesting dinosaur we were simply happy and enthusiastic: there are only 5 specimens of brooding dinosaurs known to date in the world, it is a unique find. I couldn't wait to find out more about this specimen and finally, after more than four years, I'm glad to see the paper out.

 

(MPC-D 107/15 diagram from Fanti et al. 2012, by Marco Auditore.)

2. Nemegtomaia is not exactly a household dinosaur name. Who is Nemegtomaia?

Nemegtomaia means "good mother of the Nemegt" and curiously the name was chosen long before our discovery. In the '90s, the type specimen - including a nicely preserved skull - was collected from the Nemegt Formation not far from where we found the nest: however, no trace of eggs or nest were found at the time. The discovery of MPC-D 107/15 (or Mary, as I still like to call it) definitely supports the choice of Nemegtomaia as the name for this species. Nemegtomaia is a genus of oviraptorid dinosaur that inhabited what is today southern Mongolia during the late Cretaceous period, approximately 70 million years ago. It is characterized by a well-developed crest on the skull and relatively short forelimbs with robust claws.

(Nemegtomaia skeleton reconstructions from Fanti et al. 2012, by Marco Auditore.)

3. What's so special about MPC-D 107/15?

Unlike all other nesting dinosaur that have been discovered so far, this specimen has a nicely preserved skull and therefore it was possible to reliably refer MPC-D 107/15 to the genus Nemegtomaia. Furthermore, within the context of the Nemegt area where dinosaur eggshells are frequently recovered, it was possible to refer a specific egg type to this genus. In addition, the preservation of the forelimbs allowed us to reconsider the classification of this genus within the oviraptorosaurs: unlike many other oviraptorid species, in fact, Nemegtomaia has relatively short and robust forelimbs, indicative of different adaptations and behavior.

4. In the acknowledgements section of the paper you note that MPC-D 107/15 was excavated 'under what were at times difficult circumstances'. How did you find this specimen, and what were the challenges in excavating it?

I found the specimen while prospecting in a sayr, a canyon located not far from the Camp. It was barely cropping out from a vertical cliff, about 3 feet from the valley ground. A section of the nest and of the pelvis was visible at the time, meaning that, with the exception of the tail, the skeleton was still preserved in the cliff.

(Federico did well to spot the nest, which was hardly exposed at all in the surface - just eggs and legs in cross section.)

It took a full week and the work of several people to take it out, and I must thank all the people that participated in the 2007 fieldwork (including the author of this blog! [aw, shucks - VMA]) for the help in the field.

Difficult circumstances? A mix of heavy rain, collapsing blocks of sandstone alternated with 45 degrees in the shadow are .. interesting circumstances!

(Although I didn't spend much time working on the nest excavation, I do know what Federico, Phil, and Badam are referencing when they say 'difficult circumstances'. On the second-to-last day in Nemegt, the skies opened and it poured rain ALL DAY. The nest had to come out the next day, so a team went out to the site and worked under a tarp all day in the soggy, soggy desert.)

5. What does this specimen tell us about the nesting habits of oviraptorosaurs?

Nemegtomaia has been collected in both the Baruungoyot and Nemegt formations, which are representative of aeolian/desertic and fluvial environments respectively. This indicates that Nemegtomaia was a long-living genus and adapted to different environmental and climatic conditions. The nest preserves approximately 20 eggs: we know from other spectacular specimens of oviraptorid dinosaur that they were able to laid 2 eggs at time, thus we assume that different individual laid their eggs in a single nest. As a consequence, the animals that we discover in brooding position are not necessarily the parents nor the mothers. It is possible that a male was "selected" for parental care during early development of embryos.

If you haven't yet read Fanti et al. (2012), go get it right now for free from PLoS ONE! Thanks Federico!

Fanti F, Currie PJ, Badamgarav D. 2012. New specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia. PLoS ONE 7(2): e31330.

5 Questions for Phil Bell

Hot on the heels of yesterday's interview with Caleb, here's an interview with Phil Bell of the Pipestone Creek Dinosaur Initiative. Phil is a former Currie Lab member who completed his PhD last spring, focusing on the Mongolian and North American hadrosaur Saurolophus. He recently published a paper on skin impressions in Saurolophus. Thanks to David Lloyd of the Tyrrell Museum for the great photos of work at the Dragon's Tomb in 2010!


1. What inspired you to conduct this study?

Actually, it was entirely by accident. Like so many advances in science, it came from an unresolved problem: were these two species of Saurolophus (S. osborni from Alberta and S. angustirostris from Mongolia) actually different or were they the same thing? I was at the American Museum in New York in the process of looking at the bones and skeletons of Saurolophus to try and answer that question. I mean, that’s what you do if you work with dinosaurs, you look at the bones. But I immediately struck upon a load of skin impressions. Like most people before me, I thought “that’s cool” but being the first time I had worked with skin impressions, I took the time to photograph, and draw, and measure the hell out of them. When I got to Mongolia later that year, I had the chance to visit one of the great (but little known) palaeontological treasures of the world, the Dragon’s Tomb (see Q3). This site preserves a herd of ‘mummified’ Saurolophus and you can still find loads there today. It was here that I started to notice differences in the skin impressions between the two species and from there I began my search for more specimens with skin impressions that have been stashed in museums from Mongolia, Poland, to Russia.

Phil with a block of Saurolophus at the Dragon's Tomb, Gobi Desert, Mongolia, 2010.

2. Who is Saurolophus?

Saurolophus is a hadrosaur or duck-billed dinosaur. Like it’s more famous cousin, Parasaurolophus (which actually means, ‘like Saurolophus’), it had a rod-like crest sticking out of the back of its skull, but unlike Parasaurolophus, this crest was solid. There are two species: Saurolophus osborni from Alberta grew to around 10 m in length, whereas the Mongolian Saurolophus angustirostris was a giant growing to 12 m in length.

Phil at the Paleontological Institute in Moscow in 2010.

3. What is the Dragon’s Tomb?

The Dragon’s Tomb is the name given to a site discovered by Russian palaeontologists (well, actually, it was one of their drivers who found it) in 1947 in the heart of Mongolia’s Gobi Desert. When they arrived, they found not just one but six or seven Saurolophus skeletons lying on a rocky ledge, most with skin impressions. The Russian’s named it the Dragon’s Tomb for obvious reasons and since then many more Saurolophus skeletons have been found there. Unfortunately though, fossil poachers have also relocated the spot and have caused irreparable damage by using dynamite to blast out skulls and skeletons to sell on the black market. But the place is so rich you can still find great stuff there. I’m involved in a project with Michael Ryan (Cleveland Museum) and David Evans (Royal Ontario Museum) to further explore this site and to figure out why exactly tens of Saurolophus died there.

The Dragon's Tomb, Gobi Desert, Mongolia, in 2010.

4. What is special about the skin of Saurolophus?

Well, for the moment it’s the most complex scale pattern ever seen in a dinosaur. People have known of dinosaur ‘mummies’ for 100 years (actually, last year was the 100^th anniversary of the discovery of the first, and in my opinion the best ‘mummy’ ever found; that of Edmontosaurus now on display in New York) but the complexity of their scale patterns has not been really appreciated until now. The stripy pattern on the tail of S. angustirostris was a complete surprise – one that I didn’t even believe when I first saw it. I thought it was a trick of the light or something to do with how the animal was preserved. But when I started to see it on more and more specimens, there was no denying it.

Preparing latex molds of skin. Fittingly, the latex brand is called "Dragon Skin".

5. Can different scale patterns tell us anything about the colour or colour pattern of Saurolophus?

That’s always a tricky question but without the actual colour preserved (as some people have shown with fossilized proteins that produce pigment) we can never be certain. One way of testing that question is to look at modern animals with scales (crocs, lizards, snakes). If you look closely at any of these animals you will notice that not all scales are born equal – some are big, some are small, some are long, circular or hexagonal. And they all have a function of some kind. Take a snake for example; most of the scales along its back are diamond-shaped and coloured in some way. But look at its underside and the scales are really wide, spanning the entire width of the animal, which they use to grip the ground when they’re on the move. They’re also usually a different colour to the top side. So, different shape, different function, and different colour. I’m not saying this is the way it always is but it’s a pretty compelling notion wouldn’t you say?

Thanks very much, Phil!

You can read the original paper here:

Bell PR. 2012. Standardized terminology and potential taxonomic utility for hadrosaurid skin impressions: a case study for Saurolophus from Canada and Mongolia. PLoS ONE 7(2): e31295.

And also see "Saurolophus skin suggests speciation" at Superoceras, and "Judging a dinosaur by its cover" at Dinosaur Tracking, for more coverage of this paper.