Subscription Center
April 4, 2012
| 
86
Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com!
Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com!
Regular readers might have noticed that I’m not all that keen on covering stories that get massive, global exposure across the blogosphere. Consequently, sexy dinosaur news is mostly ignored here. Sometimes, though, I suppose I have to make an exception. Maybe I have a duty to, since the Tet Zoo audience includes more than an average number of dinosaur specialists (meaning that comments and discussions can often be pretty in-depth; more in-depth than they are elsewhere on the web). Furthermore, Tet Zoo is unlike many other sites that cover Mesozoic dinosaurs in that it appeals to many readers who, while zoologically informed, aren’t Mesozoic specialists and hence don’t necessarily get barraged by the same amount of ‘new dinosaur’ announcements that I (and other dinosaur workers) do. Anyway, enough with the preamble…
Brilliant life restoration of four Yutyrannus individuals, by Brian Choo. Is that snow on the ground? You know, I think it is.
Today sees the publication of Yutyrannus huali Xu et al., 2012 in the hallowed pages of Nature. Known from three well-preserved specimens, it’s yet another feathered theropod dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. But it isn’t a dromaeosaurid, early bird or other maniraptoran – it’s a giant tyrannosauroid.
Substantially simplified phylogeny of tyrannosaurs, in this case from Benson et al. (2010). Note difference between Tyrannosauridae and the far more inclusive Tyrannosauroidea.
That is, a member of the same major group of coelurosaurian theropods as Tyrannosaurus and its close kin, but not a member of Tyrannosauridae (the highly modified, short-armed, two-fingered tyrannosauroid clade that includes Tyrannosaurus, Albertosaurus and so on). Tyrannosaurids are mostly big to very big, but non-tyrannosaurid tyrannosauroids were often small to medium-sized (1-4 m being a very approximate range). Anyone who follows me on twitter will know that I spent a significant portion of my life within recent months thinking and writing about tyrannosauroids and not much else.
Skull of Yutyrannus in right lateral view. You should be able to see the rugose dorsal crest along the length of the snout.
Anyway, as a non-tyrannosaurid tyrannosauroid, Yutyrannus is typical in having three-fingered hands, proportionally large bony nostril openings, and distal hindlimb segments that are not especially elongate for the size of the animal (Xu et al. 2012). Diagnostic (= unique) characters include the presence of a peculiar rugose crest along the dorsal midline of the snout and a bony boss on the postorbital bone. We’ll get back to those features in a minute, since there’s something very familiar about them.
The feathers!! The feathers!!
As usual, the main gee-whiz points about Yutyrannus are already being widely discussed. We’ve known for a while (since the publication of Dilong paradoxus in 2004) that at least some tyrannosauroids possess ‘stage 1 feathers’ (Xu et al. 2004). That is, filamentous integumentary structures that seem to be evolutionary precursors to the true, complex feathers that evolved elsewhere within coelurosaurian theropods. Yutyrannus is another feathery/filamenty tyrannosauroid, but it’s remarkable in being huge – it’s about 9 m long, meaning that here is the first GIANT feathery/filamenty tyrannosauroid.
A now historic representation of Eotyrannus, from an online 2001 article by Erik Stokstad. OMG, is that scaly skin?? Oooh, the regret... The moron artist should have known better (ps - irony. Artist = some guy called Naish).
As Xu et al. (2012) note, there are other giant coelurosaurs that would also have been feathered (examples: the huge oviraptorosaur Gigantoraptor, the therizinosaur Therizinosaurus, and perhaps the gargantuan ostrich dinosaur Deinocheirus), but Yutyrannus is the first really big one to actually have the structures preserved. If feathers of this sort were present in Dilong and Yutyrannus, it stands to reason that tyrannosauroids close to these two in the phylogeny would have been feathered as well. The tyrannosauroid I know best – Eotyrannus lengi – is thus depicted as fully fuzzed-up by Xu et al. (2012). I can live with that.
The structures in Yutyrannus are mightily impressive, being tightly massed together and as much as 15 cm long. While none of the three Yutyrannus specimens preserves a complete integumentary covering (if you think that’s weird or suspicious or something, go look at rotting animal carcasses some time), their filamentous structures are preserved in association with the neck, hip region, tail and elsewhere. I thus find it totally reasonable to imagine that the covering was complete across much of the body. These were big, shaggy tyrannosaurs in feathery coats – exactly the sort of thing that artists have been drawing and painting for years now. Huh, stupid artists.
Brian Choo's life restoration again, this time without the pretty background.
If you’re wondering, claims that the integumentary structures present in coelurosaurian theropods might actually be decayed collagen fibres (yes, collagen fibres – - I’m not kidding!!) are not likely and never have been.
Cold adapted tyrannosaurs?
Maniraptorans playing in the snow. An, err, somewhat speculative scene by Luis V. Rey.
Regular readers will perhaps know that I (and others) have been saying for a while that Mesozoic Earth was not the global hothouse that many have long assumed. There’s evidence for cool continental interiors and poles during parts of the Jurassic and Cretaceous (Barron & Washington 1982, , Sloan & Barron 1990, Sellwood et al. 1994), sea surface temperatures that were similar to those of the cold, modern north Pacific and Atlantic (Van de Schootbrugge et al. 2000), and some researchers think that there were glaciation events – that’s right, I said glaciation events – late in the Jurassic and early in the Cretaceous (Dromart et al. 2003, McArthur et al. 2007).
Recently, data has been compiled indicating that the Liaoning region was cool during the Early Cretaceous – its average temperature being about 10 degrees C (Amiot et al. 2011). If you insist that dinosaurs were scaly and ‘cold-blooded’, this idea of insulated big theropods running around in cool climates must seem silly, but if you disregard preconceptions and biases, I think we can now take very seriously the idea that insulated, endothermic dinosaurs were inhabiting cool, or cold, habitats.
Xu et al. (2012) suggest that Yutyrannus was ‘cold adapted’, and that the tyrannosauroids of warmer climes were scaly-skinned and not insulated in the same way. That might be correct, but it’s worth pointing out that we actually know little or nothing about the integumentary covering of tyrannosauroids outside of the Liaoning taxa. There are a few patches of scaly skin alluded to here and there, but nothing substantial, so far. I’m with Andrea Cau (and others) on the idea that ‘fuzziness’ was a gradational thing in archosaurs, with fuzz and feathering mostly (but not wholly) grading out as body size increased. That’s nicely illustrated in Andrea’s diagram below: the redder parts of the diagram are the more scaly/less fuzzy ones, while the purple parts are fuzziest/featheryest (the skeletal reconstructions were produced by Greg Paul, Jaime Headden, Scott Hartman, Marco Auditore and Lukas Panzarin). For a sharper version go here on Theropoda. And I have no idea if “featheryest” is a word.
Yutyrannus the… carcharodontosaurian?
I must confess to being somewhat sceptical of the tyrannosauroid identification for Yutyrannus. I reviewed this paper (to those who don’t know: I did my PhD thesis on basal tyrannosauroids), and noted immediately that Yutyrannus actually resembles carcharodontosaurian allosauroids in some respects. Those of you who know theropods, or who have very good memories, will recall the brouhaha back in 2010 when the carcharodontosaurian Concavenator was described from Lower Cretaceous rocks of Spain (Ortega et al. 2010). Concavenator is an awesome fossil, but what really guaranteed its appearance in the top-tier glamour mags is the claim that raised bumps on its ulnae are quill node homologues – that is, evidence for proto-feathers on its arms. I was sceptical of this at the time (the ‘quill node homologues’ look like bumps on an intermuscular line to me), and am sceptical of it still.
Life restoration of Concavenator by Raul Martin. With feathery, filamenty things on the arms.
Anyway, it’s somewhat ironic – given its alleged featheryness – that Concavenator should raise its head, so to speak, in the discussion here. But I think that Concavenator and Yutyrannus are somewhat alike. The skulls of both animals are particularly similar. Both possess a rugose dorsal crest along each nasal bone, decorated on its lateral surface by a series of subcircular (?pneumatic) recesses, both have a rounded posterodorsal boss (possibly with a concavity on its lateral surface) on the postorbital bone, and, in both, a projection from the postorbital bar invades the orbit.
Other elements of these taxa are also similar. Concavenator is superficially tyrannosauroid-like in possessing a small anterodorsal concavity on the anterior lobe of the ilium (also present in Yutyrannus) and the shaft of its ischium appears more slender than the shaft of the pubis (a feature noted in the Yutyrannus paper to be a tyrannosauroid-like character).
While the authors took account of the carcharodontosaurian-like features of Yutyrannus and modified their phylogenetic analysis accordingly, they stuck to their guns about it being a tyrannosauroid. I agree that Yutyrannus is tyrannosauroid-like in many features but, I dunno, I think it needs to be included within a larger and more comprehensive data set. Why didn’t I do this myself when I was reviewing the paper? Several reasons. One being that – so long as a given proposal isn’t fatally flawed or shot full of holes – you can’t stop authors from coming up with their own favoured phylogenetic hypothesis, even if you disgree with it. I should note that my suggestion here is just a suggestion, not an outright challenge, and I’m not all that confident about being right. I’m just sceptical.
Mark Witton's fuzzy styracosaur again. Hey, weirder stuff has happened. Oh yeah, and it's eating a dead tyrannosauroid.
Anyway, none of this stops Yutyrannus from being an awesome dinosaur discovery that will get lots of attention in future publications. And it raises lots of questions. Most evidence indicates that the tyrannosauroids of the Early Cretaceous were generally small and ecologically ‘inferior’ to contemporaneous megalosauroids and allosauroids. If Yutyrannus is a tyrannosauroid, does it show that things were more complex, and that big tyrannosauroids lived alongside big megalosauroids and/or allosauroids in some or many places? Or is it that tyrannosauroids were ‘controlling’ regions (like – the cooler regions?) where those other groups were absent? Were tyrannosaurids perhaps better adapted for cool/cold climates than other big-bodied theropod lineages, and could this have been key to tyrannosauroid success? Were the cranial bossess and nasal crest we see in Yutyrannus sexually selected characters, and is their presence in more than one individual an indication of mutual sexual selection? (Hone et al. 2012). Perhaps most interestingly of all, will more big, fuzzy dinosaurs be announced in future? Place your bets.
For previous Tet Zoo articles on some of the subjects mentioned here, see…
Refs – -
Amiot, R., Wang, X., Zhou, Z., Xiaolin Wang, X., Buffetaut, E., Lécuyer, C., Ding, Z., Fluteau, F., Hibino, T., Kusuhashi, N., Mo, J., Suteethorn, V., Yuanqing Wang, Y., Xu, X. & Zhang, F. 2011. Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates. Proceedings of the National Academy of Sciences 108, 5179-5183.
Barron, E. J. & Washington, W. M. 1982. Cretaceous climate: a comparison of atmospheric simulations with the geological record. Palaeogeography, Palaeoclimatology, Palaeoecology 40, 103-133.
Benson, R. B. J., Barrett, P. M., Rich, T. H. & Vickers-Rich, P. 2010. A southern tyrant reptile. Science 327, 1613.
Dromart, G., Garcia, J.-P., Picard, S., Atrops, F., Lécuyer, C. & Sheppard, S,. M. F. 2003. Ice age at the Middle-Late Jurassic transition? Earth and Planetary Science Letters 213, 205-220.
Hone, D. W. E., Naish, D. & Cuthill, I. C. 2012. Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs? Lethaia 45, 139-156
McArthur, J. M., Janssen, N. M. M., Reboulet, S., Leng, M. J., Thirlwall, M. F. & van de Schootbrugge B. 2007. Palaeotemperatures, polar ice-volume, and isotope stratigraphy (Mg/Ca, d18O, d13C, 87Sr/86Sr): the Early Cretaceous (Berriasian, Valanginian, Hauterivian). Palaeogeography, Palaeoclimatology, Palaeoecology 248, 391-430.
Ortega, F., Escaso, F. & Sanz, J. L. 2010. A bizarre, humped Carcharodontosauria (Theropoda) from the Lower Cretaceous of Spain. Nature 467, 203-206.
Sellwood, B. W., Price, G. D. & Valdes, P. J. 1994. Cooler estimates of Cretaceous temperatures. Nature 370, 453-455.
Sloan, L. C. & Barron, E. J. 1990. Equable climates during Earth history. Geology 18, 489-492.
Van de Schootbrugge, B., Föllmi, K. B., Bulot, L. G. & Burns, S. J. 2000. Paleoceanographic changes during the early Cretaceous (Valanginian-Hauterivian): evidence from oxygen and carbon stable isotopes. Earth and Planetary Science Letters 181, 15-31.
Xu, X., Norell, M., Kuang, X., Wang, X., Zhao, Q., & Jia, C. (2004). Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids Nature, 431 (7009), 680-684 DOI: 10.1038/nature02855
- ., Wang, K., Zhang, K., Ma, Q., Xing, L., Sullivan, C., Hu, D., Cheng, S. & Wang, S. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature 484, 92-95.
About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com!
Rights & Permissions
86 Comments
Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.
Click one of the buttons below to register using an existing Social Account.
The Overwhelming Odds Of Climate Change
The s**t hits the fan - FDA, INDs, and fecal microbiota transplants
Angelina Jolie and the One Percent
A Beautiful Fungus Graveyard
Cancer, genomics and technological solutionism: A time to be wary
Self-Publishing Tools for Science Artists
See what we're tweeting about
TetZoo Time to leave for #Rio #pterosaur symposium. Discussing reproductive strategies in pterosaurs, also #Vectidraco. Will try & tweet! #fossils
Dhunterauthor Nuevo Verdad: Geotrippin’ Parte the Seconde: Where were we before the craziness that was this weekend happened... http://t.co/ugAN2MW5a7 Dhunterauthor Why I Am No Longer A Republican http://t.co/1z8kJ3r2ND
YES! Send me a free issue of Scientific American with no obligation to continue the subscription. If I like it, I will be billed for the one-year subscription.
Share
Email
Print
I agree with Darren that the tyrannosauroid nature of this beast isn’t 100% certain. And a carcharodontosaurian affinity isn’t impossible. And, as will be seen in months to come, there is a third possibility which (odd as it is to say) is a kind of blend of the two…
Link to thisHuh! (as in: gosh, that’s interesting). Thanks, Tom.
Darren
Link to thisThis is really cool actually. Who would of thought of big fluffy dinosaurs romping through the snow? It took decades and 3 spielberg movies for the public to grasp the idea that dinosaurs weren’t huge dim-witted, clumsy, cold-blooded behemoths. Now People will have to get used to a new bizarre reality all over again.
Link to this“a kind of blend of the two”
Total guess: a megaraptoran, with Megaraptora (sometimes considered a carcharodontosaurian clade) positioned just inside Coelurosauria?
Link to thisAwesome stuff! Looking forward to the continued research of integument in dinosaurs.
Also Darren, slight typo: the caption underneath Brian Choo’s illustration (the first one, with the incredible background)says that there are, “three four,” individuals.
Link to thisSo cool forever!
My personal preference in art is to show fuzzy dinos with fuzzy feet. Highly speculative, but cold-adapted dinos make it seem fairly likely. I’m thinking Bubo scandiacus…
And oh yeah, color! I REALLY hope they have melanosomes from this guy.
So as of yet, there’s no direct evidence of integument in ornithischians (& is good evidence of the opposite), but we know Leaellynasaura lived in a cold climate, and probably some others did as well. I wonder, if we accept our best available evidence that they were scaly, then how does a scaly animal adapt to cold? What do cold weather scales look like?
Link to thisIt struck me how the illustration, which is really beautiful by the way, looks a lot more like a tyrannosauroid than the fossil. When I saw the fossil I immediately thought of something more like a carcharodontasaurian, but I’m only familiar with the superficialities (if that’s a word), so I was willing to accept their phylogenetic placing if they could demonstrate a sharing of some really key characters. It seems like whether these specimens are tyrannosauroids or carcharodontasaurians is kind of a big deal… should they really be so easily confusable, particularly with such well preserved specimens? I’m not a dinosaur guy, so that’s about as in-depth as my commentary on this subject can go (which is why I appreciate you breaking the trend and reporting on the news, Darren, you should really do it more often to help out ignoramuses like myself!).
I like the connection to ecological dominance relationships with other large theropods. Has there been any substantive work done on this issue in the literature or is this issue something that has merely been noticed?
Link to thisVery interesting idea about it being a carcharodontosaurid. Note that the matrix used is Xu et al.’s Haplocheirus analysis, which is frankly terrible. Indeed, most of the non-coelurosaur taxa are left uncoded for lots of the Theropod Working Group coelurosaur characters. Presumably Xu et al. figured they weren’t coelurosaurs, so why bother, but this means taxa are mostly coded for the clades they’re thought to belong in. Thus if e.g. Neovenator has coelurosaur-like characters, they’ll be left as unknown, and if Yutyrannus has them too, the characters will drag it toward Coelurosauria instead of allow it to be a carcharodontosaurid by Neovenator.
Not that I know that this happened in this instance or have a opinion on what Yutrannus is, but I certainly don’t trust that matrix.
Link to this“…then how does a scaly animal adapt to cold?”
A layer of fat?
Link to thisWell … surely a giant feathered carcharodontosaur would be even more awesomer than a dito tyrannosaur?
Tangentially, how far down the tree does one have to go find something that was definitely not fuzzy?
Link to thisAndreas: good question. The unpublished Carnotaurus skin impressions lack feather impressions, but as I’ve said elsewhere the types of sediment that preserves these impressions actually might not be able to pick up feathers.
Link to thisby the way, I’m glad you pointed out the high res version of Andrea Cau’s diagram.
Link to thisInitially I had thought the creature in the “basal archosauriformes” box was some sort of six legged creature – common ancestor of crocodiles and invisible garage dragons, maybe.
Now I’m just waiting for the vulturine T. Rex illustration to show up when the predator vs. scavenger argument crops up again. Talk about griffins!
I’m already thinking off all the color arguments people will have about dinosaurs:
–feathers were dark for thermoregulation (soak up heat)
–no, feathers were white for thermoregulation (to reflect off heat)
–feathers were black for wear resistance
–no, feathers were colored for social display
–no, feathers were for camouflage.
–no, feathers changed color through the seasons as the tips wore off.
And when are we going to see the first dino-sized feather louse in amber?
What fun!
Link to thiswow! When I first saw the title of this post I thought it was one of your april fools posts!
I’m more inclined towards the idea that Yutyrannus was a tyrannosaur. It just has that sort of asthetically pleasing appearance that tyrannosaur skulls so elegantly display. The pronounced cornural process on the jugal and the ventrally convex maxilla do immediately strike me after reading the paper as being (at least superficially) extremely tyrannosaurian.
I wonder if the proportionally large external naris of primitive tyrannosaurs like Proceratosaurus and Yutyrannus were related to their hunting methods. I recall Larry Martin suggesting that the conical toothed Nimravid Dinaelurus (known only from cranial remains) may have been a cheetak like carnivore because of it’s large internal and external nares. Possibly these early tyrannosaurs were similarly pursuit hunters?
Link to thisOh; secondly; i dont think the paper mentioned the fact that the close proximity of multiple specimens of this animal (2 on the same slab) seems to imply to me perhaps some kind of social behaviour. (perhaps due to limited space)
Im sure I read somewhere about a loada daspletosaur remains (diff individuals) found together that immply “gregarious behaviour” (Just found the paper its in indiana univ press The carnivorous dinosaurs; an unusual multi indiv tyrannosaur bonebed….. phil currie et al).
Anyway I think there have been other inklings of gregarious behaviour in tyrannosaurs here and there in other taxa; I just can’t quite remember.
Link to thisInteresting comments, thanks everyone. We have to keep images small here on SciAm (I use the ‘save for web’ function in photoshop, so images get scrunched down to less than 100 kb), so they’re often grainy or fuzzy, unfortunately.
James: I’m not sure about “aesthetically pleasing appearance” being a valid character or set of characters
But, yes, Yutyrannus certainly does have some tyrannosauroid characters in its skull – the maxillary process of the premaxilla mostly faces dorsally rather than laterally, for example. Is it really tyrannosauroid-like in having a ventrally convex margin to the maxilla? I’m not sure – I can’t see that it’s all that different from Concavenator. As usual, the animal in question exhibits a mosaic of features and we should try to take account of as many as possible.
And, yes, there are quite a few tyrannosauroid taxa were two or more specimens have been discovered in association. This may or may not tell us something about social behaviour.
Darren
Link to thisI know which journal the feathered ?megalosauroid has been submitted to. Just saying.
(Nature of course rejected it because the embargo had been broken; Science didn’t want to have it either anymore.)
as of yet, there’s no direct evidence of integument in ornithischians (& is good evidence of the opposite)
You managed to forget Tianyulong already.
A layer of fat?
Leaellynasaura had an insanely long, thin tail. It was more spider-like than globular. Plus, a feather layer insulates as well as a fat layer that is 10 times as thick.
Link to thisCorrection: a fur layer insulates as well as a fat layer 10 times its thickness. Feathers may be even better (though stage 1 feathers may not, who knows).
Link to thisCan’t we genetically engineer a chicken to express Stage 1 feathers as an adult, so we can do the physiological experiments? Aside from the trivial issue of getting it through institutional review, what could possibly go wrong?
Link to thisHeteromeles: I don’t know how relevant they are for models of feather origins, but unbranched quills pretty much the same as ‘stage 1′ feathers of the Prum & Brush model are already known for coucals, roadrunners and other cuculiforms, some passerine chicks etc. I wrote about this briefly here on Tet Zoo ver 2.
Darren
Link to thisThe warmest sleeping bags are filled with filamentous down feathers, not flight feathers….so maybe Stage 1 feathers are even better insulators than advanced feathers.
Link to thisHoltz- Bonaparte et al. (1990) did spend a paragraph describing Carnotaurus’ skin, and had several photographs showing what it looked like, so I wouldn’t say it’s unpublished.
Marjanovic wrote- “(Nature of course rejected it because the embargo had been broken; Science didn’t want to have it either anymore.)”
It’s things like this that make me wonder what journals are thinking. Their primary consumers are researchers, so do they think we all wouldn’t read the paper in Nature/Science just because the topic was presented at a conference elsewhere? Though on the other hand, at least we might get a detailed description now since the paper WON’T be in Science or Nature. Is there a greater irony than the fact the two “most prestigious” journals are the two I would least like a paper to be in, due to space restrictions if nothing else?
Link to thisTherizinosaurus: Wow, that is a paper I’ve not looked at in ages. Yes, you are correct, there are pictures in there.
As for the rejection for Nature: I don’t know if David has any positive information to give as to that being the reason for rejection. There may be other issues.
Link to thisto Heteromeles, note last week’s report of inch-long Yixiang fleas……..J
Link to thisI am quite surprised that Liaoning had cold climate. Is there any evidence of it in fauna, for example shortened extremities?
Link to thisAnother thing is gregariousness of large carnivores. Scaling ecology of living animals (which is in turn dictated by biomechanics) to dinosaurs gives WEIRD paradoxes.
As you know, large carnivores find it energetically optimal to hunt prey as big or bigger than themselves; which results in strong biomechanic selection for running and hunting with little margin of error (cat has no problem in catching and killing a mouse because of size difference, but lion and zebra are about equal size and strength). As the result, carnivore mammals rely on mother’s hunting skills until fully grown, and often a long time later.
Would adult and juvenile Yutyrannus a third the weight hunt together one prey, despite very different biomechanics? Or would parent Yutyrannus provide its juveniles for many years, resulting in insanely low fecundity? Or would growing Yutyrannus undergo large allometric changes, needed to run effectively at very different weights?
Link to this@Therizinosaurus
Nature just shot itself in a leg and lost a valuable publication.
BTW, you may not be aware that impact of high-impact journals is often made by few extremely highly cited papers. Sometimes it is extreme, I heard rumours that one mid-ranked journal has half of impact made by just two papers, of which one is BLAST (common sequence comparison algorithm).
Link to thisJerzy (re: comment 26 on Liaoning climate): here is the same citation given above…
Amiot, R., Wang, X., Zhou, Z., Xiaolin Wang, X., Buffetaut, E., Lécuyer, C., Ding, Z., Fluteau, F., Hibino, T., Kusuhashi, N., Mo, J., Suteethorn, V., Yuanqing Wang, Y., Xu, X. & Zhang, F. 2011. Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates. Proceedings of the National Academy of Sciences 108, 5179-5183.
As for comment 26… come on, Jerzy: dinosaurs are not mammals. Evidence from embryos and hatchlings indicates that theropods were precocial and lived and hunted separately from adults, apparently operating as distinct ‘eco-species’. See…
Isles, T. E. 2009. The socio-sexual behaviour of extant archosaurs: implications for understanding dinosaur behaviour. Historical Biology 21, 139-214.
Varricchio, D. J. 2011. A distinct dinosaur life history? Historical Biology 23, 91-107.
Darren
Link to this@20: I always thought there was something dinosaur-like about roadrunners. Maybe this explains it. Still I’m terribly, terribly disappointed that we don’t have to create a transgenic monster to study this in vivo. Really.
As for inch-long fleas, thanks for the reminder, James. I’m sure that will show up in some dinosaur animation at some point (Tyrannosauroid chases flea around vent. Humorous interlude ensues).
Link to this“Tangentially, how far down the tree does one have to go find something that was definitely not fuzzy?”
Well, David Unwin’s book Pterosaurs: Out of Deep Time contains substantial discussion of the evidence for fuzzy pterosaurs. So perhaps the MRCA of pterosaurs and theropods was fuzzy. That at least would be consistent with the fuzzy ornithscians some around here support.
On the other hand, the fuzz discussed is always referred to as hair. Sadly I don’t recall the grounds for this distinction.
On the gripping hand, Unwin refers to the case for a common origin of dino fuzz and pterosaur hair as “far from proven” or something like that.
Link to thisDavid:
Thank you – but I had thought Shelton was trying to ask a question about what other alternatives to feathers there are. And I can only think of fat, and low temperature body chemistry (as seen in many cold climate invertebrates). Admittedly neither orcas nor grayling nor Antarctic springtails have much to do with ornithischians.
From that viewpoint I can see why some people think the simplest answer to “What do cold weather scales look like?” is “Down.” .
On the other side, there is only 1 or maybe 2 examples of fuzzy ornithischians, and a handful of cold climate examples.
Link to thisI’d suggest looking at insects (Heinrich’s Thermal Warriors) for examples of hair and scales on ectotherms and various flavors of insect endotherms. Not vertebrates, but some of their strategies probably would scale of to dinosaurs.
Link to thisIt’s things like this that make me wonder what journals are thinking. Their primary consumers are researchers, so do they think we all wouldn’t read the paper in Nature/Science just because the topic was presented at a conference elsewhere?
Seconded.
Though on the other hand, at least we might get a detailed description now since the paper WON’T be in Science or Nature.
If I say more about this, I’ll pretty much give away what journal it’s been submitted to now.
I have no idea if that would be a good idea.
I don’t know if David has any positive information to give as to that being the reason for rejection. There may be other issues.
That’s what I’ve been told over dinner in the cafeteria in Berlin. “It was submitted to Nature, but then it was presented at that conference, and Nature said ‘embargo broken, buh-bye’. Science didn’t want to have it anymore either after that.” I don’t remember if Nature had accepted it, but it definitely wasn’t rejected by reviewers.
Me, I’ve hardly seen the photos. I have no opinion on whether it’s a megalosauroid, if that’s what you mean.
I am quite surprised that Liaoning had cold climate. Is there any evidence of it in fauna, for example shortened extremities?
There’s evidence in the complete and utter absence of crocodyliforms. Not a single tooth, nothing. There are champsosaurs (with their scales preserved, of course), there are squamates, there are mammals, there are dinosaurs, but crocodiles are lacking.
Link to thisAre there any turtles there? I think not!
Link to thisI was reading about Yutyrannus and according to the paper the skull grew more deeper and robust as the animal matured. Isn’t positive allometry of the skull a characteristic of tyrannosauroids?
Link to thiswell then, why no duck-feathered champsosaurus?
Link to thisMaybe I misunderstood one or another report, but I thought this adult and juvenile Yutyrannus were found together, implying social group?
In any case, problem of allometry stays – I guess juvenile theropods were longer-legged and shorter-jawed to compensate for it.
Link to thisI’ve tested Darren’s suggestion of a carcharodontosaur and/or Concavenator relationships of Yutyrannus in my large theropod phylogeny (in preparation). The analysis includes all tyrannosauroids and carcharodontosaurians (among many others) and all characters mentioned as supporting both tyrannosauroid and carcharodontosaurian affinities for Yutyrannus. It turns as a tyrannosauroid more derived than Xiongguanlong and sister taxon of the clade including the Late Cretaceous tyrannosauroids. Forcing Yutyrannus as sister-taxon of Concavenator in carcharodontosauridae produces topologies 34 steps longer than the shortes trees found. Forcing Concavenator (and Becklespinax) in Tyrannosauroidea as sister taxa to Yutyrannus the resulting topology is 16 steps longer than the shortest trees. Both alternatives must be rejected, based on my data set. Therefore, this seems an intriguing case of cranial morphology convergence.
Link to thisThis made me wonder. If they had feathers, is there any observable evidence of moult in dinosaurs or Mesozoic birds?
I see something which might be a moult on Berlin Archeopteryx specimen, between 6. and 7. primary on the left wing and 7. and 8. primary on the right wing.
If so, this among others suggests that it was over year old individual.
Link to thisThe traditional term is “plumous”, but I like “feathery/er/est”. If Lewis Carroll could coin words (eg: “chortle”), so can you!
Link to this@34: What about Manchurochelys?
Link to thisNature, from my experience, seems extraordinarily capricious about what they will or will not accept, and why. But Science seems less so. If a talk at a meeting is reason enough to reject a submission, it seems to me that almost all submissions would be rejected, since almost all of them will have been the subject of previous talks. Who delays a talk until the paper is published? Nobody I know of. I’ve never made it into Nature, but I’ve given talks about the contents of a Science paper long before publication, or even submission.
Link to thisThanks for comments. A few responses…
Crocodyliforms at Liaoning (comment 33): there were rumours last year that one had been found. I told this to Romain Amiot at the sauropod meeting in Bonn last year, but I haven’t heard anything else about it (and I previously mentioned it on Tet Zoo here). In the absence of further information, it’s impossible to say what it might mean, if anything.
Turtles at Liaoning: as Albertonykys says (comment 41), some are indeed known from the Yixian Formation. Manchurochelys manchoukuoensis – the holoptype is lost, a second specimen was reported in 2010 – is there, as is Ordosemys liaoxiensis (originally described as a new species of Manchurochelys). I think both are known from many specimens.
Darren
Link to thisOntogeny and social groups in Yutyrannus (comment 37): three specimens are known, two of which were found in close association. One is rather larger than the others, but the differences we’re seeing here aren’t major (skull lengths are, respectively, c. 905, 800 and 630 mm) – all are about similar in proportions, though with the ilium, tibia and metatarsus displaying some negative allometry if all three are assumed to represent a growth sequence (skull growth seems to be isometric). So, yes, the juveniles are somewhat longer-legged (as is typical for theropods). All data here is all from the supp. info of Xu et al. (2012).
Darren
Link to thisAny phylogenetic hypothesis must be understood to be a hypothesis – a proposal that represents an explanation for a certain set of observations (in this case, anatomical characters and their codings), but one that is subject to testing and falsification as more data is added. What I’m saying here is that no proposed phylogenetic tree is ever the “last word”.
Nevertheless (see comment 38), Andrea has tested my proposal of a possible carcharodontosaurian affinity for Yutyrannus and found that it does not explain observations as well as the tyrannosauroid proposal. That’s great news and I’m very grateful to Andrea for doing this. As he says, the cranial convergence is really interesting (needless to say, Andrea and I will have to modify the submitted Eotyrannus monograph to take account of this). You can read more about Andrea’s analysis here on his Theropoda blog.
Darren
Link to thisI have two questions about the champsosaurs in Liaoning.
First, since there are impressions of their scales, and they are not closely related to anything fuzzy, if the Liaoning climate was cold, it seems to me their presence returns us to Shelton’s quesion “What do cold weather scales look like?” , in a case where the answer is probably not “feathers”
My second question comes from the report that there are (probably) no crocodyliforms known from Liaoning. If cold kept out the crocodyliforms, why didn’t it keep out the champsosaurs? I am not seeing what they had which makes them better adapted to cold than crocodyliforms.
(Also I keep hoping I will have time to try and figure out what the timewise resolution of those oxygen isotope temperature proxies might be. All too often in Mesozoic climate proxies you have what amounts to a handful of samples for a half a million year period – or even much longer. Now in the last half million years there have been times when ice sheets came as far south as 39 N, and times when crocodyliforms ranged as far north as 37 N. )
Link to thisIf so, this among others suggests that it was over year old individual.
That’s obvious anyway; the study on its growth (and that of many other dinosaurs, including Confuciusornis and Dinornis) was published in 2004 in Nature.
@34: What about Manchurochelys?
I was wrong, that’s what!
If a talk at a meeting is reason enough to reject a submission, it seems to me that almost all submissions would be rejected, since almost all of them will have been the subject of previous talks. Who delays a talk until the paper is published? Nobody I know of.
I’ve never seen a presentation that grew into a Nature paper.
On at least one occasion, I’ve seen a presentation that was published in Nature the same day.
In other words, yes, people who have submitted to Nature (pun intended) really do keep everything top secret till the paper is out, with this one unfortunate exception that I know of.
If cold kept out the crocodyliforms, why didn’t it keep out the champsosaurs? I am not seeing what they had which makes them better adapted to cold than crocodyliforms.
Viviparity. Gravid individuals have been found in the Jehol Group.
Link to thishm, seems box turtles may occur as far north as the south western corner of Maine (about 43 N), though the Maine gov seems uncertain. If wikipedia is to be believed, the common snapping turtle ranges into southern Canada (north of 48 N). If I’m reading the wikipedia map correctly, the most northerly nesting location of the leatherback turtle is in Liaoning (about 39 N). (And as discussed in the past on this blog, adult leatherbacks range all the way to the arctic ocean, actively hunting even in near-freezing water.)
So (some) modern turtles appear to be much more cold tolerent than any modern crocodyliforms. I imagine a general roundish sort of shape, with low surface are to mass ratio is to blame. (Hm, any anklyosauria known from cold climates? )
Link to this“On the other side, there is only 1 or maybe 2 examples of fuzzy ornithischians, and a handful of cold climate examples.” -Llewelly @ 31
Say WOT?!
I hadn’t heard of the fuzzy ornithischians. Do tell. I’ve seen conjectural art of fuzzy hatchlings, but never heard of hard evidence for it.
You were right about the meaning of my question. In modern times there’s not much with scales in the polar regions. But Leaellynasaura I’d seen depicted rocking scales in a snowdrift and it got me thinking about the big picture.
I read somewhere there was something on the iguanodont/hadrosaurid line (?) in Liaoning, which would be another presumably scaly cold-weather beast. Then there’s all the aquatic reptiles of old, some of which must have entered cold waters. Mosasaurs, icthyosaurs, etc… Blubber for some, sure. What of the others? Could a heat-trapping scale have existed and what would that have been like?
Apologies as usual for layman errors, and thanks.
Link to this-
llewelly:
“the common snapping turtle ranges into southern Canada (north of 48 N)”
Latitude-wise*, the Chinese soft shell turtle Pelodiscus sinensis ranges approximately equally far north in the Amur region at the Russo-Chinese border. And the European pond turtle Emys orbicularis, on the other hand, is found as far north as southern Lithuania (about 54 N). In other words, the presence of (freshwater) chelonians at a fossil site isn’t a very good indicator of tropical, or even subtropical, conditions.
* Of course, latitude alone isn’t the whole story; climate is also influenced by other factors. For example, thanks to the Gulf Stream, the climate of Europe is relatively mild – which, among other things, allows Emys orbicularis to range as far north as it does.
Link to thisHm, any anklyosauria known from cold climates?
There’s always Liaoningosaurus, and it lacks the size and shape you’re thinking of.
I hadn’t heard of the fuzzy ornithischians. Do tell.
TIAN
YU
FUCKING
LONG!!!
Described in Nature three years ago. Also remarkable for being an Early Cretaceous omnivorous heterodontosaurid.
Link to thisDavid: Tianyulong is from the Tiaojishan Fm. (not the Jehol Group as initially reported), and hence from the Late Jurassic.
Link to thisTurtles pull some interesting physiological and behavioral stunts to get through northern winters (ref: Heinrichs’ Winter World). It’s not just cold tolerance, it’s a mix of factos: summer temps being warm enough to incubate eggs, winters being short enough to hibernate through, and suitable hibernacula being available.
Obviously you won’t see all of these in a fossil record, but the upshot is that simple latitude only really captures the death zone (as in, there’s no evidence they got this far north) rather than demonstrating the zone in which turtles could live.
Link to this“the European pond turtle Emys orbicularis, on the other hand, is found as far north as southern Lithuania (about 54 N)”
Slight correction to that: apparently, the current range of this species extends a bit further north than what I said; it seems to be present in Latvia, too.
And the former range of the European pond turtle extended further north still: in the Holocene it was present in Estonia, Denmark, and the southern part of Sweden. The northernmost subfossil remains of this species are from the latter country, close to 59 N latitude (Sommer et al., 2007).
Sommer, R.S., Persson, A., Wieseke, N. & Fritz, U. 2007. Holocene recolonization and extinction of the pond turtle, Emys orbicularis (L., 1758), in Europe. Quaternary Science Reviews 26, 3099–3107.
Link to thisThis could be nifty in shooting down that “big raptors were too big to be fuzzy” argument that various people (*cough JP fans cough*) always seem to bring up…
Also, I seem to remember hearing something about a smooth-skinned Gorgosaurus a while back? It would be interesting if it turned out that the basal ones were fuzzy, the albertosaurs had smooth skin, and the “crown king” Tyrannosaurus had scaly skin. Hmm…
Link to thisRe: Cold-climate ankylosaurs.
There are a few. Minmi is known from Australia, and we have an incredibly fragmentary specimen (basically the upper palate and a tooth) of Edmontonia up here in Alaska.
Link to thisI liked CS Shelton’s idea of Yutyrannus in Snowy Owl costume, so I drew it with no pretense of accuracy.
http://skywaterblue.deviantart.com/#/d4vt7vs
Link to thisSkywater: love it!
You weren’t inspired by those recent photos of the Snowy owl leaping up off the ground when confronted by an aggressive peregrine, were you?
Darren
Link to thisRe cold-weather ectotherms: some snakes get very far north – IIRC European adder gets barely above the Arctic Circle in Scandinavia, and garter snakes live pretty far north in Canada/Alaska. But these hibernate, and garter-snake-style mass group hibernation wouldn’t be an option for any large ectotherm.
Link to this“TIAN
YU
FUCKING
LONG!!!”
Well now, the reason I hadn’t thought of that guy is because when I learned about him, I assumed that was just a dorsal fringe similar to psitticosaurus and not indicative of general fuzziness. I read a little online back then and found the naysayers persuasive.
I found a good image of him: http://svpow.files.wordpress.com/2009/03/tianyulong-specimen.png
You think that tianyulong was covered in generalized integument? I can’t tell. Convince me, because I’d love to be convinced, and the paper is hidden behind a paywall.
Skywater- I have to make cockamamie suggestions more often.
Link to this… do we have evidence that Minmi was scaly
?
Link to thisHeat-trapping scales would be a problem for ectotherm. It should instead have an ability to change blood circulation and body area exposed to sunlight.
BTW – were pelycosaurs large ectotherms living in a relatively cold climate?
Link to thisDavid: Tianyulong is from the Tiaojishan Fm. (not the Jehol Group as initially reported), and hence from the Late Jurassic.
ARGH! How did I miss that? Where was the reassignment published?
You think that tianyulong was covered in generalized integument? I can’t tell.
I’ll reread the paper later today. In the pic you link to, there are apparently feathers on the ventral side – off the lower jaw, shoulder girdle and upper arm.
BTW – were pelycosaurs large ectotherms living in a relatively cold climate?
What cold climate?
Upland, yes (Dimetrodon teutonis, at least, lived in an environment devoid of aquatic vertebrates: there are just amniotes, diadectids, burrowing “microsaurs”, adult trematopid temnospondyls and adult Seymouria sanjuanensis), but I don’t know of any evidence for cold.
Link to thisllewelly: I’ve read somewhere that box turtles are the largest vertebrates capable of surviving being frozen.
Interestingly, Chinese alligators can survive prolonged exposure to sub-zero temperatures by digging long burrows with underwater entrances. It looks like present crocodilian distribution is way more limited than this particular species would be capable of. There are no crocodilians in Transcaucasia, Southern Europe, California or Japan – all these places have similar summer temperatures and warmer winters than the part of China where gators live. I suspect that even Nile crocodiles from Zululand could survive in San Francisco Bay or Venice Lagoon if introduced (please don’t test this theory).
Link to thisWe don’t have garter snakes in Alaska. The only ectotherm up here is the wood frog (_Rana sylvatica_), which is tiny, adorable, and able to freeze itself during the winter.
Link to thisThat’s very interesting, Jerzy – but doesn’t that imply there ought to be early Holocene or Eemian remains of crocodilians in at least some of the places you mention (ignoring those unreachable by crocodilians due to geography)? Have any been found?
Link to thisvdinets, sorry, my previous comment was directed at your #64 , not at Jerzy.
Link to this@64: Reggie the alligator survived for about two years in Harbor Lake in Los Angeles (http://en.wikipedia.org/wiki/Reggie_(alligator)). The problem with California isn’t so climate per se, it’s the lack of suitable wetlands. I suspect that, given another few decades of climate change, we’ll see feral gators in the Sacramento Delta.
Link to this@llewelly
Historically Nile Crocodiles lived in the Middle East and I think stray ones visited south Europe (not sure – I think it was talked about one time on Darren’s blog).
The problem with Japan and Europe is that the road to warm climate refugia is cut off by sea, while wildlife in mainland East Asia can freely migrate north and south.
BTW – Is there a way to block the old user name at SciAm?
Link to thisllewelly: I don’t think there are remains, but crocodilians are mentioned in a few places in Russian chronicles and in travelers’ notes from Lithuania and Poland. One entry in the official chronicle of Pskov City says “[In the summer of year 1582] numerous fierce crocodile beasts came out of the river, blocking some roads and eating people; the people were terrified and prayed for deliverance, until the beasts disappeared or were killed.” Only a minority (but not a fringe minority) of historians takes these reports seriously.
Jerzy: there are records of stray saltwater crocodiles from Japanese waters. But alligators are not as good as crocodiles at oversea dispersal.
Link to thisOh snap. Just found evidence this really is a tyrannosauroid… Look at the fluffy integument on this one:
http://991.com/newGallery/T-Rex–Tyrannosaurus-Rex-The-Slider-Anthol-468655.jpg
Link to thisThe problem with Japan and Europe is that the road to warm climate refugia is cut off by sea, while wildlife in mainland East Asia can freely migrate north and south.
Exactly. The ice ages killed them all in Europe, and then they weren’t able to reimmigrate across the Mediterranean and the Syrian desert (let alone the Caucasus).
I don’t think there are remains, but crocodilians are mentioned in a few places in Russian chronicles and in travelers’ notes from Lithuania and Poland. One entry in the official chronicle of Pskov City says
WTF. That’s crazily far north.
Link to this@David: I think we’re missing the crazy aristocrat who imported the crocs to Lithuania for…sport. Yes. Mwa-hah-hah-hah!
Link to thisDavid: of course it is. That’s why so many people are skeptical. Russian cryptozoologists tried looking for these things in large swamps recently and found all kinds of folk stories (not very consistent with a crocodilian theory), but no solid evidence.
David: Lithuania of that era was mostly an extensive wilderness, so I don’t think there were aristocrats of that kind yet.
Anyway, here’s the famous account by Gerberstein, a 16th century Austrian traveler know to be generally reliable. He wrote that in Lithuania, “Locals keep in their homes strange snakes with short legs, like lizards, with black fat body, [60—70 см] long, called gaviots… On certain days, people clean their houses and with some fear worship these creatures as they come out to consume the food offerings”.
Link to thisvdinets, that description fits a dachshund almost as well as it does a crocodile.
Also – did Gerberstein see these creatures with his own eyes, or was he describing something told to him by others?
Link to this“Gerberstein, a 16th century Austrian traveler”
Do you mean Sigismund von Herberstein?
Link to thisDavid (#72): I wonder what prevented them from migrating around the Mediterranean, considering that they were present in Palestine.
llewelly: I am not expressing any opinions, just quoting. Could be desmans or otters. My understanding is that he did see them, or at least claimed to.
Dartian: Yes. Sorry, I was reverse-translating from Slavic into Germanic, and German h is traditionally transliterated as “g” in Russian, although not consistently (hence “Hail Gitler!” in Soviet war movies).
Link to thisvdinets, I did not intend to imply anything about your opinion – it’s just that the quote strikes me as vague. Otters and damen are interesting suggestions, and certainly better than crocodiles. Damen are blind, however – would he have remarked on that?
Link to thisllewelly: damen? you mean, desmans? they are not blind.
Link to thisJust realized my reply must have been ated by the internet. Bad internet, bad!
Darren: No! I haven’t seen them, which is stunning as the photos were taken (quite literally) blocks from my old apartment. I did not even know snowy owls were transient in Chicago! I shall have to keep an eye to the sky more often.
CS: Yes, yes, make more suggestions that equate feathered dinosaurs = charismatic birds-of-prey. If we get enough Snowy Owl T-Rex and Peregrine Velociraptors on our side, we can finally win the day on this one.
Link to thisI did mean desmans, vdinets, thank you. And I had thought they were functionally blind.
Link to thisllewelly: that’s what Wiki says, but in reality at least Russian desmans react to light and movement. They are fascinating animals; I had a chance to play with them when there was a captive colony in Moscow Zoo. In the wild, they can see an approaching boat at about 10 m. Not sure about Pyrenean ones.
Link to thisDarren, the correct comparative terms for the word feathery are: more feathery, most feathery, not featheryier and featheryest
Link to thisPopular writing is often about what works, not necessarily about what’s ‘right’.
Darren
Link to thisI knew that Spielberg forgot something in Jurassic Park…
Great piece, it’s interesting to think about because typical images of tyrannosauroids are not depicted with feathers… Could we predict that the feathers were a result of natural selection?
Link to thisWell said, Darren! By the way, I heard more bull crap by peter mihalda. He claims T-rex only weighed 2 tons based on its skull. What an idiot!
Link to this