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.

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.

Animals or antediluvian monstrosities?

The famous painting Duria Antiquior, by the Victorian geologist Henry De la Beche, is acknowledged as being the first piece of palaeoart, ie. depiction of prehistoric life based upon fossil evidence.  Because of this it’s palaeontologically important, but it’s also pretty awesome in itself as a picture, with various marine creatures eating one another as pterosaurs swoop overhead, and even a rare depiction of a pooing plesiosaur.  There is in fact so much awesomeness going on that you’d struggle to find room to swing a cat (or whatever the Mesozoic equivalent is-perhaps Pakasuchus?) anywhere in the crowded landscape.  While a great picture, it doesn’t actually do a very good job of illustrating what a Mesozoic seascape would have looked like, instead depicting various monsters doing battle.

Everything looks so happy

The smiley ichthyosaurs make it all look so jolly.

This brings us to the theme of this blog post: the temptation to ‘mythologise’ prehistoric animals and the world in which they lived.  Duria Antiquior was painted in 1830, and obviously palaeontological understanding has come a long way since then.  Equally, the depiction of overcrowded, overdramatised scenes in palaeoart is fair enough.  No-one would be interested in a Mesozoic seascape if it depicted an empty ocean with something that might or might not be the silhouette of an ichthyosaur in the murky distance.  But this popular view of the prehistoric world as a planet populated by antediluvian monstrosities does still sometimes colour the way that people try to understand it.

One of the fundamental tools available to palaeontologists to help them understand extinct animals is information from animals that are alive today.  To understand how a dinosaur’s moved they would look at the principles that govern movement in modern animals, rather than making up special rules for dinosaurs.  Sometimes, however, palaeontologists give in to the temptation to treat prehistoric life specially.

Azhdarchid pterosaurs were a group of large, long-necked pterosaurs from the Cretaceous, including the famous (for a pterosaur anyway) Quetzalcoatlus.  Their shape has led some to suggest that they fed like modern ground hornbills, hunting on the ground with their enormous beaks (see picture).  One argument (among a number) put forward against this hypothesis is that any azhdarchid that landed on the ground to feed during the Cretaceous would be immediately torn apart by voracious theropods.

Quetz

Admittedly hornbills don’t eat sauropods.

But would this actually be the case? Darren Naish (a proponent of the hornbill-esque feeding idea) points out in a recent blog post that it probably wouldn’t be.  Notwithstanding that the size of these pterosaurs offered protection in itself, there’s no reason to think that every inch of the Cretaceous landscape was being constantly monitored by hungry tyrannosaurs.  Taking the modern African savannah as an example; it’s not like every animal that summons up the courage to peek around the side of a baobab tree is instantly ripped to shreds by lions.  To suggest that azhdarchids could never have been safe seems a bit like mythologising the Cretaceous environment and its predators.

It’s not just predators that have been ascribed ‘special rules’.  Amongst ornithodirans (pterosaurs and dinosaurs) are found a amazing array of crests and weird head ornaments (eg. hadrosaurs in picture below), and a number of suggestions have been put forward for why these evolved.  One of the most prominent has been that of ‘interspecific recognition’, where they helped animals to identify mates of the same species.  This hasn’t been conclusively demonstrated to be the reason for ornaments in any animals alive today, but proponents of this idea claim that dinosaurs represent a special case.

hadrosaur_heads_small

I like to think that this is what the album cover for a hadrosaur boy band would look like.

A counter-explanation put forward has been that of mutual sexual selection, where the crests have been selected for (in both genders) to aid attracting a mate (a more in depth discussion of which is found here).  In modern taxa this often seems to be the explanation for such ornaments, and so seems to me to be the more likely hypothesis for those in dinosaurs:  there is no need to invoke ‘special rules’ for extinct animals.  To do so is just another example of (inadvertently) mythologising them and their ecology.

It is true that there are cases where we can’t treat extinct taxa by the same rules as living ones because we have no living analogues to tell us what the rules are.  Enormous bipedal carnivores and giant fully aquatic reptiles are examples.  However, this doesn’t mean we ought to believe that widely applicable principles that we know from modern ecology wouldn’t apply for no reason other than that the animals in question were extinct.  If palaeontologists were studying the function of these animals’ bones they would prefer modern analogues to ‘special rules’, there’s no reason why the same approach shouldn’t be taken to inferring their ecology.

In the two examples I’ve given here, accusing the palaeontologists in question of viewing extinct animals as ‘antediluvian monstrosities’ is an exaggeration.  I do think however that they serve as examples of people applying ‘special rules’ to the ecology of extinct groups just because they’re, well, extinct.  In depictions such as Duria Antiquior such mythologising is both harmless and useful, and sometimes aspects of prehistoric life appear to have no direct modern analogues.  But to view them as anything more than animals in a world governed by the same ‘natural laws’ as those today just gets in the way of understanding these fascinating creatures.

FAQ: Ryan.

First and foremost, what’s your favourite dinosaur?

What a horrific question. It’s like asking a proud parent to choose their favourite child. In my younger days, it was all about the big theropods, tyrannosaurs and the like. But now, I can’t resist the enormous (heh…) charm of sauropods (I prefer the macronarians, Brachiosaurus and the other ‘tall’ sauropods).

Secondly, what’s you favourite (preferably extinct) animal?

A much nicer question question. Pakasuchus kapilimai. As the name suggests it’s a cat-like crocodile. What more could you want? However, honorary mention to Quetzacoatlus (the ‘evil, pin-headed, toothy nightmare monster that wants to eat your soul’, a quote from Darren Naish), because what other flying reptile with a 11m wingspan has a rap about it? Exactly.

tds_pakasuchus

Cute and scaly? Best combo ever. (Courtesy of Wikimedia Commons)

What’s your area of ‘expertise’?

I’m not huge expert in anything yet, but I have a passion for biomechanics in the archosaurs (birds, dinosaurs, crocodiles and their ancestors). I’m currently using a lot of computer software to digitally model fossils, so I guess some of my ‘expertise’ lie in digital palaeontology (the shiny-new future, more on that in a future post, probably).

How did you get into palaeontology?

Like most children of the 1990s, I grew up loving Jurassic Park. The scene where Dr. Grant (a personal hero of mine, even as I enter my twenties) first meets the Brachiosaurus is still up there as my favourite movie-moment ever. Even before that, I was an absolute dinosaur-nut. So much so, by the age of 5 I could spell palaeontologist. Since then I’ve never lost that desire to become a palaeontologist. So, after spending primary and secondary school, then college work my behind off I went to the University of Bristol to study on the Palaeontology and Evolution course. I’m now a masters student at the University of Bristol, currently looking for PhD positions to continue my career in ‘dinosaurs’.

theymoveinherds

To reiterate: this is the best film ever. Period.

What do you do in your spare time?

To be honest, I’m pretty much always reading about palaeontology. Here’s a tip for free: if you want to be an academic you have to be almost obsessed with your subject, if not, you’ll just learn to hate it. In the small amount of time I’m not holed up reading about palaeo (more likely: looking at awesome palaeo art), I’m usually performing/hanging out with Bristol Improv, reading other books, playing video games, or on Twitter (desperately attempting to get #notosuchia trending).

Favourite palaeontological paper?

Ah, I remember it well. It was the first paper I read (all the way back in the first year of my undergraduate degree) that I actually enjoyed reading. It was Rayfield (2004), and I only read it simply because it had Tyrannosaurus rex in the title. But it began my interest in biomechanics (even though I was scared by the maths behind FEA). It was one of the first papers (along with Rayfield et al. 2001) to show the importance of new computational methods in palaeontology. Essentially, I like papers with shiny pictures of fossils (and models of fossils). More recent favourites of mine include:

Allosaurus_PE_WitmerLab_still_01

The future of how palaeontologists assess om-nom-nomming in dinosaurs.

You’re a palaeontologist, so you’re like Ross from ‘F.R.I.E.N.D.S’?

If I had a penny for every time someone asks me this, I’d have paid my student loan off years ago. For simplicity, yes, I’m like Ross from Friends.

And yes Jenniston, I am still awaiting your marriage proposal.

Any tips for any budding palaeontologists out there?

If you’re still in school/college/pre-university, work hard! If you’re in university, work even harder! But seriously, if you want to go into an academic career (not just palaeontology) you’re going to have to get used to hard graft. Also, if there’s any dig sites near you (I’m looking at you American readers), then volunteer! Not only is it great fun, but it looks great when you’re applying for uni/palaeo jobs. If you can’t visit dig sites, read around the subject a lot! We know accessing the primary literature is hard (both in terms of paywalls and understanding), but don’t fear! There’s plenty of really accessible blogs (like us!) giving you news and views on all things palaeo. Also, National Geographic magazine occasionally has some nice articles (palaeo related) inside.

FAQ: Richard.

To give people an idea of who we actually are before we start dinosauring at you, we thought we’d introduce ourselves via a series of ‘FAQs’.  Here’s mine!

Richard

First and foremost, what’s your favourite dinosaur?

At the age of 6 I’d immediately have answered Deinonychus, but the naked kind (eg. picture below) without any feathers.  I would then have proceeded to bore you with my standard soliloquy on how the raptors in Jurassic Park were actually more like Deinonychus, thus justifying my obscure dinosaur choice.

bakker deino

The awkward, naked sprint from shower to bedroom was a problem even in the Cretaceous.

Since then my dinosaur tastes have progressed a bit, but I think I’ll still pick Deinonychus.  As well as being nicely symbolic of the paradigm shift towards viewing dinosaurs as active animals, it has also become feathered fairly recently, representing another change in dino-views.  It also had HUGE CLAWS.

Secondly, what’s your favourite (preferably extinct) animal?

While lots of things are awesome I think I probably ought to choose the Devonian placoderm, Dunkleosteus.  While (obviously) all Palaeozoic fish are exciting, a 10m long one with shearing jaw bones is particularly so.  Also comes highly recommended as a fancy dress costume.

What’s your area of ‘expertise’?

I think ‘expertise’, as opposed to actual expertise, is definitely the right word to use.  I enjoy systematics and evolution-based themes, in pretty much any group.  My project this year is on a group of armoured, jawless fish called heterostracans, so I’m looking forward to learning about them as the year progresses.   My undergrad degree is in Zoology, so I like to flatter myself that I bring a critical zoological eye to palaeobiology.  This is probably not actually the case.

How did you get into palaeontology?

Playground conversations about Jurassic Park and the fact that Walking With Dinosaurs came out when I was small and impressionable both contributed to a love of palaeontology from a young age.  My grandfather is a zoologist who has done work on dinosaurs, and so he fanned the flames by doing things like introducing me to a robotic Iguanodon (see picture).  I then wanted to be a military historian for a bit, before doing a degree in natural sciences, which eventually became zoology as I tried to get as far away from cellular biology as possible.  This zoology degree heavily featured palaeo, which reignited my love of it and led me to this master’s degree.

iguano robot2

The model T-8Ig Terminator was swiftly scrapped by Skynet, after proving to be even less successful at blending into human society than Arnold Schwarzenegger.

What do you do in your spare time?

Mainly musical things.  I play the ukulele and the clarinet, and dabble in a number of other instruments.  I also enjoy singing; previously this has been in Chapel Choirs and things, but has more recently been barbershop.  I also enjoy reading and baking bread.

Favourite palaeontological paper?

I really like this paper describing paired anal fins (weird!) in the jawless fish Euphanerops because the fossil is quite pretty and it has a really nicely structured, clear diagram portraying the evolution of paired fins in vertebrates.  It also provides a tantalising glimpse into the evolution of key characters in gnathostomes (jawed fish), which (as with so much in evolution) seems to form an evolutionary mosaic rather than a straightforward progression from one character state to another.

SansomPhyloOrig

Bask in the clarity of this figure! Green is for dorsal fins, red is for paired fins and blue is for anal fins. Adapted from Sansom et al, 2013

You’re a palaeontologist, so you’re like Ross from ‘F.R.I.E.N.D.S’?

Ross never actually seemed like a very good palaeontologist, so I hope not.  I’ve also only been married twice.

Any tips for any budding palaeontologists out there?

I suspect that I still count as a ‘budding palaeontologist’, but disregarding that my tips would probably centre around a general theme of ‘get keen’.  There’s an enormous number of blogs and things on palaeobiology on the internet, and through the medium of Twitter you can get information on opportunities and palaeo news directly from palaeontological luminaries (or at least those luminaries who have Twitter).