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Research Article

A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology

  • Mark P. Witton mail,

    Mark.Witton@port.ac.uk

    Affiliation: School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom

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  • Darren Naish

    Affiliation: School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom

    X
  • Published: May 28, 2008
  • DOI: 10.1371/journal.pone.0002271
  • Published in PLOS ONE

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Response to “A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology.“

Posted by DavidPeters1247 on 22 Apr 2013 at 03:49 GMT

Witton and Naish (2008) reexamined the probable feeding niche employed by the largest pterosaurs, the azhdarchids. I agree with their hypothesis that azhdarchid pterosaurs did not feed while skimming, as other pterosaurs probably did. Instead they argued that azhdarchids were stork- or ground hornbill-like generalists, foraging in diverse environments for small animals and carrion because they were poorly suited for all proposed lifestyles bar terrestrial foraging. They dismissed wading as a niche because footprints show that their feet were relatively small, padded and slender, and thus not well suited for wading.

Unfortunately, modern long-legged waders, like the black-necked stilt (Himatopus mexicanus) have relatively small, slender toes with virtually no webbing. So such toes and long legs are indeed perfectly suited to wading.

Witton and Naish (2008) reported, “Moreover, other pterodactyloids with larger pedal surface areas (most notably ctenochasmatoids) were almost certainly better adapted waders than azhdarchids.”

The ctenochasmatid clade does have relatively larger feet, but much shorter legs, better suited to shallower waters with shifting sands and surf like those surrounding Solnhofen islands. This is distinctly different from the long-legged wading azhdarchids adapted for deeper quieter inland lake waters.

Other problems are phylogenetic in nature.

1. Witton and Naish (2008) mistakenly include Bakonydraco with the azhdarchids. Bakonydraco phylogenetically nests with eopteranodontids/eoazhdarchids (Peters 2007).

2. Witton and Naish (2008) mistakenly nest tupuxuarids with azhdarchids because they share a few convergent traits. Phylogenetic analysis indicates that tupuxuarids are derived from a distinct clade of germanodactylids. Azhdarchids are derived from dorygnathids (Peters 2007).

3. Witton and Naish (2008) also incorrectly nest toothless Pteranodon with toothy Anhanguera (Peters 2007).

Still other problems are morphological in nature.

Witton and Naish (2008) report, “Langston [17], Wellnhofer [24] and Chatterjee and Templin [16] reconstructed azhdarchids with narrow brachiopatagia extending to the top of the hindlimbs, whereas Frey et al. [74] suggested that the membrane extended to the ankle, forming a much broader wing. No fossilised azhdarchid wing membranes are known, but evidence from anurognathids, campylognathoidids, rhamphorhynchids, ctenochasmatoids and non-azhdarchid azhdarchoids [86]–[91] indicates that ankle-attached wing configurations are more accurate.” My independent examination of the data (Peters 2001, not cited by Witton and Naish 2008) agrees with the Langston narrow-chord interpretation for all pterosaurs. No pterosaur shows an attachment to the ankle. All pertinent examples (e.g. the Zittel wing of Rhamphorhynchus (BSP 1880 II 8), the Vienna wing of Pterodactylus (NHMW 1975/1756), the holotype of Jeholopterus (IVPP V 12705) (Peters 2001)) show an attachment to the top of the hindlimbs following a fuselage fillet. Thus little confidence can be placed with any arguments advanced by Witton and Naish (2008) for hypothetical capabilities based on their fictional wing shape.

Witton and Naish (2008) report, “The size of these forms also dictates that they would need to process enormous amounts of probed invertebrates to sustain themselves.” Unfortunately they failed to note that azhdarchids had the relatively smallest torso of all pterosaurs and that implies they had the smallest stomach as well. Furthermore, it’s not uncommon to see dozens of wading birds from several different genera picking at a small patch beneath a shallow body of water. Now, simply exchange dozens of wading birds for a few wading azhdarchids in waters too deep for other waders and there’s undoubtedly enough food to go around, in place and not running away or fighting back like terrestrial tetrapods do.

In summary, the difference between terrestrial foraging and shallow water wading probably cannot be determined by the factors brought up by Witton and Naish (2008). Deeper water wading seeking buried invertebrates remains a possible niche environment for long-legged giant azhdarchids.

Peters D 2002. A New Model for the Evolution of the Pterosaur Wing - with a twist. Historical Biology 15: 277-301
Peters D 2007. The origin and radiation of the Pterosauria. 
Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27
This pterosaur clade phylogenetic analysis has been expanded at www.reptileevolution.com/....


No competing interests declared.

RE: Response to “A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology.“

DNaish replied to DavidPeters1247 on 25 Nov 2013 at 21:46 GMT

Response from the authors (Mark P. Witton and Darren Naish)...

We are pleased that Peters agrees with our argument that azhdarchids were not skim-feeders. With respect to his other comments – some of which purport to challenge our favoured ‘terrestrial stalking’ hypothesis (Witton and Naish 2008) – we disagree and here respond to his claims. We also wish to bring to attention the unusual misplaced confidence that Peters displays with respect to his own favoured ideas, hardly any of which (or none of which) are supported by other students of the Pterosauria.

-- Peters claims that Himantopus (note: not ‘Himatopus’) has “small, slender toes with virtually no webbing”, and hence has a foot comparable to that of members of Azhdarchidae. He also notes that this generalisation is true of other modern long-legged waders. What he fails to note or bring to the reader’s attention is that modern wading birds – Himantopus included – possess a spreading foot, where the three toes are separated by enormous interdigital angles exceeding 50°. In the azhdarchid foot, in strong contrast, the toes are parallel and closely spaced, resulting in a wholly different form of contact with the substrate. To repeat the point made in our paper (Witton and Naish 2008): the proportionally small, narrow, well padded feet of azhdarchids appear best suited for terrestrial foraging in terrestrial environments; they are essentially inconsistent with evolutionary selection for a regular wading habit. As regards Peters’s claim that azhdarchids differed from ctenochasmatids in being “adapted for deeper quieter inland lake waters”, we have to regard this as a just-so story that does not match the evidence compiled and discussed in our paper (Witton and Naish 2008).

-- Peters also notes various disagreements with some of our statements about the phylogenetic affinities of assorted pterosaur taxa. Readers should note that there is substantial disagreement over the details of pterosaur phylogeny and systematics, and that – while many areas of consensus do exist – studies differ considerably with respect to the affinities of pterosaur groups. With this in mind, it is misleading to state (as Peters does) that certain claims are ‘mistaken’ or ‘incorrect’. No, they are not ‘mistaken’ or ‘incorrect’: rather, they represent views differ from his own. Readers should also note that Peters generates his own highly idiosyncratic phylogenetic hypotheses that have yet to be supported or recovered by other workers; indeed, there are suspicions that they are erroneous due to problems with character identification and coding (Peters uses a unique photo-interpretation technique that has not withstood scrutiny), and to misapplication of phylogenetic methods (Peters includes a substantial number of juvenile specimens within his analyses, for example: his initial assumption being that these are adults which will ‘behave’ like adults when coded for analysis). For previous critiques of Peters’s ideas, methods and conclusions, we point the reader to Bennett (2005) and Naish (2012).

-- Peters also points to his disagreement with our interpretation of azhdarchids as possessing relatively broad brachiopatagia that reach the ankle region. We do not cite Peters’s 2002 paper on this subject because we do not agree with any of his conclusions. As is well known among pterosaur workers, Peters believes that, by analysing photographs on his computer, he can see the edges of wing membranes: alas, direct examination of the same specimens does not support his claims. He also disagrees with suggestions that the brachiopatagium reaches the ankle (or, at least, distal portion of the tibia) in diverse pterosaur taxa whereas our examination of specimens indicates that this is indeed the case across the pterosaur tree (Peters repeatedly cites the Zittel Rhamphorhynchus wing in connection with this argument, despite the fact that its trailing margin is known to have been extensively doctored). Based on the ankle attachment of the brachiopatagium observed in Eudimorphodon (MCSNB 8950), Sordes, the ‘dark wing’ Rhamphorhynchus, the Crato azhdarchoid SMNK Pal 3830 and other specimens (Naish 2010, Elgin et al. 2011), we conclude that Peters’s ideas about a strongly reduced brachiopatagium are in error.

-- Finally, Peters notes disagreement with our view of azhdarchids as animals requiring large terrestrial resource bases for nourishment, proposing that deep-water wading in azhdarchids could well provide their nutritional needs. We thank Mr Peters for his quaint and pleasant view of fictional pterosaurs and, while we don’t disagree with his general contention here, we would remind him that science is about looking at pieces of evidence. As recently restated in another paper (Witton and Naish 2013), azhdarchid anatomy, functional morphology and palaeoenvironmental setting strongly support our proposal that these animals were terrestrial foragers, most closely akin to
modern analogues like ground hornbills.

References --

Bennett, S. C. 2005. Pterosaur science or pterosaur fantasy? Prehistoric Times 70, 21-23, 40.

Elgin, R. A., Hone, D. W. E. and Frey, E. 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56, 99-111.

Naish, D. 2010. Tetrapod Zoology Book One. CFZ Press, Bideford.

Naish, D. 2012. Why the world has to ignore ReptileEvolution.com. Tetrapod Zoology http://blogs.scientificam...

Witton, M. P. & Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS One 3(5), e2271.

Witton, M. P. & Naish, D. 2013 Azhdarchid pterosaurs: water-trawling pelican mimics or "terrestrial stalkers? Acta Palaeontologica Polonica doi:http://dx.doi.org/10.4202...

No competing interests declared.

RE: RE: Response to “A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology.“

DavidPeters1247 replied to DNaish on 26 Nov 2013 at 19:53 GMT

It is important not to let the hopeful arguments of Witton and Naish stand unanswered.

1. With regard to spreading vs. parallel toes, there is no difference with regard to the square footage implanted in the substrate, whether muddy or dusty. So any argument dismissing parallel toes in favor of spreading toes has no validity. Witton and Naish’s quote that azhdarchid feet “appear best suited for terrestrial foraging” is not followed by any studies or experimentation, so this is a hopeful statement. Here is the evidence: Pterosaurs known to be waders, like the filter-feeder, Pterodaustro, have parallel toes, like those of azhdarchids. Moreover, the ground hornbill, like the stilt, also has spreading toes with footprint evidence here:

http://www.conservenature...

2. My “highly idiosyncratic phylogenetic hypotheses,” to quote Witton and Naish, is simply their way of saying that I was the first to include tiny and small pterosaurs that were previously ignored by other workers. When employed (see below) these prove to be key taxa linking major clades. Phylogenetic size reduction in pterosaurs follows similar evolutionary patterns exemplified by small basal dinosaurs and crocs, small basal birds, small basal mammals and small basal reptiles. As long as other pterosaur workers continue to ignore small pterosaur specimens their pterosaur family trees will continue to be rife with problems. Their purported sisters often do not resemble one another morphologically, which is a continuing problem that has been conveniently ignored.

Prior workers assumed that tiny pterosaurs were morphologically distinct juveniles of larger species. But the evidence documents just the opposite. Zhejiangopterus, an azhdarchid pterosaur, is known from a variety of sizes and the smallest of them has a long rostrum and tiny orbit, falsifying the current hypothesis of allometric growth in pterosaurs supported by Witton and Naish. The Zhejiangopterus growth series is documented and illustrated here:

http://pterosaurheresies....

Embryo pterosaurs also greatly resemble adults in morphology documenting isometric growth in pterosaurs here:

http://pterosaurheresies....

By the current evidence, most allometric growth in pterosaurs occurred within the eggshell.

3. With regard to pterosaur wing membrane trailing edge attachment points, Bennett 2013 recently confirmed the thigh attachment in the Vienna specimen of Pterodactylus. Witton and Naish report the trailing margin of the Zittel specimen has been “extensively doctored,” which is news to me since this misinformation is not otherwise in the literaure. Moreover, there is no reason why a scientist would want to trim off excess wing membrane from an otherwise excellent specimen.

4. Bennett, Witton and Naish have been critical of my methods and conclusions, but note that the criticism has cut both ways over the past few years. These three are not beyond making their own mistakes. Naish’s 2012 criticism refers to work that I had previously dismissed as wrong, rather than current work, as shown at www.reptileevolution.com, a website that is continually updated as errors are discovered. Specific errors by Bennett, Witton and Naish are listed and explored at www.pterosaurheresies.wor.... In any case, discovering errors and making corrections is the bedrock of Science. So blackwashing a worker’s entire output and future output, as Naish is wont to do, is inappropriate at best.

5. Finally, where an animal finds its lunch is not something that is going to come very often with fossil evidence. I argued against the hypotheses of Witton and Naish by offering examples they had not considered, like the tiny narrow toes of the living stilt.

6. With regard to prey volume, where you find one wading bird, you often find dozens to hundreds, all feeding, so the amount of food available underwater vs. on land is probably not an issue.

To sum up all of my arguments with a single example:
when you include small pterosaurs in phylogenetic analysis, you find that giant azhdarchids evolved from morphologically similar, but tiny protoazhdarchids, like CM 11426, just 17cm tall. Like giant azhdarchids, this specimen had a long rostrum, elongated neck, extremely elongated metacarpals and a long thin tibia with a narrow pes. Like azhdarchids, manual 3.1 was robust and the wing finger was not much taller than the first dorsal vertebrae when standing quadrupedally. Moreover, this specimen preserves the very narrow chord wing membrane promoted in Peters 2002, duplicated in the Vienna specimen and Zittel wing, and falsely dismissed as the result of “membrane shrinkage” by Elgin et al. 2011. To Elgin et al. this preservational fact had to be explained away, rather than accepted ‘as is’. The Elgin et al. 2011 paper has several other observational errors all reinterpreted here with photographs and overlays:

http://www.reptileevoluti...

So given this tiny protoazhdarchid (CM 11426) we have evidence for a tremendous spectrum of phylogenetic sizes of the same morphology, each of which probably had its own niche due to size. Azhdarchid tracks, like other ichnites, are often made in wet substrates, usually found around retreating and advancing bodies of water. So that fact biases niche hypotheses toward the aquatic and beachcombing side. Storks, herons and other stork-like birds of all sizes are generally wading forms, finding their food at the waters’ edge. So there’s a ready-made analogy present for similarly configured azhdarchids. On the other hand, the ground hornbill favored by Witton and Naish, is derived from arboreal perching forms and does not resemble an azhdarchid pterosaur in general morphology. Rather germanodactylid pterosaurs resemble ground hornbills, with their deep sharp beaks -- but they are not related to azhdarchids.

I only hope that next time Witton and Naish wish to discuss giant azhdarchid traits, they trace those traits back to their petite origin, then work from that point forward to examine the development of the azhdarchid niche and diet. Azhdarchids did not start off as giants, and many never were giants.

Witton and Naish did not consider the tiny toes of stilts, so I felt is was necessary to bring that up along with their several other errors and omissions.

Witton and Naish were not able to ascertain with evidence that azhdarchids were terrestrial predators. Nevertheless, that does not exclude that possibility.

Ground hornbills do not look like azhdarchids. Storks and herons do. So this is where the best modern analogs are to be found. Witton and Naish did not show that ground hornbills, rather than storks, more closely resemble azhdarchids morphologically. They couldn't because they don't.

I agree with Witton and Naish who reminded me, “that science is about looking at pieces of evidence,” and I add, "not dismissing valid evidence that disagrees with pet hypotheses."

References -

Bennett SC 2013. Reinterpretation of the wings of Pterodactylus antiquus based on the Vienna specimen. Supplement to the online Journal of Vertebrate Paleontology October 2013: 85.

Elgin RA, Hone DWE and Frey E. 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56, 99-111.

Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. - Historical Biology 15: 277–301.


No competing interests declared.

RE: Response to “A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology.“

paleorob replied to DavidPeters1247 on 27 Nov 2013 at 23:05 GMT

Mr. Peters wrote, "Unfortunately, modern long-legged waders, like the black-necked stilt (Himatopus mexicanus) have relatively small, slender toes with virtually no webbing. So such toes and long legs are indeed perfectly suited to wading."
The fact that one wading organism possesses these plesiomorphic features does not mean that all organisms with these features is an adept wading predator.

Mr. Peters wrote, "Witton and Naish (2008) reported, “Moreover, other pterodactyloids with larger pedal surface areas (most notably ctenochasmatoids) were almost certainly better adapted waders than azhdarchids.”
I am unaware of any peer-reviewed publication looking at the wading capability of ctenochasmatoids so this statement is unsupported.

Mr. Peteres wrote, "The ctenochasmatid clade does have relatively larger feet, but much shorter legs, better suited to shallower waters with shifting sands and surf like those surrounding Solnhofen islands. This is distinctly different from the long-legged wading azhdarchids adapted for deeper quieter inland lake waters."
Again, which studies have been published with these results? PLoS One requires all comments to be evidence and fact based.

Mr. Peters wrote, "Unfortunately they failed to note that azhdarchids had the relatively smallest torso of all pterosaurs and that implies they had the smallest stomach as well."
I am unaware of any peer-reviewed publications that show the stomach size of azhdarchids (or any pterosaurs) either from soft tissue preservation or EPB-based inferences and energetics. Furthermore the size would be contentious due to the differences between published phylogenies and Mr. Peters' preferred phylogeny. The EPB method would yield potentially disparate results.

Mr. Peters wrote, "Furthermore, it’s not uncommon to see dozens of wading birds from several different genera picking at a small patch beneath a shallow body of water. Now, simply exchange dozens of wading birds for a few wading azhdarchids in waters too deep for other waders and there’s undoubtedly enough food to go around, in place and not running away or fighting back like terrestrial tetrapods do."
There is no support for any of the assertions in this statement. Wading birds and shore birds most certainly compete for resources and these intraspecific competitions can result in violence between organisms [1][2][3][4]. Ecology is far more complex than "simply" exchanging a number of small organisms with a few large-bodied organisms. This ignores a host of energetic issues that cannot simply be ignored including trophic levels and relative prey abundance.
I'd like to make one thing clear: I don't care if azhdarchids were waders or not. My only reason for this comment is Mr. Peters has made vast sweeping ecological generalizations without any sort of support. Mr. Peters has then used these statements as "support" for his hypothesis when in fact the hypothesis does not have the evidence required to support it.

1. Triplet, P., Stillman, R. A. and Goss-Custard, J. D. 1999. Prey abundance and the strength of interference in a foraging shorebird. Journal of Animal Ecology, 68: 254–265. doi: 10.1046/j.1365-2656.1999.00280.x
2. Stillman, R.A., J.D. Goss-Custard, and R.W.G. Caldow. 1997. "Modelling Interference from Basic Foraging Behaviour". Journal of Animal Ecology. 66 (5): 692-703.
3. Vahl, Wouter K., Jaap van der Meer, Franz J. Weissing, Diederik van Dullemen, and Theunis Piersma. 2005. "The mechanisms of interference competition: two experiments on foraging waders". Behavioral Ecology. 16 (5): 845-855.
4. Yates, Michael G., Richard A. Stillman, and John D. Goss-Custard. 2000. "Contrasting interference functions and foraging dispersion in two species of shorebird (Charadrii)". Journal of Animal Ecology. 69 (2): 314-322.

No competing interests declared.

RE: Response to “A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology.“

DNaish replied to paleorob on 28 Nov 2013 at 21:56 GMT

Final response from the authors (Mark P. Witton and Darren Naish)...

Arguing with the indefatigable Peters (something we have now done on many, many occasions) is infuriating, in part because we find ourselves disagreeing with virtually every statement made by this researcher. Readers should be aware to begin with that Peters’s arguments, hypotheses and bold proclamations are based predominantly on observations derived from a non-repeatable (and thus unscientific) method termed Digital Graphical Segregation (= DGS) in which fossils are scrutinised and traced in Photoshop software. This pareidolia-based technique – renounced as unscientific by all colleagues, to our knowledge (it has ‘allowed’ Peters to ‘find’ tens of bones supposedly missed by all the qualified experts who have actually looked at the fossils first-hand) – taints the entirety of Peters’s work, a fact which makes it all the more ironic that he is so scathing about the peer-reviewed contributions of others. Again, for previous critiques of Peters, see Bennett (2005) and Naish (2012). We present our argument here as a ‘last word’ and aim to be as concise as possible.

-- The ‘terrestrial stalking’ hypothesis proposed for azhdarchids is derived from evidence gathered from rostrum form, limb proportions, foot shape and proportional size, trackways, and palaeoenvironmental, palaeogeographical and taphonomic data (Witton and Naish 2008). Rather than supporting a “pet hypothesis”, we have done our best to present data from multiple lines of evidence that seemingly converge on the same answer. Since 2008 publication of our paper, the ‘terrestrial stalking’ hypothesis has received additional support from manus form (Carroll 2013), and from additional morphological, palaeoenvironmental and palaeogeographical data (Vremir et al. 2013, Witton and Naish 2013). As explained in our paper, azhdarchids lack features of the bony rostrum and feet expected of waders, no matter what Peters may wish. Peters is right that azhdarchids superficially recall herons and storks in overall form. As we note, however, azhdarchids lack the specific anatomical features that link these birds to a wading or aquatic feeding habit. This is obvious, yet Peters simply chooses to ignore it. On proportional foot size, Peters makes erroneous statements about birds and pterosaurs and physics and feet and the other things he mentions. Azhdarchids are large with relatively small, compact, narrow feet. Ctenochasmatid pterosaurs are not as large as azhdarchids, but they have proportionally far longer, wider feet that are frequently preserved with a somewhat spreading pose. Azhdarchids are not like wading birds, with their highly spreading toes and super-elongate hindlimbs. Some indication of how reliable Peters is as a researcher comes from his erroneous linking to a cartoon bird footprint, said by him to be an accurate representation of a ground hornbill track (ground hornbills are regarded by us as ecological analogues of azhdarchids). Real ground hornbill tracks show relatively small, well padded feet where the three anterior toes are near-parallel (http://blog.africageograp...): a condition more akin to that of an azhdarchid than a wading bird.

-- On phylogeny, Peters implies in his newest comments that the only reason for regarding his phylogenetic hypotheses as problematic comes from his being “the first to include tiny and small pterosaurs … previously ignored by other workers”. The numerous tiny pterosaurs that Peters refers to always turn out to be juveniles when examined by competent researchers, yet Peters simply assumes from the outset that they are tiny adults. It is widely recognised in the palaeontological community that coding juveniles as if they are adults skews and distorts phylogenetic results (indeed, part of a dinosaur ontogeny workshop session at the 2013 Society of Vertebrate Paleontology conference was devoted to discussion of this issue). As for Peters’s claims about ontogenetic changes and the appearance of embryos, we again point to the ubiquitous use of the DGS technique throughout Peters’s work. All of this aside, however, Peters cleverly ignores mention of the fact that his phylogenetic analyses are universally recognised as untrustworthy and erroneous due to enormous problems that betray an appalling misuse of phylogenetic methods: Peters’s trees sometimes include more taxa than they do characters (e.g., 230 characters for 300 taxa), for example, and there is sometimes substantial character duplication and coding error that well exceeds those expected as normal (for an independent assessment, see this article: http://theropoddatabase.b...). We do not regard any of Peters’s trees, and thus his phylogenetic hypotheses or scenarios, as in the least bit reliable. Accordingly, Peters’s suggestion that we should reconsider our hypothesis given that azhdarchids are (according to him) derived from “petite” “microazhdarchids” should be taken as yet another Petersian story based on non-repeatable, erroneous, idiosyncratic, DGS-based observations.

-- On wing membranes, we can only point to our comment above about the direct observations of fossils made by competent workers: it is certainly possible that pterosaurs with strongly reduced brachiopatagia might exist, but none of the cases cited or discussed by Peters (in his 2002 paper on online) withstand sceptical appraisal. Peters claims that knowledge of a ‘doctored’ edge on the Zittel wing is news to him (in fact, it has been mentioned in the literature (Unwin 2006) and in online debates involving Peters: http://dml.cmnh.org/2002D...). Bennett (pers. comm. 2013) argues that the specimen’s trailing edge is likely not modified. However, he still agrees that its form is consistent with attachment to the ankle. Peters’s claims that Bennett “recently confirmed the thigh attachment in the Vienna specimen of Pterodactylus” is completely false: the Bennett abstract that Peters has in mind (Peters did not observe the presentation itself, since he did not attend the relevant meeting) actually states that the appearance of a thigh-level attachment results from the way the membrane folds when the wing is closed, and that the actual attachment is, again, at ankle level (Bennett 2013, Bennett pers. comm. 2013).

Finally, it should be noted that many colleagues have urged us not to waste time replying to Peters here, and elsewhere. While we wish that the research time spent in crafting this response could have been spent elsewhere, we feel it important to respond to Peters’s arguments since he has become a serial and serious mis-educator of students and the uninformed public. We sincerely hope that readers will be able to determine the unreliability of David Peters as a source, detect the problematic and unscientific nature of his methods and hypotheses, and perhaps contribute to some effort that slows or prevents the dissemination of his misinformation.


Bennett, S. C. 2005. Pterosaur science or pterosaur fantasy? Prehistoric Times 70, 21-23, 40.

Bennett, S. C. 2013. Reinterpretation of the wings of Pterodactylus antiquus based on the Vienna specimen. Journal of Vertebrate Paleontology 33, Supplement to Issue 3, 85A.

Carroll, N. 2013. Functional morphology of the azhdarchid manus. Journal of Vertebrate Paleontology 33, Supplement to Issue 3, 102A.

Naish, D. 2012. Why the world has to ignore ReptileEvolution.com. Tetrapod Zoology http://blogs.scientificam...

Unwin, D. M. 2006. The Pterosaurs From Deep Time. Pi Press, New York.

Vremir, M., Kellner, A. W. A., Naish. D. & Dyke, G. J. 2013. A new azhdarchid pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: implications for azhdarchid diversity and distribution. PLoS ONE 8(1): e54268. doi:10.1371/journal.pone.0054268

Witton, M. P. & Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS One 3(5), e2271.

Witton, M. P. & Naish, D. 2013 Azhdarchid pterosaurs: water-trawling pelican mimics or "terrestrial stalkers? Acta Palaeontologica Polonica doi:http://dx.doi.org/10.4202...

No competing interests declared.