AMNH pterosaur video: due for an Oculudentavis-type retraction

Recently (March 2020 to July 2020)
Xing et al. 2020 agreed to retract their paper on Oculudentavis because they said it was a bird and it turned out to be a lepidosaur.

Figure 1. Oculudentavis in amber much enlarged. See figure 2 for actual size.

Also recently (July 31, 2020)
the American Museum of Natural History posted a YouTube that reported pterosaurs were archosaurs (= birds, dinosaurs and crocs) and pterosaurs turn out to be lepidosaurs. whenever tested with typically excluded taxa. Should the AMNH be held to the same rigorous standards demonstrated by Nature magazine and Xing et al. 2020? Here’s the evidence:

Full set of comments on the AMNH pterosaur video (above)
are copied below.

Lots of misinformation here. Traditional myths are hard to kill.

No pterosaur wing membrane ever extends to the knee or thigh and no single uropatagium stretched between the lateral pedal digits. http://reptileevolution.com/pterosaur-wings.htm

No pterosaurs had their eyeballs in the front half of their skulls. http://reptileevolution.com/anurognathus-SMNS.htm 1:16

Size actually goes down to hummingbird-sized 1:41

German fossils also preserve wing membranes nicely. Not just in China. 2:18

No need to show old engravings that portray pterosaurs with bat-like ears. 2:34

Basal pterosaurs, like Dimorphodon, were bipeds with giant tree-trunk gripping foreclaws. Pedal digit 5 was not used to frame each uropatagium. Toe 5s are often preserved strongly flexed, used to help support a bipedal configuration, preserved in footprints (Rotodactylus) of pre-pterosaurs. When folded wing membranes nearly completely disappeared due to being stretched only between the elbow and wingtip. 2:54

When you test more taxa, pterosaurs leave dinosaurs and join fenestrasaur, tritosaur, lepidosaurs. These share a long finger 4, a long toe 5, a single sternum, sprawling hind limbs, a pteroid, a prepubis and many other traits not shared with dinosaurs. Sadly we’ve known this for 20 years and Alex Kellner was the peer-reviewer who approved the paper. 3:17

Not all pterosaurs walked on four limbs. We have bipedal track fossils. Only small-clawed beachcombers with flat feet left quadrupedal tracks. 4:09

When tested (ReptileEvolution.com) Archosauria includes only crocs + dinos. Pterosaurs nest with Fenestrasaurus (Cosesaurus), Tritosaurs (Huehuecuetzpalli) and Lepidosaurs. 5:30

Basal bipedal crocs were not dinosaur mimics. The both evolved from a last common ancestor that was bipedal. 5:40

The basal croc at 5:46 is not one at all, but from another family of archosauriformes. The ankle bone arrangement of pterosaurs and dinosaurs is by convergence. It happens often enough when reptiles become bipedal. Sharovipteryx for example. When scientists pull this trick, it’s called “Pulling a Larry Martin” to honor the Kansas professor who delighted in calling young know-it-alls out. 5:54

Actually dinosaurs (archosauromorphs) and pterosaurs (lepidosauromorphs) separated from one another some 335 million years ago, when the first amniotes (=reptiles), like Silvanerpeton, appeared. 5:50

The hole in the hip socket separates dinos from crocs. Like lizards and turtles and humans, pterosaurs have no hip socket hole. Same goes for the long humeral (deltopctoral) crest. No plesiomorphic reptile has ever been put forth as the last common ancestor of pterosaurs and dinosaurs, except the aforementioned Silvanerpeton. 6:02

No pterosaurs flew with hind legs trailing behind. As lepidosaurs pterosaurs had sprawling hind limbs that extended laterally, like horizontal stabilizers on modern aircraft. All preserved wing membranes show they stretched only between the wingtip and elbow, with a short fuselage fillet to mid thigh. Long narrow wings reduced drag. 11:33

No pterosaur took off by doing a dangerous jumping push-up. Better to start flapping with wings out while leaping, as birds do, instead of opening the wings later from a closed and ventral start. 11:56

The largest pterosaurs got to be that size, just as giant birds do today, because they gave up flying, as shown by their clipped wings (vestigial distal wing finger bones). They could still use their wings for thrust while running, like the earlier video images of the running swan. 12:06

If it’s tough enough for flapping swans, what the animators show at 12:40 (giant azhdarchid quad leap takeoff) is impossible, especially with ‘clipped’ wings. By the way, the elbows rose above the leading edge, creating camber. Also by the way, when Paul MacCready made his third-size flying model of Quetzalcoatlus, he added wingspan to make it work. https://pterosaurheresies.wordpress.com/2020/04/12/can-volant-fossil-vertebrates-inspire-mechanical-design/

Pterosaur wing membranes have less of an airplane-like camber and more of an ornithopter appearance, with a thick leading edge, but the rest is a thin membrane that folds to near invisibility. Forcing the air down and back, as in ornithopters, has the opposite and equal reaction of forcing the ornithopter/pterosaur up and forward. Unfortunately the animators for the AMNH used flat wings in flight, not dorsally bowed wings. 13:15

Many small pterosaurs flapped as often as small birds do (creating what should have been a blur in the animation). 14:30

Why did pterosaur ancestors learn to fly? Impressing females, rivals and predators (the video skips that step). That story is told by flapping, nonvolant Cosesaurus. Link here: http://reptileevolution.com/cosesaurus.htm

We have more than 150 pterosaur species right now. Those professors are not counting the small Solnhofen adults and multiple species within a single genus. 17:40

A cladogram that tests 250 different pterosaurs can be found here: http://reptileevolution.com/MPUM6009-3.htm

Short summary:
Just about everything the AMNH included in their pterosaur video was outdated and wrong with no evidence backing their traditional claims. So, should the AMNH retract this video? I mean, children are watching… and the AMNH should care about their public outreach.

Part 2 
If Oculudentavis (Figs. 1, 2) is a lepidosaur based on the Cau blogpost 2020 and Li et al. 2020 trait list (see below), how does the basalmost pterosaur in the LRT, Bergamodactylus (Fig. 2), match that list?

Figure 2. Skulls of Oculudentavis and Bergamodactylus compared. Not to scale. Note the dark blue palatine in Oculudentavis shows through the antorbital fenestra.

Here’s the Cau TheropodaBlogpost.com list:

1. “Absence of anti-orbital window.” AOF present in both (Fig. 2, note palatine (deep blue) is visible through AOF in Oculudentavis).
2. “Quadrate with large lateral concavity. This character is not typical of dinosaurs, but of lepidosaurs.” Not discernibly concave in crushed Bergamodactylus.
3. “The maxillary and posterior teeth of the maxilla extend widely below the orbit.” Last maxillary tooth below orbit in both.
4. “Dentition with pleurodont or acrodont implant.” Thecodont implantation in Bergamodactylus.
5. “Very large post-temporal fenestra.” As in Bergamodactylus.
6. “Spoon-shaped sclerotic plates is typical of many scaled lepidosaurs.” Plates much smaller in Bergamodactylus.
7. “Coronoid process that describes a posterodorsal concavity of the jaw reminds more of a lepidosaur than a maniraptor.” As in Bergamodactylus.
8. “Very small size comparable to those of the skulls of many small squamata found in Burmese amber.”  Much smaller skull than Bergamodactylus.

Here’s the Ling et al. 2020 list:

1. “absence of an antorbital fenestra” AOF present in both
2. “The ventral margin of the orbit is formed by the jugal.” Actually, the lacrimal, jugal and postorbital. It’s a big orbit, as in Bergamodactylus.
3. “Another unambiguous squamate synapomorphy in Oculudentavis is the loss of the lower temporal bar.” Actually the lower bar is formed by the tiny loose quadratojugal, lateral to the quadrate in both taxa.

FIgure 3. CT scan model from Li et al. 2020, who denied the presence of a quadratojugal and an antorbital fenestra, both of which are present. Colors applied here.

Only a few of the above are LRT traits.
The LRT compares 1717 taxa with 230 other characters and nests Early Cretaceous Oculudentavis with Middle Triassic Cosesaurus, a few nodes away from Late Triassic Bergamodactylus.

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References
Li Z, Wang W, Hu H, Wang M, Y H and Lu J 2020. Is Oculudentavis a bird or even archosaur? bioRxiv (preprint) doi: https://doi.org/10.1101/2020.03.16.993949
Xing L, O’Connor JK,; Schmitz L, Chiappe LM, McKellar RC, Yi Q and Li G 2020. Hummingbird-sized dinosaur from the Cretaceous period of Myanmar. Nature. 579 (7798): 245–249.

wiki/Oculudentavis

Bonus video on becoming a PhD. You’re doing research on what you set for 3-4 years, sort of like creating and supervising the LRT for the last 9 years.

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

 

New PBS Eons video: How pterosaurs got their wings

The good folks at PBS Eons
added a new video on the origin of pterosaurs. The following repeats (with added images) my comments on the PBS Eons video on YouTube.

This video is SO WRONG
so many times. The origin of pterosaurs is not ‘foggy.’

The Scleromochlus (Fig. 1) hypothesis for pterosaur origins was invalidated by Peters 2000 who tested it and all other candidates for pterosaur origins in four separate phylogenetic analyses by adding taxa to prior studies. Macrocnemus, Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama (Fig. 2) were recovered closer to pterosaurs.

Figure 1. Short-legged Gracilisuchus, along with sisters, long-legged bipedal Pseudhesperosuchus and Scleromochlus.

Scleromochlus nested with basal bipedal crocodylomorphs,
(Fig. 1) close to the origin of dinosaurs. Note the tiny hands on Scleromochlus. Note the lack of pedal digit 5 on Scleromochlus. By contrast, pterosaurs had large hands and a specialized pedal digit 5 that had two large phalanges that folded together such that the distal phalanx was dorsal side down, making an impression behind pedal digits 1–4 (Figs. 10, 11). More on this below.

Figure 2. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx. Click to enlarge.

Pterosaurs didn’t fossilize very well?
False. Look at all the excellent pterosaur fossils we know of, some with soft tissue.

Pterosaurs are not archosaurs.
Peters 2000 introduced the clade Fenestrasauria for pterosaurs + their above named ancestors. These in turn were part of a new clade of lepidosaurs, named Tritosauria, nesting between Rhynchocephalians and Protosquamates published in Peters 2007.

Cosesaurus and Longisquama have extra-large fingers,
dominated by digit 4. See: http://reptileevolution.com/pterosaur-wings.htm

Ornithodirans are a junior synonym
for Reptilia (=Amniota, see cladogram link below). Not wise to bring up this invalidated clade name.

Figure 3. Scaphognathians to scale. Click to enlarge.

The pterodactyloid grade of pterosaur
was attained four times by convergence (two from the genus Dorygnathus, two more from the genus Scaphognathus, Fig. 3). Transitional taxa were all tiny Solnhofen forms (Fig. 3). As in many other clades, phylogenetic miniaturization attended the genesis of derived pterosaurs.

As in giant birds,
Quetzalcoatlus (Fig. 4) grew so large because it was flightless. All azhdarchids over six-feet-tall had clipped wings (vestigial distal wing phalanges) good for flapping and walking on, not for flying.

Figure 4. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

No pterosaur fossils had wing membranes extending ‘the length of their legs’.
All soft tissue shows the short chord wing membrane was stretched between the elbow and wing tip.  See: http://reptileevolution.com/pterosaur-wings.htm

Figure 5. Tritosaur pectoral girdles demonstrating the evolution and migration of the sternal elements to produce a sternal complex.

How did pterosaurs get their wings? 

Convergent with theropods ancestral to birds, Cosesaurus reorganized its pectoral girdle to flap (Fig. 5). The scapula became immobile and strap-like. The coracoid became immobile and stalk-like. The clavicles, interclavicle and single sternum migrated together, then fused together. The forelimbs of Cosesaurus were too short for flight, but fully capable of flapping, probably as a mating ritual. Likewise the pectoral girdles of Sharovipteryx and Longisquama were similarly built. Of the three, Longisquama had the largest hands, but still could not fly. Bergamodactylus was the basalmost pterosaur and it could fly. See links below.

Why guess how a hypothetical ancestor learned to fly
when we have excellent samples of every stage? (see links below)

The arboreal leaping model
does not require flapping — and gliders do not evolve into flappers (e.g. colugos, squirrels, sugar gliders, etc.)

The arboreal parachute model
worked for bats, but they were seeking prey beneath their perches as fingers 3-5 then 2-5 elongated. Pterosaurs only elongated one digit: #4. It made a better wing than bug-in-the-leaf-litter trap.

The terrestrial model
is Lamarckian, growing bigger wings to catch insects just out of reach for most is not good science.

Figure 6. Cosesaurus forelimb with pro to-aktinofibrils trailing the ulna.

Sexy
The valid hypothesis for bird and pterosaur wing evolution is competitive attractiveness during mate selection (think birds-of-paradise) with cosesaur-like creatures flapping and displaying. BTW, both Cosesaurus and Longisquama are preserved with membranes trailing finger 4, (Fig. 6) which folds in the plane of the wing in Longisquama (Fig. 7).

Figure 7. 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. The Milan specimen MPUM 6009, a basal pterosaur.

Not to be outdone,
Sharovipteryx (Fig. 8) had membranes (uropatagia) trailing each hind limb. These are reduced in pterosaurs, which continue to use their hind limbs as horizontal stabilizers, their feet as twin rudders, as the flapping forelimbs, closer to the center of gravity, become ever larger, better for display, then for short flapping hops, then for flight.

Figure 8. Sharovipteryx reconstructed. Note the flattened torso.

Another false statement corrected here:
The scapula of Scleromochlus (Fig. 1) was tiny. It only had to support a tiny forelimb with vestigial fingers.

Scleromochlus had a ‘square pelvis’
because it, too was a biped. But that was nothing compared to the larger pelvis of Cosesaurus (Fig. 9), which also had a prepubis, a pterosaurian trait not found on Scleromochlus. The pelvis of Sharovipteryx was larger still.

Figure 9. Cosesaurus flapping. Tere should be some bounce in the tail and neck, but that would involve more effort and physics.

Scleromochlus had a long muscular tail.
As in crocs and dinos, and most reptiles, the caudofemoral muscles were pulling the femur. Compare that with the attenuated tail of pterosaurs, Cosesaurus and Sharovipteryx. Only pelvic muscles were pulling the femur.

Back legs longer than front legs in Scleromochlus?
That’s what we also see in Cosesaurus, Sharovipteryx and Longisquama.

Figure 10. Cosesaurus and Rotodactylus, a perfect match. Elevate the proximal phalanges along with the metatarsus, bend back digit 5 and Cosesaurus (left) fits perfectly into Rotodactylus (right).

Walking on its toes?
We have Rotodactylus ichnites (hand and footprints, Figs. 10, 11) that match Middle Triassic Cosesaurus in the Early Triassic. These include the impression of pedal digit 5 behind toes 1-4. Nothing else like them in the fossil record.

True!
Scleromochlus was like the modern jerboa, with its tiny vestigial hands, totally inappropriate as a pterosaur ancestor.

False!
Not all pterosaur tracks are quadrupedal. Only derived pterosaurs, those that frequented beaches were. We have bipedal pterosaur tracks (Fig. 12). See references below.

Figure 11. Cosesaurus foot in lateral view matches Rotodactylus tracks.

Quadrupedality in pterosaurs is secondary.
Note the backward pointing manual digit 3 in quad tracks. Note the fusion of four to thirteen sacrals into a sacrum and the elongation of the ilium to anchor large femoral muscles and anchor the increasingly larger sacrum in all pterosaurs. In order to flap, you have to be a biped.

Figure 12. Pteraichnus nipponensis, a pterosaur manus and pes trackway, matched to n23, ?Pterodactylus kochi (the holotype), a basal Germanodactylus.

All quad pterosaurs can be attributed to pterodactyloid-grade pterosaurs,
those that underwent phylogenetic miniaturization during the Jurassic. At that time, the fly-size hatchlings of the hummingbird-sized adults (Fig. 13) could not leave the moist leaf litter or risk desiccation until growing to a sufficient size. So they walked around on all fours until attaining flight size.

Figure 2. A hypothetical hatchling No. 6 alongside a fly, a flea and the world’s smallest insect, a fairy fly (fairy wasp). The fairy wasp is shown enlarged here (scaled in red) and in figure 1.

True!
The extinction of pterosaurs can be attributed to their great size at the end of the Cretaceous. They had no tiny representatives, like they did at the end of the Jurassic, to weather the rapid climate changes and/or seek shelter.

---

References

For a cladogram that documents the family tree of pterosaurs see: http://ReptileEvolution.com/MPUM6009-3.htm

For a cladogram that documents pterosaur and dinosaur ancestors back to Silurian jawless fish see: http://ReptileEvolution.com/reptile-tree.htm

For fossils and reconstructions of pterosaur ancestors, see:

http://reptileevolution.com/cosesaurus.htm

http://reptileevolution.com/sharovipteryx.htm

http://reptileevolution.com/longisquama.htm

http://reptileevolution.com/MPUM6009.htm

And here are all the peer-reviewed academic publications
that some pterosaur experts don’t want to talk about:

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

Peters D 2000b. 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 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification. Ichnos 18(2):114-141.

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

Flugsaurier 2018: Los Angeles County Museum

Flugsaurier
is a meeting of those interested in pterosaurs that happens in another part of the world every few years. I went to the first few. Saw a lot of specimens. Met a lot of colleagues. Produced a few abstracts and gave some presentations.

Over the next few days
there’s a Flugsaurier meeting taking place in Los Angeles. Many well-known and not-so-well known speakers are giving presentations this year. I will not be among them. Why?

So far as I know,
all of the conveners and many of the presenters continue to ignore a paper I wrote 18 years ago on the origin of pterosaurs from fenestrasaurs, not archosaurs. Other papers followed on wing shape, trackmaker identification and other topics, all supporting that phylogenetic hypothesis of relationships. Evidently workers would prefer to hope that pterosaurs arose from archosaurs close to dinosaurs. This is not where the data takes anyone interested in the topic who is not a party to taxon exclusion.

In addition, several of the conveners

1. subscribe to the invalid quad-launch hypothesis
2. the bat-wing reconstruction of the brachiopatagium.
3. they believe that pedal digit 5 framed a uropatagium.
4. They refuse to add tiny Solnhofen pterosaurs to their cladograms.
5. They refuse to add several specimens of each purported genus to cladograms—and because of this they don’t recognize the four origins of the pterodactyloid-grade (not clade).
6. They still don’t recognize that pterosaurs grew isometrically.
7. They still don’t accept that pterosaur mothers retained their egg/embryo within the body until just before hatching (a lepidosaur trait).
8. They still don’t accept that pterosaur bone fusion patterns follow lepidosaur, rather than archosaur patterns.
9. They accept the idea that giant eyeballs filled the anterior skulls of anurognathids, not realizing that the supposed ‘scleral ring’ on edge of the flathead anurognathid is actually the mandible and tiny teeth.
10. They reject any notion that all basal and some derived pterosaurs were bipedal, despite the footprint and morphological evidence proving bipedal locomotion.
11. They all hold out hope that the largest azhdarchids could fly.
12. I was going to say that all workers believe that crest size and hip shape identify gender, when the evidence indicates these are both phylogenetic markers, but then I found an abstract in 2018 that casts doubt on the gender/crest/pelvis hypothesis. So there’s hope.

That’s a fairly long list of ‘basics’
that most pterosaur workers ‘believe in’ despite the fact that there is no evidence for these false paradigms — but plenty of evidence for the lepidosaur origin of pterosaurs, from which most of the above hypotheses follow.

I am not attending Flugsaurier 2018
because the convening pterosaur workers deny and suppress the data listed above. Plus, I can more actively and thoroughly test assertions made during the conference from ‘my perch’ here in mid-America.

Good luck to those attending. 
Test all assertions and hypotheses, no matter their source.

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

 

 

Arcticodactylus a tiny Greenland Triassic pterosaur

Arcticodactylus cromptonellus (Kellner 2015, originally Eudimorphodon cromptonellus Jenkins et al. 1999, 1999; MGUH VP 3393) Late Triassic ~210mya ~8 cm snout to vent length was a tiny pterosaur derived from a sister to Eudimorphodon ranzii and phylogenetically preceded Campylognathoides and BSp 1994 specimen attributed to Eudimorphodon. Whether it was a juvenile or a tiny adult cannot be determined because juveniles and even embryos are identical to adults in pterosaurs. Note that that rostrum was not shorter and the orbit was not larger than in sister taxa. This specimen is one of the smallest known pterosaurs., but not THE smallest (Fig. 1) contra the Wikipedia article. That honor goes to B St 1967 I 276.

Figure 1. Articodactylus is evidently NOT the smallest pterosaur. That honor still goes to an unnamed specimen (not a Pterodactylus kochi juvenile) B St 1967 I 276.

Distinct from E. ranzii,
the skull of Arctiodactylus had a rounder, less triangular orbit. The jugal was not as deep. The sternal complex did not have small lateral processes. The humerus was not as robust. The fingers were longer an more gracile. The prepubis was distinctly shaped.

Distinct from
Bergamodactylus the femur and tibia were smaller but the metatarsals were longer, compact and nearly subequal in length with IV smaller than III.

References
Jenkins FA Jr, Shubin NH, Gatesy SM and Padian K 1999. A primitive pterosaur of Late Triassic age from Greenland. Journal of the Society of Vertebrate Paleontology 19(3): 56A.
Jenkins FA Jr, Shubin NH, Gatesy SM and Padian K 1999. A diminutive pterosaur (Pterosauria: Eudimorphodontidae) from the Greenlandic Triassic. Bulletin of the Museum of Comparative Zoology, Harvard University 155(9): 487-506.
Kellner AWA 2015. Comments on Triassic pterosaurs with discussion about ontogeny and description of new taxa. Anais da Academia Brasileira de Ciências 87(2): 669–689

wiki/Eudimorphodon
wiki/Arcticodactylus