Search Results for 'zhuchengtyrannus'

My very own Zhuchengtyrannus

As I have noted on here before, the Japanese really do love their toy dinosaurs and produce really high quality models on a regular basis and of all kinds of obscure and wonderful critters. So when a couple of weeks back I got a cryptic e-mail from Matt Lammana of the Carnegie about having a gift for me from China connected with one of ‘my’ dinosaurs, I did have to wonder if, just possibly, there might be a Zhuchengtyrannus out there. Last night I found out that indeed there was. It had arrived through the post while I was away at SVPCA (more to come there) and well, how can I not be more chuffed. There’s a real toy Zhuchengtyrannus!!

It’s tiny (just 10 cm or so) but obviously well modeled and the paint job ain’t too bad either. Rather obviously taking the lead from Yutyrannus, it’s on the fuzzy side of feathering too. Now obviously the holotype is incomplete to say the least, and so we’re left with a rather typical tyrannosaurine for a model really. Still, I *know* it’s a Zhuchengtyrannus as, if you look closely, you can see it’s written on the base.

My thanks of course to Matt for this wonderful little present, made my day to say the least. On a not entirely unrelated note, there’s a palaeoart event going on at the NHM next week in conjunction with the Dino Art book launch. See here for more details. I hope to be in attendance but Luis Rey, Bob Nicholls, John Sibbick and others will be there.

Zhuchengtyrannus strikes

Well you knew it was coming right? Yes Zhucheng does now meature a mounted Zhuchengtyrannus. Or rather inevitably, more accurately, it features a T. rex mount with the maxilla and dentary replaced with cases of the holotype. This is quite clear on the photos below as the added parts are of rather better quality and have been pained a little differently too. OK, so otherwise this is basically just another rex mount but forgive me for liking it. And it is in the process of absolutely mashing a juvenile Shantungosaurus, so what’s not to like?

Zhuchengtyrannus art II

So in the last couple of days we have had Bob Nicholls talk about his beautiful vignette of Zhuchengtyrannus and an interview with artist Brian Choo. Now we can sort of combine the two. As Brian is based at the IVPP he soon found out about the upcoming description of the new tyrannosaur and excited by the new taxa being discovered he went away and produced this:

Continue reading ‘Zhuchengtyrannus art II’

Guest Post: Illustrating Zhuchengtyrannus:

Yes another guest post and yes we’re back on the tyrannosaurines again. While I’ve already talked somewhat about the impact of the artwork (that by now everyone is familiar with) I’ve not talked process. Here is a chance to make that up as Bob Nicholls returns to the Musings again (see here, here and here for starters!) to talk about how he created this piece. My thanks once again to him for his superb work:

Being the first artist to illustrate a new species of extinct animal is a great honour.  The series of events that are required to successfully fossilise a dinosaur and for that individual to be revealed to the world millions of years after death is an epic story.  In brief, the dinosaur first died in a location where its remains were covered by sediment rapidly.  The animal’s remains then hid within the Earth and lay undisturbed for a length of time we cannot imagine.  During this vast period the dead creature’s species will evolve out of existence and new life forms will survive catastrophes to colonize our planet.  Eventually a species of energy hungry ape developed an interest in investigating planet Earth’s history and against the odds our fossilised dinosaur was discovered. One of the apes, let’s call him Dave Hone, then decided to reveal the dinosaur to his entire ape species and asked a friend, let’s call him Bob Nicholls, to illustrate the wonderful discovery.  It may sound like a simple tale, but if you really think about it, it is astonishing.  To be a small part of it makes the hair on the back of my neck stand up.  There is no greater honour for a palaeontologist than to be the first to show the world what a long extinct animal looked like.  Especially a tyrannosaur!

Sketch for the life reconstruction of Zhuchengtyrannus. Courtesy of Bob Nicholls.

The illustration of Zhuchengtyrannus took me about eight hours in total, from the first preliminary drawing to e-mail delivery.  The first sketch was a satisfactory pose but four re-draws were required to make small adjustments to the teeth, snout, nostril and eye.  When Dave was happy for me to render the colour artwork I painted it with acrylic paint on illustration card.  I chose to paint the colour scheme of a show-off male with an eye stripe and blood red patches for impressing the tyrannosaur ladies.  I wish Dave and I could have worked on the piece a little longer but it was an excellent and most enjoyable day’s work.  Zhuchengtyrannus is dead, long live Zhuchengtyrannus!

Zhuchengtyrannus life reconstruction by Bob Nicholls

OK, so I’m just milking it now – final Zhuchengtyrannus roundup

Yeah, this is still creeping along. I’m trying to stop honest and while I’m sure I’ve lost most people by now, this is more or less the end of it. (More or less because there are ZT related things to come but which won’t actually really mention the damned beast itself so from here you’re basically safe). This has, understandably, been a hectic week and I’ve still got bits of work to do related to this so I’m not quite done, even if the blog is.

Going all the way back to the Eeeek! post, I want to again thank people for being helpful and not jumping me with ZT appearing all over the web before we were ready. It is much appreciated and helped us get maximum impact with the media. On that note, I’ve yet to put up this link to the University College Dublin page where there are links to a great many of the online media about Zhuchengtyrannus including a video of me talking about it. If you’re not interested in hearing me say things you’ve already heard or read 50 times over on here then you can try and identify all the various dinosaur and pterosaur books on the shelf behind me. Fun for all the family (possibly).

And while I’m here, here’s links to all the previous posts on here introducing this guy, notes on the taxonomy, ecology, size, and artwork. And if really like this, go do a Google image search for ‘Zhuchengtyrannus’, it’s quite startling.


The art of Zhuchengtyrannus

Zhuchengtyrannus life reconstruction by Bob Nicholls

I have my longtime Musings friend Bob Nicholls to thank (well, we did pay him too) for the superb art of Zhuchengtyrannus that has accompanied the release of this work into the media. The original and Bob’s pencil sketch will soon hang proudly on the wall of my office (they’re being framed right now).

What Bob has produced is, I think, quite beautiful, but there are a couple of features in there which the sharp-eyed (or overly nit-picky) may have spotted that are worth discussing as they illustrate some of the issues of producing such a work and how things can be done to highlight certain issues or produce an effect for the reader. While much can, and has, been written and discussed about the various aspects of palaeoart (or palaeontography if you prefer) this is a nice opportunity to go a little further.

First off there is one too few teeth in the dentary. This is basically my fault (or if you want to be more generous to me, that of the authors collectively). We originally misinterpreted the broken small tooth socket at the front of the dentary, that many tyrannosaurs have, as being part of a very large first tooth. That is, the first and second sockets were smushed together and we thought they were just a single large one till a referee correctly spotted this error and we corrected it in the paper. By this point Bob had already turned in his work and it was too late to do anything about it. To be more accurate, we never told him! So if you’re reading this now Bob, feel absolved of any blame, but I didn’t tell you because I felt guilty and didn’t want you to have to go to any trouble to correct it and assumed that no-one would know or care (though I’m rather destroying the first notion by writing this).

Of course, if anything the teeth are too correct in that (first dentary tooth apart!) they are all there. Theropods shed their teeth quite regularly and it would be normal for one or two to be broken or only half exposed in the jaw rather than a nice neat row as seen here. This of course introduces the main point I wanted to make in this post: this artwork (like many others) is supposed to be illustrative. It’s created to communicate something about the animal as a living organism to people based on the fossil bones. Many people seeing this would likely be hindered, not helped, by such details and would be wondering why the teeth were uneven and oddly positioned. This artwork, (with the Musings being the only likely exception) will not be accompanied by expert commentary on theropod anatomy and physiology and was destined for consumption by the general public so keeping things simple was the order of the day. (Though for the record, Bob and I never discussed this, his draft had the teeth like this and I thought it fine to keep them like that).

Zhuchengtyrannus maxillary sculpting. From Hone et al. in press

Similar to this, the sculpting on the maxilla (seen here) is particularly prominent, and while this is a common feature of adult tyrannosaurines, to my eye at least, it’s a little bit more pronounced than I’ve seen in other tyrannosaur specimens. As such I asked Bob to emphasise this in the artwork. In reality, the muscle and fat layers and even the skin itself were probably thick enough that looking at the living animal this would be invisible, or at least rather more subtle than seen here. But again, the point here was to emphasise a characteristic of the bones in the art – to provide an obvious point of reference for someone who knows nothing of dinosaurs to make the connection between the bones and the life reconstruction.

I can see that not everyone might be happy with this. But my take would be that you have to tailor the picture to the audience and the level of information that can go with it. In emphasising the sculpting and keeping the teeth regular there is nothing especially odd or outlandish about this. It is accurate and reasonable (plausible if not probable if you like) and deviates only a little from what you might consider a perfectly accurate or perfectly probably reconstruction (this after all, is not what a human looks like – it’s informative, but not necessarily realistic as such). If I were to get this done for a dinosaur book where I could wax lyrical over several pages or include key notes and labels then I’d probably actively want to add missing teeth and reduce the sculpting to emphasise these very points, but in the circumstances this was the best way to convey the maximum information with the minimum amount of confusion.

So just how big was Zhuchengtyrannus?

After all these posts, I’d understand if you were sick of this thing by now, but there is still (sadly for you) some more to discuss. One thing that has been left untreated until now on the blog is the size of Zhuchengtyrannus. Knowing the media would immediately want to know*, we did suggest that this was an 11 m long, 4 m tall and 6 ton animal, but really, how accurate are these? And where does that place it among other theropods?

*Indeed, despite including this in our press pack, I was still regularly asked about this, and was asked for ‘real life’ examples as well.

Well first off the easy stuff – we can measure the bones we do have and that gives us a 64 cm maxilla and a 78 cm dentary, though the latter would probably have been a bit longer in life. These obviously make up a significant part of the skull, but it would have been much longer when complete. As noted before, tyrannosaurines are generally pretty conservative so we can compare the sizes of these bones to their equivalents in other specimens for comparison. There are two adult Tryannosaurus specimens with maxillae just 1 and 2 cm longer than that of ZT with one having a bigger and the other a smaller dentary, so it’s immediately fair to call this about T. rex sized. However, the specimen known as ‘Sue’ is a real monster of a rex with a maxilla some 79 cm long, which is a fair bit bigger bigger. There are several Tarbosaurus specimens in the low 60s for maxilla length, with one (I can only imagine is a juvenile) at 49 and a pretty big one at 73. Several other more basal tyrannosaurid and tyrannosaurine taxa get close, but are not quite as big as ZT.

Obviously we just have one specimen and it’s impossible to know if it was a big or small or very average specimen. Assuming the latter, it’s very slightly bigger than most specimens of Tarbosaurus and slightly smaller than most Tyrannosaurus ones. That means it’s basically about the same size as these two, and lying in between on average.

From that of course we take our other estimates of size – while Sue is about 13m long, the others are more like 11 and so in the paper we suggest that ZT was between 10 and 12 m long (or more simply, 11 m to the press). In hindsight the 4m tall might be a bit much, but not by a huge amount, and as ever with measures like this, vary a lot with what the animal is or could do. If it stretched or tilted the head up (OK, perhaps straw grasping a bit) it would probably be over 4. So onto the mass, which is inevitably the most contentious, if only because it’s the hardest to determine.

Long time readers will be aware of the huge range of masses that have been posited for all manner of dinosaurs over the years. While the ranges have been narrowing and the values converging there is still quite a lot of disagreement. Add to that the natural levels of variation between individuals and even the fluctuations of individuals (sometimes they’re fat, other times, thin) and it should be obvious that even if our calculations were 100% accurate, you would still need a range of figures for a given species and even a single individual. For an animal this size that could easily mean that a single specimen could vary by as much as a few hundred kilos and as a species perhaps the biggest and smallest were well over a ton apart or even two. As such any reasonable number is going to be ‘about’ right and with estimates for T.rex typically being around 6 tons (though up to 8 have been suggested) then 6 is a perfectly reasonable number for ZT, and though we really are extrapolating from less than half a skull, the group as a whole is conservative enough that I’d be surprised if we were much out with any of these numbers.

So where does this put this critter in the pantheon of predatory theropods? Well obviously Tyrannosaurus is bigger and Tarbosaurus is pretty much the same. I don’t think anyone would argue that (in terms of length at least) that Spinosaurus, Giganotosaurus and Mapusaurus are not bigger (and here’s a good chance to link to this old image of mine). After that, well, I’m kinda out of bigger ones. While admittedly ZT is in the same position as some possible other rivals (i.e. we have enough o make a good guess but not enough to be certain) I don’t think it unreasonable to suggest that Zhuchengtyrannus sits in the all time top half dozen.

The ecological implications of Zhuchengtyrannus

OK, I admit there’s not actually too much to say about this, but what little there is, is quite important. Zhuchengtyrannus is really rather big – a little smaller than Tyrannosaurus, about the same size as Tarbosaurus and thus as a theropod perhaps bigger than anything except these two, Spinosaurus, Mapusaurus and Giganotosaurus (and more coming on that tomorrow). It was certainly a serious customer.

More boringly, in a way, Zhuchengtyrannus is really quite a normal large tyrannosaurine –the anatomical differences are sufficient for taxonomic purposes but would probably make no real difference to the overall appearance of the animal – that is, as far as we can tell it would look in life very much like Tarbosaurus and Tyrannosaurus. While there isn’t that much of it, what we have is quite normal and it’s reasonable to infer that this animal was occupying a similar niche to the other giant tyrannosaurines (and that means predation and scavenging).

That is in itself a bit of a novelty. As I’ve noted before when discussing spinosaurs, it’s actually quite common to find multiple, similarly-sized large theropods in the better-known dinosaurian faunas. We find Allosaurus, Torvosaurus and Ceratosaurus together, Sinraptor and Monolophosaurus, Charcarodontosaurus and Spinosaurs and so on. Even when it comes to tyrannosaurines we find the smaller Daspletosaurus and Albertosaurus together (not to mention our old favourite Gorgosaurus). However, Tyrannosaurus seems to have lived alone as it were (and you can argue Nanotyrannus, but it’s quite a bit smaller) and Tarbosaurus may not have been really troubled by Alioramus. While we have no direct evidence that Tarbosaurus and Zhuchengtyrannus overlapped directly their fossils are being recovered from very similar times and only a few hundred kilometers apart. It’s really quite likely that they met and of course ZT is itself accompanied by another large tyrannosaur from the same quarry so there could have been quite a party going down.

To employ a much overused phrase, this does rather leave T. rex as the exception that proves the rule – it’s increasingly looking like the only big theropod which doesn’t come with at least one accompanying near-equally sized alternate carnivorous theropod. Despite the ever increasing similarities between the Late Cretaceous faunas of North America and Asia, T. rex does still seem to be, in at least one way, still the undisputed king of his own backyard.

Notes on the taxonomy and identity of Zhuchengtyrannus

After the quick intro to the new taxon, now it’s time to talk in a bit more detail about the bones of Zhuchengtyrannus. All we have is a maxilla and a dentary but that’s actually quite useful. A few ribs and some caudal vertebrae wouldn’t have told us much as these are rather conservative in tyrannosaurs, but happily maxillae are not and have lots of useful and important taxonomic characters in them. It is also worth remembering that pretty much any bone, or even part of one, that is diagnostically different from everything else out there is reasonable to use as the basis for erecting a new taxon (like Brontomerus and various others).

I should of course add, before I go much further, that this is a blog, not a paper. There is more detail and commentary in the actual publication than here in internet land and if you really want to dive in then go read the paper (though again the paper as it stands online is an uncorrected proof, and that has cut off part of the taxonomy stuff!!!). This here is little more (as ever) than a surface discussion of the issues for general consumption and if anything more general than normal as I hope (expect?) that a few more people than normal will be finding the Musings right now as a result of the media coverage.

For those that don’t know their tyrannosaur taxonomy as well as they’d like it’s worth noting that Zhuchengtyrannus is a tyrannosaurine and that puts it in the group of especially large and derived tyrannosaurs and as part of a Late Cretaceous group that was restricted to eastern Asia and North America. We can tell this at least in part because it is a huge theropods from the end Cretaceous of China, but the relatively straight anterior edge of the maxilla supports this, and the shape of the teeth and dentary put it well within the tyrannosaurs in general.

Zhuchengtyrannus teeth. From Hone et al., in press

At this juncture, it’s worth remembering that there are different ways of identifying species, or more specifically, distinguishing them from others. Obviously with a fossil we’re working on a morphological species concept (that is, identifying a species buy it’s anatomy), but more specifically we can separate out differences in different ways. First off we can look for genuinely unique features – a giant tooth in socket 5, only one finger on the hand, a skull twice as long as tall etc. Things that appear in our new species that don’t appear in any others (or at least any other close relatives – stripes are characteristic of tigers since even though other cats are stripey, you’d never confuse the two because of the obvious size differences etc.). Secondly though, you can look for unique combinations of characters. One species may have a long and wide skull, another a short and narrow skull. The characters of ‘long’, ‘short’, ‘wide’ and ‘narrow’ are all in play here, but you could distinguish a possible new species with a clearly distinct combination of ‘long and narrow’ or ‘short and wide’.

So onto Zhuchengtyrannus. This is diagnosed in our paper by two unique characters – a short of shelf on the anterior part of the maxilla and an odd notch in the maxillary fenestra (see figure below). Neither of these does, to our knowledge (or indeed that of the referees or various other colleagues we consulted), turn up in any other tyrannosaur specimen ever. There is also a unique combination of characters to further separate it from other tyrannosaurs in the position of the antorbital fossa and size of the maxillary fenestra.

Drawing of the Zhuchengtyrannus maxilla. The unique shelf is labelled 'S' and the notched fenestra 'mf'. From Hone et al., in press

Although the specimen was not entirely complete when recovered (and sadly the maxilla was later damaged as can be seen from the picture of the maxilla in the previous post) it was initially in very good condition. We have good reason to think therefore that all of these characters are valid ones. The bones were not broken (well they are a bit, but not where the critical characters appear) or distorted or altered and there was no sign of disease or pathologies. This is also not an issue of ontogeny (age-related changes). The animal is easily big enough that it’s hard to credit that it was anything other than an adult, and possibly a large one at that. Moreover, there is a decent literature on both ontogenetic changes in tyrnanosaur skulls and on intraspecific variation. Zhuchengtyrannus exhibits several characters that are normally only seen in adult tyrannosaurs (like the heavy sculpting on the maxilla, more on that later) and the characters we use in our diagnoses are not known to vary either through growth, or within putative populations.

For all of this, lumping taxonomists out there might well not regard this as valid (“To synonymy, and beyond!”). There are those who would still have Tarbosaurus as ‘just’ a species of Tyrannosaurus and I can only suspect they won’t like this much as a result (though I don’t know for sure of course). All I can say is that we are happy with the distinctions, and the referees and other colleagues who have examined the material were too. Taxonomy really does operate at little more than a consensus level and while this can all change, already (from what I have seen and discussed so far) the consensus is that this is a perfectly valid taxon. Of course there’s also a good chance that we will get more material of this species (indeed as noted previously, we may already, even if referral is currently an issue) which will help our cause. Given what bones we currently have, Zhuchengtyrannus seems to be as diagnostic as any other large tyrannosaur and while it could be better (we don’t have that much material), it is sufficient.

Even so, this is only the second tyrannosaurine from China and one that very probably overlaps in time, and space, with Tarbosaurus. As such, it is worth making special note of the differences between these two and again there are some more in the palatal shelf and at the back of the maxilla. In short, it should be very hard to confuse the two if you have a maxilla of either in your hands and there is even better reason to think the two are different and thus again that Zhuchengtyrannus is a genuinely new genus.

I was also reminded in comments in yesterday’s post about ‘Tyrannosaurus zhuchengensis‘ which is detailed in the paper, but initially forgotten here! Whoops. back in the 1970’s several tyrannosaurus-like teeth were recovered from this quarry and, in the manner of the day, named as a new species: Tyrannosaurus zhuchengensis. Later on a single isolated metatarsal (foot bone) was assigned to this species. What of this? Well none of these teeth or the metatarsal show any unique features that would make them diagnostic from any other tyrannosaurin short, if you got a Tarbosaurus or Tyrannosaurus tooth or metatarsal and compared them to the T. zhuchengensis material, you wouldn’t seen any real difference. As such we cannot consider this to be valid and we therefore call Tyrannosaurus zhuchengensis a ‘nomen dubium’ –  a dubious name that should never have been created and should no longer be used (and hence the use of quote marks around it in it’s initial appearance here). Of course this material might be a much earlier record of Zhuchengtyrannus, but we can’t be sure, it might belong to the second taxon, or who knows, even another tyrannosaur!

That’s rather more than I intended to say so I’ll cut it ‘short’ there. More to come tomorrow where I’ll delve into the ecology of ZT and then we’ll be onto the glorious artwork and its genesis and importance in science communication.

Zhuchengtyrannus is here!

Zhuchengtyrannus life reconstruction by Bob Nicholls

So, as probably everyone knows by now, I have a new paper out and this is the first dinosaur I have named (as a first author) so welcome please, Zhuchengtyrannus magnus. This is a very large tyrannosaurine theropod that is comparable in size to that legendary source of all dinosaur comparisons: Tyrannosaurus rex. Yep, Zhuchengtyrannus, (or ZT as I’ve been informally calling it) is a big guy with a skull over a metre in length, in the 10 metre range for total length and thus also probably around 6 tons or so.

Obviously this is a big deal for me so there’s lots more to come on this over the next few posts and so don’t panic if this first introduction doesn’t give you all the details you were hoping for. Despite the apparent paucity of the available material (as will become clear) there is a lot that can be said about this and other things that are mentioned in the paper.

First off is that name. Those who are long time readers will know I’m not at all fond of ‘place-name-saurus’ type names but some of us are born with bad names for dinosaurs, some achieve bad dinosaur names, and (in this case) some have bad names thrust upon them! Anyway, if you’ve not guessed the genus name Zhuchengtyrannus simple means ‘tyrannosaur from Zhucheng’ and the species ‘magnus’ refers to the large size. Zhucheng, if you don’t know, is a small town in eastern China and has recently achieved fame for the huge amount of dinosaur fossils that have been found there and this is the latest of a number of new taxa. It’s can be pronounced as either ‘Zoo-cheng-tie-rannus’, or with more of a ‘Joo’ for the first syllable. The latter being closer to the formal Chinese pronunciation of the name, the former a less formal anglicised one.

Locality map for Zhuchengtyrannus. From Hone et al., in press

On that note, while 2010 was celebrated as the year of ceratopsians by many, it should not be overlooked the huge number of tyrannosaurs that have cropped up in the last year or so. Teratophoneus, Raptorex, Xiongguanlong, Sinotyrannus, Bistahieversor and others have all come through recently which adds massively to the number of tyrannosaurs of various ranks in the literature. That’s quite an increase for a clade known from only about 15 species or so as little as 3 years ago and now you can rack up two more. Yes, two.

Zhuchengtyrannus maxilla (bone above, cast below). From Hone et al., in press

As for Zhuchengtyrannus itself, I’m a few paragraphs in and have yet to talk about the thing yet. It is, sadly, represented by a less than complete specimen – we have a near complete maxilla (above) and a dentary (below), both with most of the teeth intact. The maxilla is one of the main bones of the face that makes up most of the side of the snout and holds most of the teeth for the upper jaws, while the dentary is the main part of the lower jaw that again, holds the teeth. That’s not much, but happily (as I’ll be covering in a later post) tyrannosaur maxillae are full of important taxonomic characters and as a result we are quite happy with this being diagnostic as a new genus and species. While that’s not much the material we do have is in great condition (well, more on that too). As noted it is a big one and comparisons to the maxillae and dentaries of other tyrannosaurs show that it’s bigger than anything out there except Tyrannosaurs and Tarbosaurus and it’s comparable in size to both of them. Obviously there’s just one specimen here and there are bigger specimens of Tyrannosaurs at least, but this is right in the mix. There’s nothing really odd or unusual about ZT so we it is ‘basically’ just another giant tyrannosaurine in the mould of these two more famous giants.

Zhuchengtyrannus dentary. From Hone et al., in press

But it’s not the only one. While we don’t describe it or figure it, we do mention in the paper that ZT is one of, what we think, are two new tyrannosaurs at the site. In addition to the elements of Zhuchengtyrannus, there are a variety of teeth and postcranial elements including vertebrae, femora and various metatarsals. Significantly there are also another maxilla and another dentary, neither of which match ZT or those of other tyrannosaurs meaning there are probably two taxa here. However, it also complicates that postscranial material – with these pieces being isolated and there being two genera present, it’s not possible to assign them to one or the other reliably at the moment. Thus there quite probably is a lot more of Zhuchengtyrannus already in our possession, but we can’t prove it, limiting us (for now) to just the skull pieces that were found together.

Between these new taxa and others recently described Asia now seriously rivals north America in the tyrannosauroid diversity stakes. While that’s perhaps not a big surprise in the basal tyrannosauroid stakes which already had a strong Asian base and were not that big in the Americas, that the tyrannosaurids and tyrannosaurines are catching up in diversity is rather more notable. No longer is Tarbosaurus the only Cretaceous giant tyrannosaurine in Asia, so once more I must ask you to please welcome Zhuchnegtyrannus to the world and do come back, there’s lots more to say.


Hone, D.W.E., Wang, K., Sullivan, C., Zhao, X., Chen, S., Li, D., Ji, S., Ji, Q. & Xu, X. 2011. A new, large tyrannosaurine theropod from the Upper Cretaceous of China. Cretaceous Research, in press.

DOI: 10.1016/j.cretres.2011.03.005


And of course, my thanks to Bob Nicholls of Paleocreations for the magnificent artwork. And thanks to those bloggers who have held off on their own posts on this before I was ready, it’s very much appreciated. I should also make a final extra point that once again a journal has stuck up an uncorrected proof of a paper – I can see already that a rather critical part of one table has been cut off and there are a couple of errors that need fixing which is why I don’t like these things.

Niche separation in the fossil record

There is a slow but steady publication papers that describe new fossil taxa that state or imply that the presence of some new species is evidence for niche partitioning in the animal’s ecosystem. This is basically redundant and is akin to the classic ‘this new species adds to the known diversity’ as if it could do anything else. One of the fundamental ideas of niche theory is that two species will not occupy the exact same niche. If they do, one will go extinct (or be forced out) or will adapt. In other words, for two species to live alongside each other there will be, by definition, niche separation, so pointing it out as some revelation or important insight or gained knowledge from two species being present is really not the case.

Worse, it might be wrong. Most of the time with new finds we don’t have very much to go on, so we don’t actually know that it truly did occupy a unique niche. Perhaps it was a transient species and so could survive briefly in full competition with another species as it passed through or had only just invaded and in the fullness of time would outcompete (or be outcompeted) by another species. So a statement about two (or more) species with similar biology (perhaps they are close relatives) being evidence for niche partitioning is most likely either redundant or wrong. Either way, as currently reported, it’s really not needed as commentary on a lot of papers about palaeoecology.

As a related point, there is an idea floating around (online and in discussions rather than I think in the scientific literature) that large predators can’t coexist normally, especially if they are closely related. There’s an expectation that ecosystems with say three large theropods in (or even three large tyrannosaurs) would be really weird and somehow not normal or possible. I’m not sure why this idea is out there but I think it’s a misunderstanding of the above point about niche separation and is somehow a conflation of the idea that species somehow doing the same thing or eating the same prey means one will inevitably come out on top, but again this isn’t really correct.

First off, species can be catching prey in very different ways, but still competing with each other. You only need to see videos of a baitball and any combination of sharks, dolphins, whales, sealions, large fish, diving birds and others all going after the same small fish. Each has its own technique and feeds and processes food very differently, but they are in direct competition for that same resource. So just because birds are flying and have no teeth, doesn’t mean they don’t compete with the dolphins and there is at least some niche overlap between them. Even very similar and near identical species can still partition successfully depending on quite what they are eating and when. They may be separated by seasonal or daylight cycles, or be targeting different prey species even if they are hunting it in the same manner, they will be likely shifting their niches as they grow, and there could be all kinds of local differences in habitat that are hard enough to spot in living species let alone in the fossil record.

Back in my paper describing Zhuchengtyrannus I made this point and the idea that multiple similar species in ecosystems is not actually that strange. However, some ongoing work on a related issue with theropods has made me look again at this and pull out a couple of relevant examples from modern / recent ecosystems. A quick look at the distribution maps on Wikipedia (hardly the last word in science I know, but sufficient to make the point) shows that the estuarine crocodile C. prorosus overlaps with C. johnstoni in part of Australia, C. mindorensis in the Philippines and C. novaeguinea in New Guinea. C. siamensis and Tomistoma both overlap with it and each other in parts of Indonesia, and there is a similar 3-way overlap with both C. palustris and Gavialis in India. Similarly, in South America, Caiman crocodilus, Melanosuchus and two species of Paleosuchus all overlap with each other. Now, at a very local level in a given pond or a short stretch of river there might be only one or perhaps two species present, and in some cases there are some dramatic differences in skull shape and gross feeding ecology, but these overlaps and the inevitable occasional migrations or transport of individuals means they must be truly sympatric at times and probably under some competition.

For a more terrestrial example, the 2019 paper by Schnitzler and Hermann looking at fairly recent (historical) overlaps of large mammals in Asia (especially lions and tigers) has this wonderful quote [that I have modified a little for clarity] about carnivores in part of Western Asia. “The Western Asian area of the Palearctic Biogeographic Realm includes part of the continental interior of the Near East (the northeastern part of Anatolia in Turkey, and Transcaucasia – Georgia, Armenia, Azerbaijan), part of the Caspian lowlands and western part of Pakistan. [It] had an impressive assemblage of large mammalian carnivores (Asiatic lion, Caspian tiger, Asiatic cheetah, Anatolian leopard, lynx, brown bear, grey wolf, jackal, and striped hyena).”

That’s really quite a set of animals and while jackals were probably not much competing with lions for food, there’s a huge amount of overlap here. Even modern India has striped hyena, jackal, dhole, wolves, leopard, lion, tiger and sloth bears in various parts and until recently cheetah too (plus, of course, three large crocodylians) and while their ranges are now much restricted there would have been much greater overlap in the past. In short, while obviously dinosaurs are very different to mammals and crocs, the idea that a Mesozoic ecosystem couldn’t support two or three large theropod genera looks like a poor hypothesis against the kind of overlaps we see even in modern depauperate and stressed ecosystems. Multiple large carnivores, even including closely very related species from the game genus, that are known to hunt similar prey in similar ways, are commonly sympatric and there’s no clear reason to assume ancient systems were that different.

Schnitzler, A. and Hermann, L., 2019. Chronological distribution of the tiger Panthera tigris and the Asiatic lion Panthera leo persica in their common range in Asia. Mammal Review49(4), pp.340-353.

Citations of lists – a small moan

I used to do this sort of thing a lot on this blog but with the posts generally slowing it has become rather more rare (for better or worse, most readers would likely go for better I imagine) but it’s time for a moan. This is something I have seen before but recently I’ve had a whole spate of papers to review that do this and it seemed something annoying and common enough to put out publicly so that a) hopefully people will agree with me and b) then some will stop doing it.

This is about points in papers were a big long list appears in the text but then all the citations come at the end. So you get something like ‘…as seen in Tyrannosaurus, Tarbosaurus, Daspletosaurus, Gorgosaurus, Albertasaurus and Zhuchengtyrannus (Smith et al., 1994; Jones, 2001; Smith and Jones, 2005, 2007; Smith and Smith, 2016, 2017).

At best this is annoying and at worst actively cryptic about information. In my example there are six taxa and six papers so you can assume that they realte to these taxa in order, but even if they do, it’s a slight pain to work out exactly which paper refers to which one. I’ve seen examples like this with a dozen papers and then you really do have to move your finger along and count to try and work out which is which. Even so, this assumption may not be true – are those papers certainly in the right order? The only way you can find out or to check is to go and read each to follow it through. The point of citations is a paper trail of what you did and where you got the information from and to credit it correctly. So this list in this format is actually making you redo the work of the author and is hardly something that actually helps communicate information.

Worse, I regularly see such lists have different numbers of points to the number of references given. That means that at least some points are covered by a single reference (if they are more numerous) or multiple points are covered in one reference (if there are more points), but again, it’s impossible to know which is which. You are back to having to reread each paper to check.

In short, for the apparent sake of making a list look slightly nicer on the page, the information the reader often wants, even needs (which paper does or does not directly refer to which of those things in the list, be they taxa, anatomical features, localities or whatever) is obscured. Now, I do get that this easier on the eye to read than say ‘Tyrannosaurus,(Smith et al., 1994),  Tarbosaurs (Jones, 2001),but personally I don’t find that an issue, I’ve read enough papers to skim over references while reading without a problem. More importantly, it is perfectly clear exactly which paper refers to which point and so is far superior to a big lump of papers are the end.

If it’s not immediately clear, it can’t immedaitely be verified and you may have to wade through a large number of references to check. This is hardly the end of times, but for me this really helps neither the author show that they have done what they set out to or the reader follow that up. And so really, please, please, cut out the lists followed by a list of references. Authors don’t do it and referees and editors, pick up on it and ask people to make specific points supported by specific references.

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