Zhenyuanopterus, Boreopterus and the Ask A Biologist relaunch

Earlier this year the awesome new ornithocheiroid pterosaur Zhenyuanopterus longirostris Lü, 2010 was described from the Yixian Formation of Liaoning Province, China. It has pretty incredible teeth, as well as a very interesting premaxillary crest...

i-27e0e2e0589148f50dd7ba75ca9b0644-Zhenyuanopterus_longirostris_Lu-2010-April-2010.jpg

i-987ae30741c1a5bce245e46ec6e73e17-Feilongus_Nobu_Tamura_wikipedia_April-2010.jpg

And it has a lot of teeth: 86 in total in the upper jaw, and another 86 in the lower jaw (giving a total of 172). The teeth at the front of the upper jaw are about 50 mm long. This is a reasonably large pterosaur, with a wingspan of about 4 m (Lü 2010). It's clearly an ornithocheiroid, and it seems quite similar to another Yixian Formation ornithocheiroid pterosaur described in 2005: Boreopterus cuiae Lü & Ji, 2005 (you might even like to consider the idea that they could be the same thing, perhaps representing growth stages or the two sexes). Indeed, Lü (2010) included Zhenyuanopterus within the ornithocheiroid group Boreopteridae (in addition to Boreopterus, Feilongus youngi is also supposed to belong here, but I'm sceptical). Some published phylogenies find that boreopterids are outside of the ornithocheiroid clade that includes istiodactylids and ornithocheirids (e.g., Lü et al. 2006), while others find less resolution within Ornithocheiroidea (e.g., Lü et al. 2009). Boreopterids may well be part of Ornithocheiridae (and were originally included within that group), actually, but that's a topic for another time. The adjacent picture is Nobu Tamura's life restoration of Feilongus, from wikipedia. And here's the holotype of Boreopterus cuiae, from Lü & Ji (2005)...

i-03141cede0e83d37eaedf1623b918132-Boreopterus-cuiae-Li_&_Ji_2005_April-2010.jpg

One more interesting thing to say about these pterosaurs - and this isn't unique to boreopterids but goes for ornithocheirids as well - look how tiny their feet are! It also seems that some ornithocheiroids lack fibulae, but it remains uncertain how widespread this is (among boreopterids, Boreopterus lacks them but this was assumed to be preservational, while Zhenyuanopterus has them). The enormous wings and very small, weak legs of many ornithocheiroids show pretty convincingly that they were predominantly aerial, that they walked little, and that they made a living by grabbing objects while in flight. What a strong contrast to long-legged, relatively short-winged pterodactyloids like the azhdarchids.

Loads more could be said, but this was meant to be one of those 'picture of the day' things. While I'm here, now is a good time to mention that something almost entirely unconnected to the world of pterosaur research - namely, Dave Hone's Ask A Biologist site - has been relaunched today. Head on over and check it out.

And... back to pterosaurs, I may as well take this opportunity to once again advertise the internet wonder that is Pterosaur.net. Note that the site now has its own blog. Hey - this article could have been posted there, instead of here. Yeah - it could!

For previous Tet Zoo articles on pterosaurs see...

Refs - -

Lü, J. 2010. A new boreopterid pterodactyloid pterosaur from the Early Cretaceous Yixian Formation of Liaoning Province, northeastern China. Acta Geologica Sinica 84, 241-246.

- ., Gao, C., Meng, Q., Liu, J. & Ji, Q. 2006. On the systematic position of Eosipterus yangi Ji et Ji, 1997 among pterodactyloids. Acta Geologica Sinica 80, 643-646.

- . & Ji, Q. 2005. A new ornithocheirid from the Early Cretaceous of Liaoning Province, China. Acta Geologica Sinica 79, 157-163.

- ., Unwin, D. M., Jin, X., Liu, Y. & Ji, Q. 2009. Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull. Proceedings of the Royal Society B doi: 10.1098/rspb.2009.1603

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In the previous article I discussed the outside section of the Royal Society Summer Science Exhibition's pterosaur display (hosted at Royal Festival Hall on London's South Bank). The exhibition (which finished on July 4th, sorry) incorporated three flying, life-sized azhdarchids - suspended from…

Are the teeth really poking outside the jaw when the jaws are closed, or is that an illusion from the fossilization? Looks like it was easy to catch fish with those teeth, but making the fish go down the throat while on the wing must have been tricky.

They could have gone about fish-catching a number of ways. Certainly, pterosaurs like Pteranodon and Nyctosaurus catch fish on the wing. A lot of these big-toothed pterosaurs may have stood in the water, mouths agape, and waited for a fish to swim past. You can almost see Pterodaustro as a sort of "extreme" in this regard.

But yes, the teeth to stick out of the jaw, something like a plesiosaur, I imagine.

By Zach Miller (not verified) on 19 Apr 2010 #permalink

Are the teeth really poking outside the jaw when the jaws are closed

Of course.

A lot of these big-toothed pterosaurs may have stood in the water

With feet the length of their teeth, I agree with Darren that these ones didn't stand much.

By David MarjanoviÄ (not verified) on 19 Apr 2010 #permalink

An open-water skimmer that occasionally nested on cliffs? Two super-fingers, small hands, tiny feet, short non-prehensile tail, large cervical vertebrae. Wow.

DD: Who said "skimmer"?

By Nathan Myers (not verified) on 19 Apr 2010 #permalink

I wonder, do the tiny ornithocheiroid feet also apply to istiodactylids? If so, this might be a blow for Mark Witton's theory they behaved like vultures. Specialist scavengers do have to walk a lot and walk well, don't they?

Who said "skimmer"?

Or indeed "cliffs"... albatrosses don't nest on cliffs that much, do they.

By David MarjanoviÄ (not verified) on 19 Apr 2010 #permalink

It does seem to me that Boreopterus, Feilongus and Zhenyuanopterus are all one and the same thing and form a nice growth series. The principal difference is in numbers of teeth - there are more teeth in the larger individuals (i.e. Zhenyuanopterus), a pattern that is well established for other toothed pterosaurs. Despite the results of the phylogenetic analysis figured in Lü et al. 2009 (which I devised, ran and analysed) I am firmly of the opinion that Boreopterus is closely related to (and will ultimately be considered a member of) Ornithocheiridae. Doubtless, the beautifully preserved postcranial skeleton of Zhenyuanopterus will furnish us with the necessary character data to demonstrate this.

By Dave Unwin (not verified) on 19 Apr 2010 #permalink

Could they have had single-egg-bearing pouches, rather than nests? Sort of an aerobatic reptilian-monotreme-marsupial combo? That'd be cryptically cool!

Why pterosaurs had these fish-cage teeth, while birds do fine with straight beaks? Few birds re-evolve anything similar.

BTW egg-pouch. With just two eggs known for many pterosaur fossils, something seriously strange could be indeed going on. Anyway, there is some biological mystery, why we know some fossil taxa as lots, lots, lots of adults - and no young.

Why pterosaurs had these fish-cage teeth, while birds do fine with straight beaks?

How fine do they really? Maybe they do just well enough, but would be outcompeted within years if Jurassic Park brought such pterosaurs back?

Few birds re-evolve anything similar.

Maybe it's not easy to do that. But I'm just speculating here.

With just two eggs known for many pterosaur fossils, something seriously strange could be indeed going on.

Indeed.

Alternatively, the lack of a thick, hard shell could be fooling us.

Lots of young pterosaurs are known; Solnhofen is full of hatchlings.

By David MarjanoviÄ (not verified) on 20 Apr 2010 #permalink

If they spent nearly all their time in the air, could the tiny feet have held an egg tucked up, maybe with a modified tail - uroptygium (sp.) skin flap as chick brooder?

Why such an elaboration on egg guarding on pterosaurs? From all we know they could have been ovoviparous, seeing as they don't have the thick and hard egg shells birds have

RE: Comment #10 (Jerzy)

There was a bunch of large Tertiary sea birds (I think they were sea birds: how definitely is this known?) that evolved "pseudo-teeth" on their jaws. So maybe there really is an advantage to having some such structure if you want to scoop up fish.

By Allen Hazen (not verified) on 21 Apr 2010 #permalink

"Why pterosaurs had these fish-cage teeth, while birds do fine with straight beaks?"

A number of birds get along fine by developing pseudo-teeth, most notably in the odontornithes.

By Anonymous (not verified) on 22 Apr 2010 #permalink

"The enormous wings and very small, weak legs of many ornithocheiroids show pretty convincingly that they were predominantly aerial, that they walked little, and that they made a living by grabbing objects while in flight. What a strong contrast to long-legged, relatively short-winged pterodactyloids like the azhdarchids."

There is quite a variety of types of pterodactyloids. It would be interesting to see how those types compare to the variety of types of convergently evolved modern birds.

Yes, odontornithes and mergansers developed pseudo-teeth. But they are minority of fish-eating birds.

"There is quite a variety of types of pterodactyloids. It would be interesting to see how those types compare to the variety of types of convergently evolved modern birds."

Yes, it is a bit strange that eg. nobody is interested in wing shape of pterosaurs. In modern birds, it is crucial indication of behaviour (compare a goshawk and a falcon).

I would be interested eg. why nobody restores pterosaurs as hunting from perch, like kingfishers and lots of insectivorous and carnivorous birds. Or nobody asks if some could propel themselves underwater with wings like modern alcids, scoters and diving petrels... Or what about the current thinking, that lots of pterosaurs were fish-eaters, only none has adaptations to swim? Seems seriously strange.

Jerzy: this is all sounding very familiar :) What I mean is: you have made exactly the same comments before. The position of pterosaurs within ecomorphospace has indeed been examined by several researchers, and compared by those authors with the ecomorphospace occupied by birds and bats. See the discussion here, for example, and you might also like to see Hazlehurst & Rayner (1992), Chatterjee & Templin (2004) and Witton (2008). Known pterosaurs absolutely lack the features associated with perch-hunting, plunge-diving and wing-propelled diving seen variously in kingfishers, auks, diving ducks etc. You MUST learn to realise that pterosaurs were not carbon copies of modern birds - they did things differently (and pterosaurs were not all fish-eaters as often assumed, anyway). To see why this all sounds extremely familiar, see the previous responses here and here.

Incidentally, the bony-toothed seabirds are called pelagornithids, or alternatively pseudodontorns or odontopterygiforms. 'Odontornithes' is an old name used for a combined hesperornithine + 'ichthyornithid' group.

Refs - -

Chatterjee, S. & Templin, R. J. 2004. Posture, locomotion, and paleoecology of pterosaurs. Geological Society of America, Special Paper 376, 1-64.

Hazlehurst, G. A. & Rayner, J. M. V. 1992. Flight characteristics of Triassic and Jurassic Pterosauria: an appraisal based on wing shape. Paleobiology 18, 447-463.

Witton, W. P. 2008. A new approach to determining pterosaur body mass and its implications for pterosaur flight. Zitteliana B28, 143-158.

I felt I asked this before... Thanks for reminding. But I still find this ecologically strange!

Well, it might be strange if pterosaurs were the only freshwater/marine predators around, but they weren't. Numerous seabirds (like Ichthyornis and the hesperornithines) lived alongside pterosaurs in the Late Cretaceous, and birds like confuciusornithids and enantiornithines were eating freshwater crustaceans and fish during the Early Cretaceous. And of course, numerous swimming reptiles (metriorhynchoid crocs, various lizards large and small, plesiosaurs and so on in the seas; choristoderes, mesoeucrocodylian crocs and others in freshwater) might have limited the ecological opportunities available to aquatic pterosaurs. I don't think the seas, lakes and rivers of the Mesozoic were at all empty :)

John:

"There is quite a variety of types of pterodactyloids. It would be interesting to see how those types compare to the variety of types of convergently evolved modern birds."

Jerzy:

Yes, it is a bit strange that eg. nobody is interested in wing shape of pterosaurs. In modern birds, it is crucial indication of behaviour (compare a goshawk and a falcon).

Pteranodon/albatross convergent evolution:
http://en.wikipedia.org/wiki/Pteranodon

The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is a suggestion based on the fact that the Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross â 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and utilize a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land).
However, most scientists do agree that Pteranodon could flap their wings and fly with power. These two flight styles would not have been mutually exclusive in Pteranodon, or in pterosaurs in general.

"The enormous wings and very small, weak legs of many ornithocheiroids show pretty convincingly that they were predominantly aerial, that they walked little, and that they made a living by grabbing objects while in flight. What a strong contrast to long-legged, relatively short-winged pterodactyloids like the azhdarchids."

Two of the taxa within Pterodactyloidea are Ornithocheiroidea and Azhdarchoidea.
Within Ornithocheiroidea are Pteranodontids which are similar to the modern day albatross. (See post above).
Within Azhdarchoidea are azhdarchids which are considered by researchers to be "stork- or ground hornbill-like generalists".
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002…
"However, azhdarchid footprints show that their feet were relatively small, padded and slender, and thus not well suited for wading. We argue that azhdarchids were stork- or ground hornbill-like generalists, foraging in diverse environments for small animals and carrion".

Interesting convergent evolution correspondences.

And what is current wisdom about Pterodactylus habits?

And some pterosaurs correspond to modern day pelicans. Again "convergent evolution". Fascinating correspondences.

http://www.dinosaursfaq.com/Dinosaur/Rhamphorhynchus-Dinosaur.html
According to scientists and paleontologists, the Rhamphorhynchus hunted in a manner similar to the modern-day pelican wherein it would dive into water and use its long beak to scoop out fish, insects and frogs from water and then toss them down its throat pouch.
The fossils of Rhamphorhynchus that have been found have been well-preserved. One can see not just the skeleton but also the outline of the internal organs. Some of fossils have been found with the throat pouch in tact. Many Rhamphorhynchus fossils have been found in southern England and in Bavaria in southern part of Germany.

http://archosaurmusings.wordpress.com/2008/07/25/pterosaur-soft-tissues/
Throat pouches (like those of a pelican) can be seen in Pterodactylus and can be inferred in Ludodactylus.

http://www.statemaster.com/encyclopedia/Rhamphorhynchus-%28animal%29
Rhamphorhynchus probably ate fish and it is believed that one of the ways it hunted was by dragging its beak in the water, catching fish and tossing them into its throat pouch, a structure similar to that of pelicans, which has been preserved in some fossils. This method of catching fish is found today in skimmers.

@Jack: Its worth to note that skimming is no longer considered a valid option of fishing for known pterosaurs however, and the first and second sites are outdated anyways. Also throat pouches are known in non-pelican birds like frigate birds, which don't use them to trap prey.

I do wonder, however, if any known pterosaur (according to Mark Witton, this would mean at least the pteranodontians) did hunt from the water surface; I know someone stated waterborne take off was physically possible for pterosaurs, but the exact mechanism nobody told me, and thus I don't know if this is accepted widely among researchers.

Thing is, what applies to birds doesn't to pterosaurs, specially since they had more robust forelimbs than hindlimbs.

"Thing is, what applies to birds doesn't to pterosaurs, specially since they had more robust forelimbs than hindlimbs."

I don't understand you. Especially in the light of this:
http://en.wikipedia.org/wiki/Pterosaur#Parts_of_the_pterosaur_wing
"..it is possible that, like these groups, different species of pterosaur had different wing designs. Indeed, analysis of pterosaur limb proportions shows that there was considerable variation, possibly reflecting a variety of wing-plans.[14]".
And this:
"Many if not all pterosaurs also had webbed feet.[15]".

Could you say more?

Jack : pterosaurs were quadrupeds often with very enormous and powerfully muscled arms (wings), also they had weak and slim hind legs and often tiny feet. Most of their weight in walking would be taken by the arms and their takeoff actions was powered by arms, not legs. Therefore totally different from birds which have powerful hind legs and are frequently specialized for running as bipeds. Sorry, I cannot congratulate you on your knowledge of pterosaur anatomy.

By Daniella Perea (not verified) on 02 May 2010 #permalink

"Therefore totally different from birds which have powerful hind legs and are frequently specialized for running as bipeds."

When you say "birds" do you mean modern birds or do you mean the supposed early birds like archeopteryx, etc.
If you mean modern birds can you give some examples please of what you are saying.

I don't understand you. Especially in the light of this:

Dude, I don't understand why you cling to isolated sentences from Wikipedia like an American fundamentalist to isolated sentences from the Bible.

Yes, there is variation in pterosaur limb proportions -- but it's much smaller than that seen in birds!

One part that does not vary is that the forelimbs are always longer and more robust than the hindlimbs.

We have tracks of walking pterosaurs, and even one of a landing one. The landing pterosaur touched down on its hindfeet, hopped off again, and then walked away on all fours at pretty high speed.

Besides, Wikipedia is wrong in implying that we know whether most pterosaurs had webbed feet. Soft parts like webbing are almost never preserved!

When you say "birds" do you mean modern birds or do you mean the supposed early birds like archeopteryx, etc.

All of them. All theropod dinosaurs in fact!

BTW, Archaeopteryx: capital letter, ae, and italics.

By David MarjanoviÄ (not verified) on 02 May 2010 #permalink

Hang on a second. "Supposed early birds"? Why "supposed"???

Tell me, are you JackSpratt of Pharyngula infame?

By David MarjanoviÄ (not verified) on 02 May 2010 #permalink

Dude, I don't understand why you cling to isolated sentences from Wikipedia like an American fundamentalist to isolated sentences from the Bible.

David, I believe the phrase you're looking for is 'argumentum ad wikipediam'.

From the David MarjanoviÄ dude:
"Besides, Wikipedia is wrong in implying that we know whether most pterosaurs had webbed feet".

Here is the Wikipedia reference:
"Many if not all pterosaurs also had webbed feet.[15]".

This is a reference [15] to the following article:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002…

If there is some question about the wikipedia entry, perhaps you could take it up with the esteemed authors of the article.
I am only making the point that at least some pterosaurs had webbed feet, like at least some modern birds have webbed feet.

Also from the David MarjanoviÄ dude:

"Dude, I don't understand why you cling to isolated sentences from Wikipedia like an American fundamentalist to isolated sentences from the Bible."

If you have points to make then make them and support them with references. These drive-by insults just make you look foolish.

Also from the David MarjanoviÄ dude:
"One part that does not vary is that the forelimbs are always longer and more robust than the hindlimbs."

Can anyone give a few examples of this?

The most obvious example is azhdarchid pterosaurs and ornithocheirid pterosaurs...but it's true of all pterosaurs. In fact, it may be one of the most fundamental aspects of pterosaur anatomy.

David, Jack believes (somehow) that basal birds arose separately than "modern" birds.

By Zach Miller (not verified) on 03 May 2010 #permalink

"One part that does not vary is that the forelimbs are always longer and more robust than the hindlimbs."
and
"The most obvious example is azhdarchid pterosaurs and ornithocheirid pterosaurs...but it's true of all pterosaurs."

Is that also true of modern birds?

"David, Jack believes (somehow) that basal birds arose separately than "modern" birds."

This is an absurd statement. But I am not wasting time arguing about this absurdity.

Well, you sure seemed to on the other pterosaur thread, which Darren closed down. Unless you're a different Jack who believes that pterosaurs evolved into birds. I suppose that's possible, too.

Sure, most of the time, a bird's wings are longer than the legs. But that's not always the case! Songbirds often have surprisingly short wings. Ratites have tiny little wings. Penguines also have short wings. Also, birds don't catapult themselves skyward by VAULTING INTO THE AIR with their arms. Pterosaurs DID. Birds might have muscular shoulders, but pterosaur's arms were AMAZINGLY muscular. I can't find the picture of it, but one skilled paleo-artist recently reconstructed the pectoral musculature of Ornithocheirus (I think that was the genus) and it's just got MASSIVE muscles all over its arms. Puts birds to shame.

Also, go dissect some birds.

By Zach Miller (not verified) on 03 May 2010 #permalink

So we have established that:
"One part that does not vary is that the forelimbs [of pterosaurs] are always longer and more robust than the hindlimbs."
and
"The most obvious example is azhdarchid pterosaurs and ornithocheirid pterosaurs...but it's true of all pterosaurs."
and
that is also true of modern birds.

So in this respect, pterosaurs are the same as birds.
And that was my point from the beginning.

And I just told you they're not. The devil's in the details. Hell, non-hominid apes have longer arms than legs, but that says NOTHING about their relationship to birds and pterosaurs. What other animals have longer and/or more robust arms than legs?

Brachiosaurs
Giraffes
Some amphibaeneans
Turtles

I could go on. Are all of these animals related to pterosaurs and birds because of this one very vague character: "Arms longer, more robust than legs?"

By Zach Miller (not verified) on 03 May 2010 #permalink

Zach Miller:
"..this one very vague character: "Arms longer, more robust than legs"

If you find it vague take it up with David MarjanoviÄ.
It was his phrase.
I am certainly not going to argue with you. Your point changes from post to post.

I would really like to see Jack limited to one comment a day. What do others think?

By Bradley Fierstine (not verified) on 03 May 2010 #permalink

It is easy to forget the large variety of pterosaurs.
That was referred to in the article:
"The enormous wings and very small, weak legs of many ornithocheiroids show pretty convincingly that they were predominantly aerial, that they walked little, and that they made a living by grabbing objects while in flight. What a strong contrast to long-legged, relatively short-winged pterodactyloids like the azhdarchids. ".

So we have to be careful about broad-brush statements like:
"Also, birds don't catapult themselves skyward by VAULTING INTO THE AIR with their arms. Pterosaurs DID."

Perhaps some pterosaurs did (the gigantic ones perhaps) and others did not.

For example:
http://www.sciencedaily.com/releases/2009/01/090106161514.htm
"Now comes what is believed to be first-time evidence that launching some 500 pounds of reptilian heft into flight required pterosaurs to use four limbs: two were ultra-strong wings which, when folded and balanced on a knuckle, served as front âlegsâ that helped the creature to walk â and leap."

http://www.scientificamerican.com/article.cfm?id=how-pterosaurs-first-t…
"But just because an animal could do something does not mean it did, and some paleontologists remain unconvinced that Habibâs data actually explain how pterosaurs got off the ground. âWhen I read the manuscript, my first reaction was, âHmm, thatâs odd.â But if you work on pterosaurs, you get used to odd things anyway,â remarks David Unwin, a paleontologist at the University of Leicester in England and author of the book The Pterosaurs: From Deep Time. âLarge and giant pterosaurs pose a problem,â he explains, âbecause the flying speed they need to achieve is quite high, 30 or 40 miles per hour, and I have a hard time understanding how they get that fast from a standing jump.â".

"Perhaps some pterosaurs did (the gigantic ones perhaps) and others did not."

This is awesome. Your quote implies that the larger pterosaurs did vault into the air, while maybe the smaller ones didn't. Your first quote confirms the vaulting theory, and the second one contradicts your statement, which I've quoted.

This is getting nowhere fast.

By Zach Miller (not verified) on 03 May 2010 #permalink

I would really like to see Zack limited to one comment a day. His posts are irrational. What do others think?

I see there is nothing here of value. Just the same old ideas mixed with irrationality. I have other things to do.

Can't even spell my name right.

By Zach Miller (not verified) on 03 May 2010 #permalink

From the David MarjanoviÄ dude:
"Besides, Wikipedia is wrong in implying that we know whether most pterosaurs had webbed feet".

Here is the Wikipedia reference:
"Many if not all pterosaurs also had webbed feet.[15]".

This is a reference [15] to the following article:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002…

If there is some question about the wikipedia entry, perhaps you could take it up with the esteemed authors of the article.

Alternatively, you might read the article.

Searching it for "webbed" gives no results. Reducing the search term to "webb" turns up 2 results, both of them in the following paragraph:

"Using Zhejiangopterus as a template, the Haenamichnus trackmaker can be estimated to have stood almost 3 m tall at the shoulder and to have had a wingspan of over 10 m. In concert with the large size of this trackmaker, one Haenamichnus trackway has a length of 7 m and is the longest pterosaur trackway yet known [46]. It records a pterosaur moving with an efficient, parasagittal gait [46] rather than in a sprawled posture as suggested by earlier studies (e.g. [98]). In fact, the Haenamichnus trackway demonstrates that the presumed azhdarchid trackmaker had a particularly narrow gait with pes prints regularly overlying manus prints, an observation suggesting particularly efficient terrestrial locomotion compared to that inferred from other pterosaur trackways. The Haenamichnus pes prints show that the feet possessed soft tissue pads on the digits, metatarsal heads and heel in the manner of some tapejarids [91], [99]) with webbing between the digits [46]. This webbing may also have been present between the digits of the manus [46]."

Witton & Naish argue that the trackway called Haenamichnus was made by an azhdarchid, based on their comparisons of Haenamichnus to the azhdarchid Zhejiangopterus. They note that Haenamichnus was made by an animal with webbed feet (and perhaps hands) and imply that they think this might have been normal for azhdarchids in general.

This does not equate to "many if not all pterosaurs"; few pterosaurs were azhdarchids. If nobody beats me to it, I will -- I must -- correct the Wikipedia article next time I log in on Wikipedia.

Oh, and, reducing the search term to just "web" finds three results -- the two above, plus a reference to the Internet.

I am only making the point that at least some pterosaurs had webbed feet, like at least some modern birds have webbed feet.

How is that a point? Webbed feet are also found in frogs, crocodiles, and plenty of mammals...

Zach Miller:
"..this one very vague character: "Arms longer, more robust than legs"

If you find it vague take it up with David MarjanoviÄ.
It was his phrase.

It's really pathetic how you try to wriggle out of acknowledging your own mistakes.

BTW, you didn't answer my question of whether you're JackSpratt. I'll take that as a "yes", then.

âLarge and giant pterosaurs pose a problem,â he explains, âbecause the flying speed they need to achieve is quite high, 30 or 40 miles per hour, and I have a hard time understanding how they get that fast from a standing jump.â

Habib, and Jim Cunningham on the Dinosaur Mailing List, have explained how it works, and have shown the math.

By David MarjanoviÄ (not verified) on 03 May 2010 #permalink