The Pterosaur Heresies

There's something very wrong with our pterosaurs.

The Pterosaur Heresies

The best ‘Sordes’ uropatagium… is another overlooked wing

This much talked about, but rarely seen ‘Sordes’ specimen
(Fig. 1), has been known for decades. It made a brief appearance some 30 years ago at an SVP talk by David Unwin where it caused quite a stir. I haven’t seen it again since. A scale bar is not shown and the museum number is unknown, but may be one of these three: PIN 104/73, PIN 2585/36, PIN 2585/37.

Today this rare ‘tail-less’ specimen made another brief appearance
in an online Palaeontological Assocation talk “Resolving the pterosaur bauplan using a quantitative taphonomic approach” by Rachel Belben (2012, video link), one of Unwin’s students. We looked at Belben’s nearly identical 2020 abstract here.

Figure 1. Image from Belben's December 2020 talk about the pterosaur bauplan.

Figure 1. Image from Belben’s December 2020 talk about the pterosaur bauplan. That’s Belben inset in red. Click to view video on YouTube.

Not one, but two similar Sordes specimens
were presented by Unwin at SVP decades ago. Both appeared to have a distinct uropatagium stretched bat-like between the sprawling hind limbs (Figs. 1, 2). Everyone wondered whether that membrane was 1) above or below the cloaca, 2) attached or not attached to the tail, and 3) what sort of precursor taxa would gradually develop such a membrane controlled by hyperflexed lateral toes. In bats, of course, the vaguely similar calcar arises from the ankle. The toes are not involved.

Sharov 1971
first described and figured the Sordes holotype (Fig. 2, upper right) with a small drawing that appeared to clearly show a uropatagium stretched between the hind limbs and controlled by those odd Tanystropheus-like elongated lateral toes.

Unwin and Bakhurina 1994
brought this odd bit of flight membrane to a wider audience with a short paper in Nature. Their drawing (Fig. 2 middle right) paid less attention to detail.

Peters 1995
disputed the uropatagium, considering it a displaced wing membrane. That critical hypothesis was presented again in Peters 2002 (Fig. 2, left and bottom).

Elgin, Hone and Frey 2012
sided with Sharov, Unwin and Bakhurina, also paying little attention to the specimen.

Figure 4. Sordes wing drift hypothesis from Peters (2002) which attempted to show that the wings and uropatagia of Sordes were more like those of other pterosaurs than the other way around. The very deep uropatagia are misinterpretations prior to the realization that the left brachiopatagium (main wing membrane) was displaced to the ankle area.

Figure 2. Sordes wing drift hypothesis from Peters (2002) which attempted to show that the wings and uropatagia of Sordes were more like those of other pterosaurs than the other way around. The very deep uropatagia are misinterpretations prior to the realization that the left brachiopatagium (main wing membrane) was displaced to the ankle area.

Back in 2011,
the uropatagium of the Sordes holotype showed up here with another tracing (Fig. 5) that showed the displaced radius + ulna and its displaced membrane.

Figure 6. The PIN 2585/3 specimen of Sordes showing displaced left radius and ulna dragging their membranes along with them. The right wing is articulated.

Figure 3. The PIN 2585/3 specimen of Sordes showing displaced left radius and ulna dragging their membranes along with them. The right wing is articulated and shows a short chord wing membrane. Uropatagia are in red.

A new tracing of the rare specimen
(Fig. 4) shows the purported uropatagium extending far beyond the hind limb. That indicates a problem! This is not a uropatagium. Maybe that’s why we haven’t seen this rare specimen for 30 years. A closer examination reveals a series of pterosaur arm bones beneath the hind limb elements. Arm bones or not, this ‘uropatagium’ is a brachiopatagium, a wing membrane, complete with aktinofibrils (Fig. 5).

Figure 4. Color tracing applied to the rare 'Sordes' specimen reveals another displaced wing (deep blue) along with overlooked wing elements. See figure 5 for a reconstruction.

Figure 4. Color tracing applied to the rare ‘Sordes’ specimen reveals another displaced wing (deep blue) along with overlooked wing elements. See figure 5 for a reconstruction.

Adding what little is known
to the large pterosaur tree (LPT, 256 taxa) nests the rare specimen not with Sordes, but with the tiny flightless anurognathid PIN 2585/4 specimen that shares the plate with the holotype of Sordes, PIN 2585/3 (Fig. 2). We looked at that rarely seen specimen earlier here.

Figure 5. Reconstruction of the specimen in figure 4.

Figure 5. Reconstruction of the specimen in figure 4.

Distinct from the flightless PIN 2585/4 anurognathid specimen,
this one has large, robust wings.

In summary
this rarely seen specimen

  1. is not Sordes
  2. does not present a uropatagium
  3. can now explain why a Sordes-like tail is absent here
  4. evidently has never been carefully examined before
  5. has fooled pterosaur experts for decades
  6. is one source of pterosaur mythology that many pterosaur workers and their minions continue to believe in fifty years after its original description.

Someone please tell Rachel Belben
so she can wash her hands of this decades-old error and start fresh.

The Sordes uropatagium is a misinterpretation.
We need to bury this mistake and forget it. Stop promoting and believing this myth. It has been exposed.


References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeonntologica Polonica 56(1): 99-111.
Peters D 1995. Wing shape in pterosaurs. Nature 374, 315-316.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277–301.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions 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.

wiki/Sordes

https://pterosaurheresies.wordpress.com/2015/03/10/the-evolution-of-the-sordes-wing-and-uropatagia-1971-to-2011/

https://pterosaurheresies.wordpress.com/2015/03/09/how-one-sordes-evolved-into-dorygnathus-via-cacibupteryx/

https://pterosaurheresies.wordpress.com/2014/03/15/variation-in-three-sordes-specimens/

https://pterosaurheresies.wordpress.com/2012/07/17/what-is-happening-between-the-legs-of-sordes/

https://pterosaurheresies.wordpress.com/2020/10/21/svp-abstracts-3-belben-contributes-to-the-bat-wing-pterosaur-myth/

 

Enigma pterosaur wing bone from Late Campanian Utah

Farke 2021
brings us a large ‘pterosaur limb bone’ (Fig. 1) from the Late Cretaceous of Utah. The author guessed the bone was an ulna, but could not determine which end was proximal.

Figure 1. Radius RMA 22574 from Farke 2021.

Figure 1. Ulna RMA 22574 from Farke 2021. Distal is at bottom.

From the abstract
“A large pterosaur bone from the Kaiparowits Formation (late Campanian, ~76–74 Ma) of southern Utah, USA, is tentatively identified as an ulna, although its phylogenetic placement cannot be precisely constrained beyond Pterosauria. The element measures over 36 cm in preserved maximum length, indicating a comparatively large individual with an estimated wingspan between 4.3 and 5.9 m, the largest pterosaur yet reported from the Kaiparowits Formation.”

That tentative identity as an ulna is confirmed here.  
Other than its more robust width and overall size, the bone is a good match for the ulna in the more completely known Triebold specimen of Pteranodon, NMC41-358 (Fig. 3). The overall size and relative length vs. width of RMA 22574 identifies this as a large Pteranodon (Fig. 2), perhaps the largest by a few percent, rather than a small azhdarchid (Fig. 4).

So, contra Farke 2021,
this specimen can be precisely constrained rather precisely beyond Pterosauria. It just takes a little comparative anatomy and taxon inclusion. Farke employed only one Pteranodon specimen (FHSM 184) for comparison, perhaps not realizing that no two known taxa are identical, even in the post-crania (Fig. 2), and others demonstrate a wide variation in size and morphology. By the way, FHSM 184 is a large solitary metacarpal 4.

Figure 2. The largest Pteranodon post-crania compared to RMA 22574, slightly larger than the largest.

Figure 2. The largest Pteranodon post-crania compared to RMA 22574, slightly larger than the largest.

A little repair work
to the broken proximal end (elbow) helps complete the match between RMA 22574 and NMC41-358 (Fig. 3).

Figure 2. Comparing RMA 22574 with the smaller and more gracile NMC41-358.

Figure 3. Comparing RMA 22574 with the smaller and more gracile NMC41-358 scaled to the same length.

A selection of Pteranodon post-crania
can be seen to scale here and one of the largest is shown here (Fig. 2). Note the relatively shorter, broader antebrachia (= radius + ulna) in the largest, latest Pteranodon species relative to the humerus (Fig. 2 upper right). The relatively shorter, more robust, largest antebrachium with the characters of RMA 22574 is restricted to large, late Pteranodon specimens.

Figure 3. RMA 22754 compared to Quetzalcoatlus sp. which has a more slender radius.

Figure 4. RMA 22754 compared to Quetzalcoatlus sp. which has a more slender radius.

Comparisons to appropriately sized azhdarchids
(Fig. 4) do not match as well. These tend to have a more gracile, hourglass appearance.


References
Farke AA 2021. A large pterosaur limb bone from the Kaiparowits Formation (late Campanian) of Grand Staircase-Escalante National Monument, Utah, USA. PeerJ 9:e10766 https://doi.org/10.7717/peerj.10766

reptileevolution.com/pteranodon-skulls.htm
reptileevolution.com/pteranodon-postcrania.htm

Behind the scenes: that infamous ‘pterosaur precursor’ paper

Earlier we looked at
a pterosaur precursor paper that excluded all the pterosaur precursors documented 20 years ago (Peters 2000, 2007, 2009). Those four taxa were dismissed and omitted by Ezcurra et al. 2020, who cobbled together a chimaera of protorosaur and lagerpetid parts. Notably the lagerpetid foot showed it stood on only two toes. Pterosaur tracks and skeletons show pterosaurs stood on five toes. And that’s just the beginning of the sins committed by this 18 co-author venture into the imagination of confirmation bias.

From Eurekalert.org:
“Some questions still remain in this evolutionary mystery. Now that lagerpetids are the closest relatives of pterosaurs, why are they still lacking some of the key characteristics of pterosaurs, including the most outstanding of those – wings?

“We are still missing lots of information about the earliest pterosaurs, and we still don’t know how their skeletons transformed into an animal that was capable of flight,” said Nesbitt.”

pterosaur wings

Figure 1. Click to enlarge. The origin of the pterosaur wing and whatever became of manual digit 5?

Actually we already know how pterosaurs got their wings.
We’ve known for ten or twenty years (depends if your measure by data or taxa). The authors cited twenty-year-old Peters 2000. The authors provided no evidence that they actually looked inside that paper. Perhaps they believed the current propaganda and just dismissed the hypothesis. There was also a bit of wish fulfillment going on. Many workers have been hoping for decades to find a taxon to link dinos with pteros (see below).

Reporter George Dvorsky, confesses on Gizmodo.com
“These creatures [lagerpetids] seem an unlikely sister group from which pterosaurs emerged, which is probably why they’ve been ignored for so long.”

Lagerpetids seem unlikely because they have no traits shared exclusively with pterosaurs and several that dislodge them from consideration. By contrast, the omitted Cosesaurus clade has a long list of traits shared exclusively with pterosaurs.

Professor Kevin Padian
wrote a News & Views article to accompany the paper and put Ezcurra et al.  into historical perspective. Padian also omitted the Peters 2000 paper, which really should have been part of the history of pterosaur origins. Instead Padian concentrated on 18th and 19th century papers (why not just reference the Bible?), plus 4 of 10 citations were for Padian papers from the past, none on pterosaur origins. One citation was for young J. Gauthier’s PhD thesis at the genesis of software enabled phylogenetic analysis in which the clade Ornithodira (= pterosaurs + dinosaurs) was proposed and widely accepted without testing the Cosesaurus clade. To his credit, Padian 1983 reported that Dimorphodon (Fig. 2) was a biped, like birds and dinosaurs and he has ‘stuck to his guns’ ever since.

FIgure 8. Dimorphodon take off (with the new small tail).

Figure 2. Dimorphodon take off (with the new small tail).

I wrote to Dr. Padian:

Dear Kevin,

I’ll never forget the day when you and Chris Bennett gave me your sage words of wisdom: “Dave, you have to learn to perform a phylogenetic analysis.”

In 2000 when my Rivista paper came out on pterosaur origins, I added Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama to four previous published phylogenetic analyses. In each case those four nested closer to pterosaurs than all prior candidates… and for good reason. They shared more traits from snout to toes, including extradermal tissues.

Since then no one in the paleo community has let me know there are better candidates out there that I haven’t tested. On the other hand, no one has ever said, “Good job, you nailed it.”

Following your earlier advice I started adding taxa to a growing onliine cladogram at ReptileEvolution.com. Today there are 1770+ taxa on that one cladogram and the Cosesaurus clade still nests with pterosaurs, but they also nest within Lepidosauria in an overlooked third clade between sphenodonts and squamates.

It’s clear you have always preferred the ornithodire hypothesis, despite conflicting results when more taxa are added. Not sure why you stick to your guns when no evidence supports the hypothesis

Yesterday Ezcurra et al. came out with a chimaera they created out of a lagerpetid and a protorosaur that ran on two toes and called it a pterosaur precursor and you supported it with an enthusiastic news and views article, that, like Ezcurra et al. report, omitted the Cosesaurus clade.

You wrote, “Lagerpetids fit this profile, and, unlike other candidate relatives, they share some features with pterosaurs that other archosaurs do not.”

You also wrote,”Ezcurra et al. realized that, although lagerpetids didn’t fly, they share specific features with pterosaurs, such as … Their elongated hand (palm) bones (hyperelongated in pterosaurs, along with the fourth finger) suggest a good starting point for animals to evolve flight.”

By contrast, Ezcurra et al. wrote, ” …lagerpetids, as with other archosauromorphs, _lack_ the enlargement of both the deltopectoral crest of the humerus and the fourth manual digit that characterizes pterosaur wings.

We all see what we want to see. But my friends from Morristown NJ usually have a keener eye.

I was critical of Ezcurra et al. online here, with extensive evidence, if interested:

https://pterosaurheresies.wordpress.com/2020/12/10/new-pterosaur-precursor-study-excludes-all-pterosaur-precursors/

Best regards,

I have not heard back yet, and ironically, Dr. Padian is not famous for phylogenetic analysis.

Likewise I sent an email to co-author Max Langer:

Hi Max,

I was surprised, once again, to see Cosesaurus, Sharovipteryx and Longisquama omitted from a study on pterosaur origins. Very bizarre that taxa with prepubes, pterosaur-type pedes, extradermal membanes, antorbital fenestrae, four+ sacrals, elongate ilia, attenuated tails and a sternal complex were dismissed. 

Your new lagerpetid ran on two toes. That was the story, not any sort of relationship to pterosaurs.

Best regards,

I have not heard back yet.

Likewise I sent an email to lead author Martin Ezcurra
after he sent a PDF of the paper:

Thank you, Martin.

That is very kind of you to send the PDF. Fortunately someone else sent a copy in the meantime and I have been pouring over it.

I am going to be very critical of your paper. Here are the first two paragraphs.

It is good to see more material data appearing for lagerpetids, an enigmatic clade formerly known from pelvic and hind limb material and more recently from skull bits.

“Unfortunately Ezcurra et al. follow an established history of workers omitting competing taxa in pterosaur origin papers while cherry-picking comparative taxa and employing a chimaera of disassociated and unrelated bits and pieces from different genera. By contrast, the omitted taxa are complete, articulated, preserve soft tissue and nest closer to pterosaurs in several prior cladograms when added to them. Details follow.”

In addition, I think you missed some exciting details in the pes, overlooking fused bones. Your metatarsal 1 is actually metatarsal 2. Digit 1 is a vestige on this weird pes. Basal pterosaurs have five robust toes. Chanaresuchds lose pedal digit 5, so cannot be ancestral on that point alone. The taxa from Peters 2000 all have a robust pedal digit 5 on a short metatarsal, as in pterosaurs and as in Tanystropheus, which is why the first specimens of Tanystropheus were considered pterosaurian. Both are lepidosaurs, by the way.

Phylogenetically all the material continues to look chanaresuchid, not pterosaurian, as in prior lagerpetids.

Not sure who guided you not to include taxa from Peters 2000, 2007, 2009. Oh, well, it’s in print now. Most of the worst hypotheses on pterosaurs seem to come out of Southern England. Try to be more careful before accepting their suggestions.

This affair may remind you of the Oculudentavis scandal after a few days or weeks. Hopefully you’ll come out okay on the other end.

Best regards,

I have not heard back from Martin, either,

I only wish Ezcurra team and Padian
had been more critical of their own work (e.g. the two toes issue), had indicated they looked at the taxa in Peters 2000 and then rejected them and provided the reasons for that rejection, and contrary to that, simply shown their reconstruction of Cosesaurus, their reconstruction of Bergamodactylus and their reconstruction of their chimaera in one figure so readers could see their work for themselves with help from figure captions and call-outs. Figure 3 is from ReptileEvolution.com.

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

Figure 3. Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown.

Please remember,
I was the second person to see pterosaur traits in Cosesaurus. Dr. P. Ellenberger was the first, but unfortunately, he thought Cosesaurus was a bird ancestor. He never considered pterosaurs. His views and tracings were chronicled here, here and here.

Together with the Oculudentavis scandal in March 2020,
this pterosaur precursor scandal and others, paleontology is going through a nadir right now. I hope things don’t get worse before they get better.


References
Ezcurra MD et al. (17 co-authors) 2020. Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria. Nature (2020). https://doi.org/10.1038/s41586-020-3011-4
Padian K 1983. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea) based on new material in the Yale Peabody Museum.  Postilla. 189: 1–44.
Peters D 2000. 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

Cosesaurus paper on ResearchGate.net

https://gizmodo.com/scientists-uncover-the-mysterious-origin-of-pterosaurs-1845841696

https://pterosaurheresies.wordpress.com/2020/12/10/new-pterosaur-precursor-study-excludes-all-pterosaur-precursors/

150 million years of pterosaur flight efficiency

Venditti et al. 2020
attempts to chronicle an increase in pterosaur flight efficiency over their 150 million year long clade span.

From the Venditti et al. abstract:
“The long-term accumulation of biodiversity has been punctuated by remarkable evolutionary transitions that allowed organisms to exploit new ecological opportunities. Mesozoic flying reptiles (the pterosaurs), which dominated the skies for more than 150 million years, were the product of one such transition. The ancestors of pterosaurs were small and probably bipedal early archosaurs (Andres et al. 2014), which were certainly well-adapted to terrestrial locomotion.”

Citation and taxon exclusion here. Andres et al. 2014 cherry-picked four euarchosauriform outgroups for the Pterosauria: Euparkeria, Ornithosuchus, Herrerasaurus and Scleromochlus. All of these taxa have a short to vestigial manual digit 4, the opposite of pterosaurs. This list followed the direction of co-author Mike Benton, well known for citation and taxon exclusion to promote his pet hypotheses, invalidated by Peters 2000, 2007, 2009. Readers have seen Benton omissions many times. The actual ancestors of pterosaurs were not archosaurs, but these lepidosaurs: Cosesaurus (Fig. 1), Sharovipteryx and Longisquama. So Venditti et al. 2020 starts off poorly, without a proper phylogenetic context.

By the way, Andres et al.  2014 did not find ‘the earliest pterodactyloid,’ but bits and pieces of a gracile dorygnathid, Sericipterus found in the same formation.

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.

Continuing from the Venditti et al. abstract:
“Pterosaurs diverged from dinosaur ancestors in the Early Triassic epoch (around 245 million years ago); however, the first fossils of pterosaurs are dated to 25 million years later, in the Late Triassic epoch.”

False: Pterosaurs diverged from fenestrasaur ancestors (Peters 2000).

“Therefore, in the absence of proto-pterosaur fossils, it is difficult to study how flight first evolved in this group.”

False. We have those proto-pterosaur fossils and pterosaur ancestors all the way back to Cambrian chordates. Adding taxa resolved this problem in Peters 2000, 2007, 2009 and that continues today.

“Here we describe the evolutionary dynamics of the adaptation of pterosaurs to a new method of locomotion. The earliest known pterosaurs took flight and subsequently appear to have become capable and efficient flyers. However, it seems clear that transitioning between forms of locomotion2,3—from terrestrial to volant—challenged early pterosaurs by imposing a high energetic burden, thus requiring flight to provide some offsetting fitness benefits.”

Or the other way around, as documented by the four fenestrasaurs listed above.

“Using phylogenetic statistical methods and biophysical models combined with information from the fossil record, we detect an evolutionary signal of natural selection that acted to increase flight efficiency over millions of years.”

What is ‘flight efficiency’? Are hummingbirds more efficient? Or are albatrosses? Or ducks? Did the authors use the proper pterosaur wing shape (Fig. 2) ? Or the traditional invalid batwing-shape preferred by those in the Benton arc.

The Vienna Pterodactylus.

Figure 2. 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.

“Our results show that there was still considerable room for improvement in terms of efficiency after the appearance of flight.”

Without valid outgroups, how do they know? They don’t.

“However, in the Azhdarchoidea4, a clade that exhibits gigantism, we test the hypothesis that there was a decreased reliance on flight5,6,7 and find evidence for reduced selection on flight efficiency in this clade.”

Odd that these authors do not include the many examples of flightless pterosaurs, including derived and sometimes giant members of the Azhdarchidae.  They only say ‘there was a decreased reliance on flight.’

“Our approach offers a blueprint to objectively study functional and energetic changes through geological time at a more nuanced level than has previously been possible.”

There is no ‘blueprint’ here, only more misdirection and mythology. Sad that the works of professor Mike Benton have now become suspect following the present continuation of his long-standing pattern of cherry-picking and taxon exclusion favoring the textbooks and lectures that provide his income.


References
Andres B, Clark J and Xu, X 2014. The earliest pterodactyloid and the origin of the group. Current Biology 24:1011–1016 (2014).
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 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330
Venditti C, Baker J, Benton MJ, Meade A and Humphries S 2020. 150 million years of sustained increase in pterosaur flight efficiency. Nature https://doi.org/10.1038/s41586-020-2858-8

From the Nature comments section:
“The ancestors of pterosaurs were recovered twenty years ago (in Peters 2000) by simply adding Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama to four previously published analyses. Peters (2007) nested these bipedal taxa within the Lepidosauria by once again simply adding taxa. Omitting citations and omitting taxa results in statements like the following found in the Venditti et al. 2020 abstract: “in the absence of proto-pterosaur fossils, it is difficult to study how flight first evolved in this group.” Had the authors included Cosesaurus they would have known this taxon was flapping without flying due to a locked down, stem-shaped coracoid otherwise found only in birds and pterosaurs. Bats flap anchored by an analogous clavicle.”

 

SVP abstracts 9: Pushing a tiny wading pterosaur into the deep end

Habib, Pittman and Kaye 2020
add laser fluorescence to a tiny pterosaur, the still unnamed Berlin specimen, MB.R.3531 (Figs. 1a, b) we first looked at following Flugsaurier 2018.

From the Habib et al. abstract:
“Water launch capacity has been previously suggested for some marine pterosaurs based on osteological grounds, but robust estimates of specimen-specific performance are difficult without robust estimates of wing area and potential hindfoot webbing. Here, we provide the first estimates of pterosaur water launch performance that take into account preserved soft tissue anatomy.”

FIgure 1. Reconstruction of MB.R.3531, nesting with Eoazhdarcho, Eopteranodon and Aurorazhdarcho.

FIgure 1a. Reconstruction of MB.R.3531, nesting with Eoazhdarcho, Eopteranodon and Aurorazhdarcho. Shown about actual size, so this pterosaur could have stood upright like this in a 10cm per side box. See figure 1b.

Figure 1. Aurorazhdarcho primordial and the smaller Aurorazhdarcho micronyx to scale.

Figure 1b. Aurorazhdarcho primordial and the smaller Aurorazhdarcho micronyx (not a juvenile) to scale. The smaller one had better stay out of deeper waters.

Continuing from the Habib et al. abstract:
“The aurorazhdarchid pterosaur specimen MB.R.3531 from the Upper Jurassic Solnhofen Limestone was imaged using Laser-Stimulated Fluorescence, revealing significant soft tissue preservation. These soft tissues are among the best-preserved of any known Jurassic pterosaur, including for the first time, a complete actinofibrillar complex, an undistorted actinopatagium with the retrophalangeal connective tissue wedge and entire trailing edge, and webbed feet.”

Why the showmanship (= hyperbole, = falsehood)? Most of these traits have been known for several pterosaurs and from less jumbled specimens, including the  Zittel wing specimen of Rhamphorhynchus (Fig. 2), the dark-wing specimen of Rhamphorhynchus and the Vienna specimen of Pterodactylus (Fig. 3).

The Zittel wing

Figure 2. The Zittel wing from a species of Rhamphorhynchus. This is real. There is no way this wing membrane is going to stretch to the ankles. See figure 3 for comparison and phylogenetic bracketing. This is how pterosaur wings were able to be folded away when not in use. 

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 3. 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. This is how pterosaur wings were able to be folded away when not in use. 

Continuing from the Habib et al. abstract:
“These physically validated soft tissues formed the basis for analyzing water launch capability in MB.R.3531. We modeled the water launch as quadrupedal and broadly similar to modern “puddle jumping” anseriform birds that use a combination of their webbed feet and partially folded wings to push against the water surface during takeoff.”

More myth-making. Like the morphologically similar by convergence, Pterodactylus (based on the Vienna specimen; Figs. 3, 4), MB.R.3531 was a quadrupedal wader (note the tiny fore claws), but able to stand bipedally prior to take-off. Waders don’t get themselves into water too deep to touch the substrate. Ask any sandpiper, plover or stilt.

So this is much ado about nothing, based on putting the discredited Habib method of pushup take-off back on the table.

FIgure 6. Pterodactylus scolopaciceps (n21) model. Full scale.

Figure 4. Pterodactylus scolopaciceps (n21) model. Full scale. This is how pterosaur wings were able to be folded away when not in use. 

More from the Habib et al. abstract:
“Under this model, both hind limb and forelimb contact areas are critical. Under conservative assumptions regarding power and range of motion, we predict that MB.R.3531 was capable of rapid takeoff from the water surface.

Yes, of course, but from a bipedal start (Fig. 5). And from shallow ponds, no deeper than knee deep.

FIgure 8. Dimorphodon take off (with the new small tail).

FIgure 5. Dimorphodon take off (with the new small tail).

From the Habib et al. abstract:
“Our model predicts that water launch performance in pterosaurs was particularly sensitive to three factors: available propulsive contact area, forelimb extension range, and extension power about the shoulder. MB.R.3531 possessed both osteological and soft tissue features that significantly enhanced these performance characteristics (including, but not limited to, expanded internal rotator/extensor attachments on the proximal humerus, extended humeral length, chordwise distal actinofibril orientation, and webbed pes).”

If you’ll compare one with another, MB.R.3531 (Fig. 1) is convergent in most respects to a typical Solnhofen Pterodactylus (Fig. 4), down to the webbed feet. There was nothing out of the ordinary about MB.R.3531.

“These features would have limited impact on flight performance. We therefore interpret them as likely water takeoff specializations.

Whoa, partner! These traits are typical of most beach combing pterosaurs, so far as they can be determined in fossils and phylogenetic bracketing, even with unrelated clade convergence.

“The osteological specializations in MB.R.3531 are subtle, which may be related to its small size.”

I would agree that the osteological specializations are so subtle they do not exist.

“Larger marine pterosaurs appear to exaggerate these characteristics, which matches expectations from scaling.

This is false. Ornithocheirids have notoriously tiny feet, unsuitable for anything more than standing still and walking slowly. More to come.

“We show that soft tissue data can be used to help validate the dynamic feasibility of water launch in pterosaurs, suggesting it was a regular part of foraging behavior in some taxa.”

This is false. Dr. Habib, just let the pterosaur stand upright, as its ancestors did and as it was designed to do (fused sacrals and fused dorsal vertebrae dorsally, sternum + gastralia + prepubes support ventrally). Quadrupedal pterosaur tracks are more prevalent because they were made by a few clades of small-fingered beach combing pterosaurs, principally pterodactylids, ctenochasmatids and azhdarchids (Peters 2011).

Pelican take-off sequence from water.

Figure 6. Pelican take-off sequence from water using kicking webbed feet and elevated, then flapping wings simultaneously. Click to enlarge.

From an earlier 2018 assessment of MB.R.3531:
Habib and Pittman 2018 bring us a rarely studied Berlin pterosaur, MB.R.3531 (Fig. 1) originally named Pterodactylus micronyx, then Aurorazhdarcho micronyx. This specimen nests with other wading pterosaurs, AurorazhdarchoEopteranodon and Eoazhdarcho forming  a clade overlooked by other workers, at the transition between germanodactylids and pteranodontids, not related to azhdarchids (Peters 2007).

For those wondering why I don’t publish more.
Why put in the effort if competing studies are ignored? The online way is faster, briefer and can be animated with no color charges. Furthermore, the vetting process prior to publication of hypotheses like the dangerous pushup launch and the bat-wing pterosaur membrane myth, is failing time and again. Editors, professors and researchers who should be earning their paycheck from rigorously testing new hypotheses are instead granting their friends free passes in an effort to keep the status quo in lectures and textbooks.


References
Habib M and Pittman M 2018. An “old” specimen of Aurorazhdarcho micronyx with exceptional preservation and implications for the mechanical function of webbed
feet in pterosaurs. Flugsaurier 2018: The 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 41–43.
Habib MB, Pittman M and Kaye T 2020. Pterosaur soft tissues revealed by laser-stimulated fluorescence enable in-depth analysis of water launch performance. SVP abstracts 2020.
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
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 2010. In defence of parallel interphalangeal lines.
Historical Biology iFirst article, 2010, 1–6 DOI: 10.1080/08912961003663500
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605

https://pterosaurheresies.wordpress.com/2018/03/23/pteranodon-quad-hopping-water-takeoff-according-to-the-amnh/

https://pterosaurheresies.wordpress.com/2018/08/12/flugsaurier-2018-web-footed-little-pterosaur-mb-r-3531/

https://pterosaurheresies.wordpress.com/2012/12/16/water-takeoff-in-a-pelican-part-2-with-reference-to-pterosaur-water-takeoffs/

https://pterosaurheresies.wordpress.com/2015/03/23/amnh-animated-pterosaur-takeoffs/

https://pterosaurheresies.wordpress.com/2012/04/07/pterosaur-take-off-from-water/

https://pterosaurheresies.wordpress.com/2013/12/06/pterosaurs-were-unlikely-floaters-hone-and-henderson-2013/

https://pterosaurheresies.wordpress.com/2015/05/23/pterosaur-launch-talk-from-2012-on-youtube/

SVP abstracts 3: Belben contributes to the bat-wing pterosaur myth

From the Belben 2020 abstract
“Despite more than 200 years of research, the pterosaur bauplan remains unresolved.”

The only reason ‘the pterosaur bauplan remains unresolved’ in 2020 is because PhD pterosaur workers refuse to examine pterosaur fossils (Figs. 1, 2). That sounds heretical, but it’s sadly true.

Belben is from Leicester, supervised by professor Dave Unwin.

Dr. Unwin has been at the helm of the bat-wing pterosaur myth since Unwin and Bakhurina 1994 published on Sordes. Unwin’s conclusions were shown to be invalid by Peters 1995, supported by Peters 2002 and imagery found throughout this blogpost (Figs. 1, 2) and ReptileEvolution.com.

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 1. Here is the Vienna specimen of Pterodactylus in situ and with matrix removed. Now compare this figure with figure 2, 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 Pterodactylus.

Figure 2. 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.

The Belben abstract continues:
“A central issue concerns the relationship of the limbs via their inclusion in the flight apparatus and the extent of the wing membranes.”

See figures 1 and 2. It could not be more clear. More details and examples here.

“As extant birds and bats show, differing constructions have profound consequences for the locomotor ability, ecology and evolutionary history of flying vertebrates. In pterosaur specimens with fossilised flight patagia the hind limbs appear to be connected to the forelimbs via a brachiopatagium and, in non-pterodactyloids, to each other via a uropatagium.

Belben is working to protect her professor’s fading reputation. For the backstory on Unwin’s misinterpretation, click here.

Figure 5. Sordes from Elgin, Hone and Frey 2011. While we were all hoping for more detail, we got less.

Figure 3. Sordes from Elgin, Hone and Frey 2011. This duplicates Unwin and Bakhurina 1994. Compare to figure 4.

“These interpretations are disputed, however, and their applicability to the vast majority of species, which lack any soft tissue evidence, is unknown.

Disputed for good reason. This should be very clear without dispute. Phylogenetic bracketing handles those taxa preserved without soft tissue.

“This study used quantitative taphonomic data to test these models and to establish, for the first time, their distribution across Pterosauria.”

Quantitative data? Statistics? Why not just look at pterosaurs and report? Belben’s abstract sounds like more smoke and mirrors under the dark direction of Professor Unwin.

“Context is provided by bats and birds in which the construction, particularly the role of the hind limbs, is clear. Analysis of large samples, primarily from Messel (Eocene), show significant differences in hind limb posture. A symmetric, or near symmetric, ‘splayed’ posture is ubiquitous for bats, while in birds hind limbs adopt a wide range of postures, reflecting their functional and anatomical independence.”

And the trick is revealed. Taxon exclusion is once again the card played. Belbein is omitting splay-limbed lizards from consideration. Pterosaurs are fenestrasaur tritosaur lepidosaurs. Pterosaurs are neither bats nor birds. Asking the reader to look at birds and bats is what pterosaur professors do when they don’t have real evidence to support their invalid positions.

The myth of the pterosaur uropatagium

Fig. 4. The Sordes uropatagium is actually displaced wing material carried between the ankles by the displaced radius and ulna. This displacement was overlooked by all prior workers.

“The pterosaur data set consists of 300+ specimens representing almost the entire stratigraphic range of the clade and much of its anatomical, ecological and taxonomic diversity (18 out of 20 major clades). Plots of completeness versus articulation identified several taphonomic modes, the most important of which consists of skeletons that, while varying in terms of completeness, exhibit high values for articulation.”

Plots? Statistics? Stop this. Just look at some Solnhofen pterosaurs! (Fig. 1) Trace (Fig. 2). Animate if you have to.

“A splayed ‘bat-like’ hind limb posture is typical for this taphonomic mode and present in a wide range of species, including non-pterodactyloids and pterodactyloids.”

We knew pterosaurs had splayed limbs for the past 200 years. In that regard, pterosaurs are not’bat-like’. Pterosaurs remain lizard-like.

Belben! Wake up! Your tuition has been wasted. You have been groomed to accept taxon exclusion by your mentor, David Unwin.

“Critically, the vast majority of soft tissue specimens that fall within this taphonomic mode also exhibit the splayed posture (see Fig. 1). Combined, the taphonomic data for skeletal and soft tissues provides strong support for a widespread, likely universal, occurrence of hind-limb integration into the flight apparatus in pterosaurs.”

“Strong support?” “Likely?” Belben you are supporting a myth. Take off your blinders! Add splay-limbed lepidosaurs to your study. Add Sharovipteryx, Cosesaurus, etc. Then ask Dr. Unwin why he omits these taxa.

“Taphonomic analysis also revealed a significant difference between correlations of the degree of articulation of the hind limbs for non-pterodactyloids (relatively high) in which the hind limbs are connected to each other and pterodactyloids (relatively low) where they are separate.”

Stop with correlations and statistics. Look at the evidence. Trace the evidence with precision. No pterosaurs connect the wing membrane to the thigh or ankle. None incorporate pedal digit 5. None include a single uropatagium between the hind limbs exclusive of the tail. These are all 25-year-old misinterpretations of Sordes by your mentor and his minions. Click here, here and here for corrections to those misinterpretations.

We’ve seen this sort of influence before when David Hone was a PhD candidate under Mike Benton. And when PhD candidate Ross Elgin was under the influence of Hone and Frey.


References
Belben R 2020. Resolving the pterosaur bauplan using a quantitative taphonomic approach. SVP abstracts.
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeonntologica Polonica 56(1): 99-111.
Peters D 1995. Wing shape in pterosaurs. Nature 374, 315-316.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277–301.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions 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

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: