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.

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.

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 1. 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.

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.


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.

Late Jurassic pterosaur under UV light

Mike Eklund, Research Associate at the University of Texas,
is using black light (= uv light) to reveal what is ‘hidden in plain sight’ in fossils. At the HMNS.org blogsite a fully articulated and excellently preserved Late Jurassic pterosaur serves as only one of many subjects using this lighting technique (Figs. 1–3).

In case some controversial items are overlooked,
as they have been for centuries, I thought I’d highlight a few observations (Figs. 1-3).

Figure 1. Coloring the bones and membranes of this pterosaurs helps identify them here.

Figure 1. Coloring the bones and membranes of this pterosaurs helps identify them here.

For paleo-artists
note how the wing finger folds completely against the forearm. Note how the membrane virtually disappears when folded (Peters 2002, 2009), especially so at the wing tip. Also note that no part of the wing membrane ever extends to the tibia or ankle. This is evidence to counter myths perpetuated by prior pterosaur workers and artists.

Figure 2. Manual digit 5 on this pterosaur is undisturbed.

Figure 2. Manual digit 5 on this pterosaur is undisturbed.

Figure 3. Manual unguals on this pterosaur are undisturbed.

Figure 3. Manual unguals on this pterosaur are undisturbed.

This is not the first time
wing unguals and manual digit 5 have been identified in pterosaurs. Use those keywords to find previously posted specimens. Traditional paleontologists believe these bones don’t exist. That’s why I use Photoshop and the DGS technique… to share evidence. Now I encourage you to see for yourself.


References
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.

https://blog.hmns.org/2020/01/hidden-in-plain-sight-how-photography-techniques-are-helping-us-dig-deeper/

 

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.

Click to animate. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees.

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. 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.

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.


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

 

The Times (UK) declares: proof for ‘winged dinosaurs’ vaulting

According to The Times.co.uk,
“Isle of Wight find proves winged dinosaurs took off by ‘vaulting’ into the air. Following the discovery of a fossilised giant pterosaur, scientists may have resolved how the 650lb beasts took flight. The sheer size of such creatures has long baffled scientists because they seem too heavy to take off. Now research with a computerised 3D model suggests they used their massive leg and wing muscles to catapult themselves into the air.”

Figure 1. Image from The Sunday Times (UK) showing the Isle of Wight and an ornithocheird filled with helium on a smaller planet taking off by vaulting.

Figure 1. Image from The Sunday Times (UK) showing the Isle of Wight and an ornithocheird filled with helium on a smaller planet taking off by vaulting. See figure 2 for the 650 lb Hatzegopteryx. The human silhouette (gray at left) is way too small for this ornithocheirid, so they got their pterosaurs mixed-up.

“Robert Coram, a professional fossil hunter who made the find, said: “It might have been the largest flying creature that had ever lived up to that time.”

“Mr Habib explained: “Mathematical modelling indicates that launching from a quadrupedal stance — pushing off first with the hind limbs and then with the forelimbs — would have provided the leaping power giant pterosaurs required for takeoff.”

FIgure 2. From The Sunday Times (UK) showing a human to scale with a restoration of Hatzegopteryx.

FIgure 2. From The Sunday Times (UK) showing a human to scale with a restoration of Hatzegopteryx.

This article appears to follow a Witton 2019 SVPCA abstract
(coincidence?) discussing the flight capabilities of the giant azhdarchid, Hatzegopteryx, using Graphic Double Integration and Principal Component Analysis. AND this article coincides with a Scientific American cover story on pterosaurs by Dr. Habib, discussed earlier here.

The pterosaur experts talking to The Times are still not discussing
the much smaller phylogenetic ancestors of azhdarchids with longer wings, nor do they consider the reduced to vestigial distal phalanges that essential clip the wings of azhdarchids over 1.8 m (6 ft) tall, nor do they recognize the traits that attend small flightless pterosaurs.

Let’s stop promoting giant volant pterosaurs
until these objections are met and resolved. Perhaps a little backtracking and apologizing for earlier grand standing is in order here.

Figure 1. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

Figure 3. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

Let’s define giant pterosaurs
as those at least 2m or 7ft tall at the eyeball (sans crest if present). The rest are large (more or less human-sized) pterosaurs (comparable to Pelagornis, Fig. 4) or smaller pterosaurs comparable to some other extant bird (e.g. goose-, robin- or hummingbird-sized).

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

Figure 4. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

You might remember
an earlier post featuring a classified ad from U of Leicester, (UK) seeking a student to prove the vaulting pterosaur hypothesis by finding appropriate pterosaur tracks. The Isle of Wight includes several strata with dinosaur tracks. Perhaps someday they will deliver giant pterosaur tracks that suddenly end. Then we can argue if the pterosaur flew from that point on and how it did so.


References
Witton M 2019. You’re going to need a bigger plane: body mass and flight capabilities of the giant pterosaur. SVPCA abstracts.
Counter arguments based on facts appear here:

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

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

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 1. Scaphognathians to scale. Click to enlarge.

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

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

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 5. Cosesaurus forelimb with pro to-aktinofibrils trailing the ulna.

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 3. Sharovipteryx reconstructed. Note the flattened torso.

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 1. 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.

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.
Cosesaurus and Rotodactylus, a perfect match.

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.
Cosesaurus foot in lateral view matches Rotodactylus tracks.

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

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.
A hypothetical hatchling No. 6

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:
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.

Pterorhynchus dewlap now looks like a displaced wing membrane

Short one today
on an old subject: the apparent dewlap of the pterosaur Pterorhynchus (Fig. 1).

Figure 1. Pterorhynchus under UV light. Given that no sisters have such a dewlap, this now looks like a displaced wing membrane, as in Sordes.

Figure 1. Pterorhynchus under UV light. Given that no sisters have such a dewlap, this now looks like a displaced wing membrane, as in Sordes.

Now it looks like a displaced wing membrane.
We’ve seen this before with Sordes. Sorry this took so long to appreciate and understand. The proximity to the throat bends the mind that way. Those wing fibers are impressive in UV.


References
Czerkas SA and Ji Q 2002. A new rhamphorhynchoid with a headcrest and complex integumentary structures. In: Czerkas SJ ed. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum:Blanding, Utah, 15-41. ISBN 1-93207-501-1.

wiki/Pterorhynchus

Fresh data on little Ningchengopterus (not a baby pterosaur)

Yesterday we looked at a new paper on an old topic,
the ability of ‘large enough’ pterosaur hatchlings to fly shortly after hatching (Unwin and Deeming 2019). I say, ‘large enough’ because some fly-sized hatchlings of hummingbird-sized adults were not large enough to avoid desiccation due to their high surface/volume ratio. This was likely the origin of quadrupedal locomotion from bipedal pterosaur ancestors. Such tiny hatchlings had to remain within high humidity leaf litter environs until reaching that minimum size for flight. And they probably drank a lot of water.

On the publicity tour for Unwin and Deeming 2019,
the NYTimes.com published an article that contained a rather high-resolution picture of a small Late Jurassic pterosaur, Ningchengopterus (Figs. 1-3; Lü 2009) that is several magnitudes better than the originally published line drawing.

Figure 1. ?Ningchengopterus in situ. Note the narrow-at-the-elbow wing membrane and manual digit 5 near the wrist.

Figure 1. ?Ningchengopterus in situ. Note the narrow-at-the-elbow wing membrane and manual digit 5 near the wrist. There is no wing membrane connection to the lower leg or ankle, only a ‘fuselage fillet’ inside the elbow.

Ningchengopterus? liuae (Lü J 2009) CYGB-0035 was originally considered a “baby”, even though it had an adult crest. Here, in the large pterosaur tree (LPT, 238 taxa) Ningchengopterus was derived from a sister to the larger Painten pterosaur and it phylogenetically preceded Pterodactylus antiquus? AMNH 1942 (No. 20 in Wellnhofer (1970). Here it appears that Ningchengopterus was actually a basal Pterodactylus and therefore congeneric.

Despite the additional data and several scoring changes,
the nesting of Ningchengopterus in the LPT did not change. So crappy data sometimes work. Crappy character lists sometimes work. Taxon exclusion never works. Let’s treat every pterosaur specimen as a taxon, like the LPT does, and see which taxa are associated with many times larger adults… and which nest with other tiny pterosaurs under phylogenetic miniaturization.

Figure 2. Ningchenopterus reconstructed using DGS methods. Sure it's small, but not much smaller than sister taxa after phylogenetic analysis.

Figure 2. Ningchenopterus reconstructed using DGS methods. Sure it’s small, but not much smaller than sister taxa after phylogenetic analysis.

Ningchengopterus preserves a complete proximal wing membrane
(Fig. 1) that confirms the findings of Peters 2002, in which evidence for a narrow chord pterosaur wing membrane that was stretched between the elbow and wing tip was presented for all pterosaurs in which the soft tissue is preserved, distinct from traditional bat-wing models proposed without evidence by several PhDs.

Figure 3. Finger 5 in Ningchengopterus is very clear, but overlooked by all other pterosaur workers.

Figure 3. Finger 5 in Ningchengopterus is very clear, but overlooked by all other pterosaur workers.

Manual digit 5 on pterosaurs is a vestige
(Fig. 3) that has been overlooked by all prior pterosaur workers. Ningchengopterus preserves manual digit 5 without question.

Figure 6. The Painten pterosaur phylogenetically nests between two smaller specimens in the LPT. 

Figure 4. The Painten pterosaur phylogenetically nests between two smaller specimens in the LPT. This is an earlier reconstruction of Ningchengopterus.

We’ve already established
(contra tradition enforced by several pterosaur professors) that pterosaur hatchlings were nearly identical to their 8x larger adults. So how do we determine if a pterosaur is a hatchling or an adult? The answer is phylogenetic analysis. A small adult pterosaur will nest with other small adult pterosaurs. A juvenile will nest with much larger adult pterosaurs, as demonstrated here with the first juvenile Rhamphorhynchus recovered by phylogenetic analysis, a paper the pterosaur referees did not want you to read, but you can read it here at ResearchGate.net for yourself.

Figure 1. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

Figure 5. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

There is (so far) only one exception to the above rule:
The IVPP anurognathid embryo (Fig. 5) is the same size as several adult sister taxa, like MCSNB 8950 and Mesadactylus. So undiscovered adults will be giant basal anurognathids when found. One incomplete and mislabeled sister taxon, ?Dimorphodon weintraubi, is closer in size to the hypothetical adult of the IVPP embryo, demonstrating the possibility of a giant anurognathid is real. Again, phylogenetic analysis works out all such problems.

The Vienna Pterodactylus.

Figure 6. The Vienna Pterodactylus. Click to animate. Wing membranes in situ (when folded) then animated to extend them. There is no shrinkage here or in ANY pterosaur wing membrane. There is only an “explanation” to avoid dealing with the hard evidence here and elsewhere.


References
Lü J 2009. A baby pterodactyloid pterosaur from the Yixian Formation of Ningcheng, Inner Mongolia, China. Acta Geologica Sinica 83 (1): 1–8.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Unwin DM and Deeming DC 2019. Prenatal development in pterosaurs and its implications for their postnatal locomotory ability. Proceedings of the Royal Society B https://doi.org/10.1098/rspb.2019.0409

wiki/Ningchengopterus

Digitally boosting contrast to better see pterosaur wings

With all the new innovations
in seeing otherwise invisible details using UV, RTI, laser and fluorescing lighting, let’s not forget that Adobe Photoshop can boost contrast after the original digital photograph has been taken. In the present example (Figs. 1-4), the wing membrane is ever so slightly darker than the matrix, but that small range can be increased digitally.

Figure 1. The proximal wing of TMP 2008.41.001 showing original photo, original tracing along with boosted contrast and color tracing.

Figure 1. The proximal wing of TMP 2008.41.001 showing original photo, original tracing along with boosted contrast and color tracing. Nothing changes here, except the interpretation. I say this is data. Hone et al. 2015 wrongly call this ‘shrinkage’. Where is the pteroid? I would X-ray this slab. Based on the propatagium, it is probably buried.

Earlier we looked at
the TMP  2008.41.0001 specimen of Rhamphorhynchus (Hone et al.  2015). Today we’ll just rotate the images to fit the taller-than-wide blogspace format and digitally boost the contrast of the published photos to see what we can see together. Hon et al. traced the same wing membrane borders. Then they said it was ‘fake news’ due to ‘shrinkage’, but only where they wanted it to ‘shrink’.

Figure 3. Right wing and tail of the TM 2008.41.0001 specimen with contrast digitally boosted. Labels and line art from Hone et al. 2016.

Figure 2. Right wing and tail of the TM 2008.41.0001 specimen with contrast digitally boosted. Labels and line art from Hone et al. 2016.

Despite the fact
that this specimen documents a narrow-chord wing membrane stretched between the elbow and wingtip (Fig. 1), no citation to Peters 2002 was provided by Hone et al. 2016, thus fulfilling Bennett’s curse, “You won’t get published and if you do get published, you won’t get cited.”

As readers already know
Dr. David Hone deleted all reference to Peters 2000 when testing the minority view on pterosaur origins (from fenestrasaurs, Peters 2000) versus the majority view (from archosaurs, Bennett 1996), then ascribing both views to Bennett (1996) in a series of two papers (Hone and Benton  2007, 2009) discussed earlier here.

According to Hone et al. (2016):
“Each wing has a more narrow chord along  most of its length than seen in some specimens of Rhamphorhynchus (e.g., BSPG 1938 I 503a, the ‘DarkWing’ specimen—Frey et al., 2003) suggesting some postmortem shrinkage of the membranes (Elgin, Hone & Frey, 2011).”

Unfortunately,
Hone et al did not realize they were looking at a patch of mid-wing membrane in the DarkWing specimen (Fig. 4). We looked at the pre- and post-mortem disarticulation of the ‘DarkWing specimen earlier here.

Of course,
the authors did not forget to cite their own study on wing shape, Elgin, Hone & Frey 2011, in which they considered all examples of a narrow chord wing membrane (that means all examples) caused due to taphonomic ‘shrinkage.’ Their zeal for re-imagining hard data was reviewed earlier here and here.

Figure 2. Left wing of TMP 2008.41.001 showing original photo, original tracing along with boosted contrast and color tracing. Wing tip includes apparently missing wingtip ungual, but there is an articular surface there.

Figure 3. Left wing of TMP 2008.41.001 showing original photo, original tracing along with boosted contrast and color tracing. Wing tip includes apparently missing wingtip ungual, but there is an articular surface there and the membrane extends beyond m4.4.

The wing tip was twisted during burial
rotating the distal elements 180º. This was misinterpreted by Hone and Elgin in their report of the small rhamphorhychid, Bellubrunnus, in which they claimed this was the natural orientation of the wing tip elements in Bellubrunnus. We looked at that unfortunate interpretation earlier here.

Figure 1. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb restored.

Figure 4. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb restored to the invivo position. Note: the proximal portion is not exposed in situ.  The purple line is drawn based on phylogenetic bracketing. All other pterosaurs have a narrow chord wing membrane.

It is not good for paleontology
when workers ignore hard data.

The Zittel wing

Figure 5. The Zittel wing from a species of Rhamphorhynchus. Click to enlarge. Elgin, Hone and Frey 2011 dismissed this specimen as another example of ‘shrinkage’, but only where they wanted it to shrink.

The other question you should ask,
is why professional paleontologists, PhDs and professors are not calling attention to such issues? It is not good for paleontology when a civilian scientist has to point out such errors of judgement…over and over. Your paleontologists are imagining ‘shrinkage’ wherever they want to and not elsewhere, for some strange reason. Imagine their worst nightmare… backing away from their imaginary interpretations as they begrudgingly accept reality.

IF there was even ONE example
of a pterosaur wing membrane attached at the ankles, I would be the first to tell you about it. So far, all evidence purporting to do so, like the infamous Sordes holotype, has been soundly and thoroughly debunked. Please tell that to the authors listed below, plus any other artists and PhDs who need to know.


References
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
Hone D, Henderson DM, Therrien F and Habib MB 2015. A specimen of Rhamphorhynchus with soft tissue preservation, stomach contents and a putative coprolite. PeerJ 3:e1191; DOI 10.7717/peerj.1191
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.

https://pterosaurheresies.wordpress.com/2011/11/03/what-the-dark-wing-rhamphorhynchus-tells-us/

 

Vestigial fingers on the UNSM 93000 Nyctosaurus

The UNSM 93000 specimen attributed to Nyctosaurus
has only three wing phalanges and the tiny vestigial free fingers have never been looked at using DGS methods before. Well, here they are (Fig. 1).

Figure 1. Closeup of the UNSM 93000 specimen of Nyctosaurus focusing on three vestige free fingers.

Figure 1. Closeup of the UNSM 93000 specimen of Nyctosaurus focusing on three vestige free fingers. This is what happens when you no longer need these fingers. You can tell Nyctosaurus from Pteranodon in that the former never fuses the sesamoid (extensor tendon process) to phalanx 4.1. Other wrongly consider this a trait of immaturity.

Nyctosaurus sp. UNSM 93000 (Brown 1978, 1986) was derived from a sister to Nyctosaurus gracilis and phylogenetically preceded the crested Nyctosaurus specimens. Except for the rostral tip, the skull and cervicals are missing. Distinct from Nyctosaurus gracilis, the dorsals of the Nebraska specimen relatively shorter. The scapula and coracoid were more robust. The deltopectoral crest of the humerus most closely resembled that of Muzquizopteryx. Fingers I-III were tiny vestiges. Manual 4.1 extended to mid ulna when folded. Manual 4.4 was probably fused to m4.3 or it was missing and m4.3 became curved.

Figure 1. The UNSM specimen of Nyctosaurus, the only one for which we are sure it had only three wing phalanges.

Figure 2. The UNSM specimen of Nyctosaurus, the only one for which we are sure it had only three wing phalanges.

The pubis and ischium did not touch, as in more primitive nyctosaurs. It would have been impossible for the forelimb to develop thrust during terrestrial locomotion. It was likely elevated or used like a ski-pole.


The family tree of the Ornithocephalia and Germanodactylia is here. The expanded family tree of the Pterosauria is here.


References
Brown GW 1978. Preliminary report on an articulated specimen of Pteranodon Nyctosaurusgracilis. Proceedings of the Nebraska Academy of Science 88: 39.
Brown GW 1986. Reassessment of Nyctosaurus: new wings for an old pterosaur. Proceedings of the Nebraska Academy of Science 96: 47.

 

Scaphognathus wing membrane in visible light

Today a paper by Jäger et al. 1831
put the holotype of Scaphognathus (Goldfuß 1831; Late Jurassic) under various forms of illumination and re-discovered soft tissue originally noted and rarely cited.

Figure 1. Holotype of Scaphognathus GIF animation showing extent of wing membrane ignored by xx et al. 2018.

Figure 1. Holotype of Scaphognathus GIF animation showing extent of wing membrane ignored by xx et al. 2018.

Ironically
the authors ignored the most obvious aspect of the Scaphognathus soft tissue: the presence of a narrow chord wing membrane (Fig. 1), as documented by Peters (2002) and ignored ever since, per Chris Bennett’s threat, “You won’t get published, and if you do get published, you won’t get cited.”

Figure 2. Here is the Vienna specimen of Pterodactylus in situ and with matrix removed. Now compare this figure with figure 3, which shows the wings and uropatagia unfolding. There is no way to turn this into a deep chord wing membrane. And it decouples the forelimbs from the hind limbs.

Figure 2. Here is the Vienna specimen of Pterodactylus in situ and with matrix removed. Now compare this figure with figure 3, which shows the wings and uropatagia unfolding. There is no way to turn this into a deep chord wing membrane. And it decouples the forelimbs from the hind limbs.

The Vienna specimen of Pterodactylus
(Figs. 2, 3) are the prime examples of a narrow chord wing membrane, stretched between the wing tip and elbow… as in all pterosaurs that preserve soft tissue.

The Vienna Pterodactylus.

Figure 3. The Vienna Pterodactylus. Click to animate. Wing membranes in situ (when folded) then animated to extend them. There is no shrinkage here or in ANY pterosaur wing membrane. There is only an “explanation” to avoid dealing with the hard evidence here and elsewhere.

There are still no examples
of a deep chord wing membrane (attached to the ankle or tibia) preserved in any pterosaurs, as documented here, here, here and here.

References
Goldfuß A 1831. Beiträge zur Kenntnis verschiedener Reptilien der Vorwelt. Nova Acta Physico-Medica Academiae Caesareae Leopoldino-Carolinae Naturae Curiosorum, 15:61-128.
KRK Jäger, Tischlinger H, Oleschinski G, and Sander PM 2018. Goldfuß was right: Soft part preservation in the Late Jurassic pterosaur Scaphognathus crassirostris revealed by reflectance transformation imaging (RTI) and UV light and the auspicious beginnings of paleo-art. Palaeontologia Electronica 21.3.4T: 1-20. pdf
Peters D 2002. A new model for the evolution of the pterosaur wing – with a twist. Historical Biology 15: 277–301.