Where do we stand on the origin of pterosaurs today?

For most of the last 200 years,
all hypotheses of tetrapod interrelationships had to await novel and random discoveries as the number of known fossil taxa slowly accumulated over time. Expertise, persistence, access to the literature, access to fossil-bearing localities, teamwork and luck all played equal parts in helping this list to grow.

Nowadays in 2020,
we’re sitting on top of two centuries of discoveries preserved in museums, private collections and the literature. So figuring out the ancestors and sisters of any genus no longer depends on access to fossil-bearing localities, luck or teamwork. With persistence and access to the literature anyone can assemble a large taxon list, couple it with a large trait list, and recover a cladogram of tetrapod interrelationships using available software. Larger taxon lists are better because that minimize taxon exclusion, the number one problem with smaller studies.

Figure 1. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Back in 2011
PterosaurHeresies started with a 3-part review of pterosaur origins here, here and culminating here.  Peters 2000a, 2000b, 2002, 2007, 2009 and 2011 (plus a suppressed manuscript correcting earlier errors at ResearchGate.net), solved the problem of pterosaur origins and wing genesis. No new discoveries were required. Taxon inclusion neatly resolved the problem. That’s all it took… adding previously omitted taxa.

Unfortunately,
even in the present era of phylogenetic analysis by software (~1990 to the present), many pterosaur ‘experts’ continue to shrug their shoulders when the subject of pterosaur origins comes up (examples below). And they don’t really care about the genesis of pterosaurs either. If they did care, they would be running analyses that recover last common ancestors.

Ignoring the literature,
the PhDs are all still waiting for the discovery of an imaginary archosaur with a long fourth finger and a long fifth toe. For reasons unknown, the experts are overlooking the fact that archosaurs don’t have a long fourth finger or a long fifth toe. Even so, this ‘waiting for specimens’ tradition continues unabated in professional circles. Instead they should be looking for the last common ancestor of pterosaurs and its relatives among known fossil and extant taxa. Look here for an example cladogram that covers such a wide gamut of taxa that taxon exclusion is minimized: the large reptile tree (LRT, 1697+ taxa).

The imaginary dinosaur-pterosaur connection
is taught at all paleo universities. It is found in all college textbooks and popular books written by PhDs. It is repeated over and over in YouTube videos (see below). If you’re a paleo student and you want a passing grade, you have to give that answer to the professor, class after class, decade after decade, perpetuating the myth.

Given that the solution to pterosaur origins
has been in the peer-reviewed literature for the last 20 years, it’s almost comical how pterosaur workers dance around the question, “Where do pterosaurs come from?”.

“We don’t know,” is the most common answer.
The 20-year-old published hypothesis of pterosaur origins (Fig. 1, Peters 2000) continues to be ignored. That hypothesis was first labeled, “heterodox“(= different). Other PhDs (e.g. Mark Witton) labeled the author a crank. Still other PhDs (e.g. Darren Naish) attempted to divert the world away from solutions published online.

The more interesting quandary, however,
is the continuing predicament the PhDs have gotten themselves into and how it will continue indefinitely. Apparently there is just no way pterosaur workers are ever going to admit that an outsider solved the problem of pterosaur origins using the most common tool of the trade, phylogenetic analysis.

Apparently there is just no way any PhD or grad student is going to observe the specimens and repeat every aspect of the experiment that resulted in the 2000 solution to pterosaur origins. No one wants to be the second person to discover something, especially after it has been attacked from all sides or ignored for the last twenty years. Any move PhDs make now will make them all look bad. Not making any move also makes them look bad. They have a job to do. They should do it.

Pterosaur workers continue to ignore the pertinent taxa and omit the pertinent citations in favor of a myth (that pteros are dino cousins), even though they also loudly confess they have no evidence for support of that hypothesis. Often phytosaurs show up just outside the Pterosauria when fenestrasaurs are omitted or poorly scored.

In the following short video from 2009
watch German pterosaur experts Gunther Viohl and Peter Wellnhofer undercut previously published studies on pterosaur origins by remarking, “the ancestors are not known” and “in fact, it is a mystery which group of reptiles prior to the Triassic, might have given rise to the pterosaurs. So we don’t actually have the ancestor to the pterosaurs in the fossil record.”

The delighted Creationist narrator is then free to claim,
“No transitional forms have been found showing a ground lizard slowly changing into a flying reptile. There are no fossils of a ground reptile with partially developed wings. All of the known pterosaur fossils are perfectly developed.”

Actually
we do know of several ground lizards slowly changing into a flying reptile (Figs. 1, 2). They were re-described by Peters 2000 (see ResearchGate.net for additions and corrections).

Figure 2. Click to enlarge. The origin of the pterosaur wing and the migration of the pteroid and preaxial carpal. A. Sphenodon. B. Huehuecuetzpalli. C. Cosesaurus. D. Sharovipteryx. E. Longisquama. F-H. Bergamodactylus, MPUM 6009, a basal pterosaur.

Hone and Benton 2007, 2008 had high hopes
when they decided to test the results of Peters 2000 (Cosesaurus and kin as pterosaur ancestors) against the results of Bennett 1996 (Scleromochlus as a pterosaur ancestor). In their two-part paper Hone and Benton used the Supertree Method. It joins previously published cladograms, trusting their accuracy without observing specimens firsthand. Dr. Benton may have been waiting for a student interested in pterosaurs for several years because Benton 1999 agreed with Bennett 1996 in suggesting Scleromochlus was a pterosaur ancestor. Both ignored the fact that Scleromochlus had vestiges for finger 4 and toe 5, among dozens of other invalidating traits. Peters 2000 introduced better candidates and showed both PhDs were wrong by testing more taxa in four separate phylogenetic analyses based on prior studies, including Benton 1999 and Bennnett 1996.

Problems arose for Hone and Benton when their supertree results recovered Cosesaurus and kin as pterosaur ancestors. Rejecting this result, Hone and Benton dropped all data and reference to Peters 2000 and gave Bennett 1996 credit for coming up with both competing views. They had the bullocks to ignore the premise of their experiment, perhaps thinking their status as PhDs would save them. So far it has. Most of the rest of the paleo community has silently witnessed this odd turn of events without raising an objection or pointing a finger. Only Bennett 2012, 2013 reported the mistakes reported by Hone and Benton were of their own doing. Even so, Bennett 2012, 2013 continued to ignore taxa proposed by Peters 2000. Strange. Why put blinders on?

David Hone at his blogsite
ArchosaurMusings reports, “To cut a long story short, pterosaurs are damned difficult to place in the reptile tree. The truth of the matter is that currently the best supported hypothesis is that pterosaurs derived from the dinosauromorphs and thus are very close relatives of the dinosaurs.” Actually it’s not ‘damn difficult’. It simply takes more taxa. By the way, ‘the best supported hypothesis’ is not the best supported hypothesis. Rather it’s the one they teach at university, the one that omits Peters 2000.

The American Museum of Natural History
is likewise culpable. In the following video watch pterosaur expert, Alex Kellner, and Museum Director, Mark Norell, tell you pterosaurs are dinosaur relatives. But you’ll never see evidence of that because they don’t have it. It’s a traditional myth they cling to due to peer group pressure, not science.

Venerable PBS
became a frenemy of pterosaurs with the following video that omits the actual evolution of wings in favor of the traditional myth. Sadly, the promise of the headline is not fulfilled in the video.

Likewise, in the ‘It’s Okay to Be Smart’ video
Mike Habib perpetuates the archosaur origin myth. He also promotes an invalid, impossible and dangerous quad-catapult take-off technique (Fig. 3) rather than leaping and flapping at the same time for maximum thrust from the first nanosecond (Fig. 4) as birds do. He also promotes the invalid hypothesis of giant pterosaur flight.

Figure 3. Unsuccessful Pteranodon wing launch based on Habib (2008) in which the initial propulsion was not enough to permit wing unfolding and the first downstroke.

Figure 4. Successful bird-style Pteranodon wing launch in which the already upraised wing provides the necessary thrust for takeoff from moment one. This assumes a standing start and not a running start in the manner of lizards and some birds. Note three wing beats take place in the same space and time that only one wing beat takes place in the hazardous Habib model (Fig. 3).

Good scientists observe and report.
Then other good scientists repeat the experiment again and again to make sure the hypothesis is correct, rectifying errors as they appear. Sadly, that’s not what we observe among pterosaur workers.

Taxon exclusion is a powerful tool.
Some of you might remember when I was able to nest pterosaurs with turtles by taxon exclusion and again retested when more taxa were present. False positives are possible when using small taxon lists.

I never imagined
pterosaur workers would end up avoiding and suppressing a valid hypothesis in favor of a myth they admit they cannot support with evidence. Twenty years later there are still no competing papers on pterosaur origins that include accurate scoring for taxa in the Fenestrasauria and Tritosauria. This could still be a hot topic, but, no one is interested in finding out how pterosaurs got their wings anymore. Their preferred answer continues to be, “We don’t know.” The unspoken takeaway is,”and we’re not even going to try to find out because the status quo has been working for us.”

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References
Bennett SC 2008. Morphological evolution of the forelimb of pterosaurs: myology and function. Pp. 127–141 in E Buffetaut and DWE Hone eds., Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zitteliana, B28.
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoolological Journal of the Linnean Society 118: 261–308.
Benton MJ 1999. Scleromochlus taylori and the origin of the pterosaurs. Philosophical Transactions of the Royal Society London, Series B 354 1423-1446. Online pdf
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Bennett SC 2013. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology 25(5-6): 545-563.
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Habib M 2008. Comparative evidence for quadrupedal launch in pterosaurs. Pp. 161-168 in Buffetaut E, and DWE Hone, eds. Wellnhofer Pterosaur Meeting: Zitteliana B28
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Mazin J-M, Billon-Bruyat J-P and Padian K 2009. First record of a pterosaur landing trackway. Proceedings of the Royal Society B doi: 10.1098/rspb.2009.1161 online paper
Padian K. 1984. The Origin of Pterosaurs. Proceedings, Third Symposium on Mesozoic Terrestrial Ecosystems, Tubingen 1984. Online pdf
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Hist Bio 15: 277–301.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330
Prondvai E and Hone DWE 2009. New models for the wing extension in pterosaurs. Historical Biology DOI: 10.1080/08912960902859334
Senter P 2003. Taxon Sampling Artifacts and the Phylogenetic Position of Aves. PhD dissertation. Northern Illinois University, 1-279.
Sereno PC 1991. Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology 11 (Supplement) Memoire 2: 1–53.
Sharov AG 1971. New flying reptiles fro the Mesozoic of Kazakhstan and Kirghizia. Trudy of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Woodward AS 1907. On a new dinosaurian reptile (Scleromochlus taylori, gen. et sp. nov.) from the Trias of Lossiemouth, Elgin. Quarterly Journal of the Geological Society 1907 63:140-144.

https://pterosaurheresies.wordpress.com/2017/11/26/why-do-pterosaur-workers-ignore-the-most-basic-data/

Pterosaurs NOT an enigmatic group, contra Belben and Unwin 2019

The following abstract
was presented during the most recent SVPCA meeting in 2019.

Belben and Unwin 2019
are both associated with the University of Leicester. Sadly, Dr. Unwin has been responsible for many of the inaccurate to totally wrong ideas many current pterosaur workers and artists now consider as canon. Think Sordes and the deep chord bat-wing membrane stretching to the ankles hypothesis and the incorporation of pedal digit 5 into the single uropatagium stretching between the two. Think pterosaur eggs laid deep under brush or under ground. Think the archosaurian genesis for pterosaurs. Think the Monofenestrata hypothesis of relationships.

I’ll break down today’s abstract for you
as yet another example of Dr. Unwin stuck in his own groove outside of science and reality, much of it due to inaccurate observation and taxon exclusion, both of which are curable maladies.

From the Belben and Unwin 2019 abstract:
“Quantitative taphonomy [see below for definition] has huge potential for furthering our understanding of vertebrate palaeobiology. So far, however, it has been a neglected field with little development. Here we show how quantitative taphonomy can be used to determine the ‘bauplan’ of pterosaurs.

With well over 250 good fossils, many complete skeletons, some of these with extensive soft tissue, we already know the ‘bauplan’ of pterosaurs very well (Fig. 1). Start here for an introduction and links.

“With no descendants and a unique morphology, pterosaurs remain an enigmatic group despite a high degree of research interest for over 200 years.”

Pterosaurs do not have a unique morphology, nor are they an enigmatic group. Peters 2000a b, 2002, 2007, 2009 showed the pterosaur ‘bauplan’ arose gradually from a clade of taxa Dr. Unwin refuses to recognize, the Fenestrasauria, nor does he cite the above references. Dr. Unwin prefers to keep his objects of study in the ‘enigmatic’ jar for reasons that should baffle any reputable scientist. If you wonder why I have to self-cite, welcome to the world of paleo politics where academics don’t argue against a hypothesis, they don’t cite it.

“One aspect still debated is the basic construction and extent of the wing membrane, fundamental to locomotory abilities and other key aspects of their biology.”

The wing membrane question was settled over a decade ago and need not be debated because every example of pterosaur wing membrane presents the same conservative pattern: stretched between elbow and wing tip with a fuselage fillet. (Peters 2002). Precursor membranes are known in Cosesaurus (Peters 2009) and are less obvious in Longisquama. The pteroid and preaxial carpal arise from a migration of two centralia (Peters 2009). Details summarized here.

“Did the wing membrane connect all four limbs, bat-like, forming a single flight surface and single anatomical module? Were they bird-like, with separation of limbs to create four anatomical modules? Or were they a unique two or three module construction?”

This has never been a question for Dr. Unwin before. He has always promoted the invalid bat-like wing design and the invalid single uropatagium design.

Figure 1. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees and a precise impression of the wing membranes as they were. The animation extends the limbs into the flight configuration.  

“Soft tissue evidence is patchy and found in only a tiny number of species, and the insights it provides is limited.”

False. Dr. Unwin knows better. There are many excellent examples of soft tissue only one of which (Fig. 1) would be necessary to answer the wing membrane and uropatagia issues. The rest confirm the first (Peters 2002).

“Quantitative taphonomy, through metrics of completeness, articulation, and joint geometry, can test limb association, and help identify anatomical modules.”

Dr. Unwin, why don’t you stop avoiding the number one issue and just once accurately trace your first pterosaur specimen with soft tissue. Study it. Play with it. Reconstruct it. Animate it. Score it for a wide range of traits against all the 240 best known pterosaur specimens, as shown here. I think you’ll find the process enlightening and you’ll finally be able to teach your students something about your favorite subject without cloaking pterosaurs in question marks. Don’t be seen as the bumbling professor who held back pterosaur research for several decades by sticking to your invalid postulates. When the word gets out, you may find it hard attracting students, which is your livelihood.

Examining the quantitative taphonomy (= depositional setting, = everything but the pterosaur itself) only delays the inevitable day of reckoning when you will have to finally, seriously and precisely trace a pterosaur specimen and present your findings for critical review.

“Over 100 pterosaurs have been analysed thus far, with an intended data set of 200+ individuals from more than 40 species representing all principal clades. This will allow different models to be mapped across the phylogeny.”

Are you examining the quantitative taphonomy of 200+ individuals or the 200+ individuals themselves? Sounds like the former is in play. Please don’t attempt to map the different taphonomic models across your incomplete cladogram to find out what a pterosaur ‘bauplan’ is. Instead, start with the Vienna specimen of Pterodactylus (Fig. 1). Get precise with it. Don’t pass the chore down to a grad student seeking approval and fearing for their grade. Use the large pterosaur tree (LPT, 240 taxa) for sister taxa. Trace and reconstruct your own specimens. You can pull yourself out of your self-inflicted academic muck!

“Fossil birds and bats will be similarly analysed in order to provide context and constrain the models, as their bauplan can be safely inferred from extant forms.”

Figure 1. Click to enlarge and animate. Cosesaurus flapping – fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.

That’s nice. But birds and bats are not related to pterosaurs nor to each other. Why not stop wasting your time and go see Cosesaurus, Sharovipteryx and Longisquama. Don’t forget Langobardisaurus, Macrocnemus and Huehuecuetzpalli. Don’t stop until you can reconstruct and score them in your sleep. Dr. Unwin, you’re stuck in the tail-dragging dark ages. You’re supposed to be a pterosaur expert, so quit calling them enigmas. You need to turn your mind around. The following citations might help.

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References
Belben R and Unwin D 2019. Quantitative taphonomy – they key to understanding the pterosaur bauplan?
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
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. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.

Quantitative taphonomy = “This approach uses the hypothesis that taphonomic alteration varies in a predictable way with depositional setting. In other words, each specific environment (e.g., low-salinity muddy bay, storm-dominated clastic shelf) is characterized by a unique suite of physical, chemical and biological processes: these processes imprint a unique and predictable “taphonomic signature” on the death assemblage.” Davies et al.  2017

 

SVP 2018: Reproduction and Growth in Pterosaurs

Unwin and Deeming 2018 report,
“Pterosaur eggshells were pliable and occasionally bounded externally by a thin calcitic layer. Contact incubation seems impractical and eggs were likely buried and developed at ambient temperatures.”

Burial is not only unnecessary, but dangerous
given that pterosaurs are lepidosaurs and therefore able to retain eggs within the mother until just before hatching, something the authors continue to ignore. That’s why the eggs have lepidosaur-like ultra-thin external layers. No tiny fragile pterosaur wants to dig out of a buried situation. Too dangerous for fragile membranes. Unwin and Deeming are clinging to an archosaur hypothesis, ignoring all the data since Peters 2000 that nest them apart from archosaurs.

Figure 1. The V263 specimen compared to other Pterodaustro specimens to scale.

The authors report,
“Near term embryos were well ossified and hatchlings had postcranial proportions and well developed flight membranes that indicate a superprecocial flight ability.” 

As in lepidosaurs, not archosaurs.
Overlooked by the authors, cranial proportions are also adult-like in hatchlings (Fig. 1). Lepidosaurs hatch ready to eat and take care of themselves.

Regarding growth, they report,
“The growth rates recovered for pterosaurs are comparable to those reported for extant reptiles and a magnitude lower than in extant birds.” Here the authors are lumping turtles, lizards and crocs, when lizards will do.

Figure 2. Click to enlarge. There are several specimens of Zhejiangopterus. The two pictured in figure 2 are the two smallest above at left. Also shown is a hypothetical hatchling, 1/8 the size of the largest specimen.

Note,
the authors do not address isometric growth in their abstract, as in lepidosaurs, not archosaurs. Nor do they address sexual maturity at half full growth, which facilitates rapid phylogenetic miniaturization or gigantism whenever needed due to changing environs.

We’ve heard this all before. Years ago.

Respecting the embargo
other SVP abstract posts will show up after the 20th. This one made the news, so its embargo is over. That article featured BMNH 42736 (Fig. 3) labeled as a hatchling or flapling. Actually it’s a hummingbird-sized adult female. We know this because it nests with other phylogenetically miniaturized taxa in the large pterosaur tree (not with a larger specimen) and… it’s pregnant.

Figure 6. Torso region of BMNH 42736 showing various bones, soft tissues and embryo.

References
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Unwin DM and Deeming C 2018. An integrated model for reproduction and growth in pterosaurs. SVP abstracts.

Live Science online

What would pterosaurs be, if tritosaurs were not known?

This is lesson 4 in taxon exclusion…
to see where select clades would nest in the absence of their proximal taxa.

Now that
the large reptile tree has grown more than three fold in the last seven years, it’s time to ask (or ask again) some phylogenetic questions.

Figure 1. Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown.

Traditionally
pterosaurs are nested with archosauriformes, like Scleromochlus, close to dinosaurs, but only in the absence of fenestrasaurs and tritosaurs. In the large reptile tree (LRT, 1242 taxa), which includes representatives from all tetrapod clades, pterosaurs nest with fenestrasaurs (Peters 2000) and tritosaur, lepidosaurs (not prolacertiformes (contra Peters 2000, who did not test Huehuecuetzpalli, which came out in 1998).

In the absence of tritosaurs (and Archosauromorpha)
pterosaurs nest with drepanosaurs, both derived from Jesairosaurus.

In the absence of tritosaurs (and Lepidosauromorpha)
pterosaurs nest between Mei and Yi among the scansoriopterygid birds (Fig. 2) which are derived from Late Jurassic Solnhofen bird taxa, too late for the Late Triassic appearance of pterosaurs like Bergamodactylus (Fig. 1).

Figure 2. Two Mei long specimens, one in vivo, one in situ.  Click to enlarge.

Taxon exclusion
has been the number one problem in traditional paleontology. That’s why the LRT includes such a wide gamut of taxa. The result is a minimizing of taxon exclusion and the problems that attend it.

References
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

False pterosaur propaganda over at Wikipedia

On occasion I take a look at the Wikipedia page
on Pterosaurs to see where the authors have edited in Peters 2000 in or out on the origins section. At present this is what the Wiki authors say. My comments follow in bold.

“Like the dinosaurs, and unlike these other reptiles, pterosaurs are more closely related to birds than to crocodiles or any other living reptile.” [false, living lepidosaurs are closer]

“Origins
Because pterosaur anatomy has been so heavily modified for flight, and immediate transitional fossil predecessors have not so far been described [false, see Peters 2000], the ancestry of pterosaurs is not fully understood [false, see Peters 2000]. Several hypotheses have been advanced, including links to the avemetatarsalian-like Scleromochlus, an ancestry among the basal archosauriforms, like Euparkeria, or among the protorosaurs.

Two researchers, Chris Bennett (1996) and David Peters (2000), have found pterosaurs to be protorosaurs or closely related to them [false, Bennett nested pterosaurs between Proterosuchus and Erythrosuchus] [this Wiki author fails to list Cosesaurus, Longisquama, Sharovipteryx, Langobardisaurus and Macrocnemus, none of which are considered protorosaurs any more]. Peters used a technique called DGS [false, that was 5 years before DGS was ‘invented’], which involves applying the digital tracing features of photo editing software to images of pterosaur fossils. [this citation is falsely attributed to Irmis et al. 2007] Bennett only recovered pterosaurs as close relatives of the protorosaurs after removing characteristics of the hind limb from his analysis, in an attempt to test the idea that these characters are the result of convergent evolution between pterosaurs and dinosaurs. [false] However, subsequent analysis by Dave Hone and Michael Benton (2007) could not reproduce this result. Hone and Benton found pterosaurs to be closely related to dinosaurs even without hind limb characters. [false. They found pterosaurs nested between Scleromochlus and Parasuchia, Suchia, Ornithosuchia and Euparkeria after tossing out data provided by Peters 2000 based on typos later exposed by Bennett 2012] They also criticized previous studies by David Peters, raising questions about whether conclusions reached without access to the primary evidence, that is, pterosaur fossils, can be held to have the same weight as conclusions based strictly on first-hand interpretation. [false, I had studied pterosaur and fenestrasaur fossils both in the USA and in Europe] Hone and Benton concluded that, although more primitive pterosauromorphs are needed to clarify their relationships, pterosaurs are best considered archosaurs, and specifically ornithodirans, given current evidence. [remember, they tossed out contradicting evidence from Peters 2000, largely because Benton 1999 had published on the Scleromochlus and its relationship to pterosaurs] In Hone and Benton’s analysis, pterosaurs are either the sister group of Scleromochlus or fall between it and Lagosuchus on the ornithodiran family tree. [false, see above] Sterling Nesbitt (2011) found strong support for a clade composed of Scleromochlus and pterosaurs. [but Nesbitt did not include Huehuecuetzpalli, Macrocnemus, and members of the Fenestrasauria]

More recent studies on basal pterosaur hindlimb morphology seem to vindicate a connection to Scleromochlus [Witton 2015 is cited here]. Like this archosaur, basal pterosaur lineages have plantigrade hindlimbs that show adaptations for salutation. [Perhaps the Wiki author meant saltatory (leaping) locomotion, not personal greetings with a hand gesture. In any case, if anyone else thinks Scleromochlus had plantigrade feet, I’ll eat my hat. And did anyone notice, Scleromochlus has tiny vestigial hands and fingers?]

Ironically
it was Hone and Benton who did not examine the pertinent fossils, but took all their data from published work to produce their supertree, after deleting and omitting all data and reference to Peters 2000 and giving credit to Bennett 1996 for both sides of the earlier competing hypotheses. Wonder why the Wiki author fails to bring up this key fact.

By the way,
Bennett (2012) reports that pterosaurs nested between the lumbering and aquatic archosauriforms Proterosuchus and Erythrosuchus. That moves the nesting away from Scleromochlus, Proterochampsids and Parasuchians, the previous archosaur ‘favorite candidates,’ which were earlier derided as “strange bedfellows.”

One of the reasons why I stopped contributing to this Wikipedia
and started ReptileEvolution.com is to provide another avenue to data than the rubbish any author can add to Wiki pages. If you want the latest on pterosaur origins, click here. For an earlier source of much of this false propaganda click here.

Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zool J Linn Soc. 118:261–309.
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Hone DWE, Benton MJ. 2007. An evaluation of the phylogenetic relationships of the pterosaurs among archosauromorph reptiles. J Syst Paleontol. 5:465–469.
Hone DWE, Benton MJ. 2008. Contrasting supertree and total-evidence methods: the origin of pterosaurs. In: Buffetaut E, Hone DWE, editors. Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Munich, Germany, p. 35–60, Zitteliana B 28.
Irmis RB, et al. 2007. A Late Triassic Dinosauromorph Assemblage from New Mexico and the Rise of Dinosaurs. Science. 317 (5836): 358–61. PMID 17641198. doi:10.1126/science.1143325.
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330.

Don’t give up on the origin of pterosaurs!

Evidently it is still widely held
that pterosaurs appeared suddenly without antecedent. As evidence of this failure to follow the data, I came across a blog called Tetrapod Flight in which the author, Leon Linde, writes on Monday, March 16, 2015:

1. The first tetrapods to evolve powered flight were the pterosaurs. True
2. These were a group of archosaurs related to the dinosaurs, but not dinosaurs themselves. False. Pterosaurs are lepidosaurs, not related to dinos. 
3. The earliest known pterosaur was Eudimorphodon, who lived in what is now Italy around 230-220 million years ago, in the late Triassic. True enough
4. However, while the earliest known pterosaur, Eudimorphodon had specialised multi-cusped teeth not found in any of the later pterosaurs, so it would not have been ancestral to them but rather part of a distinct pterosaur lineage that died out in the Triassic. False. Multicupsed teeth are found in several Triassic pterosaurs AND in their proximal sisters. 
5. Furthermore, both Eudimorphodon and other late Triassic pterosaurs are “completely” developed, having all the typical pterosaur skeletal characteristics. True. That’s why they are called pterosaurs. They have all ‘the goods’.
6. This suggests the origins of pterosaurs may lie even further back in the past, in the earlier Triassic or perhaps even in the Permian (Wellnhofer, 1991). Yes to the earlier (Middle) Triassic (Cosesaurus) and No to the Permian. 
7. No fossils of the pterosaurs’ immediate ancestors are known. False. We have pterosaur proximal and distant ancestors going back to basal tetrapods with fins. Click here. 
8. The most likely theory on their origins is that they evolved from arboreal creatures that would leap from branch to branch, flapping their forelimbs to stay airborne longer. Actually we have evidence for this scenario chronicled here.
9. Pterosaur hips had great freedom of movement, their knees and ankles were hinge-like and their feet were plantigrade. True, True, True and False. Some beachcombers had plantigrade feet, but basal forms did not. 
10. The knees and ankles did not permit the necessary rotation for them to move bipedally, so pterosaurs were obligate quadrupeds (though they may have had bipedal ancestors). False. Like living bipedal lizards, basal pterosaurs were bipedal and agile. We have their tracks! Later forms, especially beachcombers, were quadrupedal, and we have their tracks, too.
11. A possible explanation for these features is that the early pterosaurs or proto-pterosaurs were arboreal creatures that evolved powerful leaping from branch to branch as an active mode of transport not dissimilar to that of arboreal leaping primates (Christopher, 1997). This reference should be Bennett 1997. Powerful leaping, fast running, yes, but without the use of the hands, which were flapping like those of birds and getting larger. Hard to develop wings when you’re using your hands on the ground. 
12. These arboreal leapers would not have been gliders, who merely fall slowly downwards and forwards with the help of special flaps, but rather creatures utilising a quite different form of locomotion, one that led them to eventually having their forelimbs evolve into more and more sophisticated flapping airfoils. True! But not like the image below (which appeared on the blog post). This pretty but bogus image shows no flapping and no reason or benefit to having proto-wings on this dinosaur that should have been a fenestrasaur. 

Click to enlarge. A false series of pterosaur ancestors. Artist: Maija Karala.

Sadly
this state of affairs in pterosaur research shows that the general public and pterosaur artists and workers alike are still stuck in the tail-dragging age. Evidently, they have decided to shun and overlook recent data that chronicles and documents the origin of pterosaurs.  See below and here.

References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
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. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330
Wild R 1993. A juvenile specimen of Eudimorphodon ranzii Zambelli (Reptilia, Pterosauria) from the upper Triassic (Norian) of Bergamo. Rivisita Museo Civico di Scienze Naturali “E. Caffi” Bergamo 16: 95-120.

wiki/Cosesaurus

 

 

Dr. David Unwin on pterosaur reproduction – YouTube

Dr. David Unwin’ talk on pterosaur reproduction 

was recorded at the XIV Annual Meeting of the European Association of Vertebrate Palaeontologists, Teylers Museum, Haarlem, Netherlands and are online as a YouTube video.

Dr. Unwin is an excellent and engaging speaker.
However, some of the issues Dr. Unwin raises have been solved at www.ReptileEvolution.com

The virtual lack of calcite in pterosaur eggs were compared to lepidosaurs by Dr. Unwin, because pterosaurs ARE lepidosaurs.  See: www.ReptileEvolution.com/reptile-tree.htm

Lepidosaurs carry their eggs internally much longer than archosaurs, some to the point of live birth or hatching within hours of egg laying. Given this, pterosaurs did not have to bury their eggs where hatchlings would risk damaging their fragile membranes while digging out. Rather mothers carried them until hatching. The Mrs. T external egg was prematurely expelled at death, thus the embryo was poorly ossified and small.

Dr. Unwin ignores the fact that hatchlings and juveniles had adult proportions as demonstrated by growth series in Zhejiangopterus, Pterodaustro and all others, like the JZMP embryo (with adult ornithocheirid proportions) and the IVPP embryo (with adult anurognathid proportions).

Dr. Unwin also holds to the disproved assumption that all Solnhofen sparrow- to hummingbird-sized pterosaurs were juveniles or hatchlings distinct from any adult in the strata. So they can’t be juveniles (see above). Rather these have been demonstrated to be phylogenetically miniaturized adults and transitional taxa linking larger long-tailed dorygnathid and scaphognathid ancestors to larger short-tailed pterodactyloid-grade descendants, as shown at: www.ReptileEvolution.com/MPUM6009-3.htm

Thus the BMNH 42736 specimen and Ningchengopterus are adults, not hatchlings. And the small Rhamphorhynchus specimens are also small adults.

Some things you learn are not found in any textbooks…yet.

No current discoveries are found in the latest textbooks. 
That’s because it takes time (years typically) for textbooks to be (in reverse order) assigned, accepted, distributed, printed, edited, written and illustrated, researched and concepted. Textbook publishers are out to sell the maximum number of books, so they write to the current consensus, which may be in flux on several points and hypotheses. The current consensus may also be wrong–but it remains the consensus.

There are no courses
at any colleges entitled, PTEROSAURS 101, 102 or 103. Who would attend? There are only two dozen people in the world who have an interest, who study them, or contribute to what we know about them. And where is the consensus? On some points, there is no consensus!! And all too often “the consensus” is holding on to outmoded, invalid and unverifiable paradigms (see below).

Every new fossil specimen is really a new chapter
in an ever expanding textbook on paleontology. And all paleontologists who publish are contributing authors to that future textbook.

Striiving for veracity
It is important for all workers to see things as they are in specimens, and not to reinterpret them to fit an established paradigm, no matter the temptation to do otherwise. For instance, narrow chord wing preservation in pterosaurs is not the result of ‘shrinkage’ as some workers report. Rather it is what it is, universal. All pterosaur specimens have narrow chord wings. If you know one that is different, please tell me. I know one that appears different, but that’s because part of its arm was ripped away and displaced. Look closely. That’s the way it is.

If Galileo
went to school as a teenager and found the following question on a test: “If object A at ten pounds and object B at 10 ounces both fall from 1000 feet at the precisely the same moment, how many seconds ahead of B will A strike the ground?” He’d would not have even had the opportunity to choose answer E. “zero seconds.” Common knowledge at the time, based on Aristotle, would not have allowed it, no matter the facts of this case, proven by experiment. This went on for centuries.

Similarly,
if you were in college today and were given the multiple choice question, “Which one of the following taxa is most closely related to pterosaurs? A. Dinosaurs. B. Scleromochlus. C. Proterochampsids (including Lagerpeton). D. Euparkeria. E. Erythrosucids. F. We don’t know.” You would have to pick “F” to get a good score, because that’s the current consensus… unless your professor had recently written a paper espousing one of the other answers (see below). “G. None of the above” is the better answer according to the large reptile tree where fenestrasaurs are more closely related to pterosaurs. But each one of the above (A-E) has been proposed by recent authors, not caring if they made sense or not.

Imagine the plight of the poor student in Paleontology 101 today
when he or she asks the professor about that website, “repitleevoluton.com” The professor is going to have to say, “If you want a good grade, you’ll ignore that website and provide the same answers that are in your textbook.” That’s what Dr. Darren Naish  reported online. Don’t consider, test or discuss other possibilities. Best to ignore them — if you want to advance in paleontology and get your Masters or PhD.

Take, as an example,
David Hone’s dissertation that was later published in two papers in which he proposed comparing two competing pterosaur origin hypotheses, one by Peters 2000 (Cosesaurus, Sharovipteryx, Longiasquama) and one by Bennett 1996 (Scleromochlus) using the supertree method of analysis (combining several published analyses without actually examining any fossil specimens). Aware that his professor, Michael Benton, had earlier written a paper (Benton 1999) celebrating Scleromochlus as the sister to pterosaurs, Hone decided to delete and diminish the taxa proposed by Peters. He somehow created several typos in the Peters data and then deleted the entire Peters dataset because of those typos (references and the full story here). Then Hone and Benton (2008) gave credit for both competing hypotheses to Bennett while deleting all reference to Peters 2000. As a result, Hone received his PhD, two associated papers (Hone and Benton 2007, 2008) were published and Hone gained the ability to referee pterosaur manuscripts (like mine) submitted to academic journals. I wrote to Dr. Benton about the inconsistencies and leaps of logic between the two parts of their two part paper. His reply was a sheepish, “whoops. :  )”

See how it works? 
That’s how you crush an opposing hypothesis. And that’s just the tip of the iceberg of current readily solvable problems, as Pterosaur Heresies readers are well aware. No PhD wants to admit he/she was wrong. On some problems consensus will likely never be achieved — because in order to do so all invalid candidate hypothesis writers would have to admit they were wrong.

And that’s just not going to happen.
Not without a fight or a dismissal. Let me know if you know of any instances of someone admitting they were wrong (I know of one semi-wrong situation regarding Dr. Padian and his fight with pterosaur tracks). In the origin of snakes, pterosaurs, turtles and dinosaurs there are lots of ‘right’ answers out there, but few challenges to the weaker hypothesis and no one admits to being wrong.

As history tells us, in paleontology it takes decades to turn the boat around. And paleontologists don’t want anyone else, even other paleontologists, solving their mysteries for them… even when solutions are published in the literature.

Thanks for your interest.
I will continue to study and make informed comment on new fossil specimens, (many that haven’t made the textbooks yet). I will throw a spotlight on problems and celebrate solutions as they are verified or not in the large reptile tree. And I encourage you to do the same. If I can do it, anyone can do it.

There are too many paleontologists who
follow matrices, textbooks and papers blindly
and not enough paleontologists who have the balls to say, “Hey, there’s something wrong here.”

We’ll help fix the world of paleontology someday.
Unfortunately, it’s not going to happen this year. After four years of working with the large reptile tree, and improving it, and enlarging it year after year, it still has not been accepted for publication or gained intrigue among basal reptile workers. They don’t like it. It rocks the boat.

References
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoolological Journal of the Linnean Society 118: 261–308.
Benton MJ 1999. Scleromochlus taylori and the origin of the pterosaurs. Philosophical Transactions of the Royal Society London, Series B 354 1423-1446. Online pdf
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

News on the Origin of Pterosaurs on YouTube

I just uploaded a pterosaur origins video on YouTube. Click here to view it.

Click to view this “Origin of Pterosaurs” video on YouTube. 17 minutes long. 

Palaeontology [online]

Header for website paleontology online. Click to go to the website.

A website (new to me, but looks like it’s been around for awhile) palaeontologyonline.com is, in their own words,

“Palaeontology [online] is a website covering all aspects of palaeontology. The site is updated with articles about the cutting edge of research, by the researchers themselves. These are usually written by experts in the field, but are aimed at non-specialists. Articles vary widely in their content: some serve as an introduction to palaeontological or interdisciplinary fields, while others outline events in the history of palaeontology. Some contributions include summaries of recent findings and advances in rapidly evolving disciplines, and some focus on a particular geographic region or time period. Finally, some of our articles are based on the experience of being a palaeontologist – what life and work is really like as a fossil worker.  Our online format allows researchers to explain their work with the aid of an unlimited number of figures and videos.”

Commissioning editors (who are responsible for inviting contributions and overseeing the website) are:

Russell Garwood: Invertebrate palaeontologist; Peter Falkingham: Postdoctoral research fellow in the fields of vertebrate palaeontology and ichnology (trace fossils); Alan Spencer: Palaeobotanist; Imran Rahman: Postdoctoral researcher in invertebrate palaeontology and evolutionary genetics.

Some great pages here. Check out this placodont page.

The pterosaur page was written by Dr. David Hone, who states, “The origins and the relationships of the pterosaurs have long been contentious, although a consensus is forming on both issues. Often confused with dinosaurs, pterosaurs are members of their own clade, but are close relatives of their more famous cousins.

Over the years, palaeontologists have hypothesized that pterosaurs originated from various parts of the reptile evolutionary tree. Very early researchers considered them to be the ancestors of birds or even bats, and for a long time it seemed that they were probably basal archosaurs (the clade that contains dinosaurs, birds, crocodilians and some other groups). More recently evidence has begun to stack up that they are a separate group to the dinosauromorphs (dinosaurs and their closest relatives) but that the two groups evolved from a common ancestor. Most researchers now support this position. This makes pterosaurs reasonably close relatives to birds, but they are not bird ancestors as is sometimes wrongly reported.”

Well, par for the course…
Sad to see when there actually is a verifiable better relationship out there, but then that would involve actually acknowledging the literature (Peters 2000, 2002, 2007, 2009, 2011) and/or testing candidates one vs. another. But nobody wants to do this without fudging the data or reducing the inclusion set. It’s time to either recognize the literature or argue with it. The large reptile tree found a long line of pterosaur ancestors between Ichthyostega and Longisquama. Almost any one will do, as we learned earlier with turtles and pterosaurs.

References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
http://www.reptileevolution.com/pterosaur-wings.htm