Gallery and print store

Monday, 17 August 2015

A new book, Recreating an Age of Reptiles, coming this Autumn


Twitter and Facebook followers will be aware that teases of new artwork and allusions to a second book form the majority of my recent social media output. Today, the teases stop and the covers are coming off : Recreating an Age of Reptiles, a collection of my recent palaeoartworks, is due out later this year. I'm really thrilled to see enthusiasm from the online community for this project. Every time I mention this book I have someone ask a question or two about content, availability etc. With that in mind, I thought I'd provide some answers via a quick FAQ. I'll do my best to answer any further queries in the comments below.

1. So, what is this exactly?
Recreating an Age of Reptiles is a print-on-demand collection of my palaeoart from the last few years. Encouraged by a very positive social media response to the question of 'would people buy a book of my stuff?', I've been putting it together throughout the summer. The focus is on art, not text, and most of the latter focuses on the artwork more than the palaeobiology of the depicted animals. As I often attempt at this blog, it would be great to try to tackle both the scientific and artistic angles simultaneously, but there just isn't enough room for in-depth scientific discussion of each image. That said, I'm sure certain images will form the focus of articles here eventually.

2. How much new stuff is in there?
There's just over 60 images in the book, being a mix of new and old, with the bulk of it forming revised images from the last few years. Some of the revisions are substantial, but they're almost all to do with technique and colours: the compositions are very similar to the original versions. There are a bunch of completely new images in there too: giant vampire squids, the 'new look' Hatzegopteryx, Repenomammus and others. I've held back, or only partly revealed, many of those images, so hopefully there'll be plenty of surprises to even regular readers.

3. Any sketches or concept work?
Alas, no. To be honest, I don't really have any: working digitally removes a lot of need for dedicated drafting and conceptualising. I have included some older versions of concepts which have been redrafted several times where I think their evolution is particularly interesting.

4. What sort of format will this be in?
Pending some sort of formatting disaster with test versions, expect a full-colour, letter-sized (8.5 × 11", or 216 × 279 mm), soft-bound volume with 100 pages. I'm printing copies with Lulu, the same company that printed All Yesterdays and the Cryptozoologicon, so check those titles for an indication of quality (if you don't have copies of these, rest assured it's pretty good. Also, go buy those books! They're great, and All Yesterdays is a definite must-have if you're interested in my volume).

Draft cover art for what the kids are already calling RecARep.
5. Will there be a hardback version?
Sorry, no. I'd love to have a one too, but the costs are prohibitive for large, full-colour print on demand hardbacks. We're talking c. £100 for a 100 page volume - no-one should be spending that amount of money on a 100 page book. If anyone knows a way around this, I'm all ears, but I have no plans to pursue hardbacks at the moment.

6. What will this cost?
The likely pricetag is going to be £20-25 for each book. I know that's a little on the steep side, but the reality of print on demand is that each book costs nearly £20 just to produce - the profit margin here is not huge. Books published on a larger scale are made cheaper through bulk economy: alas, that's not an option here. That is, unless any publishers are reading and want to sign me up for a cushy deal...

7. Will there be a cheaper electronic version?
I expect so, although my focus is getting the physical version sorted first. An ebook should be available soon after.

8. 'Age of Reptiles'? What do you think this is, the 1950s?
A number of people have commented on the the title of this book, wondering why I've chosen the term 'Age of Reptiles' when it has connotations to more archaic views of many Mesozoic animals. There are a number of reasons I went for this title, not the least being that the world really doesn't need another tome entitled "[Something something] dinosaurs and other prehistoric creatures".

Firstly, the focus of the book is not just dinosaurs, or even Mesozoic archosaurs. These animals dominate, but there's sufficient other taxa in there to warrant a title which doesn't overtly emphasise specific groups of animals. Secondly, the term 'Age of Reptiles' accurately describes the time period covered in the book, it being popular parlance for 'Mesozoic'. Given the dream that a book like this might sell a few copies outside a hardcore palaeontology demographic, it seemed sensible to use phraseology which is widely understood. Thirdly, 'Age of Reptiles' resonates within palaeoart, it being the title of Zallinger's seminal 1947 Peabody Museum mural as well as Ricardo Delgado's Age of Reptiles graphic novels. The latter was a big influence on my childhood art, a fact not lost on me when choosing the title. Finally, our advances in dinosaur palaeontology in the last few decades have not stopped dinosaurs being members of Reptilia (the turtle, lizard + archosaur clade): ergo, the title is scientifically sound. I'm sticking with it.

9. Will there be signed copies?
Possibly. I'll figure that out later.

10. When is it out?
There's not a specific date yet, and the honest answer is 'when it's done'! All being well, that won't be very long off: there's some text to finish and proofing to do, and then we're good. I'm aiming for copies to be available mid-late Autumn.

Right, that should do for now - I'm happy to field any additional questions in the comments below, or on Twitter, Facebook etc. Thanks to all who've given their support thus far, and needless to say, there'll be updates soon.

Friday, 31 July 2015

Where next for the Jurassic Park movies?

Which creative direction would you take one of the most successful movie franchises of all time? Apparently, I would start by desaturating it of all colour. Read on to find out more.
To the surprise of no-one, the mega-successful, $1.5 billion box office juggernaut Jurassic World is getting a sequel. If you’re part of the broader contingent who thought the film was silly fun, that’s probably good news. If, like me, you thought the film was lacking in some areas, you may be less excited. Regardless, speculation is now rife about what the film will cover, and where it will pick up the sequel-bait left dangling at the end of the last film. Despite being less than bowled over with the Jurassic World, 22 years of investment in the franchise and obvious interest in the palaeo-theme of the series means I’m still curious about where this franchise goes. I’ve been involved in a lot of Jurassic World dissections online as well as with real human beings, throwing ideas around for what might work in another Jurassic instalment, as well as what could be maintained or improved on from the other films. The process has led to a lot of ideas and even some rough pictures which I thought I’d share here. Note this post contains mild spoilers for Jurassic World. 

Where the series stands

Any opinion about the future of a series is reliant on opinions of the existing products. Hence, it seems sensible to provide some context on where I think the Jurassic films stand before delving into ideas for new films. From conversations with others and reading lots of reviews, I get the feeling that my view is similar to many others: the Jurassic films are very samey, the sequels aren’t especially well structured, and the franchise needs fresh ideas. 

Let’s unpack that a bit. All four films have the same setting (tropical island theme parks which go wrong, or tropical islands where things have already gone wrong), similar characters (kids, a grumpy/cynical lead, a corporate scumbag, a romantic couple of two headstrong individuals) and the same major scenes (the ‘giant dinosaur vs. vehicle attack, which strands victims from civilisation’ scene, a Velociraptor chase, a panning shot of glorious dinosaurs in harmony with nature, exploring abandoned/ruined buildings etc.). Similarly, by at most the 50% run time mark, each film becomes the same 'chased by dinosaurs' skit. Even the new elements brought in for Jurassic World – dinosaur hybrids (we’ll get to those in a moment) – didn’t alter this: the role Indominus was interchangeable with that of the Tyrannosaurus or Spinosaurus from the previous movies. 

This repetition might stem from knowing what has pleased audiences in the past, but perhaps also the limited narrative scope available to the Jurassic films. Those elements more-or-less define the franchise, and jettisoning them risks losing much of what we identify with the brand. This is probably why the original Jurassic sequels were just the first film without the theme park-backdrop, and why Jurassic World was basically a ‘reimagined’ version of the original. All three follow-ups are extremely conservative from a creative perspective, mostly trading on nostalgia for the first film. It might be argued that this inability to move out of the shadow of the original might indicate Jurassic Park was better left as a contained, single story. I think there's some truth to that, but, whatever, the sequels are happening. It’s clear that avoiding/escaping (chose your own words there) sequel mediocrity is reliant on creativity being shot into the franchise in the form of a new direction or focus, or maybe even a genre transition. I'd wager that the success of the franchise relies on the next film pulling this off.

The right plot, and right level of complexity, is also important for the next film, because the last three movies have each had real issues with these. The first two sequels were seemingly bored and uninterested in their own story (The Lost World) or so underwritten that they seemed to just run out of ideas (Jurassic Park III). Jurassic World, by contrast, had enough going on to fill two or three films. The result was the same as being underwritten: poor characterisation, a loss of atmosphere and tension, and plot devices straining to get the story running. As an example, look at how brief and daft the release of hyper-dangerous Indominus was: folks who’ve watched this animal grow up are shocked they can no longer see her (so she waited years to do her camouflage tricks?); trained experts don’t check for basic equipment faults before waltzing into her pen without any concern or protection; trained experts get scared; trained experts open her cage door, allowing her to escape. Compare that to the original, where the very threat dangerous animals escaping is a key issue, built up over a long period of time. There's discussion from characters, establishment of the level of security across the island, introduction of important location, the animals are teased, and their escape is revealed via tense, iconic scenes. Jurassic World raced through this important, potentially dramatic story point so quickly and nonsensically that it had no weight or impact, as it did for virtually all other potentially interesting scenes, because there was so much else to cram in. With Jurassic sequel plots being either too simple, or too crowded. 

There are allusions that the Jurassic series recognises that it has issues with repetition, Jurassic World effectively rebooting the series to take the story off elsewhere. I must admit to not liking the direction being hinted at now - militarised dinosaurs, weaponised hybrids and so on – and hope they abandon them for the next film. To me, this is the least interesting direction this franchise can take, it being both a recognised story cliché as well as promising little more than extended CGI dinosaur battle sequences no more interesting than watching someone play a video game. 

And we already have lots of palaeoart which does that for us.
We're already at saturation point for movies like that, and despite their box office success, their appeal is not universal. I find it odd that we were all laughing at those abandoned human-dinosaur hybrid concepts for the fourth Jurassic film – but what Jurassic World hinted at isn’t a million miles off that. I'm sure there are lots of interesting ideas that could be explored without turning this franchise into live action Dino Riders.
All that said, if that's where I think we stand with this franchise, where do we go next?

Introduce a genuinely new fossil species: our own ancestors

Movie algebra dictates that primitive humans + dinosaurs + modern day setting = vehicular mayhem. 
The last two Jurassic movies have tried to add novelty by introducing new dinosaurs. The problem with this is that dinosaurs, as antagonists, only offer slight variations on a theme. So how about introducing something really different: put fossil human species into the films. I’m thinking specifically of early Homo species here: things with obvious anatomical differences to modern humans, but also similar enough that they could be played equally for eeriness or sympathy. This seems like such ripe ground for storytelling, and could be framed as a publicity seeking exercise in a park setting (museum exhibitions of our own fossil history are pretty popular after all, and apes are often 'star animals' of zoos) or as a nefarious means to have human-like subjects for commercial or scientific exploitation.

The social and ethical issues of creating, caging and exploiting very human-like species make for numerous interesting points of discussion and impetus for plot developments. Where is the line between caging an animal and a person? What rights do stem-humans have? What rights do artificially-created stem humans have? How would people react to seeing their own recent ancestry behind glass and fences? Is it right to use our close relatives for entertainment, and if not, where is the line between them and other animals? What I like about this concept is that strong messages can be implied with subtlety – even the design of human enclosures would be meaningful - allowing for an adventure story to play out with layers of subtext beneath. Our ancestors would also add a whole new dynamic to the franchise as antagonists, being resourceful, tool-using, intelligent and emotional adversaries. It’s easy to imagine how an escaped ‘movieised’ stem-human could really put a spanner in the works any smoothly running facility. From a filmmaking perspective, we could see this as bringing classic components of classic dinosaur b-movies (cavemen) to modern audiences, and minus the cheesiness associated with those characters: fur bikinis, grunting language and so forth. 

Do the ‘hybrid species’ thing properly

It was almost a given that the lacklustre design of the Jurassic World hybrid species will be brought up here, but for good reason: it was a huge missed opportunity. I know Indominus has defenders, but the design is just so uninspired and the potential wasted. For anyone familiar with palaeoart, Indominus is just an animated version of John Sibbick’s 1985 Allosaurus restoration, whitened and with spikes. For movie goers, the hyped abilities of the animal were pointless outside of two scenes, and pretty redundant even there. As is well known by now, artist Brian Engh launched the #BuildaBetterFakeTheropod Twitter campaign as a response to the dull design of Indominus, encouraging artists to upload more interesting concepts for a genetically modified dinosaur. What a treasure trove of ideas that turned out to be! There’s several images there which could be key drawings to launch whole movies. If you've not checked it out yet, go and take a look now. I can wait.

A 25 m long, pseudotoothed beastie with prehensile feet. It kills SUVs for sport.
What is readily apparent from these works is that there's real horror potential in the Jurassic films: it’s actually pretty easy to make a creepy, scary dinosaur antagonist, even if you just blend elements of modern and fossil theropods. Keep those guys off camera for as long as possible, shoot them in the dark and shadows, and we could have a movie full of scares akin to tenser scenes from the first Jurassic movie. If we’re after a genre shift, a Jurassic film akin to Aliens (which the last film already nods to) might be neat: a siege movie where the hybrid creatures are scary, rarely glimpsed, powerful and barely understood by the film’s characters. Or a film where human characters, lost in some wilderness, simply have to survive being followed and hunted by weird, dinosaur-like creatures while they search for rescue. There’s potential for some interesting character-led films there, the protagonists stewing in an increasingly tense, hopeless situation as strange-looking animals close in. Push that 12A/PG-13 rating to its limit!

"Say, did you remember to flick the gene for determinate growth?" "...whoops."
If not horror, then why not use the hybrids is to enter ‘classic’ monster movie territory? Make the creatures really outlandish and huge, ala those of 50s B-movies, and more like unleashing a natural disaster than a rouge animal. This was the idea behind the #BuildaBetterFakeTheropod entry above, which is a play on hyperbole already associated with dinosaurs as the 'biggest animals ever'. Well, this hybrid is quite literally the biggest animal ever: it makes blue whales look as impressive as tinned sardines. There’s enough movies out there about giant creatures aggressively attacking cities and towns however, so my suggestion would be to make such a creature sympathetic, more King Kong than Pacific Rim. Make it a freak loner, very much an animal in behaviour and attitudes, and persecuted for causing problems by simply existing: eating other dinosaurs to sustain itself (sauropods seem like ideal snacks for this thing) and causing masses of damage whenever it travels across built up areas. In doing so, there’s fun to be had with other species escaping just because this thing trod on an enclosure fence. A tragic ending is, of course, a must for this creature. 

I like the potential for exploring accountability from the Jurassic scientists with this one, real old-school ‘man has gone too far’ stuff, especially given the commercial drive underlying hybrid production in the last film. Some of this was alluded to in Jurassic World when the keeping of Indominus in isolation was discussed: the undercurrent was that scientists made an animal, then made a monster by treating it terribly. This theme was rapidly forgotten (and, indeed, contradicted later on: for an animal supposedly brought up in isolation and with no idea of its own identity, it could identify and communicate with Velociraptor pretty instantaneously…) but, as a seed of an idea, it’s a good one, and may warrant exploration in another film. Needless to say, there's plenty of scope here for spectacle as a giant theropod smashes its way around, as well as for exploration of themes about exploitation of science and nature in pursuit of profit.

Give some dinosaurs actual character, other than roary videogame protagonists

It's a bit like Born Free, but with more Awesomebro potential.
Another new element of Jurassic World was that some dinosaurs were actual characters, with names, motives and everything. Well, I say ‘motives’: like all characters in Jurassic World, their actions were dictated more by plot contrivances than personality. Still, though I expected to dislike all the Velociraptor wrangling stuff, the first few scenes of it showed more potential than I anticipated. I disliked the stuff later on because it just got silly – the motorcycle thing, the Velociraptor/Tyrannosaurus tag team – but a movie which explored that relationship in more depth, and then tested it in a way other than just fighting other dinosaurs, could be interesting. 

Such a story would need to spend more time establishing the dynamics of human/dinosaur interactions than the latest movie, but that needn’t be done in a boring way: Rise of the Planet of the Apes showed how summer blockbusters can work cross-species sci-fi dramas into fast moving stories with big climaxes. We’d need to show Velociraptor as more than just a perpetually roaring, biting machine, and see evidence of intelligence other than that pertaining to finding and killing. We’d also need to feel that it was vulnerable, and thus unlike the other Jurassic films where there’s no consistency to animal mortality (i.e. we see the same injuries happening to different animals, but only some are hurt because of plot demands). I can’t see this forming the focus of a whole movie, but as a concept, I think more could be done with it. Bonus points to the filmmakers if they make a sympathetic, believable dinosaur character, and then have it die at the end, perhaps when rescuing a small boy from a well or barn fire. We could call it Velassieraptors.

Finally, Hollywood knows de-extinction is a real thing, right?

Jurassic World 2: sauropods vs. ecological destabilisation. "The race is ON."
One of the questions commonly asked of palaeontologists is whether cloning extinct animals is ever going to happen. Since the original film, the answer to that has gone from a straight ‘no’ to a ‘well, actually people are genuinely trying to resurrect some recently extinct species’. The core sci-fi concept of the Jurassic films is now reality in the form of de-extinction, and the related idea of rewilding (recreating extinct ecosystems using extant animals, or clones of extinct animals, typically for the purpose of stabilising dynamics of ecosystem or certain habitats). Both are genuine areas of research and discussion, as well as no small amount of controversy. 

A lot of discussions around de-extinction involve the nitty-gritty of reconstructing genetic material (it seems to be extremely difficult to do, even with recently-extinct species), which probably wouldn't transfer that well to film. But both de-extinction and rewilding have pragmatic and ethical issues which are relevant to the Jurassic films. What do you actually do with a resurrected species, other than keep it in a zoo? Let it roam wild somewhere? How many individuals should you make? Who, or what, raises them to adulthood and teaches them how to be whatever they’re meant to be? Who is accountable for the wellbeing of an ‘artificial’ animal? Shouldn’t we be putting these efforts into saving extant species more than resurrected ones? What impact will releasing cloned animals have on existing ecosystems? How precisely do we control and manage these artificial ecosystems?

Bringing some of these to the fore might make for an interesting movie. What do you do with islands overrun with long extinct species? Odds are, most of them will die in the absence of artificially-supplied food sources, so who’s going to step in to sort that out? Should some animals be moved elsewhere to balance out their populations? Could animals be grown and engineered to rewild parts of the world in need of ecologically-stabilising, long-extinct large animals? (That's not hypothetical: such schemes are being proposed and trialled, for real, in many places across the Northern Hemisphere.) Again, there seems to be a wealth of scenarios and stories in those questions, and lots of scope for adventure: rounding up and figuring out what to do with free-roaming dinosaurs, the creation of a ‘Jurassic nature reserve’, moving and introducing dinosaurs into new places and habitats, protecting them from evil poaching types, keeping fledging ecosystems in balance… Lots of cool stuff.

Most importantly, it's not lost on me that this concept lends itself well to another touchstone of dinosaur fiction and film - freakin' dinosaur-wrangling cowboys. A film which gets to introduce the complexity of cutting edge, controversial conservation issues and features people rounding up dinosaurs on horseback? There’s not a single part of my brain that doesn’t like the sound of that. It could be like Valley of Gwangi but, you know… good when the dinosaurs aren’t on screen. 



OK, that’s my lot. Hollywood, I’m waiting by the phone. Any Jurassic movie ideas of your own? The comment field is below...

Thursday, 23 July 2015

A year of Tyrannosaurus rex artworks

A minor milestone was reached this week at my print store - there's now 50 different bits of art in there. Given that I only started selling prints less than a year ago, I'm happy to see some substantial growth in my catalogue already (albeit with some cheating - many are 'reworked' older pieces, rather than entirely new bits). Lots more will be available in the near future - I'm holding several bits back for various reasons, including a project I'll elaborate more on soon. Working on these in relative secret is why things have been a bit quiet around her for the last month.

Teasers of unreleased artwork: Troodon, Repenomamus, diminutive azhdarchid and Diplodocus. We'll revisit the reason for holding these back in due time.
Scanning through my shop revealed an unexpected bias in my output this year. I make an effort to portray varying subjects and taxa, and find most interest in reconstructing lesser depicted species, scenarios and behaviour. I don't think I do too badly with this - at least within the context of Mesozoic reptiles - so was surprised to find 5 images dedicated to the same species, and one which has been painted, sculpted, animated and rendered to death: Tyrannosaurus rex. Two of these were commissions, but that still leaves three on my own head. I'm forced to concede that I must be a closet Tyrannosaurus fan - I had no idea.

I thought it would be fun to show the last year's worth of king tyrant art: some of them may still be fresh in your memory, but two are new (well, reworked). I realise that I've almost got a growth series across these images, and I've ordered them according to this. As usual, you can grab high quality art prints of these from my store.

Tyrant dinosaurs vs. bees. Bees are winning. Click here for prints.
First up is my tyrants and bees, the image I created to raise money for various bee charity causes in February of this year. Auctioning a framed version and sales of prints raised £249 for the Bumblebee Conservation Trust and a £30 contribution for a new beehive at the Cumberland House Natural History Museum, who also received the image for use on a display board. As you may remember, it shows two infant tyrants checking out a honey bee nest, molecular data indicating that honey bee ancestors were alive in the Late Cretaceous. My favourite bit of the image remains the smaller animal on the right, losing the battle with tiny arthropods. I like the fact its arms aren't really long enough to cover its eyes.

Resting rexes, and bonus moths. Click here for prints.
Next is Chidumebi Browne's reclined teenage Tyrannosaurus commission, from November 2014. These animals are heavily based on BMRP 2002.4.1, the probable half-size Tyrannosaurus with proportions and facial structure quite different to large adults. Of course, some would argue that this makes this image feature Nanotyrannus, but I don't want to get into that here. Those wanting to open that can of worms may want to read Thomas Carr's blog post (and comments) on this topic, as well as Mark Wildman's take on the same debate. 

Dating tip: romantic sunsets don't count for much when you're crushing your partner's skull. If you fancy a physical copy of this scene of violent tyrannosaur copulation, you might be a bit odd. Nevertheless, prints are here.
Something new now - a reworked take on my mating, neck-biting tyrants. Those with long memories will recall the first guise of this image appeared in 2013 with my comments on All Your Yesterdays, the crowd-sourced follow up to All Yesterdays. As explained in that post, a number of tyrants show evidence of having been bitten around the jaws and head, with the area around the braincase of some specimens being badly damaged. I'd been looking at Savannah monitors shortly before rendering the original of this, and found their toughened neck skin - which apparently exists because of rough copulatory behaviour - of interest. I tend to have half my mind on prehistoric animals when looking at modern ones, and it wasn't long before I was wondering if some Tyrannosaurus injuries were the result of similarly violent nuptial encounters. This reworked version includes some very minor anatomical tweaks, slight colouration changes, and a vastly more detailed background.

Triceratops and Tyrannosaurus: finally bro-dogs. Get printed up here.
Another commission from Chidumebi Browne resulted one of the strangest pictures I know of featuring Tyrannosaurus - but hopefully one which is interesting and thought provoking. Alongside this big female (note the similar colour to the red teenage animal in Chidumebi's first commission - this is the grown up version of a female in that 'universe') is a baby Triceratops, the idea being that it's been interspecifically adopted by the tyrant. I provided a long commentary on this image and the likelihood of the scenario back in March, concluding that this image might not be as crazy as it first seems. Quite a few modern animals - including dinosaurs - are known to kidnap or inherit the offspring of other species, although there's not always clear explanations for why it happens. I tried to imply a bit of a story in Chidumebi's concept, those marauding adults in the distance taking clear, hungry interest in the Triceratops infant. I get the feeling this scene wouldn't stay peaceful for long.

A Late Cretaceous evening, ruled by an especially robust tyrant. You can own a copy of him if you click here.  
Finally, one more new image: a major overhaul of one of the first images posted at this blog (end 2012). Changes include anatomical tweaks, a revised pose (now trotting, not standing), new colouration (the cranial pattern is a nod to the judge helmets in Dredd, because scientists predict Tyrannosaurus are some of the few things in life more badass than that movie) and a heck of a lot more background detail. The depicted animal is a 'robust' Tyrannosaurus morph - note it seems the 'robust' and 'gracile' forms are extremes of anatomical variation rather than distinct categories. My goal here was to make the animal look big and heavy - appreciating that tyrants are relatively long-legged and gracile for their size, they're still absolutely huge. I thought of bears a lot when painting this chap - I wanted him to have that same imposing aspect without going all 'awesomebro' on it. Tyrannosaurs - especially big ones - should look like animals you'd instinctively keep a good distance from.

OK, that's all for now. Soon, hopefully, some details on that project alluded to above. 

Thursday, 25 June 2015

On Jurassic World and real 'raptors': Velociraptor, Deinonychus and Achillobator

The online palaeontological community has no shortage of words on the recently released Jurassic World movie – most of them concerning the deplorable disregard for the last two decades of dinosaur science. What of the movie itself? The critical response seems to divided, most reviewing it as a great popcorn movie, and the rest as a predictable, sexist and cynical summer film. My own take is the latter: Jurassic World was just another forgettable, contrived entry in the Jurassic Park franchise, best noted for having the worst effects, silliest plot, and most outmoded characters of the entire series. Never quite sure if it’s making fun of modern franchise culture or revelling in it, the convoluted story revolves around (SPOILER ALERT) hokey family values, dinosaur-dinosaur team ups, dinosaur-human team ups and weaponised artificial species to form a plot akin to a particularly dumb, low-grade B-movie. There are some good ideas in there that could, in isolation, make for interesting science fiction, but there’s so much going on that nothing has a chance to develop: plot threads are introduced, contradicted and abandoned with rapidity. Most of the story is churned along by really contrived, forehead-slappingly stupid decisions made by the characters, and the pandering to the ‘awesomebro’ crowd is, at times, shameless. Was I the only person cringing when two characters told us, in weirdly meta-fashion, how ‘awesome’ and ‘badass’ they thought the (already shark-jumping) motorcycle/Velociraptor scenario was? In all, while I can’t say I strongly disliked Jurassic World, its few redeeming features are undermined by the contrivances, tropes and fan-servicing, over-stuffed plot, and flat characters. After two other disappointing sequels, Jurassic World is yet another demonstration that the Jurassic franchise really needs to evolve away from the original film to remain interesting. Predictably, it’s made a truckload of money already.

Anyway, this isn’t a review of Jurassic World: we’re here to talk about dromaeosaurs (yeah, not ‘raptors’: sorry, Jurassic fans, but another set of dinosaurs have held priority to ‘raptor’ since 1873). The velociraptors are back in force in Jurassic World, in all their leathery-skinned, broken-wristed, overtoothed glory. Of all the Jurassic World dinosaurs, the velociraptors have moved furthest from being relatively ‘believable’ animals in the first movie to the realm of true sci-fi monster. By Jurassic World, the behavioural and physical attributes they’ve gained in each sequel has finally made them totally unstoppable killing machines, demonstrably invulnerable to all damage except when the script calls for it (and thus largely removing their potential for being thrilling characters or antagonists. Oh, wait, we're not reviewing the film!). Inspired by their movie cousins, I thought I’d share some recently completed dromaeosaurid palaeoart here. Without appreciating it, presenting these three images together acts as a foil to the Jurassic depiction of dromaeosaurs, showing these animals as exploitative and flawed creatures, and as products of natural evolution, rather than reptilian versions of Geiger’s Alien. As usual, prints of all these images are available to purchase from my print store.

Velociraptor: picking on the little guy

Famous dromaeosaurid Velociraptor mongoliensis chases a juvenile oviraptorosaur, Citipati osmolskae. The oviraptorosaur parent doesn't approve.

First up is Velociraptor mongoliensis, the dog-sized namesake of the Jurassic dromaeosaurs. In this revised image (the first version of which topped another Jurassic World inspired piece) Velociraptor is shown predating a much smaller theropod, a juvenile oviraptorosaur Citipati osmolskae. The idea emphasised here is that, like most predators, Velociraptor probably hunted easily dispatched and overpowered prey, like juvenile animals, rather than larger, more dangerous individuals. A distressed oviraptorosaur parent is shown in the background as attempting to scare the predator off, arms extended, jaws agape, probably making a lot of noise. It strikes me this is the ‘classic’ palaeoart pose so often depicted as leaping from canvases to our faces – I think it works a lot better in the context of a full scene rather than in isolation. The Velociraptor is adorned with two small feather fans on its snout, structures for which we have no direct evidence, but which don’t seem too audacious in light of some cranial display features of modern predators.

Deinonychus: superklutz

Deinonychus antirrhopus: Deadly. Savage. Clumsy.

Next is another famous dromaeosaur, the North American species Deinonychus antirrhopus. This image was commissioned by ReBecca Hunt-Foster for the Utah Bureau of Land Management, as part of a public display on the Mill Canyon Dinosaur Tracksite. This Cedar Mountain Formation locality, once a scummy, slimy shallow body of water, preserves a multitude of sauropod, ornithopod and theropod tracks, including several belonging to dromaeosaurs. We call these tracks Dromaeosauripus, and at Mill Canyon their most likely trackmaker is Deinoynchus, it being a Cedar Mountain Formation species of correct stratigraphic provenance and appropriate size to make these specific Dromaeosauripus traces. Some of the Mill Canyon Dromaeosauripus tracks record running animals, which is pretty neat: it’s hard not to wonder what impetus made these animals charge over the Mill Canyon microbial mat 100 million years ago.

Alongside some of these tracks are long gouges in the ancient mud seemingly made by two-toed animals losing their grip on the substate, wobbling about before regaining their balance – are these the tracks of noble Deinonychus almost falling over? Quite possibly, although it’s not definite that they record the same individuals as those leaving the charging Dromaeosauripus prints.

ReBecca thought it would be fun to demonstrate that some Mill Canyon dinosaurs weren’t the most sure-footed of creatures, and requested my services to do so. I was happy to do this. In any sustained bout of animal observation it becomes apparent that all species routinely trip, slip and blunder about in the way that we do, and recreating this seemed a wonderful alternative to our regular diet of epic and ‘awesome’ palaeoart. The fact this image features Deinonychus is even better: even outside of Jurassic Park, dromaeosaurs are regularly depicted as particularly ferocious, cunning predators, earning them the nickname of ‘lions of the Cretaceous’. Well, awesomebros, here's our noble, cunning Cretaceous lion picking a whole bunch of oopsie-daisies, while a couple of normal Deinonychus prey items – Tenontosaurus – look out from the far distance and laugh.

Achillobator: giant dromaeosaur, silly hat

Giant Mongolian dromaeosaurid Achillobator giganticus ominously excavating the burrow of a small dinosaur. Azhdarchid pterosaurs gather to collect the dislodged bugs.

The Late Cretaceous, Mongolian species Achillobator giganticus is not a household name, but that may well change over time. This species is large bodied (only second to Utahraptor in the dromaeosaurid size game) and robust, bearing a deep snout, stout limbs and a large set of hips. It probably wasn’t a fast runner, but all indications are that it was a powerful predator suited to wrestling and grappling, perhaps ideally suited to ambushing larger prey. In this illustration, I’ve speculated that the powerful limb girdles and appendages of Achillobator are for a specific purpose: digging out and killing burrowing reptiles. Lots of tetrapods, including lineages around in the Mesozoic, were burrowers: fossorial activities are known in extinct and modern dinosaurs, as well as crocodylomorphs, certain lepidosaurs, and stem-mammals. The Mesozoic was thus likely full of burrowing species, and it’s not crazy to think that powerful predators could trap and excavate these animals from their own homes with the right equipment. In the scenario depicted above, the robust feet and enlarged hips of Achillobator make for powerful digging tools, while the short but powerful arms are ready to catch and grapple with escaping animals. If their prey doesn’t emerge voluntarily, those feather crowns will block burrow entrances once the head and jaws are inserted to extract the animals directly – this is a nod to the cranial form of Tibetan foxes, which have wide heads for the same purpose.

Of course, this image and concept is little more than an All Yesterdays-style speculation – to be honest, we don’t really have enough of the Achillobator skeleton to know exactly what it did for a living. Nevertheless, following another run with the Jurassic movies, I find it refreshing, grounding and intriguing to think of large dromaeosaurs as real products of evolution, as creatures adapted to the environment they lived in, and the species they coexisted with. As is often the case, reality ends up being far more interesting than fiction.

OK, that’s all for now. If you’d like to know more about the diversity of ‘real’ dromaeosaurs and other feathered dinosaurs, I heartily recommend Matthew Martyniuk’s excellent Field Guide to Mesozoic Birds and other Winged Dinosaurs.

Friday, 19 June 2015

New paper: walking with early pterosaurs

Non-pterodactyloids like Dimorphodon macronyx are meant to be slow, sprawling terrestrial locomotors. So what's up with this image of one running with erect limbs? Read on... Prints of this image are available.
Readers interested in flying reptiles will know that a recent, major paradigm shift in our understanding of these animals concerns their terrestrial locomotion. In short, perceptions of pterosaurs as awkward, clumsy terrestrial creatures have been overturned to models of upright, proficient walkers and runners. This reinterpretation is founded on a substantial amount of evidence from skeletal anatomy, trackway data, as well as reconstructions of muscle kinematics, and underpinned recent proposals of terrestrial foraging in some pterosaurs (most famously of course, the azhdarchids - read this for an overview of their research history) - famously stark departures from classic views of pterosaur palaeobiology. However, it is really only pterodactyloids, that group of Jurassic-Cretaceous pterosaurs which contains the majority of pterosaur diversity, that much of this work on terrestriality really applies to. It seems all pterosaur tracks are actually pterodactyloid tracks; most 3D fossils we've used to understand limb joints and motion are pterodactyloid fossils, and most detailed discussions of step cycles, stride lengths and so on are based on pterodactyloid proportions.

Non-pterodactyloids are considered somewhat differently. Our views on early pterosaur walking and running are less researched and more controversial than those of pterodactyloids, and we've seen several ideas on this topic emerge since the 1980s. These include non-pterodactyloids as bird-like bipeds (briefly discussed here); as slow and terrestrially ineffective lizard-like quadrupeds; as quadrupeds which were adept climbers; or quadrupeds with sprawling forelimbs but erect hindlimbs, which had to run bipedally. From these, the notion of early pterosaurs as particularly laboured terrestrial locomotors has emerged dominant. In several cases, this perception has been important when interpreting pterosaur history and biology: how early pterosaurs foraged, their roles in Mesozoic ecosystems, and patterns in their fossil record have all factored in the terrestrial ineptitude of the first flying reptiles (e.g. Unwin 2005; Ősi 2011; Butler et al. 2013). There are three core assumptions forming the foundation of non-pterodactyloid terrestrial incompetency:
  1. The broad, hindlimb-spanning membrane (uropatagium) of early pterosaurs 'shackled' their hindlimbs, preventing anything but slow, shuffling gaits
  2. The absence of pterosaur tracks before the Middle Jurassic demonstrates that these animals rarely walked, allegedly because they were so awful at it
  3. The sprawled limbs of pterosaurs made quadrupedal terrestrial locomotion slow and difficult. 
Pterodactyloids, with their fully erect limbs and split uropatagia, freed themselves from these constraints and 'terrestrialised' the group, leading to the formation of a track record which roughly corresponds to the earliest occurrences of pterodactyloid remains.

All this sounds fine, until the realisation hits that many of these assumptions are on somewhat shaky logical ground. Indeed, available data and well-known specimens can be used to undermine them to the extent that we might want to reconsider the whole 'terrestrially inept non-pterodactyloid' concept. In a new paper, published this week in PeerJ, I've attempted to do just that, outlining how we probably know a lot less about the terrestrial prospects of non-pterodactyloids than some suggest, and that some of our chief assumptions about these animals may very well be incorrect. Being a PeerJ paper means you can read the whole thing for yourself, for free (along with the review history) but let's summarise the main points here, tackling each of the points raised above in turn.

1. Large hindlimb membranes ‘shackled’ early pterosaur legs

Pterosaur and bat uropatagia compared. A, tracing of Sordes pilosus fossil, showing one of our best known uropatagia specimens; B, reconstruction of Rhamphorhynchus skeleton, mapped out with likely membrane distributions for non-pterodactyloids; C, terrestrially-competent vampire species Desmodus rotundus, complete with uropatagium rather like that of non-pterodactyloids. From Witton (2015).
Notions that the proportionally large hindlimb membrane of early pterosaurs (above) would impede terrestrial locomotion are not based on much in the way of detailed analysis of pterosaur soft-tissues. It really is just the size of the membrane, and the fact it was anchored extensively across the leg and fifth toes, which suggests it impeded terrestrial activity. Evidence that this membrane was particularly stiff or unyielding has not been presented, unlike other parts of pterosaur wings, which seem to have been stiffened and reinforced by long fibres. To the contrary, several workers have suggested that pterosaur uropatagia were probably as elastic as other membrane tissues close to the pterosaur body (Unwin and Bakhurina 1994) – those which were flexible enough to permit huge strides and running behaviours recorded in pterosaur trackways. In light of this, suggestions that this organ 'shackled' their hindlimbs seem a bit odd.

Moreover, there are plenty of modern animals with analogous uropatagial structures which locomote terrestrially without problem – examples include several bats with terrestrial capabilities described as being ‘rodent-like’. Many of them even make habits of grounded foraging, digging, crevice-crawling, running, climbing and other complex behaviours. All this occurs without their membranes being damaged, snagged or being otherwise restricting locomotion. Much of this is aided, it seems, by uropatagia being elastic, shrinking away when their limbs are not in flight configuration. Of course, there are some animals with large hindlimb membranes which aren’t particularly hot on the ground, but zoologists have labelled aspects of limb strength and myology as more important here than membrane size. This seems to be a second complication for the idea that large uropatagia were problematic for walking in the way suggested by some pterosaur workers. In concert with what we know of pterosaur membrane anatomy, I'm left wondering what, if any, deleterious effect non-pterodactyloid hindlimb membranes had on their terrestrial prospects.

2. Trackways = terrestrial proficiency

I must admit some surprise that a number of pterosaur workers consider trackway presence and abundance to correlate with terrestrial competency. This is especially so because it is widely acknowledged that the pterosaur fossil record, and that of early pterosaurs in particular, is generally poor. This is not to say that a deficit of early pterosaur tracks is definitely meaningless, but negative evidence is only significant when all other factors are accounted for. To appreciate the deficit of early pterosaur tracks as significant, we’d ideally want to have a good understanding of pterosaur ecology and behaviour, as well as their abundances in habitats suitable to track making. Neither of these are the case at present. Moreover, the track records of many Mesozoic animals are poor, even those which, on paper, have vastly greater track-making potential than early pterosaurs. Examples include widely distributed, entirely terrestrial clades like certain dinosaurs, crocodylomorphs, and mammaliaforms. Even relatively recent, large bodied terrestrial animals – like ceratopsids and tyrannosaurs – have track occurrences countable on the digits of one hand, despite their increased bulk ensuring that they leave deeper, long-lasting and theoretically more-preservable prints. Needless to say, applying 'pterosaur logic' to these animals - assuming that they avoided making tracks because of terrestrial ineptitude, and were reliant on other means of transportation - leads to some... interesting ideas on other potential forms of locomotion.

Revised locomotion in tyrant dinosaurs, ceratopsids and mammaliaforms, brought to you by the 'no footprints = terrestrial competency' hypothesis.
Of course, no-one thinks the lack of footprints in these groups is anything to do with terrestrial competency. The fossil record is full of strange quirks reflecting a secret recipe of ancient animal behaviours, taphonomy, sampling, interpretation, and plain serendipity, so scare track data may have no significance at all. Or it might. We don't know, because we can't account for all variables. But that doesn't matter, because what we can do is use available data - that of limb functionality - to draw conclusions about the terrestrial prospects of these groups. That has to trump an absent track record, because we cannot test the significance of our conclusions on a negative dataset. Until we know more about early pterosaur functionality, ascribing the absence of a footprint record to their terrestrial capacity is probably getting ahead of ourselves, and puts the approach of pterosaur researchers at odds with other branches of vertebrate palaeontology.

3. All non-pterodactyloids had sprawling forelimbs

I’m going to cut to the chase here by pointing out that evidence for sprawling pterosaur hindlimbs is not especially strong – most arguments made to support it are now a little old-school, to the extent that they conflict with modern approaches to assessing limb joint function. There’s been a lot of work done on pterosaur hindlimb posture and it seems all flying reptiles had at least upright hindquarters - let's leave that there. But what about sprawling forelimbs? Certainly some early pterosaurs – specifically rhamphorhynchines, and probably ‘campylognathoidids’ - had to sprawl, because their glenoids (shoulder joints) restricted movement of the humerus below the shoulder itself. Their articular surface allows for plenty of room for movement above the shoulder, and some room for fore-and-aft motion, but a large bony ridge prohibits the forelimb adopting anything like an upright pose. This isn't controversial: several authors have already noticed this.

However, several non-pterodactyloid specimens seem to have rather different glenoid morphologies to those of rhamprhorhynchines and 'campylognathoidids'. Species like Dimorphodon macronyx, and perhaps some wukongopterids, have shoulder girdles which lack that ventrally-restrictive bony stop. Instead, their glenoids which are ventrally open, the articular surfaces wrapping around the underside of the glenoid body to meet the shoulder girdle itself rather than a jut of bone. This morphology is borne out by several three-dimensional Dimorphodon glenoid specimens and is unlikely to represent chance distortion of a glenoid into a more 'open' morphology. These specimens seem to indicate that at least some early pterosaurs were capable of tucking their forelimbs underneath their bodies.

Variation in early pterosaur shoulder girdles. Images on the left shown the shoulder joint of Dimorphodon macronyx - note how the (shaded) articular surface extends to the underside of the glenoid (bottom image, and left photograph) to make a ventrally-open shoulder joint. By contrast, the glenoids of certain other non-pterodactyloids (images top right) have articular surfaces only on the dorsal and lateral glenoid surface: the ventral is blocked by a bony ridge. In this morph, the humerus clearly cannot rotate much beneath the shoulder at all. A schematic of the ranges of motion offered by these two shoulder types is shown at bottom right. From Witton (2015).
It’s not a given, however, that the ability to fully adduct a limb correlates with a habitually upright stance: range of motion alone tells us little about habitual joint postures. Is there anything in early pterosaur anatomy to suggest which forelimb postures these animals preferred? Potentially, yes: the end of their humeri. Recent work on the forelimbs of quadrupedal tetrapods has identified anatomical correlates of routine sprawling and erect postures in elbow skeletons (Fujiwara and Hutchinson 2012). Because these joints have to take the strain of standing, different poses emphasise the development of characteristic muscle groups and their corresponding bony attachment sites. Having positively tested this thoroughly on modern animals, we can start to use it on fossil ones, including pterosaurs. Fujiwara and Hutchinson (2012) have already looked at pterodactyloid humeri and suggest they have all the right features for an upright limb. Ergo, if we see pterodactyloid-like humeral morphologies in earlier pterosaurs, they might have had upright limbs, too.

Pterosaur humeri in anterior view, showing variation in distal humeral shape in non-pterodactyloids (A–F) and pterodactyloids (G–I). A-B, Dimorphodon macronyx; C, Archaeoistiodactylus linglongtaensis (a likely wukongopterd); D, Rhamphorhynchus muensteri; E-F, Dorygnathus banthensis; G, Pteranodon sp; H, Montanazhdarcho minor; I, Dsungaripterus weii. Note how Dimorphodon and Archaeoistiodactylus are far more pterodactyloid like in humeral morphology than Rhamphorhynchus or Dorygnathus: does this implicate erect limbs in some early pterosaur species? Scale bars represent 10 mm, except for G and H, which equal 50 mm. From Witton (2015).
As with shoulder anatomy, it turns out there some potentially significant variation here. Rhamphorhynchines and (probably) 'campylognathoidids' - taxa seemingly confined to sprawling - have humeri which are quite different from those of pterodactyloids. Their elbows are very narrow, being little wider than the condyles necessary to articulate the forearm. This fits well with the predictions of Fujiwara and Hutchinson, because we would expect pterosaurs confined to sprawling to have different anatomy to tall-standing pterodactyloids. Dimorphodon and wukongopterids - those pterosaurs with less restrictive shoulder joints - have a different elbow anatomy however: a distal humerus which is broadly expanded beyond the margins of the forearm articulations. In virtually all details, these humeri have distal ends very similar to what we see in pterodactyloids and, all else being equal, that might imply a similar loading regime at their elbows. We might take this an an indication that upright postures were adopted regularly in these non-pterodactyloids, which marries nicely with observations made about their ability to tuck their forelimbs under their bodies. The idea that Dimorphodon and wukongopterids were also sprawlers is less parsimonious because we have to explain why some early pterosaur humeri don’t resemble those of obligate sprawlers, but instead look so similar to those of pterosaurs we’re confident had erect forelimbs.

This observation might be quite significant for considerations of terrestrial abilities in early pterosaurs. Sprawling postures are not as restrictive to locomotion as some pterosaur literature suggests (sprawling does not limit its users to slow crawling, and is actually quite useful for certain habits, like climbing or accelerating quickly), but there might be something to the idea that upright locomotion is better for sustained, active terrestrial habits. Indications that the likes of Dimorphodon and wukongopterids were capable of walking on fully erect limbs, without impedance from their uropatagia, suggest they have greater terrestrial potential than previously anticipated. Perhaps our views on the likely habits of non-pterodactyloids might benefit from further research.

Further indications of terrestriality?

The possibility that some early pterosaurs had erect forelimbs is only one indication that these taxa may have been more terrestrially adept than we’ve previously considered. I think our views on these animals have been biased by the familiarity of taxa like Rhamphorhynchus: these sprawling, slender-limbed species with oversize forelimbs don’t look like the hottest terrestrial locomotors in town (see Dorygnathus illustration, below), and this perception may have bled into our consideration of non-pterodactyloids as a whole. In actuality, taxa like Dimorphodon, Preondactylus, anurognathids and others have pretty chunky, proportionate limbs: we could take their wing fingers away and they still look capable of looking after themselves using terrestrial locomotion alone. Several authors have noted features indicative of strong running and leaping abilities in early pterosaur hindlimbs, and this might apply to their forelimbs too.

It’s also intriguing to note that some features found in pterosaur digits – sesamoids immediately above and behind their claws – are only otherwise found in terrestrial reptiles (lots of squamates and one fossil stem-turtle, Proganochelys). No-one seems to know exactly what function these antungual sesamoids perform, but I've speculated that they are related to claw contact with hard surfaces. Sesamoids seem to mostly offer two functions: enhancing joint leverage or protecting tendons from extremes of motion. Claws routinely deflected backwards by contact with substrata might necessitate a bony element in the tendon to ensure nutrient flow to the tendon is maintained, or else to facilitate better leverage when actively hyperextending claws to prevent claw blunting. It's difficult to think what else a sesamoid above and behind a claw can really help with, especially given their occurrence in animals as different as pterosaurs, lizards and a stem-turtle. I'm not the first to suggest pterosaurs could retract their claws (Frey et al. 2003), and some sort of hyperextension would explain the large digital articular surfaces seen in pterosaurs with antungual sesamoids compared to those lacking them. Again, there is clearly need for more research here, but the take-home is that this anatomical aspect of non-pterodactyloids is only mirrored in terrestrial animals, and might present another feature signifying greater terrestriality than expected in early pterosaurs.

Tying this all together

A 'traditional' view of a non-pterodactyloid standing posture: Dorygnathus banthensis with sprawling forelimbs. How the development of this feature fits into pterosaur evolution remains to be seen: earlier pterosaurs (both stratigraphically and phylogenetically) may have stood quite differently. Prints of this image are available.
It's noteworthy that features proposed as potentially signifying terrestriality in early pterosaurs are not neatly mappable to any current concept of non-pterodactyloid phylogeny. Even comparatively simple models of early pterosaur evolution show complex changes in shoulder girdle morphs, humeral anatomy and and limb robustness as we trace evolutionary pathways up the tree. Nevertheless, the potential for upright postures, running behaviours and other features of proficient terrestriality seem deeply rooted in Pterosauria because some of the oldest, 'most basal' pterosaurs possess such indicative anatomy. A lot of what is said here complements ideas already in pterosaur literature. To use a well-studied example, there are lots of hints that the Lower Jurassic Dimorphodon was terrestrially adapted: it seems proportionally heavy to the extent of impeding flight potential, has been strongly suggested to have a diet of insects and small vertebrates, and has a suite of features suited to climbing (see the previous post). Combine these with the possibility of erect limbs, subcursorial limb proportions, robust extremities and so on, and we've got a pretty good argument for Dimorphodon being terrestrially competent, and maybe even adapted for a primarily terrestrial existence. It's hard to think of a lifestyle more opposing to traditional interpretations of non-pterodactyloid palaeobiology than that, but a multitude of disparate research projects seem to be collectively pointing that way.

In all, my point for writing this synthesis paper is to demonstrate how little we've really looked into the terrestrial prospects of early pterosaur species. If even basic variation in their limb arthrology remain poorly studied, how can we claim to understand their terrestrial prospects or plug our models into our Big Picture of Pterosaur Evolution? Even if everything I've said here ends up being challenged, I hope at least this new paper stimulates some detailed research into this rather poorly explored area of pterosaurology. Until that happens, my suggestion is that we avoid blanket-statements about the terrestrial prospects of non-pterodactyloids.

Those interested in early pterosaur funky morph might be interested to know that I'm talking about the flight performance of Dimorphodon at Flugsaurier 2015. Registration is open until 30th June, so get your interest registered quickly!

References

  • Butler, R. J., Benson, R. B., & Barrett, P. M. (2013). Pterosaur diversity: Untangling the influence of sampling biases, Lagerstätten, and genuine biodiversity signals. Palaeogeography, Palaeoclimatology, Palaeoecology, 372, 78-87.
  • Frey, E., Tischlinger, H., Buchy, M. C., & Martill, D. M. (2003). New specimens of Pterosauria (Reptilia) with soft parts with implications for pterosaurian anatomy and locomotion. Geological Society, London, Special Publications, 217(1), 233-266.
  • Fujiwara, S. I., & Hutchinson, J. R. (2012). Elbow joint adductor moment arm as an indicator of forelimb posture in extinct quadrupedal tetrapods. Proceedings of the Royal Society of London B: Biological Sciences, 279(1738), 2561-2570.
  • Ősi, A. (2011). Feeding‐related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet. Lethaia, 44(2), 136-152.
  • Unwin, D. M. (2005) The pterosaurs from deep time. Pi Press.
  • Uwnin, D. M., & Bakhurina, N. (1994). Sordes pilosus and the nature of the pterosaur flight apparatus. Nature, 371(6492), 62-64.
  • Witton, M. P. (2015). Were early pterosaurs inept terrestrial locomotors? PeerJ 3:e1018; DOI 10.7717/peerj.1018

Monday, 8 June 2015

Why Dimorphodon macronyx is one of the coolest pterosaurs

How to make Dimorphodon macronyx fly: chase it down with a Sarcosaurus-like dinosaur. The most recent illustration of the 'reluctant flier Dimorphodon' hypothesis, based on predicted wing parameters of this heavyset pterosaur. Prints of this image are available.

With Jurassic World about to start assaulting the box office and intelligence of palaeontologists around the globe, it seems appropriate to take a look at some of the science behind the animals featured in the film. Being just about to move house (copious books and fossils = Worst. Moving. Experience. Ever.) means I can't write about them all, but we have time to look at one of the pterosaurs they're featuring, and coincidentally also one of my favourite fossil species: Dimorphodon macronyx. I was quite chuffed to hear Dimorphodon was going to make it to the big screen, but... oh dear. Poor Dimorphodon has been really mangled by the infamous reconstruction approach of the Jurassic World film makers, and the information on their website is really awful - powerful talons for snatching fish? Seriously?. From what we've seen so far at least, I wonder if it's one of the worst reconstructions in the film.

"Now that is one big pile of..." From the Jurassic World wikia.

Clearly, the Dimorphodon of Jurassic World is going to be nothing like the Dimorphodon known to researchers. OK, that's hardly a shock, but it's a shame nonetheless. Dimorphodon is not a theropod-headed scaly dragon, but an especially interesting and significant animal to pterosaur researchers. I'm involved in several Dimorphodon related projects at the moment - one should see fruition next week - and thought I'd share some of the basis for my fascination here.

OK, smart guy, what was Dimorphodon really like?

Dimorphodon is one of the best known early pterosaurs. Seemingly unique to Lower Jurassic rocks of Dorset, UK (Mexican material previously referred to Dimorphodon likely represents a different taxon), it is perhaps the oldest pterosaur known from anything like three-dimensional remains. This doesn't include skull material, which is always preserved with the topography of a pancake, but much of our Dimorphodon limb and body fossils have some, if not entire, three-dimensionality to them. Although a complete skeleton has never been found, several half- or near-complete specimens are known along with a lot of associated material. The upshot of this is that a fairly decent understanding of Dimorphodon osteology has been held for almost 150 years (so, yeah, the Jurassic World animal is less accurate than renditions put together by Victorian palaeontologists. It's not the only Jurassic World species to suffer this sort of problem). With most older pterosaur fossils being either mere fragments or entirely squashed skeletons, Dimorphodon represents an important insight into early pterosaur anatomy. This is especially so because some aspects of its skeleton - particularly jaw shape, dental anatomy and wing proportions -indicate it is a rather 'plesiomorphic' species, closely related to some of the oldest known pterosaurs, such as the Triassic taxa Peteinosaurus and Preondactylus. This might make it particularly informative as goes the anatomy of the first pterosaurs, with all sorts of potential for investigating their locomotion and ancestry. It must be said that this is only one interpretation of Dimorphodon phylogenetics however: the interrelationships of early pterosaurs are particularly contentious, and other workers suggest it plots much further away from the base of the pterosaur tree.

Restored Dimorphodon macronyx skeleton. From Witton (2013).
Dimorphodon is widely known for its dentition, its 'two form teeth' providing a generic namesake. The larger teeth of Dimorphodon are sometimes incorrectly portrayed as splaying from its jaws, somewhat like those of rhamphorhynchine or ornithocheird pterosaurs. So far as we can tell, though, they were more-or-less vertically orientated. These bigger teeth possess carinae - cutting surfaces running along the anterior and posterior dental margins. Only the posterior region of the lower jaw has the second type of tooth - very small, sharp cusps which are positioned at regular intervals to make the jaw resemble a hacksaw blade. These were clearly the subject of heavy use in life: some specimens possess broken tips.

D. macronyx tooth morphologies. Note the broken tooth exploded from the main image. From Ősi (2011).
Its not only teeth which make Dimorphodon characteristic, however. The size of the skull is quite remarkable compared to other early flying reptiles, and a forerunner to the trend of large skull sizes that would develop later in monofenestratan pterosaurs. The fact all Dimorphodon skulls end up being flattened indicates that the skull bones were not robust. That said, although likely full of air in life, the skull of Dimorphodon is still large enough to occupy a proportionally large amount of body mass, as were the hindlimbs (Henderson 2010). We tend to think of early pterosaurs as scrawny-legged animals which couldn't walk if their lives depended on it, but Dimorphodon limbs are pretty well built. Indeed, the hindlimbs are so strongly put together that Dimorphodon was the pterosaur behind the controversial 'dinosaur-like bipdeal pterosaurs' concept discussed through the 1980s and 1990s. I've been wondering of late whether we can consider that idea fully refuted now: at least one individual still champions the idea, but they have not really countered the wealth of evidence set against pterosaurian bipedality. For those not keeping score, that evidence includes the anterior centre of gravity occurring in all pterosaurs; issues with hindlimb musculature efficiency at poses imposed by bipdal gaits; problems with neatly folding the wing; the wealth of quadrupedal pterosaur trackways; trackway and osteological characteristics indicating plantigrade feet; and scaling regimes of pterosaur limbs matching those of quadrupedal volant animals, but not bipedal ones. Although a minority of these points have been partially refuted (sometimes controversially), evidence supporting the bipedal pterosaur hypothesis is thin on the ground compared to that for quadrupedality, and this applies to Dimorphodon as much as anything. I'm coming to the opinion that the use of bipedal or quadrupedal gaits is not really a debated topic for pterosaurs now.

The hands and feet of Dimorphodon are also robust, and equipped with large, trenchant claw bones (these, of course, provide the specific namesake, 'macronyx'). There are indications that the extensor muscles controlling these might have been powerful, as every claw on both hands and feet is equipped with a neighbouring sesamoid - those intra-tendinous bones serving to enhance muscle output or protect tendons against powerful joint motion. Interestingly, the only other animals with these claw-adjacent sesamoids are lizards and a 'bottom walking' fossil stem-turtle - more on that another time. As with all pterosaurs, there is no indication that their hands or feet were for grasping, and their claws are really nothing like talons (take that, Jurassic World website).

Dimorphodon wings are interesting for their contrasting proportions to the rest of the body, as well as those of most other pterosaurs. Although the wing fingers of Dimorphodon are decently sized - they occupy over half the length of the entire arm - the overall wing length is a bit on the small size, at least compared to predicted Dimorphodon masses. At least 3 studies have independently predicted relatively high wing loading in Dimorphodon, suggesting those relatively big skulls and legs were not accommodated for with increases in wingspan. First-principle interpretations of these results - that Dimorphodon flight may have been a bit more fraught and energy-demanding than similarly-sized pterosaurs - is being borne out in assessments of wing shape (Witton 2008) and flight studies (which I'll be talking about at Flugsaurier 2015). I went so far in 2008 as to suggest that Dimorphodon was a 'reluctant flier', because its predicted wing parameters seemed to closely match those of game birds and other woodland avians - those which take flight when they have no alternative, and keep their flight durations short (see illustration at top of post). Early indications from more detailed assessments are that aspects of flight we normally assume for pterosaurs - soaring and gliding - may well have been challenging, or effectively impossible, for Dimorphodon. These predictions of a heavyset pterosaur by myself and others are something of a first for flying reptile studies: mostly, we've remarked about how lightweight and glide-efficient pterosaurs were, not the opposite.

The Puffinodon: another palaeoart meme? 

What sort of lifestyle did Dimorphodon lead? Considering we're talking about a pterosaur, you can almost guarantee that someone has proposed that Dimorphodon ate fish. Some authors - perhaps Bakker (1986) was the first - have noted similarity between the skull of Dimorphodon and that of puffins, taking this to mean that these animals lived similar lives of diving into the water in pursuit of nektonic prey. Lots of artists have been inspired by this idea.


The palaeoart meme of 'Puffinodon'. Note that related puffin-inspired Dimorphodon art, not shown here, exists where dark body colours contrast with a variably coloured, vertically-striped bill. I'm as guilty of the latter as anyone.
The 'Puffinodon' concept doesn't do very well under testing. For one, the skulls of Dimorphodon and puffins aren't really that alike. Most of what makes up the deep cranial profile of puffin bills is soft-tissue, not bone. Moreover, puffins and other diving birds have wings well-adapted for 'flight' under water in that their wing bones are somewhat flattened, with thick bone walls. Dimorphodon wings, by contrast, are actually broader in some respects than those of other pterosaurs (stay tuned for more on that), and there are no indications that it had thickened bone walls. To the contrary, there are indications that its postcrania was pneumatised, at least in part.

That's the skull of Atlantic puffin (Fratercula arctica) on the left, Dimorphodon on the right. Grey shading indicates soft-tissue. Puffin skull modified from Schufeldt (1889).
So what did Dimorphodon eat? A comprehensive study of early pterosaur skulls and teeth concluded that Dimorphodon jaws were well-suited to a diet of insects, carrion and small vertebrates (Ősi 2011). That actually chimes pretty well other interpretations of Dimorphodon palaeobiology: there are indications that Dimorphodon was an adept climber, a fast runner, and - as discussed above - possibly flight restricted. A diet of insects and small vertebrates fits with these assessments of locomotor habits suited to terrestrial realms pretty well, and we might imagine Dimorphodon as better adapted to chasing down lepidosaurs and large beetles than it was diving for fish. Indeed, there are some pretty cool aspects of Dimorphodon anatomy indicating it may have been really at home on land - as in, as much as pterodactyloids were. This might come as a surprise to some, seeing as non-pterodactyloids have largely been thought of as terrestrially inept. We'll have to wait just a bit longer before I can talk about those, however.

So that's Dimorphodon in a few paragraphs, then: nothing like the animal we'll be seeing this summer at the cinema, and perhaps nothing much like other pterosaurs, either. If early pterosaurs and their lifestyles are your thing, stay tuned for some new ideas on that very soon.

References


  • Bakker, R. T. (1986). The Dinosaur Heresies. London: Penguin.
  • Henderson, D. M. (2010). Pterosaur body mass estimates from three-dimensional mathematical slicing. Journal of Vertebrate Paleontology, 30(3), 768-785.
  • Ősi, A. (2011). Feeding‐related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet. Lethaia, 44(2), 136-152.
  • Shufeldt, R. W. (1889). Contributions to the Comparative Osteology of Arctic and Sub-Arctic Water-Birds: Part V. Journal of anatomy and physiology, 24(Pt 1), 89-116.
  • Witton, M. P. (2008). A new approach to determining pterosaur body mass and its implications for pterosaur flight. Zitteliana, 143-158.
  • Witton, M. P. (2013). Pterosaurs: natural history, evolution, anatomy. Princeton University Press.