Tetrapod Zoology

The Wellnhofer pterosaur meeting, part I

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I’ve caught up on my sleep; I’ve watched the Star Wars trilogy and The Wicker Man; I’ve listened to at least one Kate Bush album (well, two.. ok, three); and I’ve spent an appropriate amount of time catching up with my family (on Sunday we went to Longleat Safari Park). While it’s true that I have thoughts on three quite different conferences to report, I thought that I’d start by writing about the one that’s freshest in my mind – and, anyway, I have to write up a proper article on this specific conference for publication, so it helps if I do this now. As readers will know (first thoughts here), I returned over the weekend from the Peter Wellnhofer Flugsaurier conference, held at the Bayerische Staatssammlung für Paläontologie und Geologie (Bavarian State Palaeontological Collection – BSPG). What happened at the meeting? Hey, I’ll tell you what happened…

Well, actually, I’m not going to review everything: there were about 28 talks at the meeting, and I don’t know how many posters. Instead I’m only really going to cover my personal highlights, though I will at least try and allude in the loosest sense possible to the other stuff. Talks were broken down into systematics and taxonomy, diversity and ecology, anatomy and physiology, skulls, wings, flight and locomotion and ‘other areas of research’. Discussion sessions covered functional morphology and taxonomy and systematics.

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Beginning with the systematics and taxonomy section, Brian Andres provided an overview of how the competing schemes on pterosaur phylogeny match up. Dave Peters provided a whistle-stop tour of his unique view of pterosaur diversity and phylogeny. For those that don’t know, Dave uses a ‘photo-interpretation’ technique to discover various details of anatomy, both in pterosaurs and in diverse other reptiles. There is, to put it mildly, a general feeling of scepticism that what he reports accurately reflects morphology, but he has claimed the discovery of bizarre dorsal frills and enormous soft-tissue cranial crests, multiple hitherto-unseen babies, novel details of dentition (even in taxa universally regarded as edentulous), and much else besides. Dave has then used these new details to produce an entirely novel phylogeny – radically different from that generated by any other pterosaur worker. He argues that pterosaurs cannot be (yes, ‘cannot be’) ornithodirans or archosaurs, but are in fact lizards. Anyway, he packed all of his discoveries into one talk: fast, intense, very alternative [adjacent image shows the BSPG Pteranodon sculpture, made by Peter Wellnhofer].

Taissa Rodrigues discussed the systematics of Coloborhynchus and Anhanguera: both are similar keel-crested ornithocheiroid pterosaurs and, while some authors (e.g., Fastnacht 2001) have opined that at least some (perhaps all) Anhanguera species should be sunk into Coloborhynchus, Taissa argued that the type species of the two genera are different enough for the two genera to be kept apart. It’s a pretty complex subject that I won’t explain in greater depth: I will be working on Coloborhynchus at some stage in the future (thanks to a new specimen of the type species C. clavirostris), so will return to it then.

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Last year, Dave Martill and I argued that both Tupuxuara leonardii and Thalassodromeus sethi should be regarded as junior synonyms of Tup. longicristatus (Martill & Naish 2006). While we still have problems with Tup. leonardii, it became obvious soon after our paper was published that Thalassodromeus really is quite a different beast from Tupuxuara: the two differ notably in the anatomy of the palate and lower jaw, in the position of the orbit, and in other details. So when Alex Kellner came up to me on the first day of the meeting and said that, after his talk, I would surely be in agreement with him that Thalassodromeus was a distinct taxon, I was already telling him (with some slight embarrassment) that we had back-tracked and already agreed with him on this issue. Alex’s talk mostly concentrated on splitting vs lumping in Cretaceous pterodactyloids, and he cautioned against the idea that taxa based on fragmentary remains (such as those from the English Cambridge Greensand) should be used as ‘gold standards’ (my term, not his) for the far superior material that comes from, for example, the Brazilian Santana and Crato formations. Again, this is a complex area that I don’t have time to cover here. Alex’s abstract mentions the new taxon Thalassodrominae, coined for Thalassodromeus and Tup. leonardii, but I don’t recall this being mentioned in the talk. If these two taxa really do group together, Tup. leonardii would need a new generic name [in the adjacent image, Mark Witton and Dave Peters discuss Mark's poster on a new azhdarchoid taxon from the Brazilian Crato Formation].

Moving now to the section on diversity and ecology, Junchang Lü quickly reviewed all of the Chinese pterosaurs: that’s about 28 genera and 32 species. A disturbingly high number of taxa are now being suggested to be allied to, or part of, Istiodactylidae, including Haopterus and Longchengopterus, and I only learnt at the meeting that Yixianopterus might be a lonchodectid (might). Another new Huaxiapterus specimen – apparently representing yet another species in this genus – was shown. It had a tall, rostrodorsally curved frontal crest as well as a premaxillary one. Darren Naish (me) gave a brief review of Lower Cretaceous pterosaur diversity in Europe: essentially an extension of the stuff I do on the fauna of the Wealden Supergroup. Istiodactylids are now known to have had a more extensive range in the Barremian than thought previously; Coloborhynchus has a ridiculously long stratigraphic range (if all species referred to this genus really belong there) and there is a new C. clavirostris specimen; I also spoke about lonchodectids (hence interest in Yixianopterus mentioned above), European gnathosaurines and dsungaripterids… and whether we should expect anurognathids and tapejarids to be discovered in the European Barremian.

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Afflicted by a terrible illness, Dave Hone spent the first few days of the meeting coughing, sneezing and spluttering his way through proceedings, his voice reduced to a harsh croaky whisper. That’s great when you’re the one welcoming delegates to the meeting, and giving a talk, but in the end it worked out. Anyway, nodules on the vocal chords aren’t fatal. Dave spoke about mutual sexual selection in pterosaurs – an area that Dave, I and Ines Cuthill are currently working on. Because both sexes in some pterosaur species are ornamented, it has sometimes been doubted that the crests might have had a role in sexual display. But it is well established that, particularly in birds, both sexes can be ornamented (for a recent review see Amundsen 2000). We’re going somewhere with this, stay tuned.

Incidentally, Dave and I also had a poster at the meeting titled ‘Perceptions of pterosaurs through time – a brief history’. This was essentially an excuse to put up pictures of Tarzan fighting a giant rhamphorhynchid, Raquel Welch being carried off by a bat-winged pteranodontid, a Gary Larson cartoon, and much else besides.

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Moving now to the anatomy and physiology section of the meeting, Dave Unwin (and an absent D. Charles Deeming) reviewed what we now know of pterosaur eggs and embryos. Variability in pterosaur eggshell structure isn’t that problematical given the morphological variability seen in the eggshells of some living clades, and pterosaur eggshell porosity indicates that the eggs were buried. Interestingly, Dave reported that he and Charles had ‘predicted’ the appearance of an unhatched pterosaur embryo long before one was found: the picture, showing a baby folded up in the only position that makes sense, is apparently uncannily similar to the real thing. Pterosaur babies seem to have been hyperprecocial, and to have developed in thermal environments that were close to ambient, and the inference in the talk (and abstract) is that this implies a physiology for pterosaurs similar to that of extant lizards, turtles and crocodilians. I’m not sure it does. As demonstrated by mound-nesting birds (not all of which use vegetation mounds: the eggs may be buried in sand or soil), there is no tidy correlation between the degree of parental care and physiology.

Ok, loads more to come, but I have to stop there and go to work. In the next post I will cover such things as pterosaur pneumaticity, tapejarid ecology, the quarter-ton ‘It could look a giraffe in the eyes’ Quetzalcoatlus, and (hopefully) that amazing new Triassic taxon I mentioned previously.

Refs – -

Amundsen, T. 2000. Why are female birds ornamented? Trends in Ecology & Evolution 15, 149-155.

Fastnacht, M. 2001. First record of Coloborhynchus (Pterosauria) from the Santana Formation (Lower Cretaceous) of the Chapada do Araripe, Brazil. Paläontologische Zeitschrift 75, 23-36.

Martill, D. M. & Naish, D. 2006. Cranial crest development in the azhdarchoid pterosaur Tupuxuara, with a review of the genus and tapejarid monophyly. Palaeontology 49, 925-941.

Comments

  1. #1 David Marjanovi?
    September 18, 2007

    he has claimed the discovery of bizarre dorsal frills and enormous soft-tissue cranial crests, multiple hitherto-unseen babies, novel details of dentition (even in taxa universally regarded as edentulous), and much else besides.

    I should mention that the babies are entirely unossified, which is simply not possible, are often clustered around very juvenile specimens, which is highly suspect, and, on closer inspection, turn out to be in at least some cases to be unrelated irregularities of the matrix itself (see face and pyramids on Mars).

  2. #2 Dave Hone
    September 18, 2007

    Wow, what a review! Many thanks. I’ll link Dinobase to this as soon as I am able. I fly in 18 hours and have just started packing….. oh dear.

  3. #3 Mike Keesey
    September 18, 2007

    the new taxon Thalassodrominae, coined for Thalassodromeus and Tup. leonardii, but I don’t recall this being mentioned in the talk. If these two taxa really do group together, Tup. leonardii would need a new generic name

    Why are vertebrate paleontologists so in love with monospecific genera nowadays? Surely if these two species belong to the same clade, exclusive of other known species, then the natural name for it is … Thalassodromeus?

  4. #4 Greg Morrow
    September 18, 2007

    Any chance of seeing your poster sessions reproduced here?

  5. #5 Nick
    September 18, 2007

    Alex’s abstract mentions the new taxon Thalassodrominae, coined for Thalassodromeus and Tup. leonardii

    Uh…He means ThassodromEinae, right?

    [from Darren: well, that's not how it's spelt in the abstract]

  6. #6 Darren Naish
    September 18, 2007

    Thanks to all for comments. Some responses… Mike wrote..

    Why are vertebrate paleontologists so in love with monospecific genera nowadays? Surely if these two species belong to the same clade, exclusive of other known species, then the natural name for it is … Thalassodromeus?

    Well, if – hypothetically – these two taxa do form a clade, they’re still subjectively ‘different enough’ to remain as distinct genera. And, yes, I used my patented Holtz genericometer to work this out. In other words, if they do form a clade, I’m not sure why they have to be assumed to be so close as to be congeneric.

    Greg wrote…

    Any chance of seeing your poster sessions reproduced here?

    That’s a really good idea. I don’t have the file (nor was I smart enough to photograph the poster), I’ll get it off Dave once he’s settled in at his new office.

  7. #7 Nathan Myers
    September 18, 2007

    If ever there was a pterosaur I would guess had given up flight for a less strenuous terrestrial existence, it would be Quetzalcoatlus. Do we have any good reason to believe it still flew? I don’t think wing membranes tell us anything certain; those could have been necessary to retain for mating display, and/or to provide shade so it could see what was under the water. Is there any adaptation other common to terrestrialized birds that we would expect to find if Q. had taken that route?

  8. #8 Zach Miller
    September 18, 2007

    Well, Quetzalcoatlus had awfully long wings, and its movement would’ve still been restricted by the patagium on its arms and possibly legs (although pterodacyloids seemed more able to move on land than their long-tailed cousins). One would think that a truly terrestrial pterosaur would shrink down its enormous fourth finger, but who knows.

  9. #9 Nick
    September 18, 2007

    Uh…He means ThassodromEinae, right?

    Argh. That should be Thalassodromeinae, of course.

  10. #10 neil
    September 18, 2007

    Because both sexes in some pterosaur species are ornamented, it has sometimes been doubted that the crests might have had a role in sexual display. But it is well established that, particularly in birds, both sexes can be ornamented (for a recent review see Amundsen 2000). We’re going somewhere with this, stay tuned.

    I scratched my head rather hard at a recent talk on dinosaur ornamentation where the presenter stated flatly that dimorphism was a prerequisite for sexual selection. I asked him specifically about pterosaurs and got the reply ‘short story? yeah it’s the same as in dinosaurs, it’s all about species recognition.’

    I suppose that working out that your potential mate is a conspecific is sort of the base-level criterion for sexual selection…but surely some of these elaborate structures go beyond that? I look forward to hearing the long story.

  11. #11 Alan Kellogg
    September 18, 2007

    When you get down into it taxonomy is rather generic. Though it does get into the specifics at times.

    Nathan, Quetzy was just not built for living on the ground. Very light, very fragile. You want something substantially more substantial when you’re ground bound.

  12. #12 Alan Kellogg
    September 18, 2007

    When you get down into it taxonomy is rather generic. Though it does get into the specifics at times.

    Nathan, Quetzy was just not built for living on the ground. Very light, very fragile. You want something substantially more substantial when you’re ground bound.

  13. #13 Mike Keesey
    September 19, 2007

    Well, if – hypothetically – these two taxa do form a clade, they’re still subjectively ‘different enough’ to remain as distinct genera. And, yes, I used my patented Holtz genericometer to work this out. In other words, if they do form a clade, I’m not sure why they have to be assumed to be so close as to be congeneric.

    It’s all about nomenclatural utility. I’m under no illusions that one genus is somehow “equal” to another, nor should anyone be. What it really boils down to is giving something a new name when there’s already one in existence. Why bother?

    Or, to put it another way, why are we bothering to give species names to Mesozoic tetrapod fossils at all, if we’re just going to sort them all into monotypic genera anyway?

  14. #14 nemo ramjet
    September 19, 2007

    Amazing overview, Darren!
    Dave Peter’s bizzare views interest me very much, do you think there’s a resource of his ideas on the net? There used to be a site called The Pterosauria, but it seems to be down and out now…

  15. #15 David Marjanovi?
    September 19, 2007

    Or, to put it another way, why are we bothering to give species names to Mesozoic tetrapod fossils at all, if we’re just going to sort them all into monotypic genera anyway?

    That is the real question. After all, to apply any species concept (except the chronospecies concept maybe… never mind), we have to at least pretend approximating some kind of population biology. With Mesozoic tetrapods, we can almost never do that, so giving them species names is frankly nonsense. I’m not the first to notice that “species names are just for honoring colleagues”.

    Of course, we all know the reason why it’s still done: the ICZN wants it so.

    It is a big advantage of the PhyloCode that it does not require putting every organism into a species in order to put it into a named taxon. If I discover a new placodont LITU in my thesis, I won’t pretend I know it’s a species under any of the 25-or-so concepts out there. I’ll just name a clade for it.

    There’s a paper on phylogenetic nomenclature that has “classifying species vs. naming clades” in the title, IIRC.

  16. #16 Georgalis Georgios
    September 19, 2007

    Very interesting all these, but please let’ not fight again for the nomenclature issue. We all know that ICZN is a little strict, but this is a matter of tradition and thus : stability. So, with all the respect David, lets just follow the binomianals. Palaeontology has more important tasks to solve.

  17. #17 David Marjanovi?
    September 20, 2007

    but this is a matter of tradition and thus : stability.

    How is it stability if the name of a species changes every time someone shifts it — for whatever reasons or lack thereof — from one genus to another?

    But that’s a completely different problem. I haven’t said anything against recognizing and naming species, not even against using binominals for that. I’m only against pretending we can recognize a species (under any species concept) in those cases when in fact we can’t. Under the ICZN we have to pretend — for no particular reason. Why can’t we name a genus and directly give it a type specimen instead of a type species? We simply aren’t allowed to, for no reason I can see.

  18. #18 Lars Dietz
    September 20, 2007

    Nemo: Dave Peters is apparently reinventing the whole amniote phylogeny now (with results that look rather strange to others. As far as I know, he doesn’t have a website any more, but he apparently published some stuff in Prehistoric Times. I haven’t seen this, but it’s been mentioned on the DML.

  19. #19 Georgalis Georgios
    September 20, 2007

    For sure it is a matter of pretending and obeying some laws. I was meaning that binominals is just a mean of classification. I agree that some times is rather complicating, with so many species being transfered from genus to genus, but in my opinion this nomenclature is one of the meeting points between zoology and palaeozoology.

  20. #20 David Marjanovi?
    September 21, 2007

    “Meeting points”? As its name says, palaeozoology is a part of zoology. It consists only of meeting points. :-)

  21. #21 Mike Keesey
    September 21, 2007

    but in my opinion this nomenclature is one of the meeting points between zoology and palaeozoology.

    (Side note: paleozoology is part of zoology. You probably mean neozoology vs. paleozoology.)

    For Recent species, maybe. For everything else, clades are where the disciplines meet.

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