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

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.

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


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