A digit of the English sauropod Cetiosauriscus. After yesterday’s entry it seemed a good idea to shift subjects a little and this is about as different as I can readily manage at short notice. Sauropods being what they are (an my knowledge of them being what it is) I’m not actually sure if this is manual or pedal, but well, it’s nice enough as sauropod digits go.

Now from the perspective of a palaeontologist / biologist my answer is generally a simple one – who cares? These animals never met and could not have done so. Even IF they somehow managed it, they would almost certainly not engage in any kind of full on fight to the death. Even if they did, what would that tell you really? I’m sure there were bigger adult rexes than the smaller Giganotosauruses say, but bigger G.s than the smallest Tyrannosaurus individuals. So you have to compare theoretical maximums or averages, but that may not mean much if you’ve ever seen a hyena go for a lion or wolverine go for a bear. Big is not the same as bad, let alone victorious.

None of this will tell you anything about the animals at all, their biology, evolution, life history, lifestyle, ecology or behaviour. It’s an understandable preoccupation for kids and while I don’t think it’s worth the hassle it can be a window into further thoughts and interest.

Which do you think would win? Why do you think that one would win? Could we look at any of those things in fossils? Bite marks, bite strength, mass estimates, tooth shapes, eyesight, acceleration, intelligence – all of these things have been written about seriously by palaeontologists and zoologists with all manner of detail and information available. Reasonable inferences can be made by looking at living species and how they behave (what do different predators do when they encounter one another?) not to mention variation within species about how they are built and how they might act.

The question might be mundane, even vacuous, but there’s much that can be discussed and more importantly learned, if the question is a hook to expand people’s horizons and interest.

Now to sit back and wait for all the comments of “But t. rex wud win coz he is THE KING!!!”.

This one is in the Bristol Museum and is featured here simply because it’s the one mount of the genus I’ve been able to take decent number of photos of with a decent camera. I’d say more, but well, with Henirich now blogging, I’m really not sure I can say anything about this guy that he hasn’t already said or won’t say better. Lots more photos to come tomorrow of various views of parts of the skeleton, but it seemed best to start with a couple of general views.

Reviews are really useful. After all, it’s impossible or at least exceedingly hard to dive into a new subject (or even keep up to date effectively, or simply refresh your memory) from scratch. This is true of course for academics, but also for students of all levels, technicians and the general public – we all have to start somewhere. Review papers (in general) provide a foundation on a subject, giving the first principles of the issues at hand and the outline of what is known and how and what it means. It is not an end in itself, anyone with serious pretensions to work in that subject should be reading much further and wider, but this will be the place to start and of course provides a great resource for a given topic.

However, oddly it seems an awful lot of journals don’t really like publishing them. While there are dedicated review journals out there, my recent experiences with them is that they are overflowing with submissions or requests by people to produce submissions, so clearly lots of people are writing them or want to write them. The huge interest in things like TREE and the massive citations accrued by papers in them or something like the Dinosauria shows people are using them. However, a great many journals simply say that they will not publish reviews, or review-like manuscripts (or similarly useful things like catalogues of specimens, lists of localities or whatever). We seem to be in the odd position where people want to write something, readers recognise their value, they are widely used and cited, but the journals don’t want them.

Moreover, even the review journals can be difficult when it comes to reviews! A paper of mine was ultimately rejected from QRB because one referee demanded that we include new primary data and an analysis of this. I don’t disagree that a review can still contain new data and new ideas, but really? A review paper in a review journal has to contain new work and analyses? Even those that do publish seem to go in for either the tiny (TREE papers are just a few pages) or the monolithic (Annual Reviews in Earth Sciences) with little scope for something say in the 10 page range.

A few more journals willing to accept such manuscripts or even a couple more journals dedicated to reviews would seem to benefit all and sundry and I for one hope this can be encouraged.

The presence of a latitudinal biodiversity gradient (LBG), whereby species richness is highest in the tropics and declines polewards, is a pervasive pattern affecting the majority of life on Earth today, and was recognised by early naturalists such as Charles Darwin and Alexander von Humboldt (whose foundation coincidentally partly supported the research outlined below). Despite its near ubiquity (on both land and in the sea), the causes of the gradient are less well established, with numerous hypotheses proposed over the last fifty or so years. Most of these have been refuted, leaving climate and the distribution of area as the two most likely causes. Understanding the cause and evolution of the gradient is vital to predicting biodiversity loss driven by present-day climate change and explaining geographical variation in biodiversity; as such the fossil record offers a unique perspective on this issue.

Previous work investigating the deep time LBG focused on marine invertebrates – these studies tended to find support for a modern type pattern throughout the Phanerozoic (approximately the last 530 million years). Little prior work has been carried out on terrestrial species, but the few studies to look at the deep time LBG on land found no evidence for a modern pattern until after the Eocene (approximately 30 mya).

Along with colleagues from the UK (Roger Benson, Paul Upchurch, Richard Butler and Paul Barrett) and USA (Matt Carrano), we looked at the LBG in Mesozoic dinosaurs (including birds). Using a number of different methods to mediate for sampling biases in the fossil record, we found no evidence for a modern type pattern at any point in the 160 million year evolutionary history of Mesozoic dinosaurs; instead we found dinosaur diversity to peak at palaeotemperate latitudes (30-60° North and South). The consistency of this result across analyses for different time slices indicates that this pattern is not controlled by climatic fluctuations – evidence suggests that the climatic gradient was “flatter” in the Mesozoic than today (i.e. there was less of a difference in temperature between tropical and temperate regions) – but was instead driven by the amount of available land area in latitudinal belts.

Residual dinosaur diversity after controlling for sampling, plotted against non-marine area (NM area) and palaeogeographical reconstructions for the Late Triassic (bottom), Jurassic (middle) and Cretaceous (top). From Mannion et al., 2012

Given that living birds conform to the modern day pattern, a significant change must have occurred at some point in the last 65 million years. Evidence from molecular phylogeny (and work on fossil insects) suggests that this change occurred at the end of the Eocene (34 mya), following the strengthening of the climatic gradient and an increase in seasonality. As such, there is no evidence for a modern type LBG on land before the last 30 million years.

Mannion, P. D., Benson, R. J. B., Upchurch, P., Butler, R. J., Carrano, M. T. and Barrett, P. M. 2012 (Published online). A temperate palaeodiversity peak in Mesozoic dinosaurs and evidence for Late Cretaceous geographical partitioning. Global Ecology and Biogeography, doi: 10.1111/j.1466-8238.2011.00735.x

While I’m not a big one for covering extant taxa (well, as specimens, obviously the live ones often put in appearances) the kiwi is on my mind having been completing a bit of work on alvarezsaurs recently. Clearly the two are not that close, but the tiny remnant arms of the kiwi made me think of them and that’s enough of a reason for it to pop into my head and thus onto the Musings. So here it is.

Incidentally, the mount is in one of the endless small museums down in Liaoning. There are so many in fact, I can’t remember exactly which one this is, though I think it’s the main one in Jinzhou.

This is the skull of the Middle Jurassic tyrannosauroid Guanlong, the crested dragon. Or more specifically it’s the skull of the referred specimen, a near complete juvenile animal that’s in nearly as good condition as the adult. One thing it lacks though is the famous crest of the genus. While this could be put down to ontogeny, a look at the skull in dorsal view shows obvious signs of damage and there was most likely some form of crest here originally, though probably rather less well developed than the adult.

Today Tom Hübner takes us through his recent paper on the bone histology of

Many of you might know it already that I finally got a rather long paper on the bone histology of a small ornithopod dinosaur (Dysalotosaurus) published in PLoS ONE. 29 pages sounds like a lot but I wanted to break with tradition a bit to publish only as brief a paper as possible. This had something to do with the beginnings of my studies on bone histology because most papers at that time restricted the information to the most necessary facts which was quite difficult to follow and reconstruct. Without the personal help of ‘experts’ I never would have understood all that. Another reason for the length of the paper is the enormous variation in the microstructure of the bone. Many times I was struck by a completely different type of tissue and it needed some time to identify them and sort them out. That’s because ‘variation’ is also one of the three main topics of the paper.

Anyway, for everyone interested in bone histology, I think it is worth reading [seconded, it's a great review as well as providing new information and analyses]. The most important aspect is the usage of a new type of growth cycles for life history reconstructions which might be applicable for other vertebrates as well, especially when they lack lines of arrested growth (LAGs).

From Hubner, 2012. Thin sections of Dysolotosaurs bone in normal and polarised light

Some might wonder why such a small animal delayed sexual maturity until about its 10th year of life because it should suffer many losses by all types of predators. Well, that’s a good question and difficult to answer. One strategy is definitely the precocial breeding strategy, but the predators could also be the reason for delayed sexual maturity. The animals would not start breeding until they were large and strong enough to withstand the additional stress of mating and breeding, and they still had at least 5 years for reproduction because, according to the size-frequency distribution, only after about 15 years of age decreased their abundance within the herd significantly. Large ornithopods, on the other hand, had the opposite strategy (see Cooper et al. 2008) by outgrowing predators in a short time. Most of them also had altricial breeding behavior. This, and other arguments presented in the paper, could be a good non-phylogenetic difference between small and large ornithopods in general, but there is still much do to before this can be a strongly supported theory. As always: “More fossils and more studies …”.

From Hubner, 2012: Comparative growth rates of Dysolotosaurs with other dinosaurs and mammals

Constructive criticism is always welcome, so don’t hesitate to post them. I’m still not at all too old to change my mind. Well, this is science – nobody can learn something new without knowing where the mistakes are.

As this is in PLoS ONE, the paper is freely available here.

Hübner TR (2012) Bone Histology in Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia) – Variation, Growth, and Implications. PLoS ONE 7(1): e29958. doi:10.1371/journal.pone.0029958

This is a mount that stands on display in the Carnegie and has no name attached to it. The reason is quite simple – the specimen has yet to be formally described. The consensus is that is a new taxon and will be getting a name in due course. However, having not actually seen the original material (well, beyond a few bits) I don’t know how complete this is or which bits of the mount are reconstructed (though I’d guess the skull is all sculpted).

Oddly enough, I saw this (or perhaps a duplicate) in Japan a few years ago as part of a touring exhibit. I’d wondered what it was then as I didn’t know which taxon it belonged to, only of course to later discover it hadn’t been named. It does hinder your ability to diagnose something when it’s not actually in the literature.

Here we have the tops of two hadrosaur skulls and thus the crested parts of them. Below is Corythosaurus though obviously rather more developed that the individual I showed yesterday. Above that is the famous Parasaurolophus with its long posteriorly directed tube-like crest. Hadrosaur crests have had all manner of function assigned to them (as, would you believe, we discuss in this paper) but there’s little to evidence to support most of the more extreme ideas (like it being a snorkel in Parasaurolophus despite, you know, not having any openings) and in the majority of cases they are best interpreted as being signalling structures.

Having covered a stray Lambeosaurus skull just before the end of last year, it’s time to catch back up with the last of the Carnegie images (and boy have I made these last!). And I do have some more ornithopods to go, or more specifically, hadrosaurs. First off is this rather nice Corythosaurus that’s mounted in a quadrupedal stance. While I’ve not seen that many hadrosaur mounts most have been as bipeds, and those that are down on all fours usually have the head right up, so this is different if nothing else. Nice too to see the ossified tendons being prominent too. Tomorrow, more head crests.

Pathologies have had the odd mention on here before (like here, here and here) and this one is rather minor as they go. It’s on the foot of the Tyrannosaurus specimen known as Jane. It’s pretty small, little more than a swelling and roughened bone on one of the pedal phalanges. Still, it suggests there was a fracture on infection at the site and this animal had clearly suffered some kind of injury in its young life. Hardly uncommon, but neat all the same.

This is the arm of the Dryosaurus skeleton I put up earlier in the week. You can see here quite clearly that the bones are held in ‘cradles’ that then are bolted onto the main support for the skeleton. This technique for mounting specimens has become popular recently (the remodeled dinosaur gallery in the Humboldt in Berlin uses the same methods) and it’s a welcome change from the old style. The bones used to be bolted directly to the frame meaning that they were often drilled through or had rods and bolts put through the bones themselves.

Obviously this is infinitely preferable to any form of damage or manipulation of the bones. It allows them to be put out on public exhibition, but it *also* allows them to be removed as single units as the cradles can be simply taken off the frame, and the whole thing doesn’t have to be taken apart to get to a single element. As a compromise, it’s relaly pretty good.

Yep, more Carnegie. This is the ‘open’ part of their dinosaur lab, with preparators working behind glass in a way that visitors can see them and their work. These kinds of displays are becoming ever more common and it’s hard not to like them. It brings a really secretive part of the world of palaeontology out and into the open so people can see the painstaking work that goes into freeing bones from rock and restoring them to their prime (well, prime for something 100 million years old and crushed).

On the other hand though, I can imagine it’s a less than perfect working environment, especially on busy days. As long as the *whole* lab is not open to scrutiny (people need privacy and delicate work needs perfect concentration) I think it’s a great education tool.

In addition to the mounted skeleton shown yesterday, as usual the Carnegie provided a little extra something. In this case it’s a nearly complete skull of a young Dryosaurus (the label lies in the orbit and it’s facing to the left).

I must confess to knowing little about this ornithischian (also true of many ornithischians I admit) though it helps illustrate one small point. Not that long ago, it was thought that sometime in the Middle to Late Jurassic there was a landbridge from Africa to North America. This was invoked to explain the apparent incredible similarity between the Tendaguru and Morrison faunas. Both had Dryosaurus, and Allosaurus and Brachiosaurus, and both had stegosaurs and diplodocids.

However, better examination of the available material makes the Tendaguru brachiosaur not Brachiosaurus, the allosaur not Allosaurus and the small ornithopod is Dysolotosaurus and not Dryosaurus. In short, there’s no need to invoke a special land-bridge since the two faunas are not identical. Similar sure, with each having representatives of the same families, but that’s hardly surprising – look to the modern world and the two continents feature felids, canids, mustelids, bovids and others and such comparable faunas are quite normal.

I’m not quite out of Canegie photos yet, so here are the mounted Ceratosaurus and Dryosaurus. My first of either and while it is cool to see a young Ceratosaurus (I simply didn’t know there were specimens of animals this size) I must confess I had hoped to see an adult Allosaurus-sized individual. Still these are both classic Morrison taxa and added still more to my ‘first time’ list of species that I got from this trip to the U.S.

First off, here’s a superb opinion piece on cranks vs scientists and highlighting the importance of science outreach.

Second, here’s a short piece on the H-index, a measure I don’t like much.

Finally, I’ve just discovered I’ve been missing out on Dan Chure’s ‘Land of the Dead’ blog. Whoops! Well, you can always catch up now and read all the old posts.

This was my first ever trip to an American zoo and I have to say I was impressed. OK, so I’d expect nothing less, but this was nevertheless an excellent day out. The layout was great, the species interesting, and as usual even for a real zoo-phile for me, there were some unique treats.

Just to get the slight bad out of the way first, a couple of turkeys, flamingos, penguins and an ostrich aside there were literally no birds at all in the zoo. I assume the presence of the aviary has a lot to do with it, but it was still a little jarring that there was nothing at all. I wouldn’t call it a negative as such, but it does rather under represent a pretty major group of vertebrates to say the least, and I can’t see how couple of enclosures would really kill them or impact on traffic to the aviary. My other very minor gripe would be (ironically) the lack of local species, or more rather there were setups for porcupine, skunk and American beaver but none of them were on show, which for me was a shame as these are things I’ve not seen before, dull as they may be to most visitors. Such is life and it’s not the major issue, but it piqued me at the time.

So onto the good, and there is so much good. The enclosures were generous and well-planned, there were some great mixed exhibits, and the layout was clever. You revisit most of the enclosures at some point, doubling back and coming across rhino or lions again from a different angle and gaining a new vantage point and an opportunity to see something missed before, and some of the environments were well stacked Hagenback style to increase the look of the thing. ‘Difficult’ animals like polar bear, African elephant and gorillas were all doing well and showing natural behaviours. In the case of the elephants, the bull was clearly unhappy about something and was giving a full on rumble – something I’d not even seen in Kenya. There’s real power in there, would could feel the room vibrate which was no mean feat given the volume of concrete involved. As for the gorillas, something unique: a pair of silverbacks. Apparently the two are twins and get on fine with each other, so the colony has a pair of dominant males.

Onto the superb and brand new aquarium. This has a strong conservation focus with an admirable record for breeding seahorses and keeps numerous corals which is no easy task. There was a colossal marine tank full of the usual sharks and reef fish, a lovely Amazon setup full of the big and bold, a nice penguin tank, a great collection of large rays and best of all (if sadly unphotographable) a pacific giant octopus nursing thousands of her eggs.

Most memorable though was the outside aquarium for sand tiger sharks. A massive enclosure with viewing ports at various levels and a walk through tunnel too, this was simply bare walls and lit by the overhead sun. The effect however, was magical. Huge animals cruising incredibly slowly and gently around the tank, barely moving their tails or fins it was silent and beautiful, not just the sharks themselves, but their shadows too and those against the stark blue walls with the ripples of light from above was worth watching in its own right.

Finally there was an exhibition centre, objectively to bring the animals closer to the public, though in reality not much more than a combined reptile and small-mammal house with numerous snakes, lizards some bats and the like. And finally a new mammal – an American possum, if looking a bit rough around the edges. All in all a great day, a great zoo and great fun.