9 things you may not know about giant azhdarchid pterosaurs

The 2015 version of the giraffe vs. azhdarchid vs. person image, now in it's fifth iteration (see the general history of these images through the years: 2006; 2007; 2009). The giraffe is a big bull Masai individual, standing a healthy 5.6 m tall, close to the maximum known Masai giraffe height. The pterosaur is a 10 m wingspan Arambourgiania philadelphiae (for reasons I cannot go into now, it is not wise to consider the appearance of giant azhdarchid taxa interchangeable any more: this should not be considered Hatzegopteryx thambema or Quetzalcoatlus northropi). The Disaknowlegement provides the human touch. These characters will receive some additional company soon.

The splendid beasts that are giant azhdarchid pterosaurs have occupied my thoughts a lot of late, mostly thanks to three upcoming talks I'll be delivering about them at upcoming conferences and society meetings. Preparing that number of talks in a short space of time has given me a whole new interpretation of the term 'death by PowerPoint' so, to take a break from animating slides and producing diagrams, here's a quick run down of 10 factoids you may not know about giant azhdarchid pterosaurs (the likes of Quetzalcoatlus northropi, Hatzegopteryx thambema and Arambourgiania philadelphiae - as if they need introduction) and their smaller relatives. Even if these facts are familiar, please feel free to enjoy the new bits of artwork accompanying the post. Those of you really into the ever evolving depiction of these pterosaurs really should also pay a visit to this recent Tetrapod Zoology post: I'm clearly not the only one with giant pterosaurs on the brain.

They nearly weren't called 'azhdarchids'
'Azhdarchidae' is a terrific name. It's short but mysterious, relatively easy to spell, and PR friendly enough that even the British tabloid The Sun has used the term on at least two (I think) occasions. The name 'Azhdarchinae' was coined by the late Lev Alexandrovich Nesov in 1984 from the Uzbek word 'azhdarkho', a name for a mythical dragon, and also the nomenclatural basis for the medium-sized Uzbek azhdarchid Azhdarcho lancicollis. Nesov's name encompassed all three azhdarchid genera known at that time: Azhdarcho, Titanopteryx (now known as Armabourgiania) and Quetzalcoatlus. Almost simultaneously, however, the exact same set of taxa was being roped into another group by Kevin Padian, which he termed Titanopterygiidae after, obviously, Titanopteryx. Nesov's 'Azhdarchinae' pipped the far-less elegant Titanopterygiidae to the publishing punch by a matter of months, and took nomenclatural priority for the group. Padian elevated Azhdarchinae to 'family' level in a short note in 1986, giving us our now familiar term, 'Azhdarchidae'.

Lev Alexandrovich Nesov holds the fossil cervical vertebra, notarium and jaw tip of the azhdarchid Azhdarcho. Image from Unwin (2005).

Tiny bodies
Despite their giraffian proportions, giant azhdarchid torso were relatively tiny. Witton and Habib (2010) noted that, like many pterodactyloid pterosaurs, their torsos were probably only a third or so longer than their humeri, suggesting a shoulder-hip length of about 65-75 cm for an animal with a 10 m wingspan. That's a torso length not much larger than your own, although they were considerably more stocky and swamped with muscle. Azhdarchid shoulders, in particular, are well endowed with attachment sites for flight muscles, as are (for pterosaurs) their pelves and hindquarters.

Giant azhdarchids did not suffer from flight power shortages
Many internet commenters often roll out the idea that giant azhdarchids would struggle to take off from the ground, even allowing for new ideas like quadrupedal launching. These folks need to get out of their armchairs, however, and check out some classic work on animal flight and giant pterosaur takeoff. James Marden's 1994 work on animal takeoff found some surprisingly consistent scaling trends among animal flight power and takeoff ability, allowing us to predict the muscle power of even long extinct fliers like Meganeura, Archaeopteryx and a 10 m span azhdarchid. The resulting aerobic power output of azhdarchid flight muscles - all 60 kg of them (a fairly safe bet for a 250 kg azhdarchid given what we know of animal flight muscle fractions among modern fliers) - is a bit rubbish, only 4.52 N/kg of body weight. Animals need to be generating 9.8 N/kg to fight gravity, so this would seemingly ground our giants. Bear in mind, however, that swans, albatross, vultures and turkeys also have aerobic power outputs of around 4.5 N/kg from their flight muscles, and they can fly just fine. The secret to their takeoff lies in the great power of anaerobic muscle contraction, which provides twice the power achieved under aerobic regimes. Using anaerobic power, giant azhdarchid power outputs are 10.098 N/kg of body weight, a value surpassing the 9.8 N/kg and matching the anaerobic power outputs of a 10 kg swan or 1 kg vulture (see graph, below). In terms of power availability, then, giant azhdarchids would not have struggled to launch any more than a large bird, so all these suggestions about poor takeoff ability and whatnot can be put to bed.

Scaling of flight performance with body size under anaerobic power output. The dashed line is the minimum lift needed to overcome gravity. Anaerobic power is 225W/kg, the upper limit of avian anaerobic output. From Marden (1994).

An unsurpassed 80 million years of evolutionary history, and growing
Azhdarchids are undeniably best known from Upper Cretaceous rocks, but they also have a patchy and sometimes controversial Lower Cretaceous record. Recently, Gareth Dyke and colleagues (2011) demonstrated that the group were probably present at the very base of the Cretaceous, in Berriasian (c. 140-145 Ma) deposits of Romania. Given that azhdarchids are definitely present at the final stage of the Cretaceous, this gives the group a stratigraphic record spanning the entire Cretaceous: 80 million years in total. This is longer than any other pterosaur group. Two cervical vertebrae from the Late Jurassic of Africa may extend their temporal range another 5 million years, although the affinity of these specimens remains controversial.

A much improved skeletal reconstruction of the small azhdarchid Zhejiangotperus linhaeiensis over my oft-reproduced effort from Witton and Naish 2008. Note the use of pacing strides, a gait indicated by pterosaur trackways but seldom seen in pterosaur palaeoart.

More than just long necks
When we describe azhdarchids, we often use two qualifiers: 'toothless' and 'long-necked'. In fact, these pterosaurs are brimming with characterising features (above). Their rostra are particularly elongate compared to all other pterosaurs, their orbits are depressed well into the lower half of their skulls, their wing metacarpals and femora are atypically long, and their extremities are short and robust. Their mid-series cervical vertebrae are famously simplified into almost tube-like structures, and their humeri are deceptively derived from the pterodactyloid norm. The wing fingers of azhdarchids occupy a relatively small 47% of their wing lengths, a value only approximated by one other pterosaur group, the closely related thalassodromids. Artists, take note: grounded azhdarchids should not be reconstructed with their folded wing fingers stretching skywards over their backs: they couldn't reach that far.

But no, seriously, the long necks
The cervical vertebrae of giant azhdarchids are poorly known, with only a few specimens (and even fewer good ones) being recovered to date. These rare fossils do, however, clearly indicate substantial neck proportions in at least animals like Arambourgiania. The holotype cervical V of this animal is around 660 mm long, and is missing an estimated 100 mm from its posterior end. Steel et al. (1997) scaled this vertebra isometrically with relatively complete neck skeleton material from the 4.7 m wingspan azhdarchid Quetzalcoatlus sp. to predict a whopping 3071 mm length for cervicals III-IX in Arambourgiania. The use of isometry here is questionable (Witton and Habib 2010), but is defensible given the amount of azhdarchid neck material available to these authors in the mid-nineties. Ongoing work I'm involved with (which will hopefully be published before we're too much older) has attempted to apply allometry to calculations of giant azhdarchid neck lengths. The results are a little more conservative than the 3 m offered here, but we're still landing in the "seriously long neck" camp. Whether azhdarchids will retain the title of absolutely longest necks outside of Sauropoda (Taylor and Wedel 2013) remains to be seen however: I suspect they may ultimately just be pipped by the weirdo protorosaur Tanystropheus. Dammit.

The 'Big Necks Which Don't Belong to Sauropods Competition', won by the giant azhdarchid Arambourgiania. From Taylor and Wedel (2013).

Finally, some data on neck arthrology
The necks of azhdarchids are not just famous for their size, but are also renowned for their rather inflexible joints. These widely discussed features have been the bane of many azhdarchid lifestyle interpretations (see Witton and Naish 2008 for a review), but actual quantification of their arthrological range has been lacking until recently. This is, in part, because a complete 3D azhdarchid cervical series has been elusive for many years, but Alex Averianov (2013) recently produced a composite digital neck skeleton for Azhdarcho to figure out their range of motion. The results were more-or-less what we all expected: very limited range in the mid-series, with most of the mobility limited to the extremes. A surprising amount (but still fairly restricted) range of motion was afforded at the neck base, however. As may be expected, this study is very welcome to those of us interested in the biomechanics and functional anatomy of these animals, and I'm glad to see it.

Averianov's (2013) reconstructed neck arthrology of Azhdarcho lancicollis. That's one stiff neck.

Incidentally, some folks have asked me what I think of Averianov's suggestion that azhdarchids weren't what Darren Naish and I termed 'terrestrial stalkers' in our 2008 paper (generalised terrestrial foragers which spent much of their time wandering over Cretaceous plains in search of small animals and rich plant material like modern storks and ground hornbills). I won't say much now, but Darren and I don't agree with the alleged 'flaws' put forward against our hypothesis, and especially do not agree with the proposed 'aerial scoop feeding' counter hypothesis. Our formal reply has just been through peer review, and we hope to complete the minor tweaks needed to get it ready for publication very soon.

Swimming piscivores and aerial hawking: genuinely suggested azhdarchid lifestyles
It's well known that most recent 'serious' proposals of azhdarchid lifestyles are things like skim-feeding, terrestrial stalking and wading, but many other, frankly outlandish palaeoecological hypotheses have been thrown at azhdarchids over the years. Lev Nesov perhaps takes home the prize for the most bizarre ideas, proposing in his 1984 paper that azhdarchids could swim to find food (both along the surface and by diving) and pursue 'poorly flying' vertebrates through the air. In the same paper, he also advocates skim-feeding as a probably azhdarchid lifestyle. I remain unsure which part of azhdarchid anatomy indicated to Nesov that these animals had superhero-like abilities to acquire food.

Sauropods give a giant azhdarchid the evils. Seems they don't like being buzzed at close range. 

The awesomopower of giant pterosaur flight
Although azhdarchids are frequently discussed for their natty terrestrial capability nowadays, it's important to remember than any substantial travelling they had to do was probably performed in the air. Computations of the flight abilities of giant azhdarchids have returned seriously impressive results (Witton and Habib 2010). As mentioned above, azhdarchids likely employed anaerobic power for strenuous flight activities like takeoff and perhaps flapping bursts, and likely relied mostly on thermal soaring and flap-gliding like modern raptors to remain airborne for long periods. Their minimum sink and best glide speeds are steady cruises at 16.3 - 24.9 m/s (58.7 - 89.4 kph) but, if they were in a hurry (such as looking for a source of uplift), speeds of up to 48.3m/s (173 kph) were possible for short durations. We estimated that azhdarchids had about 90 - 120 seconds of anaerobic burst power before tiring, meaning these animals could go from a standing start to - literally - several kilometres away in the space of a few minutes. Yowsers. What's more, the size and bodily resources available to such large creatures permitted tremendous flight times: up to 16,000 km of travelling without resting or foraging were likely possible. That's the equivalent of an animal flying from London to Vegas non-stop, realising it forgot its passport, and then flying home again without touching the ground.

And that's your lot for now, folks. If you want to know more about azhdarchids, be sure to check out my book for a whole chapter about them, which is something like the second biggest entry in the entire thing. Things may go quiet over the next few weeks while I'm away at various conferences, but posting will resume when I get back.

References

• Averianov, A. O. (2013). Reconstruction of the neck of Azhdarcho lancicollis and lifestyle of azhdarchids (Pterosauria, Azhdarchidae). Paleontological Journal, 47(2), 203-209.
• Dyke, G. J., Benton, M. J., Posmosanu, E., & Naish, D. (2011). Early Cretaceous (Berriasian) birds and pterosaurs from the Cornet bauxite mine, Romania. Palaeontology, 54(1), 79-95.
• Marden, J. H. (1994). From damselflies to pterosaurs: how burst and sustainable flight performance scale with size. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 266(4), R1077-R1084.
• Nesov, L. A. (1984). Pterosaurs and birds of the Late Cretaceous of Central Asia. Paläontologische Zeitschrift, 1, 47-57.
• Padian, K. (1984). A large pterodactyloid pterosaur from the Two Medicine Formation (Campanian) of Montana. Journal of Vertebrate Paleontology, 4(4), 516-524.
• Padian, K. (1986). A taxonomic note on two pterodactyloid families. Journal of Vertebrate Paleontology, 6(3), 289-289.
• Steel, L., Martill, D. M., Kirk, J. R. J., Anders, A., Loveridge, R. F., Frey, E. & Martin, J. G. (1997). Arambourgiania philidelphiae: giant wings in small halls. The Geological Curator, 6, 305-313.
• Taylor, M. P., & Wedel, M. J. (2013). Why sauropods had long necks; and why giraffes have short necks. PeerJ, 1, e36.
• Unwin, D. M. (2005). The pterosaurs from deep time. Pi Press, New York.
• Witton, M. P., & Habib, M. B. (2010). On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PloS one, 5(11), e13982.
• Witton, M. P., & Naish, D. (2008). A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS One, 3(5), e2271.

Pterosaurs invades the newpapers, this weekend!

Good news, everyone! If you've not already made the plunge and bought Pterosaurs, you can enjoy a teaser article in this Sunday's (11/08/13) Observer to sample it's flavour, available both online and in dead-tree format. The piece covers mostly familiar ground for those with an ear for the jungle drums of pterosaur research, but may serve as a useful taster for current pterosaur science for anyone else. Perhaps of wider interest will be the showcasing of artwork taken straight from the book itself, including several pieces which are yet to be seen elsewhere. If this is the final impetus you need to buy the book, there's promise of a discounted price and free shipping from The Guardian Bookshop. I'll pop a link to the article into this post when it becomes available. (UPDATE: The article has now been posted: find it here).

While I'm stroking my PR cat, of further note is that Pterosaurs was reviewed in New Scientist by Jeff Hecht earlier this week, concluding that "[the] explanations and diagrams shed vivid light on the most intriguing creatures that ever flew, and in richer detail than even [Wellnhofer's 1991 pterosaur encyclopedia] could have managed just two decades ago." The article also features images from the University of Portsmouth Southbank pterosaur display, including our late, 10 m wingspan model of a flying azhdarchid. RIP, BigQuetz.

If this isn't quite enough of a pterosaurian fix for you, don't forget about the Pterosaurs talk being held at the Natural History Museum, London, this September.

Childhood dinomania: the greatest of all palaeontological mysteries?

Sinornithoides youngi, a long-legged, gracile troodontid from China. But why are he and his contemporaries so darned popular, and particularly with children?

Perhaps the greatest question that surrounds prehistoric animals is nothing to do with their palaeobiology or evolution at all. An enormous question, and one that perhaps continues to defy satisfactory answer, concerns their endless cultural appeal. Why are these long-dead animals so darned fascinating to us? Internationally, vast sums of money are spent on research into them, the care of their fossils and the educating of others about them. We put their remains on display in vast, elaborate museums, write no-end of books and articles on them. But why? Why are we do dedicated and passionate about these animals, to the point of near obsession in some individuals? I can understand that a few components of palaeontology have clear rewards. Palaeontologists specialising in invertebrates and microfossils are essential components of any team hoping to find hydrocarbon reserves, giving their research obvious application and financial implications. Such studies may also shed light on rates and mechanisms of evolution, which has bearing for the conservation and preservation of our modern biota. Most fossil vertebrate lineages, however, are of little use for, well anything. They may be interesting, but the scant nature of their fossil record doesn't allow their use in any applied studies. Our interest in them is purely academic. Knowledge for the sake of knowledge, I guess we could say.

Minor interests
Of course, interest in fossil vertebrates is not confined to academics and, in fact, the largest audiences for prehistorically-themed topics is under 10 years old. Of all fossil animals, the appeal of Mesozoic reptiles to young individuals is particularly well known, and encouraged by adults for good reason. Mesozoic reptiles introduce children to important concepts of science and the natural world, provide wonderful material to teach mathematics, literary and drawing skills, and, unlike many other things kids are interested in, they represent reality. Learned information about Mesozoic reptiles are learned facts about things that actually happened, not some silliness about Pokémon, ThunderCats, or... blast, who the devil do children like?... Or Morgan Freeman.

Young interests in palaeontology aren't really questioned, they're just accepted and ran with. Discussions as to why young people are so interested in Mesozoic reptiles aren't uncommon, but they're of secondary concern to nurturing childhood interests in the topic. As Dave Hone wrote about this topic at his Lost Worlds, " I won't pretend to know why, but kids really do love dinosaurs and the important thing is that they do." There's certainly nothing wrong with this attitude, but the why of this question has been on my mind of late. My second cousin is as dinosaur-obsessed as any young boy should be and I'll be spending the day with him next week. I'll also be gaining a nephew before too long. Between these two small members of my family clan, I'm expecting to have to play the cool, 'dinosaur'-researching relative for a while yet. All of which makes me wonder why, why why are small people so interested in these animals?

Proof that I liked 'safe monsters' as much as anyone when I was small. What's a 'safe monster'? Read on! (image by me, age 7[ish]. My younger self bore amazing powers of prediction for my own future with the pterosaur attacking dinosaur).

Standard responses
The most common explanation I've heard to this question is stressed in this article and others like it. Mesozoic reptiles are monstrous, and kids like monsters. They like these even more however, because they're long dead, and therefore 'safe'. Unlike real monsters, like the bogeyman, things that live under the bed and recent Discovery Communications documentaries, Mesozoic reptiles can't hurt us any more. Under this logic, extinction is the key agent here. Kids like the security that extinction offers between themselves and the monsters they're reading about.

Jurassic Park author Michael Crichton offered a completely different explanation, linking dinosaurs with authority figures, like parents. He wrote in his 1993 novel:

"...he mused on what it was about Dinosaurs that appealed to kids. He decided that dinosaurs represented a sort of symbolic authority to kids, a sort of surrogate parent. Just like a parent, they were simultaneously frightening yet accessible, and they presented an authority figure they could love. He also thought that children found satisfaction in saying the names of the animals, as that represented a sort of power of the vanished giants, showing a form of control."

Here, it would seem, it's not extinction at all that's key: it's the perception of authority and accessibility that Mesozoic animals seemingly offer children, and their own desire to master and control their expression. Other common explanations include an escapist quality to learning about the distant past, being able to express our childhood selves through acting out dinosaur fantasies, and because dinosaurs are strange, and yet real beings.

I've got to admit that I cannot really reconcile any of these explanations with what I know about being interested in Mesozoic animals, either as an adult or a child. They - particularly the first two suggestions - seem to complicated, too 'psychological'. I cannot ever remember associating Tyrannosaurus with my parents, or disliking other monstrous creatures because they weren't long extinct. I don't think the 'distance' between myself and dinosaurs, or any other monsters, really mattered. The fact that Mesozoic animals once existed was kinda cool I guess, but clearly not a deal-clincher: I was interested in plenty of make-believe things when I was small. And while kids are undoubtedly irrational sometimes, I don't think their grasp of what is a tangible, 'real' threat and slightly scary but fantastic beast isn't as blurred as the above explanations suggest. I note that many of the suggested points are rather anthropocentric, explaining that our childhood selves are interested in these animals because they reflect our own lives somehow, but that also doesn't seem right. My childhood interest in dinosaurs and the like seemed more innocent than that: I just wanted to know more about them and play within their universe. These ideas don't even seem like explanations which, in hindsight, chime with a deeply buried feeling associated with my childhood obsession with all things Mesozoic. Conversations with friends and colleagues suggest these explanations are similarly unfamiliar to them.

This makes me wonder if we're thinking about this the wrong way. We seem to expect that the appeal of Mesozoic reptiles to children is a unique trait, an X-factor, something inherently mystical about these animals which mean most children will be under their spell at some point. There may be, but I wonder if we're over-thinking this. Perhaps there is no unique factor behind the popularity of Mesozoic reptiles with young humans, and they're popular with kids for the same reasons that a lot of things are. Maybe the reason children like Mesozoic reptiles is very simple: they're just really cool.

The Anatomy of Cool
Let's run with this idea for just a moment. Mesozoic reptiles certainly tick all the boxes for Cool Things That Kids Like. Starting with the most obvious: they look awesome. Innumerable cartoons and comics featuring appealing characters and creatures are testament to the power awesome-looking beings have over children. The muscular bodies, dynamic postures, horns, frills, teeth and claws of many Mesozoic reptiles are clear signs of badassery, and kids of all ages respond positively to that. Perhaps the consistent choice of favourite dinosaurs in youngsters reflects this. Although most children's dinosaur books introduce a wide selection of species, it's the most anatomically extreme and charismatic species that are picked out by generation after generation as Top Dino. Triceratops, Tyrannosaurus, Baryonyx, Velociraptor, Ankylosaurus, Brachiosaurus and so forth are consistent favourites. Some kids - especially cootie-ridden girls, because they're rubbish and smelly - might like prefer cuter, baby versions of dinosaurs,  but they still pick babies of the most immediately interesting taxa. By contrast, no kid has ever said that their favourite dinosaur is Iguanodon or Hypsilophodon, because they're freakin' boring to a sub-10 year old. This is despite them being among the 'safest' dinosaurs, bearing no real offensive equipment and having no interest in eating children. Kids dig awesome, even if it's a little scary, and their favourite dinosaurs are full of it.

Do kids like Sinornithoides? I don't know that they do, but it would definitely score Cute Points when they realised that the holotype was found in a Mei-like sleeping posture. Of course, Sinornithoides was described by Russell and Dong way back in 1993, including discussion of its sleeping posture, meaning it pre-dates the announcement of sleepy Mei by over a decade. This fact seems mostly overlooked nowadays, however.

Mesozoic animals are also immediately characterisable. A cursory glance at a menagerie of Mesozoic animals reveals which ones are 'good' - the plant and fish eaters - and which are 'bad' - the carnivores. Universes designed with young people in mind go to great lengths to give their characters similarly recognisable traits of good and bad. They also, as with Mesozoic reptiles, make their characters wear their lifestyles on their sleeves. It's immediately clear that they spend their time doing interesting things because their appearance (clothing, physical characteristics, objects they carry) consistently reflects their habits. When do we see warrior characters in children's shows put their weapons down, or adventurers leave their backpacks and hats behind? Never, because it's part of who they are. The same is true of Mesozoic reptiles: their lifestyles are clear from their anatomy, and their habits are obviously interesting. As with invented universes, this allows even young children to have a fairly immediate, if very basic understanding of the dynamics of the Mesozoic world, and that makes it fun to play with and think about. I've written before about how some Mesozoic creatures even come with pre-conceived ideas of 'character': the frills and horns of some dinosaurs recall the armaments of knights, the powerful jaws and teeth of tyrannosaurs make them obvious threats, and so on. These perceived anthropomorphisms may tie into the choice of favourite species among children, perhaps reflecting elements of wish-fulfilment and reflection of individual  personalities, but the same applies to their selection of a favourite Transformer or mutated ninja turtle.

What about complicated Latin and Greek names? Surely they must have some unique appeal? It's perhaps no coincidence that many favourite Mesozoic animals are also those with the coolest names. Animals with undoubtedly disastrous (Futalognkosaurus) or boring (the infinite numbers of Placename-osaurus we now have) names are unlikely candidates for being any child's favourite. The strong, weighty names of Deinonynchus, Pteranodon, Plesiosaurus and Diplodocus are where it's at. Really, they aren't actually too different or more difficult to say than invented names of child-approved fantasy universes. A of extinct animal names are no trickier or less familiar to children than the names of Star Wars or Lord of the Rings characters, for instance. There may be no more psychological significance to a child saying the word 'Gallimimus' than there is them saying 'Legolas' or 'Dagobah'.

The stats and factoids associated with Mesozoic reptiles are perhaps also factors in childhood palaeo cool. Any juvenile palaeo nut worth their salt knows the size, mass, biogeography, geological period, lineage, and diet of a hundred extinct species. Our brains are sponges for that kind of stuff when we're small, but not only for Mesozoic animals. Kids get obsessive about all manner of data, hence the success of all these newfangled Japanese card playing games with weird animals and, before them, things like Top Trumps, complex board and video games and RPGs. It seems that, if children like a topic, and the information is there to be learned, they'll take it in whether it has a dinosaur stamped on it or not.

Sinornithoides again, acting as end-of-post wallpaper

We've now also created a rich array of Mesozoic reptile merchandise for children to enjoy - toys, games, books, films and TV shows and so on - which, again, mirrors the development of universes invented for child consumption. These are food in the purest form for the imaginations of small children, enhancing their ability to play out their own interpretations of the Mesozoic in the same way that the merchandise of invented franchises allows kids to play within other universes. Unlike many franchises aimed at children, however, Mesozoic reptiles rarely disappear from fashion, and their merchandise is always easy to obtain. Indeed, I wonder if the perpetual availability of Mesozoic reptile merchandise and media has made it almost certain that child interests in these animals will never go away. Given the ripeness of childhood minds for the awesomeness of Mesozoic reptiles and the associated financial gain from making Mesozoic merchandise, we may be creating a self-fulfilling prophecy that children will always be introduced to and inspired to learn more about these animals.

The discussion at the end

With all these things considered, I really wonder if Mesozoic reptiles have, or indeed need a mysterious 'X-factor' to explain their appeal. I don't think it's been an intended goal of palaeontologists or merchandisers, but these two contrasting industries have created a window into the Mesozoic that children can enjoy on many levels, developing a world which couldn't be more child-friendly if someone designed it. The many parallels we see between childhood palaeo culture and industries designing universes to interest children are surely a reflection of this. Cool, identifiable creatures with interesting lives, awesome names and stats, and a wealth of merchandise. That description could describe how children will interpret palaeontology, or it could describe the way they'll interpret Doctor Who.

As a final point to chew on, I think it's interesting that we don't really feel a need to explain the childhood appeal of superheroes, spaceships and giant robots by means of an X-factor', but we do for Mesozoic reptiles. Adults just accept that kids find these more anthropocentric topics inherently awesome and interesting, and that's good enough. Why doesn't that work for palaeontological topics? Is it a little worrying that we think like this? That the raw appeal of the natural world, which kids seem to intuitively grasp as interesting and awesome, isn't a strong enough draw on it's own, and requires rationalising into a more a anthropocentric model to explain it's childhood appeal? Maybe there's something to be learned from that. General knowledge and understanding of the natural world is critically poor, biological education is consistently being attacked by anti-scientific groups, and media groups increasingly think that the natural world needs sexing up with human interaction and made-up science. Maybe if we just remembered that it's OK to find the natural world fascinating and awesome because it is, and that we don't need to make ourselves the centre of everything, these issues wouldn't be anywhere near as big and worrying as they are.

Reference

• Russell, D. A., and Dong, Z. M. 1993. A nearly complete skeleton of a new troodontid dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People's Republic of China. Canadian Journal of Earth Sciences, 30, 2163-2173.