Cartorhynchus: helping ichthyosaurs crawl back into the mainstream.

Over the last 12 months or so, I’ve been researching ichthyosaurs for my masters project, and since then, I’ve been working on publishing my results. As such, I’ve learnt a fair bit of ichthyosaur palaeobiology and systematics. I’m no expert, but at this early stage in my academic career, I can say that at the moment, ichthyosaurs (specifically ichthyosaur endocranial anatomy) are my ‘specialisation(s)’, perhaps even making me an ichthyo-sir (heh). To this end, Motani et al.’s recent publication in Nature was massive news for ichthyosaur palaeobiologists. And that’s why it’s got its own little blog post.

What’s all the fuss about then? This year (2014) marked the anniversary of the 200 years since the first appearance of ichthyosaurs in scientific literature, and ichthyosaurs are closely associated with palaeontological celebrities, both historical (Mary Anning) and rather more recent (Alfred Romer). In those 200 years, we’ve learnt a lot about ichthyosaurs, and whilst they’re not ‘some kind of fish-lizard’, they are diapsid reptiles that were some of the first tetrapods to evolve a thunniform (fish/tuna-like) bodyplan, which aided them in their marine adventures. We know what colour some of them were thanks to melanosomes (Lindgren et al. 2014), we also know that they gave birth to live young, like mammals and some sharks do. We have exceptional fossils of ichthyosaurs actually giving birth, and others with amazing detailed and undisturbed soft tissue outlines. However despite all these amazing discoveries, we still don’t know a whole lot about two major aspects of ichthyosaur palaeobiology: their precise biomechanical function (we can’t create fancy 3D digital models due to the lack of 3D specimens, most ichthyosaur remains are mostly pancake-flat, even the really awesome ones) and perhaps more importantly, how they place in wider diapsid phylogeny.

The miracle of ichthyosaur birth, over 200 million years-ago. Very cool.

The miracle of ichthyosaur birth, over 200 million years-ago. Very cool.

Now before I go any further, it might be a good idea to explain what I mean by diapsid. Diapsida is a group of organisms (more specifically tetrapods) that have two temporal fenestrae (holes) in each side of their heads. Now this is a pretty large group, including archosaurs (dinosaurs, birds and crocs), lizards, snakes and tuataras. So whilst we have some vague idea where ichthyosaurs lie within this pretty large evolutionary tree, we’re not entirely sure. Why? Well because we don’t have transitionary fossils, ichthyosaurs previously (before Motani et al. 2014) appeared in the fossil record as highly adapted marine reptiles, well suited to the marine environment (remember, they look like fishes). So without any hint of which precise group of terrestrial organisms they evolved from, the topic of where ichthyosaurs came from is highly debated. So much in fact that in 2006, a very prominent ichthyosaur worker, Michael Maisch declared that the placement of ichthyosaurs within Diapsida was “…impossible…” (Maisch et al. 2006) without more basal specimens.

The internal phylogeny of ichthyosaurs isn’t a much better state either, with tree topologies changing at every opportunity of the last 10 years or so, threatening to change again when new systematic methods are applied. This again is largely due to the lack of well preserved three-dimensional specimens. But it’s not all doom and gloom, amazingly preserved specimens like those used in Lindgren et al. 2014 have shown us the colour of these ancient fish-dolphins (joke name, please don’t take it seriously), and Fischer et al. 2013’s discovery of Malawania has helped, to some degree, solve the internal phylogeny of at least neoichthyosaurs and ophthalmosaurs (ichthyosaurs from the Jurassic onwards). And obviously, my work on ichthyosaur endocranial and neuroanatomy from an exceptionally three-dimensionally preserved specimen will be hopefully  well received (more on that in the coming months). So it’s not all doom and gloom. But still, ichthyosaurs aren’t exactly the Brangelina of the palaeontological scene, no sir, those celebrity couples occupying all the headlines are dinosaur discoveries such as Deinocheirus and Dreadnoughtus, and the number of ichthyosaur workers isn’t exactly huge.

To my shocked delight, on the afternoon of the 5th of November, 2014 I stumbled upon a fresh new ichthyosauriform, in a Nature paper. Good heavens! Could it be true? Well, of course, other wise I’d have spent the last hour typing madly about ichthyosaurs for no apparent reason. Catorhynchus lenticarpus (‘shortened snout’, ‘flexible wrist’) is a weird, small beast. At first glance, you’d be forgiven for thinking that Catorhynchus wasn’t even a ichthyosaur at all. Well, technically, it isn’t an ichthyosaur at all, it’s an ichthyosauriform.  Catorhynchus comes from the Lower Triassic, approximately 248 million years-ago, and whilst some would call it an ‘ichthyosaur’, the Ichthyosauria (essentially all of the things your properly allowed to call ‘ichthyosaurs’) didn’t occur until later on in the Triassic. So, what the hell is Catorhynchus? Simple, it’s an ichthyosauriform, an ichthyosaur-looking creature which is more closely related to Ichthyosaurus communis than to a hupesuchian? Wait, what the hell are hupehsuchians, and what do they have to do with anything?

Hupehsuchians, think ichthyosaurs but a little more 'vacant' looking.

Hupehsuchians, think ichthyosaurs but a little more ‘vacant’ looking.

Good question. Hupehsuchians are a weird bunch of marine reptiles, who you’d be very much forgiven for calling ichthyosaurs, because well, they look quite a lot like ichthyosaurs. This simple fact has led many researchers to state that ichthyopterygians and hupehsuchians were related, however, there’s been little evidence to really cement this (just because two organisms look the same/have similar features, doesn’t mean they’re closely related. For example birds and bats both have wings, but they evolved powered flight independently and convergent to each other). As I’ve previously said, this is due to the lack of really primitive fossil ‘ichthyosaurs’ as well as our fairly poor understanding of where ichthyosaurs fit relative to other diapsids. However, Catorhynchus has given us a glimmer of hope, enabling us to, for the first time, really start to understand how ichthyosaurs first came about. Now, thanks to Catorhynchus, we think that ichthyosauromorphs (which now includes hupehsuchians) originated in China in the Earliest Triassic, which was a warm tropical archipelago ‘back in the day’. This is interesting, as we know that other groups of marine reptiles, such as sauropterygians (plesiosaurs, pliosaurs et al.) may have also originated in this area at the same time, so Earliest Triassic China may have provided very good conditions to harbour the evolution of many marine reptiles.

Phylogeny of ichthyosauromorphs, modified from Motani et al. 2014.

Phylogeny of ichthyosauromorphs, modified from Motani et al. 2014.

Don’t worry, I’ll stop teasing you now, I’ll actually talk about the fossil for a bit. With a host of unusual features such as really short snout, large flippers and a short body length (the shortest of all ichthyosauromorphs, estimated at a tiny 40 cm) and a really deep lower jaw, Catorhynchus is a weird beast. Yet, despite all these abnormalities, it looks like an ichthyosaur, I mean look at those big eyes! However, it also looks like a juvenile ichthyosaur. For me, and other ichthyosaur workers I’ve spoken to, this is the main reason why people of sceptical about drawing so many big conclusions from Catorhynchus. However, other people (untrustworthy creator of reptileevolution.com) have said that it certainly can’t be an ichthyosaur, and has to be an ‘ichthyosaur-mimic’, because yeah, if it has loads of scientifically diagnostic features of an ichthyosaur the most obvious answer is that it wants you to think it’s an ichthyosaur, just to troll the scientific community, and then years later scream ‘psyche!’ to everyone, you know, because fossils love to mess with us, the jerks.

Catorhynchus fossil from Motani et al. 2014. E represents a  newborn Chaohusaurus, for comparison.

Catorhynchus fossil from Motani et al. 2014. E represents a newborn Chaohusaurus, for comparison.

ANYWAY. I think it’s worth pointing out that it realistically might turn out to be a juvenile, even though Motani et al. do present some evidence that it’s a fully grown adult, for example the forefins of Catorhynchus are almost as long as its skull, a feature found exclusively in adult individuals. However, it’s also worth mentioning that even despite this, Motani et al. don’t completely dismiss the possibility of this specimen being a juvenile. Essentially, I feel it’s best to take this discovery with a pinch of salt until we find a few more specimens of Catorhynchus. Despite this uncertainty, we can be fairly sure that Catorhynchus may have been amphibious. Yeah, that’s right, amphibious and NOT an amphibian. Other articles have said that Catorhynchus is an amphibian, this is incorrect, as Amphibia form their only little group of organisms, which ichthyosauromorphs aren’t part of! However, Catorhynchus is amphibious, i.e. it shares its time between land and water. How do we know this? Well from the fossil, Motani observed that the carpus may have allowed the flipper to bend in a way much like the flippers can bend in seals, and since seals have flippers for limited terrestrial locomotion, it seems likely that this was also the case for the flippers of Catorhynchus. Motani also presents a case for suction feeding in Catorhynchus, which brings the contentious debate of whether other ichthyosaurs fed via suction feeding back to the table.

To summarise Motani and friends have presented the world with a new ichthyosauromorph which, if verified with further specimens, will help us to really start to understand how ichthyosaurs (and perhaps marine reptiles more widely) first evolved, as well as to understand the place of ichthyosauromorphs within Diapsida. And since it was published in Nature, it might turn a few heads, perhaps persuading more people to join the very small field of ichthyosaur of palaeobiology. As always let us know what you think, comment below or Tweet us (or indeed, even Facebook us).

Not only was it amphibious, Catorhynchus was also the most miserable of all the ichthyosauromorphs.

Not only was it amphibious, Catorhynchus was also the most miserable of all the ichthyosauromorphs.

SexyPlac: love in the time of placoderms.

At the beginning of last week, fossil fish made a rare appearance in the news. Although I secretly cling onto the futile hope that this was because the world just can’t get enough of placoderms, it was probably actually because the story was about sex – dirty, Devonian sex – with a Nature paper from Long et al. revealing the earliest evidence of vertebrate internal fertilisation in the appropriately named fish Microbrachius dicki. Microbrachius (first described in 1888 by the palaeoicthyological machine Ramsay Traquair) is a placoderm from the Devonian (about 419-359 Mya) of Scotland, and said evidence comprises pelvic claspers, similar to those used for internal fertilisation in modern sharks. While the traditional view of the evolution of internal fertilisation is that it evolved from external fertilisation, Long et al. argue that Microbrachius shows that it was in fact the other way around: the modern spawning of many bony fish is derived from an internally fertilising ancestral state. Either way Microbrachius adds an interesting chapter to the story of the placoderms.

Placoderms

Phylogeny showing the various placoderm morphophologies (note that here they’re monophyletic, and sister group to extant jawed vertebrates). (From Palaeos.com)

Placoderms were a group of heavily-armoured jawed fish from the Devonian with a diverse range of morphologies; these included flattened ray-analogues such as the rhenanids, the holocephalan-like ptyctodontids, and the more conventionally fish-shaped arthrodires, which included massive predators such as Dunkleosteus. Antiarchs, the group to which our hero Microbrachius belonged, have a particularly weird bodyplan that led to them initially being described as arthropods: a box-like, plated body with jointed, armoured pectoral fins and closely-set eyes. The phylogenetic relationships of placoderms are still poorly understood, but they lie somewhere on the gnathostome stem as the closest group to modern jawed fish. Historically they have been thought of as a monophyletic group, ie. comprising all of the descendents of a single common ancestor. More recent finds, such as Entelognathus – a placoderm with osteichthyan-like facial bones – suggest they may form a paraphyly, with some groups and taxa (eg. Entelognathus) more closely related to modern gnathostomes than others.

Phylo

Diagram illustrating (a) monophyletic placoderms, where placoderms are all descendants of a single common ancestor, and the sister group to living jawed vertebrates, and (b) paraphyletic placoderms, where some groups of placoderm are more closely related to living gnathostomes than others.

Many aspects of placoderm anatomy are of great interest to palaeontologists due to the information they provide about the ancestral state for vertebrates, and those pertaining to their sex-life are no different. In addition to live birth in the ptyctodontid placoderms (Materpiscis), structures described as pelvic claspers have been described in both ptyctodontid (Austroptyctodus) and arthrodire (Incisoscutum) placoderms. The closest analogue to these claspers in modern vertebrates is the pelvic claspers of cartilaginous fish. Male sharks and rays have an extension of the pelvic fin pointing backwards, which is used to channel sperm into the female whilst mating, while male holocephalans go one further and have two claspers in addition to their pelvic ones: one anterior pair further forward on their body, and one single clasper on the midline of their head. While both placoderm and chondrichthyan claspers are grooved structures and are found in roughly the same place, they have important differences, which suggest they aren’t actually homologous: the claspers of sharks are made of cartilage and attached to the pelvic fin, whereas those of placoderms were made of dermal bone (like their armour) and were completely separate from any other structure.

Sexyplac male2

a-c are the pelvic clasper (with reconstruction) of male Microbrachius. d-g are claspers in other placoderms, and h-i show the fossil Microbrachius with claspers in situ. From Long et al.

The claspers of male Microbrachius are like those of other placoderms in that they are grooved dermal plates separate from the pelvic fin. Like the claspers of ptyctodonts, those of Microbrachius are hook-shaped (arthrodire claspers are thin rods), and would have been immobile. Female Microbrachius have also been described with blade-like plates in the same region, with ornamentation (ie. bumps and ridges) on the surface that would have faced inwards. The authors interpret these as genital plates, which would have received and gripped the males’ claspers whilstmating. With this interpretation, the presence of claspers can be used to infer the presence of internal fertilisation, reconstructed by the authors as a form of side-by-side copulation apparently akin to square dancing.

Sexyplac female2

Female Microbrachius with genital plates labelled (from Long et al.)

This is all very well, but if we already know that claspers are widespread in both placoderms and modern sharks, why do we care about Microbrachius? One reason is that in a scenario of placoderm paraphyly (ie. where the various groups are arrayed along the gnathostome stem), antiarchs are likely to be the most rootwards group, ie. least closely related to living gnathostome. Long et al. argue that if placoderms are paraphyletic then internal fertilisation, present in chondrichthyans and in multiple placoderm groups including the most ‘primitive’, is likely to be the ancestral state of jawed vertebrates. This would in turn mean that the spawning behaviour of today’s bony fish and amphibians, where females lay eggs and the males fertilise them externally, is actually secondarily derived from internal fertilisation, completely changing how we understand the evolution of internal fertilisation in vertebrates.

Sexyplac phylo

Figure showing the presence and absence of pelvic claspers through (paraphyletic here) placoderms and other vertebrates. (From Long et al.)

While this would be an exciting, paradigm-shifting set of circumstances,it remains far from firmly established. One issue, which the authors acknowledge, is that placoderm paraphyly is far from definite. While it has been repeatedly found to be the case in various recent analyses, the various taxa and groups tend to switch position a lot between analyses suggesting that the result isn’t very stable. If placoderms, or even just placoderm groups with claspers, were monophyletic then internal fertilisation with pelvic claspers could just be a synapomorphy (uniting character) of this group, derived independently from that of chondrichthyans. It’s also possible that the various placoderm claspers aren’t homologous at all. Structurally they appear (to my untrained eye, at least) quite different and in some antiarch taxa, such as Bothriolepis, no direct evidence of claspers has been found despite there being thousands of known specimens. If the claspers aren’t homologous, it doesn’t actually mean that the internal fertilisation isn’t, but it would reduce the argument’s weight somewhat.

Sexyplac

Microbrachius apparently loves an audience. Mandatory listening. (From Long et al.)

Whatever the answer, this new description of Microbrachius offers an intriguing glimpse into the sex life of a 400 million-year-old fish. Its significance will ultimately come down to the resolution of placoderm phylogenetic relationships, as well as a better understanding of the homology of the claspers in various placoderm taxa. At the very least we can be thankful for the serendipity of the first fish known to have sex coincidentally having the species name dicki.

 

References

Long et al. (2014) Copulation in antiarch placoderms and the origin of gnathostome internal fertilisation. Nature.

Deinocheirus: why beer-bellies are bad-ass and the importance of being weird

Today started out as a fairly normal day. I overslept thanks to marathonning House late into the night/morning (note: not due to working late/early on my publication, oops), I dragged myself out of bed and into the office. I then, still half-asleep checked Twitter (the morning ritual was well underway) and then suddenly, I displayed both ends of the NedryGrant excitement chart (patent pending) simultaneously. Deinocheirus. It was DeinocheirusDEINO-RUDDY-CHEIRUS! At the moment, I’m in an office full of volcanologists, so no-one understood my excitement (in fact most thought I had some form of disposition, I mean I was practically frothing at the mouth with excitement). I immediately texted Richard and all my other palaeontological friends/colleagues with two words: DEINOCHEIRUS PUBLISHED.

My face on the morning of the 22nd October 2014. (I even laughed like a Dilophosaurus).

Story time

So why was I so stupidly excited? Well, I’m glad you asked. To explain this excitement, our tale begins in 1965. It was July, and the Polish-Mongolian Palaeontological Expedition had stumbled upon a ‘monster’ find. Forelimbs and a shoulder girdle 2.4 metres long belonging to a 70 million-year-old dinosaur with surely the largest forearms of a bipedal animal ever. However, that was all they found. What in the Seven Hells was this magnificent beast? Surely these the arms of some superpredator, akin to Allosaurus or perhaps a mega-Velociraptor? Deinocheirus mirificus was (‘unusual horrible hand’) was ‘born’. For seven-years, this was the most likely explanation. In this time, palaeontologists and members of the public alike went wild with fantastical recontructions of this new and wacky beast, some even going as far as noting that the arms were used much like those of a giant sloth. Alas, in 1972 John Ostrom (the guy responsible for revolutionising the way we think about dinosaurs in relation to birds in the 60s) noted that the bones in the forearm of Deinocheirus appeared similar to those found in the ornithomimosaurs, a group of secondarily-herbiverous theropod dinosaurs very similar to modern ostriches. This agreed with the sentiments of the team that initially discovered Deinocheirus, so it was settled, the beast was in fact an ornithomimosaur. Mystery solved. Right?

Dem Claws.

Dem Claws.

Unfortunately not. Fast forward a little over 40 years later to October 2013, and we still hadn’t found any more remains of the all-too mysterious Deinocheirus. That was all to change. At the SVP 2013 Symposium (one of the biggest annual events in palaeontology) there were hushed, exciting whisperings of new Deinocheirus material (apparently, I couldn’t afford to go). And then, a speaker emerged and confirmed it, Deinocheirus was back, the mystery was apparently solved. New material had been discovered and we now had a 95% complete skeleton to work with. However, this wasn’t fully shown at SVP, and the entire palaeontological community had to wait with baited breath until the work was published. One of the greatest mysteries of 20th and 21st century dinosaur palaeontology had been solved, but we had to wait. It was agonising. Personally, I grew up enthralled with the mystery of Deinocheirus as did many palaeontologists, both young and old, so to be kept in the dark like this was painful.

The Big Reveal

Fast forward again, exactly (pretty much) to a year later. Late October 2014. A dreary-eyed, 20-something-year-old palaeo grad-student is almost hyperventilating over an image he found on Twitter. Ladies and gentlemen, Deinocheirus has landed. And bloody hell if it isn’t the weirdest thing we’ve ever seen.

Deinocheirus-990x980

The Beer-Bellied weirdo in all it’s glory. Deinocheirus mirificus.

Mystery Solved

Standing almost as tall as T. rex, and weighing in at a hefty 6 tonnes Deinocheirus is the biggest ornithomimosaur to dateSo it was big, no biggie right (heh)? Wrong, in addition to it’s monstrous size it’s also (and I might have already said this) bloody weird. With a really deep lower jaw, no teeth, huge forearms, relatively small hindlimbs, a big old “beer belly” (the best description of dinosaur’s anatomy ever, thanks Tom Holtz!) and tall neural spines (similar to those seen in SpinosaurusDeinocheirus sure is different to the ‘typical’ ornithomimosaurian body plan of Galimimus, with long legs and many other features that suggested it was a fast runner. Quite the opposite, Deinocheirus was a big, sluggish brute with a huge appetite. After 50 years, the mystery of Deinocheirus seems to be solved then, it’s a incredibly odd looking, slow moving, bulky, T. rex sized, beer-bellied behemoth. Myth busted, right?

Skeletal reconstruction of Deinocheirus mirificus. Modified from Lee et al. 2014.

Skeletal reconstruction of Deinocheirus mirificus. Modified from Lee et al. 2014.

Again, wrong. These new specimens are that good that we can already begin to hypothesise how Deinocheirus actually lived out it’s seemingly odd, slow lifestyle. Deinocheirus was discovered in the Nemegt Formation, a deposit which is 70 Million years-old (Late Cretaceous), and was an ecosystem similar to that of the Okavango delta today. First off, over 1400 gastroliths were present, probably used to aid in digestion of food, (mainly plants) making up for the lack of teeth. The morphology of it’s jaws and its broad bill (similar to those found in hadrosaurs and ducks) suggest that certain muscles associated with biting were small, meaning that Deinocheirus probably ate soft (and possibly water-dwelling) plants. But there wasn’t just some stones in that big beer belly, no sir! Evidence of a half-eaten fish was found as well, indicating that Deinocheirus was no means a fussy eater, and probably a ‘megaomnivore’ eating pretty much anything it could get it could swallow. This seems to fit well, especially when you consider Deinocheirus’ place in the Nemegt ecosystem, as generalist ‘all you can eat’ type deal (finally, a dinosaur I can relate to) it wouldn’t be in such harsh competition with the other herbiverous dinosaurs in the area that mostly ate plant matter from trees. However, not only do you need to outcompete you friendly neighborhood herbivores to keep on truckin’ in a Cretaceous world, you also need to be not eaten yourself. The main threat in the Nemegt ecosystem was probably the 12 metre long, 5 ton tyrannosaur, Tarbosaurus. However, Deinocheirus seemingly has an answer to everything by sacrificing speed for bulk and size, it was probably too big (and bloody hell, those claws) for Tarbosaurus to safely take on.

Deinocheirus_fin_colcorr_lres

Deinocheirus in situ. Image credit: Andrey Atuchin.

We also know a few more tricks that Deinocheirus had up its exceedingly large sleeves. Remember those Spinosaurus-like neural spines? They were probably there to support the bulky beer belly, similar to an “asymmetrical cable-stayed bridge“. It also had broadended tip-toes (pedal unguals, to be technical), allowing it not to sink when wading into wetter areas. And those claws? No longer used as lethal disembowlers, but for digging/plant gathering. So Deinocheirus seemingly was perfectly adapted to life on the braided, meandering rivers of the Nemegt ecosystem, unafraid of pesky Tarbosaurus, perfectly content to munch away until its heart (and beer belly) was content, and then waddling to the next patch of river to devour (and P.S Deinocheirus didn’t half walk funny).

And the moral of the story is…

By now, you’ve probably found literally hundreds of grammatical and spelling errors, due to the fact that I’ve been excitedly vomiting words onto my laptop in wave after wave of dino-induced mania. Yes it’s weird, and yes I love it because it’s pretty much me in dinosaur form, but why is this important? You’ll probably see this on IFLS (I F***ing Love Science) in a summary post, with ‘weird fat dinosaur discovered’ alongside ‘cure for cancer found’ and ‘artificial intelligence finally sorted’, making palaeontology, yet again look like the stupid and childish sibling of all the other sciences (e.g. “dino with big nose discovered”, unfortunately not a joke). But this is more than just some crazy guys with beards and stetsons finding a random pile of bones and shouting eureka until Nature finally publishes their work. Oh no. This, as well as many other finds over the last year shows us just how extreme dinosaurs can get. In the past 12 months, we’ve had a new, now with more swimming (TM) Spinosaurus recontruction, Dreadnoughtus, possibly the largest dinosaur ever, as well as long-snouted and pygmy tyrannosaurs. Not to mention feathered ornithischians (R). Dinosaurs have often been regarded as evolutionary extremes, and we’re only now beginning to understand just how these extreme animals lived and evolved.This understanding allows us to further understand evolution works, and how organisms can evolve in various environments and under different conditions.Not only is Deinocheirus a weird and wonderful beast, but when we look at it as a living, breathing animal, rather than a poster-child for all things weird and wonderful, we can begin to further understand  the evolutionary processes involved in theropods, a group which would garner the evolution of an incredibly diverse and successful group of animals, the birds. Deinocheirus exemplifies that palaeontologists, by investigating extremely adapted animals, such as dinosaurs, can further the understanding of the the process of evolution, one of the most important processes on Earth, and just how far it can go, and what wonderfully strange creatures it can help to explain.

So there you have it. Deinocheirus. It sure is a good day to be a palaeontologist.

Dino Sirs on Tour: Prog Pal 2014, Part 1 (Ryan).

Since the schedule for conferences is jam-packed (and then when the day’s over, everyone is in the pub until people stagger back to hotel rooms), Richard and I could barely take the time just to keep you updated on Twitter during Progressive Palaeontology 2014. However, we’d thought we’d share our experiences (as this our first proper palaeontological conference) and hand out some tips for anyone out there whose thinking about going to a conference any time soon. Anyway, first off, I’ll (Ryan) give my accounts of ProgPal 2014.

Progressive Palaeontology (just Prog Pal to most) is an annual symposium/conference/get-together/piss-up where palaeontologists early in their career (predominately PhD and Masters students, with some keen undergraduates) come together and present their work. It’s a fairly small event, with around 100 people in attendance and lasting only a day. This makes it a perfect introductory conference, with a laid-back atmosphere that isn’t quite as scary as SVP or Pal Ass. Anyway, here comes the blow-by-blow account of my Prog Pal 2014 experience..

Tip #1: Preparation is the key to success. Aside from an opportunity to see what other palaeontologists are up to, conferences are about networking, and getting yourself ‘out there’. Some time before the conference starts, you’ll be sent a list of abstracts of all the people presenting, as well as a list of all the people in attendance. Check through this list and see if there’s any names that you’d like to work with, and plan all the people you want to shake hands with before you get there.

05:30: Christ it’s early. Christ I’m hungover. Richard and I decided we’d drink fairly heavily after the induction and icebreaker session. Big mistake, as I’ve got to give a talk today, my first ever talk at a conference. I wake up and can’t get back to sleep, so quietly practice my talk over and over.

06:42: Richard finally decides to stop snoring and wake up. Lazy so and so.

Tip #2: DON’T DRINK TOO MUCH THE NIGHT BEFORE THE CONFERENCE.

08:15: Richard and I are at the closest Wetherspoons (pub) to the National Oceanographic Centre (where Prog Pal was held this year), and our hangovers are subsiding after a hearty (and well priced) breakfast. With excitement and glee (as well as the grease from the breakfast) in our hearts, we set off to the NOC.

08:45: We arrive at the NOC and put up our posters. We’re a little late to the proceedings (like the rebels we are), so our posters are right at the far end. Great.

Tip #3: If you’re present a poster, put it up ASAP. Remember, you want the prime real estate so more people have the chance to see the work you’ve spent months slaving away on…

08:46: I impulse buy a Temnodontosaurus PalaeoPlushie. SO CUTE. (And accurate!)

09:00: Jon Tennant himself kicks of the talks of Prog Pal 2014 with a phylogeny of dwarves. No seriously, actual dwarves. (And then talks for a bit about atoposaurids).

Slightly disappointed when I realised the talk was on atoposaurids rather than actual dwarves.

Slightly disappointed when I realised the talk was on atoposaurids rather than actual dwarves.

09:51: Mid-way through one of my supervisors’ (Ben Moon) talk (on the phylogeny of ichthyosaurs) I have a “oh s**t” moment as I realise his data makes the published phylogeny I used in my analyses obsolete. Welp, back to the drawing board on that hypotheses.

10:30: Coffee break time! It’s also the start of the first poster session, so Richard and I eagerly away the throngs of people who love ichthyosaurs and stem-gnathostome evolution.

10:31-10:50: Richard and I get a grand total of 2 people each looking at our posters, whilst the throngs of people congregate at the other end of the conference hall…

Richard and I next to our posters. The person who photographed us here accounted for probably a quarter of the people who looked at our posters all day...

Richard and I next to our posters. The person who photographed us here accounted for probably a quarter of the people who looked at our posters all day…

Tip #3: I reiterate, if you can, place your poster where most people will see it!

10:40: One of my hypotheses get’s put through the ringer by Colin Palmer (a prominent worker in the field of pterosaur flight). He presents valid points, so it’s back to drawing board on yet another hypothesis.

Tip #4: Prepare for criticism (usually constructive). Conferences are about showing your work off to other scientists, and some people may know more about certain things than you. That’s okay, it might take you down a completely different path with your study, perhaps to new and exciting work!

10:50-12:30: The second session is talks on invertebrates and early vertebrates (even Richard ‘fish and early vertebrates 4 lyfe’ Dearden finds some parts a little dull). For most of it I have know idea what’s going on. I muddle through until Robert Lemanis’ talk on ammonite shell function, which was AWESOME.

12:54: Over lunch, Richard learns that he missed out on meeting Philippe Janvier (as he came to Prog Pal rather than go to the Woodward Symposium). For pretty much all of lunch he lets me know how he’ll never forgive himself.

13:25: Richard’s still going on about Philipe bloody Janvier.

13:30: Luckily, the third talk session starts, so Richard gets away unharmed.

Tip #5: Never mention Philippe Janvier in the presence of Richard.

14:15 PM: Sam Giles gives an absolutely wonderful talk on an exceptionally preserved actinopterygian skull from the Devonian. She really knows how to give a talk, and she presented some awesome CT data!

15:00-15:20: Another poster session. Robert Lemanis and I chat away about CT resolutions. (And I heartily congratulate him on making ammonites really cool).

15:20-16:53: Over the next hour and a half I was too nervous to remember anything, as my talk was coming up. Jon Tennant sends me an amusing Tweet.

Fairly sure this is Jon Tennant's favourite meme ever.

Fairly sure this is Jon Tennant’s favourite meme ever.

16:53: I give my talk, and the nerves get the better of me. I have some form of brainfart and stutter over the same point for what felt like an eternity. Somehow I get back on track and finish on time. Phew. I’m still in a foul mood for an hour or so.

Tip #6: Never let the nerves get the better of you. Yes it’s much easier said than done, but at the end of the day, you’re giving a speech about something that you probably know more about than anyone in the world, so you have a right to be there and ace it.

Yours truly about to give a talk. I didn't have butterflies, I had azhdarchid pterosaurs in my stomach...

Yours truly about to give a talk. I didn’t have butterflies, I had azhdarchid pterosaurs in my stomach…

17:40: Audrey Roberts chats to me whilst I’m posted by my poster. We chat for a while about ichthyosaurs. It was great to meet another ichthyosaur worker!

18:00: It’s over, the posters are taken down and we head on over to the Royal Thai Pier to begin the evening’s festivities.

18:04: We realise it’s absolute pissing it down and spend the next 15 minutes walking gloomily.

18:19: Fear not! We arrived at the restaurant and chowed down on some tasty (and much too hot for Richard’s liking) food. Winners of the day are announced, and it was great to see so many Bristol students (and alumni) take home prizes! Wine is consumed.

20:25: Richard’s supervisor buys him a drink, I look over to my supervisor in a desperate attempt to get a free beverage. No chance.

Richard looking pleased with himself after eating something hotter than a fish finger sandwich. Our friend, Amy, looking miserable as always.

Richard looking pleased with himself after eating something hotter than a fish finger sandwich. Our friend, Amy, looking miserable as always.

21:00: We’ve made it to the same Wetherspoons as last night, we feel like we’re home at last.

21:01-22:00: I hang out with the Bristol MSc cohort, and we all drink far too much. Although not as much as Richard’s supervisor, who’s still buying Richard drinks. No sign of Ben buying me a drink.

22:30: Richard (now fairly drunk) announces we should mingle. So we stand up, and immediately take drunk selfies for a bit.

Tip #7: Make sure either a) they can’t see you or b) that the people you planned to network with you at the conference are drunk enough to forgive you taking selfies. Or just ask them to join in.

Tip #8: On a more serious note, the pub is great way to network in an informal setting, if you don’t get the time to speak to people during the conference.

23:04: Ben Moon reveals to me with wry smile he probably should have given me his phylogeny a while back. No kidding. Still, it gives me something to look at over the summer.

23:10: Jon Tennant tells me he voted for my talk, saying my work was ‘progressive’ and ‘cool’. Somewhat tipsy, it was hard not to straight up hug the guy.

23:30: I watch a fellow MSc student hilariously try and get 4th authorship on Richard’s future paper, despite doing absolutely nothing. Unfortunately, Richard’s having none of it.

23:35: Richard brings up Janvier again and I seriously consider glassing him.

23:50: Last orders, Richard and I stay classy and order two double G&T’s.

00:00: We set off back to the hotel, fairly inebriated.

The last photo I took at Prog Pal 2014. A selfie (of course). We were sober, honest.

The last photo I took at Prog Pal 2014. A selfie (of course). We were sober, honest.

And their we have it ladies and gentlemen, Progressive Palaeontology 2014. Unfortunately, I wasn’t able to attend the field trip to the Isle of Wight the next day, as I had to give a talk back in Bristol. I had great fun, and I’d like to take this opportunity to thank everyone who made Prog Pal possible this year, you guys did a wonderful job of organising the whole thing. Finally, I just like to summarise a few things about conferences:

  • Always prepare who you want to network is, as my Nan often says (and it really does apply to the academic world) “it’s not what you know, it’s who you know”, so it’s vital that you take every opportunity to meet and greet people that you’re interested in working with.
  • Be prepared for constructive criticism. It’s a huge part of the academic process (and it always hurts a little bit more in person).
  • If your presenting a poster, think about where abouts in the conference hall you’ll be located (if you get the choice).
  • If your giving a presentation, don’t let nerves get the best of you, and remember that you know your stuff, otherwise you wouldn’t be there!
  • Most of all, have fun, it’s so invigorating to spend time with lots of people who are passionate about the same kind of things you are.

Stay tuned for Richards account of Prog Pal (and prepare to read about Philippe Janvier…) over the next few days.

Announcing TDS on Tour: Progressive Palaeontology 2014

Dear avid TDS readers, Richard and I humbly apologize for not posting for what seems like an epoch. We’ve both been incredibly busy with various palaeontological projects. To make up for it, we’re providing coverage of Progressive Palaeontology 2014 ! Prog Pal is an annual conference (this year in Southampton) for palaeontologists early in their career (masters and PhD students for example), and is a great way for people like Richard and I to try our hand at conferences (as the big ones like SVP can be pretty scary for first-timers). It’s also a great way to meet fellow palaeontologists and present your ideas. Both Richard and I are presenting at Prog Pal this year; Richard with a poster on early stem-gnathostome evolution, and myself on the function and phylogeny of the endocranium.

 

progpal

 

Our coverage will start tomorrow, and will mainly be on our Twitter and Facebook, where we’ll be more than likely giving you mundane updates when we inevitably get stuck in traffic on our way down to Southampton. We’ll also put together a post each on our experience from the conference and tips for fellow first timers, along with our highlights etc. We know that the acclaimed Palaeocast will also be providing (albeit much better and complete) coverage of Prog Pal 2014, so we urge you guys to check those out over the next few days! After Prog Pal, Richard and I also hope to get the blog back on track, now we have a smidgen more time on our hands.

For more information of Progressive Palaeontology, click here.

For more information on Palaeocast, click here.

Click here for our Twitter page, and here for our Facebook page.

What’s New(s): 11/04/2014

Avid readers of TDS, we have again not published as often as we’d have liked to over the last few weeks, as deadlines are piling up over here in TDS Towers. Fear not, as below is a bountiful harvest of palaeontological news, five of the most succulent morsels, handpicked by Richard and I, for your entertainment.

Embry-old

Fossilised creatures generally, even those as big as dinosaurs are pretty rare. The forces of nature and preservation all stack up against palaeontologists when we try and find fossils. So when very small fossilised early stage embryos from over 500-million-years-ago are found, it certainly doesn’t go unnoticed. Whilst not new to science, the latest publication of fossil embryo’s gives some much needed insight into how such small and delicate structures were fossilised. Researchers from Missouri and Virginia Tech have found fossilised embryos in the Shuijingtuo Formation (China) which are around 500 million years-old (from the Cambrian period). Despite not being the oldest fossilised embryos (the fossil record of embryos stretches back beyond 580 Mya in the Doushantuo Formation, Pre-Cambrian), the Shuijingtuo embryos contain the soft tissue impressions of the chorion (the fertilisation envelope). The authors also suggest that in this fossil deposit, the preservation of these soft tissues is more common due to these tissues being (somehow) selectively phosphatized. At this point, how these small and rare embryos got to be preserved is all that is known of the Shuijingtuo embryos, but future discoveries on what organisms these embryos belonged to, or even better preserved embryonic soft tissues will prove to be very exciting reads in the months and years to come.

Whilst not the embryos in question, they have caused a massive stir over the years.

Ancient ‘Sp-eye-ders’ from M(ontce)A(u-les-Mines Lage)RS(tätte)

I’m (Ryan) a huge arachnophobe. So I wasn’t best pleased when Richard brought this (albeit interesting) tidbit of news to my attention. A new extinct species of harvestman from the Carboniferous, Hastocularis argus, was recently discovered in France which has allowed the authors to comment on the evolution of the group. It’s also thrown up some eye-opening surprises. Before I continue on the subject, the jovial title of this story is wrong. Whilst harvestmen are arachnids, they aren’t spiders, they’re actually more closely related to mites. Regardless, the discovery of H. argus has allowed Garwood et al. to investigate the origins of harvestmen more closely, as the exoskeletons of these arachnids are rarely preserved in the fossil record. With the creation of a new mite suborder, Tetrophthalmi (which includes H. argus and the Devonian species, Eophalangium sheari), Garwood et al. have, contrary to previous beliefs, argued that the diversification of modern harvestmen occured later in geological time (Carboniferous, rather than Devonian).

The (albeit not so scary looking) Hastocularis argus rendered in full 3D glory.

The (albeit not so scary looking) Hastocularis argus rendered in full 3D glory.

Modern harvestmen have just a single set of eyes, the medial pair (central). However, the 305-million-year-old H. argus has two pairs of eyes, a medial and a lateral (outer) pair. In the same paper, Garwood et al. report that work on modern harvestmen has revealed that despite the passage of over 300 million years, they still retain some genetic framework for these lost lateral eyes. This paper (despite being on arachnids *shudders*) is pretty great, as it combines modern 3D visualisation techniques (CT scanning), phylogenetics and some genetic work in order to really get a handle on the origins of a previously poorly known group. This again proves that the combination of palaeontology and biology is a real ‘dream team’ when it comes to unearthing evolutionary relationships.

 Cambrian heart-thropod’s gets palaeontologists’ blood pumping

I genuinely rewarded myself with a break after making that title, the puns have (if I do say so myself) been exceptional this week. Regardless, a fascinating insight into the evolution of the cardiovascular system has been published in Nature Communications this week (7th April). An exceptional specimen of Fuxianhuia protensa, a 520-million-year-old arthropod from Chenjiang deposits has been described, and with a cardovascular system almost intact. Even though the phylogenetic placement of Fuxianhuia is controversial to say the least, in 2012 it was discovered that Fuxianhuia had a relatively complex brain, suggesting by the early Cambrian, arthropods already had similar visual capabilities as modern insects.

 

Fuxianhuia reconstruction from Ma et al. (2014). a) cardiovascular system and CNS; b) whole body reconstruction; c) cardiovascular system in relation to the gut.

Fuxianhuia reconstruction from Ma et al. (2014). a) cardiovascular system and CNS; b) whole body reconstruction; c) cardiovascular system in relation to the gut.

Perhaps it is a tad unsurprising that this latest Fuxianhuia discovery reveals that the cardiovascular system of arthropods from the early Cambrian were relatively advanced, and more than able to keep the ‘complex’ brain oxygenated with blood. The combination of an advanced cardiovascular and neural/visual system has led Ma et al. to conclude that F. protensa had well developed sensory (using vision and its antennae) system, and in life it was a highly mobile forager. They also conclude that even by the Cambrian Explosion, arthropods had evolved many advanced biological systems.

Teenage Mutant Ninja Hupehsuchians, swimming in a half shell.

Because what would a blog post on TDS be without a marine reptile? (Also, it’s taken until the 4th news piece to get to a tetrapod, what is this nonsense?). Moving on swiftly, the next discovery presents a new species of marine reptile, Parahupehsuchus longus. After taking a quick look at the holotype of P. longus (pictured below) you’d be very much forgiven if you thought it was an early Triassic ichthyosaur. P. longus is in fact a hupehsuchian, which a group of diapsid reptiles from around 250 Ma, and are known exclusively from one locality, in Hubei Province (China).

An incredibly dumb looking hupehsuchian, Nanchangosaurus (a close relative to Parahupehsuchus).

An incredibly dumb looking hupehsuchian, Nanchangosaurus (a close relative to Parahupehsuchus).

So what makes Parahupehsuchus so cool? Well in its defenceP. longus has a weird expansion of its ribs (similar to the ribs of turtles, that’s how they ‘make’ their carapace) which overlap to form a ‘bony tube’. As indicated by the aforementioned pun, Chen et al. think that this is used as a defence mechanism. Whilst the fact that the same kind of defence mechanism (revolving around the expansion of the ribs) has convergently evolved in at least 2 groups of marine diapsids is fairly interesting, it’s the wider implications of this discovery that really make Parahupehsuchus cool. What does any creature needs a defence mechanism for? That’s right Captain Obvious, defence. This almost definitely means that during the early Triassic, there were large predators and a higher trophic level was present at this time. This is odd, you wouldn’t expect this trophic level to recover so quickly after the Permo-Triassic extinction event (commonly referred to as ‘when life nearly died’, so you know, it’s pretty potent). Chen et al. make 2 pretty bold claims from this one discovery, stating that the recovery from the event was faster in the marine realm (specifically faster in marine predators) and that this marine tetrapod predator trophic level is probably the first one ever to emerge in evolutionary history.

Bird’s and pterosaurs had to Cope with one another

Cope’s rule, simply put is a hypothesis that states evolutionary lineages, over time, increase in size. Pterosaurs have long been the poster child of Cope’s rule in the fossil record (along with horses) going from small rhamphorhynchids in the late Triassic to the huge (and probably flightless) azhdarchids of the Cretaceous. The study by Benson et al. set out to try and understand this apparent trend in pterosaur size evolution further. They found that up until the late Jurassic/early Cretaceous the average wingspan didn’t really go above 1m, and over the cretaceous there was a sustained increase in wingspan, until you reach the monstrous 10m+ wingspans of azhdarchids such as Quetzacoatlus northropus.

Obligatory funny, only very slightly related picture.

Obligatory funny, only very slightly related picture.

A controversial notion that it was the emergence and radiation of the (somewhat smaller) birds in the late Jurassic/early Cretaceous that drove the evolution of large size in pterosaurs. In a unexpected turn of events, Benson et al. actually suggest that this may well be the case, citing a possible combination of ‘intrinsic factors’ (such as terrestrial living in azhdarchids and other flight mechanisms in other groups) and ‘extrinsic factors’ (such the evolution of birds, which would have taken the niches occupied by small aerial feeders away from the pterosaurs) as the cause of the switch to selection of a larger body size in pterosaurs. It just goes to show that competition can be, in some cases, used to explain macroevolutionary processes and patterns.

References

Brose, J. et al.  (2014) Possible Animal Embryos from the Lower Cambrian (Stage 3) Shuijingtuo Formation, Hubei Province, South China. Journal of Paleontology: March 2014, Vol. 88, No. 2, pp. 385-394.

Garwood, R. J. et al. (2014). A Paleozoic Stem Group to Mite Harvestman Revealed through Integration of Phylogenetics and Development. Current Biology, http://dx.doi.org/10.1016/j.cub.2014.03.039.

Ma, X. et al. (2014). An exceptionally preserved arthropod cardiovascular system from the early Cambrian. Nature Communications 5, 3560, doi:10.1038/ncomms4560.

Chen X-h, et al. (2014) A Carapace-Like Bony ‘Body Tube’ in an Early Triassic Marine Reptile and the Onset of Marine Tetrapod Predation. PLoS ONE 9(4): e94396. doi:10.1371/journal.pone.0094396

Benson et al. (2014). Competition and constraint drove Cope’s rule in the evolution of giant flying reptiles. Nature Communications 5, 3567, doi:10.1038/ncomms4567.

What’s new(s): 22/03/14

We’ve got a range of stories for you in this week’s What’s News including evolving cetaceans, pygmy dinosaurs, and aquatic ground sloths.

A long-mandibled porpoise

Cetaceans are fairly weird animals to begin with: secondarily aquatic even-toed ungulates (like cows and sheep) that are grouped with hippos in the colourfully-named group, the Whippomorpha.  They’ve lost their back legs, have adapted their front ones to form flippers, and have developed dorsal and tail fins, and this morphology has proved extremely successful as they have radiated to fill many niches in the oceans, including filter feeding, suction feeding and giant squid eating.  A new fossil porpoise has recently been described from the Pliocene of California that adds to this diverse array of morphologies with it’s bizarrely shaped lower jaw.  The lower jaw of Semirostrum cerutti extends well past its upper jaw to form a prognathous projection, which was apparently well nourished by arteries.  This morphology is most similar to the mandibular morphology of skimmer birds, which fly low and close to the water while using their long and highly sensitive lower beaks to probe for underwater prey.  The authors argue that the properties of Semirostrum’s mandible suggest it did a similar thing in sediment at the bottom of the sea.

skimmer porpoise

A reconstruction of a ‘skimming’ Semirostrum and his joyous friend.  (From Racitot et al)

Evolving echolocation

Continuing on the whale-y theme, modern whales are split into two groups: the Odontoceti, or toothed whales, and the Mysticeti, or baleen whales.  The baleen whales filter feed small animals with their baleen, while the toothed whales (which include Semirostrum, who we just met) use echolocation to locate their larger prey, which involves emitting calls and listening to their echoes like a sort of biological sonar. These echolocating  vocalisations are associated with a unique array of features in odontocete skulls, that serve to amplify and  receive the sound.  The newly described Oligocene whale fossil Cotylocara macei is argued to possess these features, including dense snout bones argued to act as an acoustic reflector and a lot of room for the anchoring of a muscle associated with echolocation, the maxillonasolabialis (yep, apparently that’s a thing).  This brings the evolution of echolocation firmly down the odontocete stem, meaning that it evolved shortly after they diverged from mysticetes about 34-30 million years ago.

Whale phylo

If Cotylodira did echolocate, it suggests an origin where the arrow is pointing.  From Geisler et al.

Swimming sloths

As well as the familiar cetaceans, many other mammal groups have famously made the move to an aquatic life including manatees, seals and otters.  Common adaptations to this aquatic life are pachyostosis, the swelling of the solid outside layer of bone, and osteoschlerosis, the densification of bone, adaptations which are both argued to have evolved to reduce the animals buoyancy.   Were you to visit the Miocene-Plocene of Peru you might meet a less well-known aquatic mammal with these adaptations: the ground sloth genus, Thalassocnus.  While modern sloths seem happy to go for the occasional swim, this animal was adapted to an underwater life, and probably fed on marine vegetation.  A number of species of Thalassocnus existed throughout time, and Amson et al studied slices of their bones to track the evolution of pachyostosis and osteoschlerosis.  They found it could be tracked through the successive species as they increasingly adapted to aquatic life, offering a rare high-resolution view of the evolution of a trait, as well as further proof that sloths are awesome.

sloth bones

The ribs of Thalassocnus plotted onto a phylogeny, becoming denser as the genera adapted to marine life. The fact I put up this and resisted the urge to post one of the internet’s many sloth pictures is a testament to my dedication to palaeobiology and to you, dear reader. From Amson et al.

Pygmy Tyrannosaur

Another thing that’s awesome is, of course, dinosaurs, and we have two dinosaurs for your delectation and delight this week.  The first of these is a tyrannosaur, Nanuqsaurus hoglundi, the generic name (Nanuqsaurus) of which means ‘polar bear lizard’, surely one of the cooler (pun obvs intended) dinosaurian names.  This tyrannosaur was described last week from material found in Alaska, and defies the popular perception of tyrannosaurs as enormous carnivores by being relatively small.   As well as adding to our understanding of tyrannosaur diversity, this is particularly interesting as Alaskan members of another dinosaur genus, Troodon were found to be about 50% larger than their more southerly counterparts.  This was originally argued to be due to Troodon’s characteristically large eyes giving it a competitive advantage over other theropods in the low light conditions of the Arctic, selecting for larger body size.  The fact that Alaskan tyrannosaurs are, conversely, smaller is argued by the authors to add weight to this idea, with the claim that the opposite situation applied due to their diminished ability to see: a lowered competitive advantage resulted in selection for reduced size.

Pygmy

Size of Nanuqsaurus (A) compared to other tyrannosaurs (B-E, T. rex is B).  ‘Normal’ Troodon is F, with Alaskan Troodon as G.  From Fiorillo and Tykoski.

The ‘chicken from hell’

You’ve probably already heard of the second dinosaur that we encounter this week, the ‘chicken from hell’, Anzu wyliei.  Given that the generic name of the taxon is taken from an ancient Mesopotamian feathered demon (tbh, probably trumping polar bear lizard) one might question why it needs to be described as a ‘chicken from hell’, but hey ho.  Anzu is a new, and the most complete, member of the Caenagnathidae, members of the oviraptorsaurs like the more familiar Oviraptor. The Caenagnathidae contains taxa such as the massive Gigantoraptor, but so far is poorly known; Anzu goes some way to solving its relationships.   Like many other oviraptorsaurs it had a large, cassowary-like crest and no teeth; much debate has been had over exactly what dietary niche this group inhabited, and no firm answer has yet been reached.  Whatever its exact niche, Anzu is about 67million years old, and so it dates from immediately prior to the K/T mass extinction, and was found in the famous Hell’s Creek formation, showing that this locality still has information, and dinosaurs, to offer.

Screen Shot 2014-03-22 at 17.06.24

Anzu’s skeleton reconstructed. From Lamanna et al.

References

  • Racicot et al (2014) Unique feeding morphology in a new prognathous extinct porpoise from the Pliocene of California, Current Biology
  • Geisler et al (2014) A new fossil species supports an early origin for toothed whale echolocation, Nature
  • Amson et al (2014) Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru, Proc. Roy. Soc. B
  • Fiorillo and Tykoski (2014) A diminutive new tyrannosaur from the top of the world, PLOS One
  • Lamanna et al (2014) A new large-bodied oviraptorsaurian theropod dinosaur from the latest Cretaceous of Western North America, PLOS One

Taxon of the Week: Koumpiodontosuchus

Dear reader, don’t be put off by such a name, nor by the fact that poor little Koumpiodontosuchus has been dwarfed by Nanuqsaurus, the recently descovered ‘pygmy’ tyrannosaur (more on that when Richard finishes the latest What’s News), because this little Cretaceous critter raises some interesting questions about eusuchian phylogeny. It’s also going to be fairly short, as Richard and I are crazy busy at the moment.

Sometime in March 2011, a lady, out with her family, discovered part of the skull of Koumpiodontosuchus, and almost immediately handed it over to Dinosaur Isle, a museum on the Isle of Wight, UK (as can be seen in my dorky picture on the about page of TDS). In a rather coincidental turn of events, some months later the second part of the skull was donated to the same museum by other denizens of the Isle of Wight. The now completed skull was then meticulously studied by Dr. Steve Sweetman et al. of the University of Portsmouth. Cut to the present day, and what we have is a new species of bernissartiid crocodile (a group that includes some of the smallest neosuchian crocs, i.e. modern crocs and their immediate ancestors) from the Early Cretaceous. Koumpiodontosuchus adds to the already diverse ecosystem we see in the Early Cretaceous of the Isle of Wight, which includes an allosaur (Neovenator), Iguanodon, Polacanthus (a thyreophoran), Eotyrannus, good old Baryonyx and a brachiosaur (as well as some azdharchid pterosaurs and mammals).

A wonderful reconstruction of early Cretaceous life on the Isle of Wight. Courtesy of Mark Witton.

A wonderful reconstruction of early Cretaceous life on the Isle of Wight. Courtesy of Mark Witton.

Estimated at only 66cm in total length, Koumpiodontosuchus aprosdokiti (roughly meaning button toothed, unexpected) is a small croc with a big name. As the name suggests, Koumpiodontosuchus has ‘button’ teeth (broad and flat) situated at the back of the jaw, with pointier teeth towards the front. This dental arrangement meant that Koumpiodontosuchus could have a good crack at both catching fish at eating hard-shelled material such as molluscs. Despite its neat arrangement of teeth, its not Koumpiodontosuchus’ crowning glory. That prize belongs to the choanae.

Koumpiodontosuchus reconstruction, again by Mark Witton. Also, casual Neovenators in the back there.

Koumpiodontosuchus reconstruction, again by Mark Witton. Also, casual Neovenators in the back there.

In crocodiles, the choanae are found in the upper jaw and form the internal nostril openings (holes). Despite containing all the extant crocodiles and their recent common ancestors, Neosuchia has a subgroup called Eusuchia (“true” crocodiles”) in which all modern crocs are found. Now, there are many defining features that allow palaeontologists/taxonomists/biologists to distinguish eusuchians from the larger pool of neosuchians, but a big defining feature in recent years has been the placement of the choana(e) within the pterygoids, towards the back of the skull (if you’re getting a bit lost with crocodilian cranial anatomy, the Witmer/Holliday Lab 3D alligator project really does help a bunch). Bringing it back to the early Cretaceous of the Isle of Wight, Koumpiodontosuchus is a non-eusuchian neosuchian (it’s just a neosuchian, no big deal), so you’d expect it not to have its choana placed at the back of the skull, between the pterygoids. 

Holotype of Koumpiodontosuchus. Choana circled in red. Amended from Sweetman et al (2014).

Holotype of Koumpiodontosuchus. Choana circled in red. Amended from Sweetman et al (2014).

Well would you look at that, a choana at the back of the skull and between the pterygoids, now that sure is a turn out for the books. So what does this mean? Well it adds to the amassing evidence from other extinct crocs (e.g. the Madagascan Mahajangasuchus, a rather ugly looking brute from the late Cretaceous) that the placement of the choana(e) within the pterygoids, on its own, might not be a might sign from the taxonomic gods that the croc you’re looking at is a eusuchian.

TL;DR: Koumpiodontosuchus is a cool new (small and cute) croc from the early Cretaceous of the Isle of Wight who, despite its size, manages to further challenge the taxonomic rules that define key groups of crocodylomorphs. Pretty cool, even if a tad unpronounceable.

What’s New(s) 7/04/2014: Definitely not just Torvosaurus

This week, the internet’s latched onto Torvosaurus and not let go. However, there’s been plenty more new palaeontological discoveries than a new European megacarnivore.

Torvosaurus gurneyi: Europe’s new heavyweight

If you haven’t heard about the new species of Torvosaurus that’s been discovered this week, then you’ve either been hiding under a rock, or you just simply hate dinosaurs. The news come from Portugal, after Hendrickx & Mateus redescribed bones initially thought to belong to the American species Torvosaurus tanneri. They name a new species, Torvosaurus gurneyi (named after James Gurney, artist of the wonderful Dinotopia series), distinct from T. tanneri based on numerous features including less teeth on the maxilla (for example). Dated to 157-145 Ma, T. gurneyi roamed the late Jurassic, and it would be hard to miss, considering size estimates settle around 33ft in length. Sure, it’s not T. rex, Spinosaurus or Giganotosaurus, but it does mean that T. gurneyi is the largest carniverous dinosaur discovered in Europe to date. So what does this all mean? Considering two species are now found on either side of the Atlantic, Hendrickx & Mateus hypothesise that some form of geographical barrier (such as geological uplift) separated multiple populations of Torvosaurus, and these (now completely separate) populations evolved to different local conditions (this idea is commonly termed vicariance).

Skeletal reconstruction of Torvosaurus gurneyi from Hendrickx & Mateus (2014).

Skeletal reconstruction of Torvosaurus gurneyi from Hendrickx & Mateus (2014).

Adipose fins no longer (of a) single (origin).

Far from it for me to encroach on Richard’s beloved fish, but this week new insight into adipose fins has shed some light on convergent evolution of fins (and vertebrate limbs more generally). You’re wondering what an adipose fin is, aren’t you? Go and look at the figure below.

Redundant caption is redundant.

Moving on, Stewart et al., using phylogenetic and anatomical evidence from over 600 species of fish concluded that the adipose fin, despite being widely regarded as vestigial with no clear/agreeable function, has been found to have evolved repeatedly and independently. Adipose fins have also evolved multiple features such as fin rays, which suggests that complexity and new types of tissue can evolve by activating certain developmental modules. Stewart et al. earmark this study as important to future work on the evolution of the limbs (and their complexity) in vertebrates. The study also challenges the long held notion that dermal skeleton evolved first, followed by the evolution of the endoskeleton. It also hints thats one may evolve without the other.

Daohugou, Jehol’s attractive older sibling

Yes, that was an unnecessarily creepy title. Moving on. The Jehol Biota, over in China is a lower Cretaceous ecosystem, represented by numerous localities (mainly of the exceptionally preserved lagerstatte variety). Jehol localities have given us a plethora of exceptionally preserved dinosaurs, pterosaurs, birds and mammals over the last 20 ish years. Recently, older deposits (Jurassic) from the same geographical region have been discovered. Sullivan et al. link the Daohugou locality to numerous other localities by the presence of a salamander, Chunerpeton tianyiensis, the key species that confirms the link of these localities to form the Daohugou biota. Much like in last week’s What’s New(s), with the discovery of a ‘new Burgess Shale’, this exceptionally preserved ecosystem has an incredible potential to provide vital information on the evolution of dinosaurs, birds, pterosaurs and mammals. The locality has already produced 13 well preserved pterosaurs (as well as five salamanders, two lizards, five dinosaurs, four mammals, oh, and a frog), so the future looks bright for Jehol’s older sibling.

Aforementioned salamaber. Also, dat preservation.

Aforementioned salamaber. Also, dat preservation.

Ocepeia: a very old afrotherian

The final two stories revolve around Cenozoic taxa, because it’s all too apparent that TDS is considerably lacking in Cenozoic palaeontological goodness. The first story centres around afrotherians, a superorder of mammals that have an African origin (including elephants, tenrecs, aardvarks, hyraxes and dugongs). The afrotherian in question is Ocepeia (O. grandis and O. daouiensis). A Ocepeia skull was discovered in the Selandian of Ouled Abdoun Basin (what a name) in Morocco. It dates to around 61 Ma, which immediately makes it the oldest afrotherian skull to ever be discovered. Now this is interesting, because this skull shows a mixture of primitive and derived features, as well as a mix of ungulate-like afrotherian (elephants, sea cows and hyraxes) and insectivore-like afrotherian (aardvarks, sengis, tenrecs and golden moles) features. This means that Ocepeia appears to be a ‘transitional form’ between these two subgroups of Afrotheria. This in turn provides significant evidence that Afrotheria may well have evolved specifically within Africa in the latest Cretaceous/early Tertiary. Pretty cool, for a mammal.

Reconstruction of Ocepeia from Gheerbrant et al. (2014).

Gastornis goes vegetarian for lent

Second in our short series of Cenozoic news is Gastornis. If you haven’t heard, Gastornis is a 2m tall terror bird which lived approximately 56-45 Ma (Paleocene-Eocene kinda time), that was previously thought to terrorise and eat small horse ancestors. This horse-heavy carniverous diet has been but into question for some time, and new evidence from Angst et al. suggests that whilst looking terrifying, only the plants of the Paleocene and Eocene had to worry about that enormous beak. Angst et al. form two lines of evidence, first they looked at carbon isotopes of bone apatite, and compared it to other herbivores (both mammals and birds). They found the results of this isotope analysis to be similar to the results gained from the other herbiverous taxa. Secondly, they look at (hypothetical) reconstructed jaw muscles of Gastornis, and again found that it shared similar looking jaw muscles to other herbiverous birds. Don’t worry Gastornis, you’re still scary to me (I mean your an almost 7 foot tall bird with a beak that looks like it can cut a man in half).

Don’t worry kids, science says these two are just playing and having fun.

 

References

Hendrickx C., Mateus O. (2014) Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods. PLoS ONE 9(3): e88905. doi:10.1371/journal.pone.0088905

Stewart, T. A. et al. (2014). The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages.Proceedings of the Royal Society B: Biological Sciences, 2014; 281 (1781): 20133120 DOI: 10.1098/rspb.2013.3120

Sullivan, C. et al. (2014). The vertebrates of the Jurassic Daohugou Biota of northeastern China. Journal of Vertebrate Paleontology 34 (2): 243 DOI:10.1080/02724634.2013.787316

Gheerbrant E. et al. (2014) Ocepeia (Middle Paleocene of Morocco): The Oldest Skull of an Afrotherian Mammal. PLoS ONE 9(2): e89739. doi:10.1371/journal.pone.0089739

Angst, D. et al. (2014). Isotopic and anatomical evidence of a herbiverous in the Early Tertiary giant bird Gastornis. Implications for the structure of Paleocene terrestrial ecosystems. Naturwissenschaften DOI 10.1007/s00114-014-1158-2

 

Announcing the official TDS Facebook page.

Afternoon to all readers of The Dino Sirs. Richard and I have an announcement to make, TDS has an official Facebook page! Either click like on the sidebar widget or follow the link (click me). We’ll announce all our future posts as well as post amusing (vaguely) palaeontological tidbits, as well as our pictures etc. from conferences etc.

Obligatory related humorous tidbit.