Psittacosaurus, Allosaurus, Baryonyx, Wulatelong, Aurornis and Torvosaurus. Oh my!

You lying fossil! I believed in you!

It seems that within the last month paleontologists have been publishing a lot of new discoveries about some well-known dinosaurs, as well as discoveries from two new guys guy that I'll get to further down. Some of these discoveries have been of great interest to me, and it has encouraged me to write about it here before school ends and I get more free time to talk about other stuff.

*I don't want this blog to become a sort of news blog where people can come and hear about all the latest discoveries, but if there is something in the news that I find interesting, then I'll post about it. I won't be talking about every little news item, though.

To start off I wanted to talk about a heartbreaking discovery concerning Psittacosaurus. Psittacosaurus is a basal ceratopsian, and also currently holds the record of most known species of any non-avian dinosaur genus. It's also one of the best known dinosaurs, with hundreds of specimens that include details about its internal and external anatomy (even including color!), as well as its diet, ontogeny, and behavior. One of the greatest examples of the latter was the discovery of 34 juvenile Psittacosaurus nested underneath the body of the adult animal, for a long time considered to be one of the greatest examples of parental care among any dinosaurs. Until it was found to be a fake.

A re-analysis of the specimen in question by Zhao and associates found it to be a composite. The 34 juveniles and the 'adult' turned out to be glued together, and the 'adult' specimen in question wasn't even of reproductive age. All in all very disappointing, especially for myself, as the magazine article I've been writing for the last month happened to focus on this particular specimen, and with the news having been published four days before my article was due for publication, I was unable to revise it in time to make the deadline. That was really depressing for me, and I felt like I let a lot of people down. Updates are being made for the next issue, however. Or perhaps I'l focus on less-researched topic than dinosaur parental care, which is what I had originally planned. Perhaps I'll discuss discoveries of juvenile dinosaurs together in nests separate from adults. For instance, although the Psittacosaurus composite is no longer considered an example of parental care, the 34 juveniles still died together, and Zhao also talked about a new specimen which preserves multiple juveniles of differing age groups together, so there certainly are a lot of interesting points remaining to discuss.
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In other news, Witmer Lab has been at it again. This time they reconstructed the neck musculature of Allosaurus using computer models and found that, unlike Tyrannosaurus, Allosaurus did not suffer from as much forward inertia. The lighter head allowed the head to swerve and move around faster than big, boxy-headed Tyrannosaurus and thus the animal was probably more agile. This also brings to mind one of my old predator vs. scavenger posts, where I said that T-rex suffered from a large amount of inertia and likely couldn't turn quickly. This was no problem for Allosaurus.

Animation by Witmer Lab. I own nothing. Forever alone....

 

Another interesting observation that they made was that they think they revealed the feeding style of this predator. Apparently unlike Tyrannosaurs, which are thought to have used their jaws to violently shake and tear off pieces of meat, Allosaurus seems to have used its jaw to slice off pieces of meat rather like a predatory bird. This really interests me as a study last year also reported that dromaeosaurids had a predation-style similar to eagles, restraining the prey with the limbs while slicing off pieces of meat with the jaw. Perhaps Allosaurus was doing a similar thing as dromaeosaurids, slicing off pieces of meat on large animals like sauropods and stegosaurs, eating them alive. Extremely gruesome and somewhat revolting, but an efficient feeding strategy nonetheless.

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Baryonyx, perhaps not as much of a fish-eater as we thought.



Onto another fan-favorite, remember my post about spinosaurids a few month back? In it I talked about how Emily Rayfield conducted a study of a number of different theropods, including Suchomimus, and found something odd. Despite its length and lack of any notable features that would resist torsion, Suchomimus has a skull that could resist excessive force just as well as other large theropods. At first I thought that this was odd, and even she noted at the end of the paper that her numbers were inconclusive and required more in-depth studies, but now she and Andrew Cuff have come back with a new paper that backs up this idea.

By using the skull of Baryonyx, a close relative of Suchomimus, they ended up with the same results. Not just that but they also cross-reference the skull with that of living crocodilians (an American Alligator, African Slender-snouted Crocodile, and Gharial) and Spinosaurus and found that Baryonyx could withstand just as much torsion as some crocodilians and theropods, contrary to some studies suggesting that Baryonyx could only withstand as much torsion as a gharial. She also found that Baryonyx's skull reacted very different mechanically than a gharial, contrary to many other studies, including her own. One thing that really shocked me though was that she did find that Spinosaurus' skull reacted mechanically similar to that of a gharial, which again is contrary to some reports that it was better at withstanding mechanical forces than members of the Baryonychinae. Despite this, Rayfield and Cuff firmly state that when size is accounted for, both of the skulls "absolutely outperform all crocodilian taxa”.

I've yet to see how the paleontological community has reacted to this discovery, and it hasn't gotten much press, but now Rayfield and Cuff have suggested that perhaps the Spinosauridae as a whole might not have been obligate piscivores, but instead that perhaps diet was more reliant on size of the individual, as it is in living crocodilians. For example, juveniles crocodiles feed on small animals like fish and insects, mid-sized individuals mostly feed on fish and small game, and larger adult crocs mostly feed on land animals. This is an cool theory, and similar theories have been suggested for other theropods, so it certainly seems likely.
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Note the elevated toe claw.
Bear in mind, this is a oviraptorid, not a Deinonychosaurian.

Wulatelong gobiensis is a new species of basal oviraptorid from the Gobi Desert, and is the fifth new species of oviraptorid to be described this year. It's been a cool discovery not just because it is relatively complete, but it also seems to have died articulated in a relatively natural condition. However, the head and neck are preserved badly, and there aren't any unusual traits about it that make it stand out. It looks just like your average, run-of-the-mill oviraptorid at first glance, until you look down at the foot.

Although the original describers said nothing about it, images such as the one above clearly show that the second toe of this oviraptor has a large claw that is elevated off the ground. As I said, this specimen is articulated in a natural position, so it seems the claw was held in that position in life. If you don't know where I'm going with this, let me help you....

IT'S AN OVIRAPTORID WITH A DROMAEOSAUR-LIKE SICKLE TOE CLAW!

Currently there has been a lot of talk about this specimen, and some scientists are even stating that it might have implications for the evolution of such enlarged hyperextendable claws, that perhaps the ancestor of oviraptorids and dromaeosaurids had such a structure, and even that the trait might be common throughout the Ceolurosauria. It's a bit of a mess right now, but the curious thing that myself and the paleontological community are shocked about is the fact that Xu Xing and the original describers of the specimen don't even remotely bring this up in their paper. It's strange. The animal is found articulated in its natural position showing the claw hyperextending like that, and there's no mention of it whatsoever? I hope we get to hear more about this guy and get a confirmation about such an amazing example of a non-Deinonychosaurian sickle claw. As for why an oviraptorid would need such a claw on its foot, I don't know, but here are some ideas:


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New relationships of basal birds. Time to start rewriting the text books.....
Borrowed from Theropoda.


Aurornis xui (and yes, it is named after Xu Xing, although to my knowledge he didn't work on the specimen) is a new species and genus of basal bird from the mid-Jurassic of China, and has dethroned Archaeopteryx as the "earliest bird" by about 15 million years. It's a pretty awesome discovery, as it provides a snapshot of how birds got their start, and in this case, has also provided a new area of analysis for researchers looking into the question of where Archaeopteryx falls on the theropod family tree. In this case, they found that it is more derived than Aurornis, and that it, along with Anchiornis, Xiaotingia, and Rahonavis(!) are all basal birds. Not just that, but they also found that the troodontidae are not closely related to dromaeosaurids or deinonychosaurians at all! Instead, they seem to be apart on an unnamed sister-group to the avialans, which would explain why troodontids share so many similarities with birds, more so than they share with dromaeosaurids.

However, despite this new find nobody should think of the chapter on Aurornis xui  as being closed, as I'm sure that in a few months we'll be getting another rebuttal paper stating some alternative ideas. The history of birds is filled with a lot of complex data, and we're at the point that defining birds as a group is harder than it looks, as there is literally no major differences between basal birds and other members of Paraves. We still have a lot more work to do, but having Aurornis with us will hopefully make it easier and not fuzzier.

Perhaps the most shocking find of all in this paper was the discovery that they made with Balaur bondoc. Apparently, it's not a dromaeosaurid; it's a basal bird and sister taxon to Pygostylia! That's a shocker, but there's good reason to think this is the case. The conclusion was based on a direct observation of the specimen, and a new monograph that came out that also came to this conclusion.

So, Balaur is some kind of Cretaceous dual-clawed killer dodo. That's going to take A LOT of getting used to...
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We FINALLY get some big theropod eggs and embryos!
And look at them, such cute little baby Torvosaurus.....

Torvosaurus was the largest predator in the Jurassic (ignoring Epanterias and Saurophaganax as they haven't been properly identified yet). This huge, heavily-built predator with serrated teeth, robust arms, and killer demeanor terrified most around it, but now we know that this species had quite a softer side, as Torvosaurus has now provided the first ever non-avetheropod eggs! Talk about a long wait! Nearly 200 years since the first Dinosaurs were described and 100 years since the first Maniraptor eggs were discovered, and it's only now that we're getting some big theropod eggs? Fossilization is horribly bias sometimes, but I'm happy that we finally found them. Now we just need a thyreophora and neoceratopsian nest and I can die peacefully.

Moving on with this amazing find: These eggs are actually not THAT new; apparently they were first unearthed in 2005 but are only being described now. They were found in a clutch along a hillside and consist of a large number (exact number unknown) in the Lourinhã Formation in West Portugal. For those who are also dino-nerds, you'll remember that a clutch of eggs from the the Allosauroid/Coelurosaur Lourinhanosaurus were also found here. This might suggest that perhaps the area was favorable for breeding theropod females, or maybe that the fossilization process there is biased towards dinosaur eggs. Either way, somebody's got to check out that area for more of these clutches.

The microstructure of the eggs is also unique among theropods, as it has only one eggshell layer, while most theropods have two and birds have three. The eggs also seem to have been buried, as the openings in the eggshell are large to let in air, and the eggs themselves are not disturbed, suggesting that they were already buried by the mother. They were either buried in sediment or plant material, similar to what is seen in crocodiles, so perhaps parental care in this species was also crocodilian-like, but I'll save talking about that for my revised article. ;)

So, what's your favorite discovery in paleo-news recently? Feel free to share, and as always, stay tuned and stay sharp!

References:

Cuff AR, Rayfield EJ (2013) Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians. PLoS ONE 8(5): e65295. doi:10.1371/journal.pone.0065295

Eric Snively, John R. Cotton, Ryan Ridgely, and Lawrence M. Cotton, Ryan Ridgely, and Lawrence M. Witmer (2013) Multibody dynamics model of head and neck function in Allosaurus (Dinosauria, Theropoda). Palaeontologia Electronica Vol 16, Issue 2, 11A 29pp.

Godefroit P., Cau A., Hu D.-Y., Escuillié F., W. Wu, G. Dyke 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature doi:10.1038/nature12168

Qi Zhao, Michael J. Benton, Xing Xu, and Martin J. Benton, Xing Xu, and Martin J. Sander (2013) Juvenile-only clusters and behaviour of the Early Cretaceous dinosaur Psittacosaurus. Acta Palaeontologica Polonica (in press) doi: http://dx.doi.org/10.4202/app.2012.0128

Ricardo Araújo, Rui Castanhinha, Rui M. S. Martins, Octávio Mateus, Christophe Hendrickx, F. Beckmann, N. Schell & L. C. Alves (2013) Filling the gaps of dinosaur eggshell phylogeny: Late Jurassic Theropod clutch with embryos from Portugal. Scientific Reports 3 : Article number: 1924
doi:10.1038/srep01924

Xu X., Tan Q.-w., Wang S., Sullivan, C., Hone, D. W. E., Han F.-l., Ma Q.-y., Tan L. & Xiao D. 2013. A new oviraptorid from the Upper Cretaceous of Nei Mongol, China, and its stratigraphic implications. Vertebrata PalAsiatica 51 (2): 85–101. 

Walking with Dinosaurs: The 3D Movie

First things first, I must apologize for about a month's absence in activity. I have currently been preoccupied by end-of-the-year work at school so my schedule has been really busy, and the rest of my time has been occupied by my magazine article work, family activities, and enlisting to volunteer at my local museum, so I haven't been able to find the time to write. Luckily, during the little free time I have had, I have been reading a lot of new books and scientific papers, so expect when all this is done to have a lot more posts by me.

However, that isn't why I'm here right now. I'm posting to talk about something awesome that was announced by 20th Century Fox on Wednesday. I shouldn't really have to say anything, just look at the trailer:

Yes, a Walking with Dinosaurs 3D movie that will be coming out this Christmas. For Dino-Fans like me, this is a godsend. Quite literally this is what the Dinosaur community has been looking for, for ages. I couldn't believe it when I saw it, as it's almost too good to be true. As for why, I'll list the reasons below.

• Feathered Raptors!!! - If you look at one of the scenes towards the end, their is a sincere feathered Deinonychosaur (It looks to be a Troodon, but I'm not drawing conclusions yet). I have been wanting to see feathered dinosaurs in a movie for so long, and we're finally getting it. It's 100% scientifically accurate, and much better looking than the 6ft bipedal iguanas in Jurassic Park. 
• Realistic Dinosaurs - Truly, I have never seen more scientifically accurate looking extinct animals. According to Mark Witton on his blog, he as well as other paleontologists and paleoartists like David Krentz, Tomas Holtz, Scott Sampson, Luis Chiappe, and Victoria Arbour have all been involved in re-creating these animals. Heck, according to him they even consulted Mark about the anatomy on the inside of the pterosaur's mouths trying to get every detail as scientifically accurate as possible. I watched over the trailer about a dozen or so times now and I can find only 1 scientific inaccuracy in it (which I will discus below), but seeing as many documentaries fail at even getting that right, this is truly amazing.
• Dinosaurs Acting like Dinosaurs - Unlike Jurassic Park, where the animals are nothing but hideous monsters, or Land Before Time and Disney's Dinosaur, which featured talking, human-like dinosaurs, by the looks of it this appears to be what the title suggests: a 3D movie about Dinosaurs, not human-like or Sci-Fi movie monsters, they act like Dinosaurs. Now, there have been some suggestions in the comments of some of the trailers that these animals will talk, but seeing as they don't talk in the trailer (instead making a lot of animal sounds), it's based on the groundbreaking documentary series that goes by the same name, and seeing as the description of the actual movie states that it will be about real-life dinosaurs, I highly doubt the animals will talk.
• Feathered Raptors!!! - Did I mention how amazing this is?
• New, Somewhat Unique Story - The story seems to be following the life of a young Pachyrhinosaurus, born young and weak climbing up to become an alpha male in his herd, and the hardship he faces. At least that's what I got from watching the trailer. However, if you do a little research online it seems that it isn't just following the life, it's a rivalry story. Apparently it doesn't just focus on the main Pachyrhinosaurus, but also on another Pachyrhinosaurus, his brother, and about how they grow up together. I'm guessing that the brother is probably the second little Pachyrhinosaurus slightly larger than our hero in half of the scenes, as well as possibly the other big individual shown during the clash towards the middle of the trailer. This is certainly an interesting concept to put into a Dinosaur movie, especially since every dinosaur movie I've ever really watched seems to be (according to my dad) about getting from Point A to Point B and there are meat-eating theropods in-between. In this movie you're following the life of this individual as well as the hardships he face,s not just with vicious predators and a terrifying world he has to live in, but with his own brother and himself. That's a new and interesting concept that I haven't seen before in a Dinosaur movie, and I can't wait to see how they play it out in the film.

So as you can see there are a lot of reasons for me to be excited about this movie. It looks simply awesome that they were able to get this many things right, and I can certainly say that I'm now way more excited about this movie than I am about Jurassic Park 4 (which has crushed the hopes of the paleontological community by saying that feathered raptors will not be appearing in the film) and even Pixar's new film The Good Dinosaur set to come out next year, which is apparently a cartoony film about a human and his Sauropod friend (that is probably going to talk). The later is an interesting scenario, but not anything I'm really that interested in at 16 years of age.

However, being the scientist-in-training I am, I am disappointed about a few things. For one, seeing as they got so many things right in this movie, the one glaring inaccuracy out of the entire movie turns out to be our hero himself. Young Pachyrhinosaurus specimens don't show flat faces like the individual in this show. Instead they have a weird growth sequence where juveniles develop a small horn at a young age which later develops into the horn as they mature. This is seriously an extremely minor thing, and in fact I don't even know why I'm bringing it up. I guess it's somewhat disappointing that in a movie where they got everything so right, the fact they missed one thing kind of annoys me.

I also wish we had feathered Tyrannosaurs, seeing as Yutyrannus was found earlier last year, but according to Witton they designed the Tyrannosaurs before the Yutyrannus discovery came out, so I guess it's acceptable. I also wish the dinosaurs were maybe a little less shrink-wrapped and more speculative, as that's what paleontologists have been trying to push towards nowadays, but again the dinosaurs look great anyways so it's acceptable, and in truth that'd probably be asking for too much.

After hearing the news about JP4 having featherless raptors and getting another new predator appearing, that has definitely lowered my expectations and now I really don't care about the franchise anymore. This on the other hand looks spectacular, so I'm pretty dang excited! Can't wait for this to hit theaters! What's everyone else's thought? Feel free to share!

The Plague of the Hesperonychus Meme and its Inaccuracy

That darn Hesperonychus meme again! Trust me, there are plenty more where these came from.
A random collection of pictures by various paleontologists.

I'm not normally one to criticize artwork, but I feel like something needs to be said about this. For those of you who have been keeping up with paleontological blogs (hopefully including mine) you'll remember that All Yesterdays has gotten a lot of praise for pointing out the flaws in modern paleoart, and the memes made by artists who are unfortunately copying other people's work. Darren Naish pointed out some classic memes in his presentations following the publishing of his book, which you can watch here, including the "Freaky Giraffoid Barosaurus" and the black and white Phorusrachus memes, both of which have basically become the norm for the two, but I think I found another.

Those of you who keep up with dinosaur news will remember the discovery of "America's Smallest Meat-Eating Dinosaur" Hesperonychus elizabethae (Currie 2009) (which is technically not true; that title probably belongs to one of our species of Shrike). Hesperonychus was a dromaeosaurid, or more specifically, a member of the subfamily microraptorinae and is the youngest member as well as the first to be discovered outside of Asia. This has made it of particular interest to paleontologists, and has shown that the rather primitive microraptorinae survived close to, if not until the end of the Mesozoic.

However, what is sad about this wonderful little animal is that ever since its description it has been routinely portrayed as holding its tail almost vertically in the air like a lemur (an image further made iconic by the lemur-like tail stripes on many illustrations), with what look to be relatively short arms, standing on the ground with a mostly brownish coloration. Apparently this original "look" was based on a reconstructed model of Hesperonychus following its publication, and it has since been condemned to this appearance. I know there are certainly more dinosaurs that have been condemned to far worse appearances, but I find this to be not just a pressing problem for Hesperonychus because of the "unoriginality loop" it has fallen into, but it also is being portrayed rather inaccurately.

For one, the tail of Hesperonychus has never been found. Indeed, we've only found a partial hip and a few hand bones belonging to the animal, so there is nothing suggesting that it was any different than other microraptorines. Not just that, but you don't see many other raptors holding their tails up in the air, now do you? Might be a fun idea to try, but the majority of fossil evidence currently suggests that microraptorines possessed feathered disks and fronds on their tails. Current research has shown that these tail fronds have an aerodynamic advantage (Habib & al. 2012), and are actually very similar to rhamphorhynchid pterosaur tails (Persons & Currie 2012), which is consistent with the idea that microraptorines were gliding animals. However, even terrestrial dromaeosaurids seem to have had such fronds, showing that they likely had an advantage while on the ground as well. The tails seen on the reconstructions of Hesperonychus, however, much more closely resemble those of primitive Coelurosaurs like Sinosauropteryx, and seem totally un-dromaeosaurid-like.

Given, I know that the tail has not been discovered for this animal, and thus the reconstruction can be based off the artists own personal ideas. But when the reconstruction has been drawn over and over again countless times in the same way with no creativity whatsoever, it gets very annoying. 

And the re-occuring features don't stop there. Often times Hesperonychus tends to be portrayed with what appear to be very short front limbs. This is certainly not always shown; indeed the illustration in the lower right-hand corner in the image above seems to have appropriately-sized arms based on the fossil finger bones and related species, but many of the others just seem to be way too small. The brown coloration has also become routinely shown on this creature, but dinosaur coloration has been shown to have varied widely based on our current melanosome evidence. Again, there is nothing wrong with portraying it as brown, but it's terribly unimaginative after the hundredth time.

Finally, Hesperonychus is almost never shown with the correct large flight feathers on its forearms that are seen in almost all other dromaeosaurids. This is perhaps due to the original description of the animal, as it was described by Longrich and Currie, who believed that because its size more closely matched that of the large microraptorine Sinornithosaurus millenii, it was probably flightless. Sinornithosaurus has a reduced wing, vaned symmetrical feathers, and seems to be too large to be able to glide, and this was also assumed for Hesperonychus.

This seems to be a valid argument, but as for why they decided to make their mount completely lack vaned feathers on the arm when they are still present in Sinornithosaurus does not make any sense, and has definitely contributed to the look of the animal. Also, despite Longrich and Currie's conclusion, it is still possible that Hesperonychus was a gliding animal: another dromaeosaurid, Graciliraptor lujiatunensis is in the same size range as both Sinornithosaurus and Hesperonychus, but feather impressions show that it had large, asymmetrical wing feathers and wings that approached similar proportions to the gliding Microraptor, and thus it too may have been able to glide (Martyniuk 2012). This leaves open the possibility that Hesperonychus would've been able to glide as well, and it certainly would be a nice alternative to the illustrations of walking around on the ground like some Cretaceous lemur or something....

So those are some of my thoughts about this somewhat over-used paleoart meme. Maybe if I'm up to it I'll draw a more realistic Hesperonychus with long arms, large flight feathers, and a horizontally positioned tail climbing through the branches.

Yeah, I draw. Given, I don't normally draw and I'm definitely not the best at it, but that doesn't stop me from occasionally trying. If I'm sucessful at a pic, I'll make another post to show you guys. If it was a failure, I'll never bring it up again. 'Til then, stay sharp!

Refferences:

Habib, M., Hall, J., Hone, D. and Chiappe, L. (2012). Aerodynamics of the tail in Microraptor and the evolution of theropod flight control." 72nd Annual Meeting of the Society of Vertebrate Paleontology, 20 October 2012.

Longrich, Nicholas R. and Currie, Philip J. A microraptorine (Dinosauria-Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences of the United States of America, 106 (13), (2009). 5002-5007 DOI: 10.1073/pnas.0811664106

Martyniuk, Matthew P. A Field Guide to Mesozoic Birds and other Winged Dinosaurs. Vernon, New Jersey: Pan Aves. (2012) 

Persons, W. S. and Currie, P. J. (2012), Dragon Tails: Convergent Caudal Morphology in Winged Archosaurs. Acta Geologica Sinica - English Edition, 86: 1402–1412. doi: 10.1111/1755-6724.12009

Dinosaurs on Ice is out!

Brilliant illustration by Julio Lacerda of an Arctic Troodontid
You can see this stunning image and more on my first published article.

So, as I've said in a number of previous posts, I was asked back in October to write an article for a magazine called AncientPlanet Online Journal, an online magazine which talks about current research concerning archaeological discoveries and our ancient Earth. I'm sincerely happy to announce that after all my hard work, the article has been published! You can now read the full article in Vol. 4 published on March 12th. I would've written earlier, but I just had my wisdom teeth removed and wasn't able to work on a post (and as a result of the surgery, my face currently looks like a pufferfish).

Now for a little back story. When I was first asked by the editor of the magazine to write the article, I was, quite frankly, dumbfounded to say the least. After starting this blog in December 2011, this was a major step up! In looking over the other articles in the Journal, I could tell that my work would be published alongside some pretty amazing scientists, and I was honored to say the least. So I went for it, and after a few weeks of researching and writing, I came up with a piece that I was proud of. Thank you to the editor, Ioannis Georgopoulous, for having in faith in me to follow through and deliver a solid final product. I was also able to collaborate with young paleoartist Julio Lacerda, who has to be one of the best paleoartists on Deviantart I've ever seen for his stunning reconstructions of dinosaurs and other extinct animals. I asked permission to use some of his artwork in my article, and he happily agreed. Thank you, Julio, for letting me use your incredible art. I'll have to think of a way to properly thank you, but in the meantime, I recommend all of you visit his blog at The Casual Paleoartist, which shows all of his amazing work.

So there you have it, my very first published article. Now I have to decide on what to write for my next one. Any ideas? As always, I'll be happy to take suggestions. Until then, stay sharp!

Why I'm Ptero-fied of Pterosaurs: Giant Pterosaurs and Killer Storks

AHHH!!! RUN AWAY!!! HIDE ME!!!
Image by Mark Witton

Putting aside the horribly awful, facepalm-inducing title as well as the girly screams from your host here at the moment, Pterosaurs are a group of archosaurs related to (but not considered) dinosaurs that lived during the Mesozoic. They were the first vertebrates to develop powered flight, which they developed by evolving an elongated 4th finger and a layer of skin called the patagia from this finger to the hind limbs, and they just took off from there (no pun intended). In recent years especially, fossils of this family have shown really amazing things about their lifestyles and behavior. We now have fossil eggs showing that unlike many modern-day birds and bats, some pterosaurs may have been able to fly right after birth (Unwin 2005); specimens preserving soft tissue have shown that many pterosaurs had crests made up of soft tissue on their heads for displaying their age, health, and even gender (Lü et al. 2011), as well as being covered in some kind of fuzz termed pycnofiber (Alexander et al. 2009). In my opinion though, the most ground-breaking of all is that despite being often portrayed as giant seagulls and pelicans, the majority of species didn't practice this diet. Indeed, we now know of vulture, hawk, bat, stork, and even toucan analogs among the pterosaurs.

Terrifying Terror that is an Azhdarchid

Seeing as I've given a lot of love to crocs (speaking of which, I'll continue that crocodylomorph series in a bit) and other ambiguous animals from the Mesozoic here, it only seemed like a matter of time before pterosaurs popped up. However, seeing as I am a big fan of these animals, it seems ironic that I'm writing a post on how I'm downright scared of them. Given it's not the whole group that I'm afraid of, it's a specific family of them called the azhdarchids.

My God, it's eyeing him hungrily.....
Pic by Mark Witton, and showing him.

The azhdarchidae is a family of pterosaurs which only appeared near the end of the Cretaceous (although I have heard of some possible early Cretaceous remains) and include the largest of all pterosaurs, such as Hatzegopteryx and the famous Quetzalcoatlus, which could have wings up to 33 ft long, and stand as tall as a giraffe (earlier claims that these animals reached sizes in excess of 40 ft aren't considered valid). These animals, like most pterosaurs were, for a long time, portrayed as skim feeders — skimming along the surface of the water picking up fish as they went. However, most recent work on these animals have shown that they were in fact stork-like in ecology, and were better adapted to ground-feeding than aerial skimming (for a review, see Naish 2010 or follow this link), and this is the key reason why I personally find these animals rather threatening. Storks and birds with a similar ecological niche today eat just about any small animal they can fit in their mouth, and seeing as Hatzegopteryx and Quetzalcoatlus both reached titanic sizes, would that mean we would be on the menu?  Most people would probably think that time travelers going back to the Mesozoic would meet dangers mostly from carnivorous theropods, but could these azhdarchids be an equal, if not greater threat? It's an interesting idea, and indeed, it's been talked at length before by other scientists. But just to see how dangerous they would be, I'm going to look over them a bit and see for myself.

To determine how much of a threat an animal might be to humans, normally there are three factors involved. The first is behavior: is the animal naturally agressive? This is the major determining factor to tell how dangerous many animals are, but since azhdarchids are extinct we can't know this. The other two are easier: numbers and threat. Is the animal common enough that it will come into contact with people often? And what features does it have that can cause damage to us? Knowing this, let's see what azhdarchids bring to the fray:

As for numbers, we know of numerous giant azhdarchids as of now, and it doesn't seem like Hatzegopteryx and Quetzalcoatlus are alone: two more undescribed giants have been found in the Dinosaur Park and Two Medicine Formation, both of which may reach the same sizes. Thus, there are a lot of species which could hypothetically be a threat, and since the fossil record tends to be rather fragmentary, it is quite possible that there were even more giant pterosaurs out there that are waiting to be found, and indeed, may never be found. Thus, seeing as they are a common animal in their ecosystem, they fill at least the quota for frequent interactions for hypothetical time travelers. But could they actually pose a threat? 

Hatzegopteryx's reconstructed head compared to, believe it or not,
Giganotosaurus', the theropod with the largest head. Who's scarier again?
Pic from Deviantart's Dean Hester (Fragillimus335)

The answer is, somewhat surprisingly, a most definite yes. They could indeed pose a great threat to us humans. And no, not in that cliche "Pteranodon with teeth flying off with people in its talons" imagery shown in so many old movies; but in a dynamic, cursorial running-down fashion. (Seriously, Pteranodon means "toothless wing," so why do movie makers constantly show it with teeth? It's more comical than scary!) Studies of azhdarchid proportions have shown that their limbs are actually similar to those of living hooved animals, and that while they might not be able to actually run, they could still move at fairly high speeds over land (Unwin 1997) (Unwin 2005) (Mazin 2003). But what could they do when they actually caught up to us? Again, they're equipped for handling prey our size: the adjacent image shows the reconstructed heads of Hatzegopteryx and Giganotosaurus, currently the theropod with the largest skull. As you can see Hatzegopteryx dwarf's Giganoto's 1.8 meter skull, reaching an astonishing 3 meters long (I'll admit the proportions may be a bit off though; Giganoto's head looks too big). You might think that this is only the case with the skull's length, but that's also not the case; Hatzegopteryx's jaw was an astonishing minimum width of 50cm at the rear (Buffetaut et al. 2003). I, for example, have a shoulder width of about 46cm, Hatzegopteryx could easily swallow me whole.

Now, you put all those traits together, and then realize that along with being fast runners, having huge skulls, and being downright gigantic, they could also fly. Despite some scientists saying that some of these huge pterosaurs were in fact too large to fly, most of these conclusions are based off bad assumptions of flight mechanics and scaling (Witton 2010). Thus, what would stop them from just flying into something like a Terra Nova-style compound and eating everyone in sight? The only way time-travelers would be safe would be if they either built large domes (which would cost an immense amount of money) or by residing in caves or underground bunkers, which might produce other problems. Of course, the most cost effective way to avoid all this would just be to shoot them, but I would like to keep such amazing animals away from such a sad fate.

So as you can see, I would personally find these animals to be a far greater threat in any time travel or Jurassic Park-style film than the majority of the dinosaurs that show their faces on-screen. In fact, based on living animals, I would imagine that predatory dinosaurs would spend most of their time sleeping, like living predatory animals, and would've probably only fed once every one or two weeks. Azhdarchids on the other hand, would've probably been feeding far more frequently on us smaller animals, like living storks and herons, and would be a much more common and frequent threat. Of course, azhdarchids are long extinct, and us humans have never had to worry about giant, long- necked animals with beaks coming down to snatch us up. Or have we?

The Dwarf Man vs The Giant Stork

 

In 2010, fossils from the Liang Bua cave on the Island of Flores in Indonesia had identified such an example of a relationship. The cave is best known for its assemblages of fossil stegodonts, giant rats, and the dwarf human species Homo floresiensis, who is arguably the most important human species ever found. Discovered in 2003, Homo floresiensis, or the Hobbit Man, was discovered and announced to be the only example of a species of dwarf human, which evolved by the means of island dwarfism. These hobbits were only about a meter at their tallest, and are really interesting in the size of their brain and apparent ability to use tools and produce fire. I won't go into it, as this is not my specialty, but I recommend people check them out even if you're not very interested in human evolution.

 

It's not fantasy: man-eating storks in recent times!
Image by Inge van Noortwijk

Anyway, what do tiny humans have to do with giant killer azhdarchids? As I was saying, in 2010 fossils of a giant bird were uncovered in the same cave. Dubbed Leptoptilos robustus, it was a giant flightless stork and stood a staggering 2 meters tall, or twice as tall as these hobbits. It's a member of the same genus as living marabou storks, but had reduced flight abilities, such as robust bones. It's unknown if they actually were flightless though, since a complete skeleton has yet to be found, but they were definitely losing their flight capabilities. This has been attributed to the fact that Flores 20,000 years ago was devoid of mammalian predators, and thus the stork may have been taking up the same role as they did on mainland continents (Meijer & Due 2010). True, it had to share that role with Komodo Dragons, which lived on the island at the same time. But what does this mean for our little hobbit?

Seeing as adult Homo floresiensis were still a good 3ft tall, it's safe to say that they were likely off this bird's menu, as its beak was simply too small to manage them. This doesn't exclude children though, and indeed, these storks would've posed a great threat to any baby or even young hobbits on the island, but would the hobbits have fed on these birds? Fossils have shown cut marks on other animals from the island, notably the stegodonts, but according to an interview, cut marks have yet to be found on any of this bird's remains. Still it would be great to actually see a fossil showing predation on one or the other now, wouldn't it?

Anyway, as for what you've gotten out of this today? The lesson is, if you're ever stuck between a T-rex and a Quetzalcoatlus, take your chances with the Rex. Stay sharp and see you soon.

References:

Alexander W. A. Kellner, Xiaolin Wang, Helmut Tischlinger, Diogenes de Almeida Campos,, David W. E. Hone, & Xi Meng (2009). The soft tissue of Jeholopterus (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane Proc. R. Soc. B : 10.1098/rspb.2009.0846

Buffetaut, E., Grigorescu, D. and Csiki, Z. 2003. Giant azhdarchid pterosaurs from the terminal Cretaceous of Transylvania (western Romania). In: Buffetaut, E. and Mazin, J. M. (eds.) Evolution and Palaeobiology of Pterosaurs, Geological Society Special Publication, 217, 91-104.

Mazin JM, Billon-Bruyat J, Hantzepergue P, Larauire G (2003) Ichnological evidence for quadrupedal locomotion in pterodactyloid pterosaurs: trackways from the late Jurassic of Crayssac. In: Buffetaut E, Mazin JM, editors. Evolution and Palaeobiology of Pterosaurs, Geological Society Special Publication,. 217. : 283–296.

Meijer, H. J.M. and Due, R. A. (2010), A new species of giant marabou stork (Aves: Ciconiiformes) from the Pleistocene of Liang Bua, Flores (Indonesia). Zoological Journal of the Linnean Society, 160: 707–724. doi: 10.1111/j.1096-3642.2010.00616.x

Lü J, Unwin DM, Deeming DC, Jin X, Liu Y, & Ji Q (2011). An egg-adult association, gender, and reproduction in pterosaurs. Science (New York, N.Y.), 331 (6015), 321-4 PMID: 21252343

Naish, Darren. Tetrapod Zoology Book One. Great Britain: CFZ Press. (2010)

Witton MP, Habib MB (2010) On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness. PLoS ONE 5(11): e13982. doi:10.1371/journal.pone.0013982

Unwin DM (1997) Pterosaur tracks and the terrestrial ability of pterosaurs. Lethaia 29: 373–386.

Unwin, D. M. 2005. The Pterosaurs from Deep Time. New York, Pi Press.

Websites:

Pterosaur.net, It’s dumb, it’s awesome, it’s… Our lives with pterosaurs, part 2, accessed March 3, 2013. http://pterosaur-net.blogspot.com/2012/04/its-dumb-its-awesome-its-our-lives-with.html

3 Reasons Why Byronosaurus is Awesome



Artist's depiction of Byronosaurus jaffei from Wikipedia,
Probably one of my favorite troodontids due to the incredible number of specializations it has.

 
Deep down, Byronosaurus has always held a special place within my heart. I first learned about this particular animal in 2008 (even though it was discovered in 1993), after looking through an art book titled Feathered Dinosaurs: The Origin of Birds, written and illustrated by John Long and Peter Schouten, with a forward by Luis M. Chiappe. This was probably one of my favorite books of my earlier junior-paleontologist years, and it still pleases me to simply thumb through the wonderfully fantastic illustrations. They are a feast for the eyes!

Looking through the book for the first time, I remember coming across this particular creature with its bizarre appearance and interesting anatomy looking back at me with its thin snout, numerous tiny teeth, and huge eyes. Over time, I became fascinated with the animal and I decided to examine it further. Three distinct traits of its anatomy and behavior stood out at me more so than most other dinosaurs. At this point, the only word to define what I think of this beast is simply awesome — and I will explain why.

Its Quirky Ears

An owl's skull showing the bizarre placement of its ears
Byronosaurus had similar ears, if not more bizarre....

Byronosaurus' most notable feature is one that is not obviously seen in any illustration of the animal, but you would probably notice it instantly if you were holding a skull of the creature. The ears of Byronosaurus are extremely large, but curiously, they're also asymmetrically aligned on the head, a trait once thought to be exclusive to only one other family of animals, that happen to also be Dinosaurs — owls.

Some species of owls have asymmetrical ears in order to enhance their hearing, as it allows a wider area of sounds to enter their ears, as well as allows them to pinpoint the exact location of prey (note that not all species of owls do, however, as some species have perfectly aligned ears). The famous facial disks of many owl species also help channel sound into their ears, as their shape acts like a large satellite dish. Some northern species are quite capable of locating a single lemming in more than a foot of snow simply by listening to its movements from perches, sometimes more than a half-mile away. All in all it's an extremely effective way of locating prey, and I'm surprised that it isn't an anatomical feature more commonly found in animals.

Byronosaurus was, I believe, the first troodont to show such a feature, as its skull is one of the most complete of any troodont (according to my research, but please correct me if I'm wrong). Other troodonts also have been shown to possess asymmetrical ears, which suggests that hearing was very important for these animals as a whole, and studies of the braincase show that indeed it was one of their primary senses, maybe even more so than sight. Unlike owls however, Byronosaurus' inner and middle ear has also been shown to be asymmetrical, while owls have it limited to the external surface. Does this mean that Byronosaurus was more sensitive to sounds than owls? Further study is needed before we can tell, but it certainly does suggest that hearing was extremely important for these animals.

Pinocchio Jaw

Photo of the holotype's snout

Along with being the first non-strigiforme animal to show an asymmetrical ear, Byronosaurus' well-preserved skull has also shown a very bizarre form of dentition and jaw morphology unlike that of most dinosaurs. Most troodontids are known for having a wide, U-shaped jaw, with blade-like teeth with coarse serrations and a large denticle size. This has lead troodontids, and famously Troodon itself, to be thought of as possible omnivores, as their jaws resemble herbivorous and omnivorous lizards like Iguanas.

Byronosaurus' jaw on the other hand, is anything but that of a typical troodont. The jaw is elongated, pointed, depressed, and very narrow, a far cry from the broad, rather deep, U-shaped mouth of other troodonts, and giving Byronosaurus a very-pointy face, making it basically the dinosaur version of Pinocchio. Along with that, Byronosaurus also has very different teeth; they are small, needle-like, lacking serrations, and there are far more of them than in other troodonts. This all points towards a very different method of feeding, but just what was that method?

The ears may give us a clue. As I said, owls use their amazing hearing to pinpoint the exact location of hidden prey without even seeing it. Byronosaurus was likely able to do similar things with its ears, and the teeth could be used to grab onto small prey. However, other troodonts have asymmetrical ears and are currently thought to have fed on small prey items in this way, but they don't have Byronosaurus' unique dentition, which seems far more specialized in that regard.

 

A theory was put forth to explain its skull in the Feathered Dinosaurs book I mentioned. The authors noted that the snout and jaw are fairly reminiscent of the African Bat-Eared Fox, which is a very specialized species of canine that feeds on almost an entirely insectivorous diet. The fox's jaw is long and narrow in order to probe into cracks and holes to get at termites, which is its primary food source, and it uses its small, needle-like teeth to cut up the tough exoskeletons of these invertebrates. Interestingly enough, its huge ears are used in pinpointing the exact location of insects crawling among foliage or underground. Do these traits sound familiar? (Vid above showing some Bat-Eared Foxes in action)

 

So perhaps Byronosaurus is a Bat-Eared Fox analogue; but there is another possibility we should explore. The toothy dentition is also similar to that of fish-eating animals like the Indian Gharial and spinosaurid theropods, so perhaps Byronosaurus was a piscivorous troodont. It's notable that some species of owls, like the Balakiston's Fish Owl and Pel's Fishing Owl, as their names suggest, are dedicated piscivores. These owls use their ears to hunt fish at night by listening for disturbances on the surface of the water, so this is also an equally good fit for Byronosaurus' possible diet. As for which is more likely, I'll leave that for the scientists as well as all of you to decide. (Vid above showing some owls fishing in some artificial ponds)
 

Eggs, Young, and... absence in Parenting? (Gasp!)

 

As we all know from almost 100 years now of collecting dinosaur eggs, dinosaurs had incredibly varied ways of raising young and making nests. Sauropods abandoned their young, but gave them a good first chance by laying them near volcanic vents; many hadrosaurs constructed large nests and guarded their young in large colonies; and many ceolurosaurs may have been brought up mostly by dad. Given this incredible diversity of breeding habits in dinosaurs, should it be a surprise that we may have found one more?

 

In 1994, two very young, juvenile skulls of Byronosaurus were discovered by Mark Norell, which give us a good look at exactly how this weird dinosaur grew up. (Note, however, that they are only tentatively assigned to Byronosaurus. There is an alternative possibility that they belong to the recently discovered Zos Canyon troodontid, which has yet to be described.) The juveniles were extremely young, possibly even embryos, and show extremely large eyes and shortened faces, giving them the "cute" look characteristic of young animals. However, what is interesting is the location where these eggs were found: deep in the heart of a oviraptorid nest, with a ring of oviraptorid eggs surrounding the specimens.

 

Oviraptorid were primarilly herbivorous theropods common in the region at the time. Oviraptorid adults, juveniles, and nests have been well-documented for almost 20 years now, but this is certainly a conundrum. How do you get two juvenile troodontids in the nest of another dinosaur? Theories have gone back and forth for a while about this.

 

 

One explanation is that the adult oviraptorid was feeding on the juveniles and left their remains in the nest. A possibility, but modern birds often try to keep their nests clean of feeding debris, and indeed many species will often carry fecal matter and uneaten scraps off to make the nest less conspicuous to predators. Birds from ostriches to eagles do this regularly, so why the oviraptorid would leave its nest dirty and conspicuous like this would not make much sense. (The video above shows an adult female Robin removing its young's fecal pellets)

 

Another possibility is that the juveniles were preying on the unborn oviraptorids. Predators will often feed on eggs of other young, but still, how bold must these juveniles be to want to take on an oviraptorid nest when they are litterally just a few days out of the egg?

 

The last possibility, however, really caught my attention. Some have suggested that the juveniles were present in the nest because Byronosaurus was a brood parasite. Brood parasites are animals that benifit by laying their eggs in other animal's nests, and in return have their eggs and young cared for by the "host" parents. Brood parasitism is surprisingly common in birds, evolving independently at least seven times in birds, as well as in a number of reptile and even insect lineages. Most famous of these animals is the Common Cuckoo (Cuculus canorus), which lays its egg inside another bird's nest. To see this animal in action, David Attenborough has a great documentary on its particular behavior, which you can see here.

 

While it does seem like we're speculating quite a bit on this topic, there is some evidence to back up this theory. For example, the fact that there are two individuals is evidence in itself. Unlike modern birds, which can only lay one egg at a time, reptiles and dinosaurs lay two eggs at a time. If a female Byronosaurus really did lay its eggs in the oviraptorid nest, then we should expect two young to be present because that is what the female would end up producing. 

 

If these troodontids really did practice brood parasitism, it would certainly be a major scientific discovery that would tell us a lot about dinosaur breeding behaviors. But of course, would it really be that much of a surprise? After all, as noted above, dinosaurs exibited a number of extremely varied forms of reproduction, and since all dinosaurs were egg-layers, there are a huge number of options available for some species to cheat on their parental duties.

___________________________________________________________________________

So there you have it: Byronosaurus jaffei, the assymetrical, pinocchio-nosed, insect-eating, fish-catching, parental cheating son-of-a-gun dinosaur. I hope this has been an informative post, and as you all probably know by now, I'm open to taking questions of all kinds.

Also, for those who are interested..the next edition of AncientPlanet Online Journal should be coming out very soon. I don't have a date, but my article will be appearing in it along with numerous other articles submitted by paleontologists, academicians, scientists, grad students and the like. You can also expect a blog post here covering everything I went over, as well as possibly some stuff that was scrapped at the last minute. ;)

Meanwhile, stay sharp, and I'll see you on the net!

Giant Dromaeosaurids

So, during my short a absence (partially due to testing at school, partially due to an illness I've had) I've been cooped up and unable to work on some of the blog posts I've started. Yesterday, I decided to make another video, this time devoted to four species of giant dromaeosaurids: Utahraptor ostrummayosorum, Achillobator giganticus, Austroraptor cabazai, and Itemirus medullaris.

Itemirus medullaris, is extremely poorly known, despite the fact it was found in the 50's, which is unfortunate because it seems to represent a huge species of velociraptorinae, making it a first. I was also going to note the huge dromaeosaurid teeth found in England as well as a few fragmentary remains that might belong to dromaeosaurids, but since they all haven't been named or properly described yet, we're just going to have to stick with these guys for the time being.

Expect more deinonychosaurs soon, and remember that I take requests for post topics. I might even make a video if someone really requests it. :)