Dsungaripterid pterosaurs and the proliferation of Wittoniana

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In celebration of the upcoming Flugsaurier conference (conference # 3), I thought I'd post some nice pterosaur pictures. I'm speaking at the meeting, so am spending 'spare' time on pterosaurs and not much else (I am happy to report that I'm able to continue with the day-job on marine reptiles - more on that in the future). The large picture is yet another I've nicked from Mark Witton: it depicts the Lower Cretaceous Chinese dsungaripterid pterosaur Dsungaripterus weii Young, 1964, and for the full-size version of the picture (this version is cropped and resized) you need to go here. Mark was mentioned in Science magazine last week, I think in the 'editor's choice' column. Huh. A paper in PLoS Biology, a mention in Science.... I am pleased to report that there aren't yet any signs of ego-inflation, but I'll keep you posted.

Dsungaripterids have really interesting skulls, with toothless jaw tips (they are up-curved in Dsungaripterus but not in the other taxa), and unusual blunt teeth that look suited for crushing shelled prey. You can see these features, and others, in the reconstructed D. weii skeleton shown in the pic below. It was photographed in the Beijing Museum of Natural History and comes courtesy of Dave Hone; thanks Dave. A recently described dsungaripterid from the Lower Cretaceous Upper Tugulu Group of China, Lonchognathosaurus acutirostris, differs from Dsungaripterus in having a very long and straight rostrum that doesn't appear to have been so robust (Maisch et al. 2004) [some other dsungaripterids are similar, but not as long-snouted as Lonchognathosaurus]. In Dsungaripterus, extra bone seems to have in-filled the ventral part of the orbit, giving it a strongly reinforced cheek region. It is only a matter of time before someone does stress-modelling work of some sort on these pterosaurs: when that happens, we'll have some useful info on bite strength and all that stuff (actually, pterosaur worker Michael Fastnacht might already have done such work, but if so I haven't seen it - it might be in his unpublished phd thesis).

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The hindlimb and pelvic morphology of dsungaripterids indicates that they were well suited for terrestrial locomotion - perhaps more so than most other pterosaurs - with relatively robust limb bones well able to resist compression and buckling (Fastnacht 2005). This is in agreement with the fact that their fossils come from terrestrial environments; in fact we have increasingly good evidence that dsungaripterids and members of a related pterodactyloid pterosaur clade were not seabird analogues (as has so often been said of all pterosaurs [e.g., Naish & Martill 2003]), but radiated widely inland. More in this in future: Mark and I have a big project in the pipeline on this subject, and other papers on it are due to be published soon.

Anyway, this was meant to be a picture-of-the-day submission, not a proper article. Mark says a lot more about these pterosaurs in his article here. Back to work... as if the conference situation weren't silly enough, I'm talking at the Bournemouth Natural Science Society about baleen whales tomorrow.

Refs - -

Fastnacht, M. 2005. The first dsungaripterid pterosaur from the Kimmeridgian of Germany and the biomechanics of pterosaur long bones. Acta Palaeontologica Polonica 50, 273-288.

Maisch, M. W., Matzke, A. T. & Sun, G. 2004. A new dsungaripteroid pterosaur from the Lower Cretaceous of the southern Junggar Basin, north-west China. Cretaceous Research 25, 625-634.

Naish, D. & Martill, D. M. 2003. Pterosaurs - a successful invasion of prehistoric skies. Biologist 50 (5), 213-216.

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Actually the photo is not from the IVPP, but the Beijing Museum of Natural History. That's probably my error when I sent it to Darren. Still, its a lovely reconstruction.

[From Darren: thanks for correction, I've now changed the text]

And as for the skulls Michael Fastnach has been working primarily on the various ornithocheirids, but I am sure he is interested in taking on these guys. We can ask him next week :0)

Very cool. I want one of these. It would beat the hell out of having just a damned parrot.

I can see them crawling round picking up ground dwelling insects.

Or, if they were actualy seabird anagelous (did I get that right?) a tame one might be very helpful at the tiresome task of prawn deshelling.

Or, even more radicaly, they lived on the backs of giant dinos, clambering round and delicatley picking off hard shelled parasites.

(do you think they flew well?, or spent more time on the ground??)

Hmm, a terrestrial shell-cracker...maybe they were scooping up ankylosaur hatchlings!

Kudos to Witton on another beautiful illustration, I'd say a little macrocephalization is called for.

The proliferation of Wittoniana? Neat.

Thanks for posting the image Darren, and to Neil for the praise. I've actually been drawing pterosaurs furiously (as opposed to drawing furious pterosaurs) for the last few weeks, so folks attending the Munich talk should see some images yet to be posted on the web. Some of them might even crop up in a talk by a certain blogger...

Speaking of which: Darren, your inbox should now be crawling with pictures of the NHM Gnathosaurus. Hope they prove useful.

Well, I think it's silly to say that pterosaurs...all pterosaurs...were seabird analogues. The fact is, their remains are found most often in marine deposits, but their paper-thin bones would probably not do well in a terrestrial depositional environment. Thusly, pterosaurs may have radiated wildly in terrestrial environments, but the fossil record may be biased against terrestrial pterosaurs. Can you imagine flightless pterosaurs? I can't either, but you never know!

Hmm, a terrestrial shell-cracker...maybe they were scooping up ankylosaur hatchlings!

A group of 5 Pinacosaurus babies is known. They didn't have armour yet.

I can see them crawling round picking up ground dwelling insects.

For that they were a bit big... I dimly remember Dsungaripterus as having a wingspan of 3 m...

By David Marjanović (not verified) on 04 Sep 2007 #permalink

Why not flightless pterosaurs? There were islands, right? Seeing how eagerly birds give up flight whenever they can, pterosaurs must have done the same.

By Nathan Myers (not verified) on 04 Sep 2007 #permalink

Why not flightless pterosaurs? There were islands, right? Seeing how eagerly birds give up flight whenever they can, pterosaurs must have done the same.

Then why do bats never do it?

By David Marjanović (not verified) on 05 Sep 2007 #permalink

"Why not flightless pterosaurs?"

Er...well, islands tend to not withstand the erosional effects of Deep Time very well.

There is also another consideration.Secondarily flightless maniraptorans seem to be a dime a dozen practically from the get-go, same with insects.

Pterosaurs and chiropterans, not so much, hell, so far, not at all!Even azdharchid pterosaurs and mysticinid bats, as well adapted to scurrying around on the ground as they were/are, have never produced flightless forms.

Of course this could simply be an aspect of preservational bias.Perhaps Otego or some other deposit in New Zealand will reveal a truly flightless bat.Perhaps a deposit in Europe will reveal flightless insular azdharchids.

Or, there is another, more likely reason, which is that pterosaurs and bats can't seem to get rid of the connection their patagia forms between their limbs, all four which are intensively invested as part of the flight apparatus.Birds and insects get around this problem by having at least one pair of fully functional limbs suitable for standard terrestrial locomotion.

If you take into the fact that the majority of flightless birds either live on islands without predators (Dodos, etc) are very large (most ratites), or highly specialised (penguins) then it becomes even more apparent that bats and pterosaurs are unlikely to evolve furhter towards flightlessness than they have already.

I always thought that the reason pterosaurs were always considered seabird analogues was because they were mostly known from marine deposits- there probably were plenty of pterosaurs which never saw the sea, but because of their skeletons they were very unlikely to be preserved.

By David Godfrey (not verified) on 06 Sep 2007 #permalink

Why not flightless pterosaurs? There were islands, right? Seeing how eagerly birds give up flight whenever they can, pterosaurs must have done the same.

Then why do bats never do it?

There are many kinds of bats. Bats which feed on flying insects would not do well on isolated islands, since mostly non-flying insects live there due to winds carrying away flying adults.

Fruit bats on islands roost on mangroves which require iron and copper nutrients in the soil so coral reef atoll isles which are poor in Fe & Cu are poor are also poor in fruit and fruit bats. Besides, fruit bats fly to angiosperm branches to eat, climbing would be inefficient. I can't see any gain for a non-flying bat on an island and wouldn't expect one.

Flightless pterosaurs? No idea, but one that dove part- or full-time like a cormorant, a penguin or an auk might be possible, considering some had dense bones. Crunching crayfish, eggs, river snails, mollusks? The pic seems a bit pelican-like to me, an acknowledged amateur.

DDeden:

"Flightless pterosaurs? No idea, but one that dove part- or full-time like a cormorant, a penguin or an auk might be possible, considering some had dense bones. Crunching crayfish, eggs, river snails, mollusks? The pic seems a bit pelican-like to me, an acknowledged amateur."

Diving pterosaurs seem unlikely to me, because they would loose a lot of body warmth throw their wing membranes. At the very least they would be able to land on the water and swim in the surface, but a fully aquatic pterosaur would probably require flightlessness to be developed first on land.