Pterosaur hands and feet: Smyth et al 2024
Here’s a new paper on pterosaur hands and feet.
In brief: “Smyth et al. show that pterosaurs exhibit significant disparity in their hand and foot morphologies. This indicates that they occupied a broad range of locomotor
ecologies. Early pterosaurs were adapted for climbing, while later forms evolved
more effective terrestrial locomotion, which facilitated diversification and the evolution of gigantism.”
“more effective”? No. Better for beachcombing? Yes.
Not cited: Peters 2011, “A catalog of pterosaur pedes for trackmaker identification.” So the curse of Chris Bennett continues, “You will not get published and if you are published you will not be cited.”
Smyth is a young student. Co-author David Unwin has been around for decades. The authors decided to omit several pertinent citations. Instead you’ll see the authors take credit for several ‘firsts’ found in Peters 2011 and elsewhere. Kids, this is how they play.
Figure 1. Uropatagium of Sordes according to Sharov 1971 and Unwin/Bakhurina 1994.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordessharov2.jpg?w=134″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordessharov2.jpg?w=209″ class=”size-full wp-image-153″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordessharov2.jpg” alt=”Uropatagium of Sordes according to Sharov 1971 and Unwin/Bakhurina 1994.” width=”209″ height=”469″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordessharov2.jpg 209w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordessharov2.jpg?w=67&h=150 67w” sizes=”(max-width: 209px) 100vw, 209px” />
Figure 1. Uropatagium of Sordes according to Sharov 1971 and Unwin/Bakhurina 1994.
“Small, early, long-tailed pterosaurs (non-pterodactyliforms) exhibit extreme modifications in their hand and foot proportions indicative of climbing lifestyles.”
On the face of it, this doesn’t make sense: “extreme modification” on “small, early pterosaurs”. Evolution works in tiny steps, even at the phylogenesis of pterosaurs (Fig 2), as Peters 2000b and Peters 2000 showed. Neither were cited in Smyth et al.
The source
for this ‘extreme modifcation’ is a misinterpretation of Sordes pilosus (Fig 1), first illustrated by Sharov 1971 (also not cited) , then retraced by Unwin and Bakhurina (Fig 1) with less detail. As Peters 1995 reported, this is a misinterpretation. A displaced left wing has drifted posteriorly (Fig 3). The actual wing membrane (undisturbed in the right wing) has a shallow chord, and is stretched between the wing tip and elbow. Small crescent-shape uropatagia are found behind each knee (Peters 2002, also not cited by Smyth et al).
Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=174″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=584″ class=”size-full wp-image-85059″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg” alt=”Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron.” width=”584″ height=”1005″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=584&h=1005 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=87&h=150 87w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=174&h=300 174w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and a the lagerpetid, Dromomeron, which is not related to pterosaurs. Smyth et al don’t understand that pterosaurs were able to flap and grow wings because their ancestors were bipedal.
Publicity for Smyth et al segue to:
“The evolutionary adaptations that allowed ancient pterosaurs to grow to enormous sizes have been pinpointed for the first time by paleontologists in the Center for Paleobiology and Biosphere Evolution at the University of Leicester. The discovery revealed a surprising twist—the ability to walk efficiently on the ground played a crucial role in determining how large the biggest flying animals could grow, with some reaching wingspans of up to 10 meters.”
That ability first occurred (and several times by convergence) in phylogenetically miniaturized taxa (eg Fig 6), the continued in larger and larger forms. The authors are unaware of that fact. See Bergamodactylus in figure 2 to see how basal pterosaurs were long-legged (like Sharovipteryx and Longisquama) and therefore not quadrupedal.
The Sordes uropatagium is actually displaced wing material carried between the ankles by the displaced radius and ulna.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=584″ class=”wp-image-149 size-full” src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg” alt=”Figure 3. Sordes pilosus in situ (left) and interpreted (right) with a displaced left radius and ulna contributing to the posterior displacement of the wing membrane.” width=”584″ height=”459″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=584&h=459 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=150&h=118 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=300&h=236 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg?w=768&h=603 768w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/07/sordes-uropatagia.jpg 900w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 3. Sordes pilosus in situ (left) and interpreted (right) with a displaced left radius and ulna contributing to the posterior displacement of the wing membrane.
Correction:
Pterosaurs, like all tetrapods,could have walked efficiently on the ground at their beginning (Fig 2), middle and end. Smyth et al don’t understand that pterosaurs were able to flap and grow wings because their ancestors were bipedal (Fig 2).
Figure 2. The phytosaur, Parasuchus, surrounded by putative sisters according to Nesbitt 2011. Euparkeria was more primitive. Eudimorphodon and Ornithosuchus were more derived. Does anyone else see a problem here?? Why was this nesting not widely criticized?
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg?w=295″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg?w=584″ class=”size-full wp-image-6889″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg” alt=”Figure 2. The phytosaur, Parasuchus, surrounded by putative sisters according to Nesbitt 2011. Euparkeria was more primitive. Eudimorphodon and Ornithosuchus were more derived.” width=”584″ height=”594″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg?w=584&h=594 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg?w=147&h=150 147w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg?w=295&h=300 295w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/08/euparkeria-parasuchus-pteros.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 4. The phytosaur, Parasuchus, surrounded by putative sisters according to Nesbitt 2011. Euparkeria was more primitive. Eudimorphodon and Ornithosuchus were more derived. Does anyone else see a problem here?? Why was this nesting not widely criticized?
Under ‘Phylogenetic Analysis’ Smyth et al reported,
“To locate changes in autopodial morphology within an evolutionary framework, we analysed a modified version of the pterosaur morphological character matrix (Smyth & Unwin, under review), which was expanded to include as many pterosaur OTUs as possible in which the manual or pedal digits are preserved. This resulted in 95 active taxa with Euparkeria capensis designated as the outgroup. The matrix contains 187 characters.
The large pterosaur tree (LPT) includes 263 well-represented taxa (several are skull-only) based on 183 characters. The authors cherry-picked the unrelated and dissimilar Euparkeria (Fig 4) for their outgroup, preferring to follow a whim than the literature. A turtle would have been a closer relative. A tuatara or iguana even closer. Huehuecuetzpalli and Cosesaurus (Fig 3), progressively closer after testing 2325 candidates in the LRT.
That’s why the LRT exists:
to minimize taxon exclusion by including so many disparate taxa.
“This study shows that disparity in autopodial morphology across Pterosauria is much higher than has been previously appreciated,”
The catalog (Peters 2011) includes many more examples of pterosaur pedes.
“Evolving from as-yet-unknown gliding ancestors in the Triassic, non-pterodactyliform
pterosaurs were the first, and only, group of archosaurs to effectively exploit arboreal/scansorial niches in the early- to mid- Mesozoic.”
This study omitted previously published materials on pterosaur origins from flapping (not gliding) ancestors. If the scientific method were used by the authors, previous studies would have been cited, confirmed, refuted or modified – not omitted.
According to Publicity at Phys.org:
“Co-author Dr. David Unwin from the University of Leicester added, “In early pterosaurs, the hind limbs were connected by a flight membrane which severely impeded walking and running. In later, more advanced pterosaurs, this membrane became separated along the midline, allowing each hind limb to move independently. This was a key innovation that, combined with changes to their hands and feet, greatly improved pterosaurs’ mobility on the ground.”
That ‘severaly impeded’ sort of uropatagium Bauplan (Figs 1, 5) was debunked nearly 30 years ago (Peters 1995) and several times since (see citations below).
Unwin can’t let go of errors he made back in 1994.
Perhaps worse yet, no other pterosaur worker has confirmed those errors (without making the same errors themselves), always in fear of upsetting someone who might someday referee a submitted manuscript. Kids, this is how they play.
More outgroup taxa
The authors’ figure 6 cladogram cherry picks two other outgroup taxa, the large basal dinosaur, Herrerasaurus and the small basal crocodylomorph (with tiny hands and no pedal digit 5), Scleromochlus. What happened to Euparkeria (Fig 4)?
Rather than 95 ingroup taxa (see above), only 50 were included in their figure 6.
Figure 5. Sordes pilosus in vivo according to Smyth et al 2024. This is a misinterpretation of the fossil not corrected since 1995. See figure 4.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg?w=162″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg?w=553″ class=”size-full wp-image-89611″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg” alt=”Figure 5. Sordes pilosus in vivo according to Smyth et al 2024. This is a misinterpretation of the fossil not corrected since 1995. See figure 4. ” width=”584″ height=”1081″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg?w=584&h=1081 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg?w=81&h=150 81w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg?w=162&h=300 162w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/10/sordes.invivo588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 5. Sordes pilosus in vivo according to Smyth et al 2024. This is a misinterpretation of the Sordes fossil (see figures 1, 32) not corrected by co-athor Unwin since Unwin and Bakhurina 1994. See figure 4 for corrections. No other pterosaur documents the incorporation of pedal digit 5 into any membrane. It is always a free structure. Note the right wng: it is correct.
Smyth is in the unenviable position
of wasting time and paying tuition for his professors to teach him debunked myths about pterosaur structures. These ‘pterosaur experts’ are also teaching the lad that it is okay to cherry-pick outgroup taxa and to omit pertinent citations, rather than working through these problems using the scientific method and a wider gamut of taxa.
Once again, I am glad I was never subjected to the pressures of academia,
only the Bennett curse (see above).
Figure 4. Two of the smallest pterosaurs that both have a large sternal complex. BMNH42736 and B St 1967 I 276.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg?w=584″ class=”size-full wp-image-22458″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg” alt=”Figure 4. Two of the smallest pterosaurs that both have a large sternal complex. BMNH42736 and B St 1967 I 276.” width=”584″ height=”421″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg?w=584&h=421 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg?w=150&h=108 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg?w=300&h=216 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/04/tiny_pterosaurs_n6_bmnh42736.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 6. Two of the smallest pterosaurs BMNH42736 and B St 1967 I 276 were among the first to become quadrupedal in one clade of pterosaurs. This pterodactyloid-grade was attained at least 4x by convergence. These several transitions were overlooked by Smth et al based on taxon exclusion.
What enables a pterosaur to walk quadrupedally?
Comparing Bergamodactylus (Fig 2) to B St 1967 I 276 (Fig 6) the answer is clear: longer metacarpal, shorter hind limb. This change in morphology was ignored by the authors.
The authors confess,
“Admittedly, there are some regards in which the hands and feet of lepidosaurs are more comparable with those of pterosaurs, as both groups are quadrupedal and share a plantigrade pes.”
AND pedal digit 4 is the longest of the forward facing digits
AND pedal digit 5 has a lepidosaurian to tanystropheid bend
AND manual digit 4 is longer than 3 in lepidosaurs, but not in archosaurs.
Bipedal extant Chlamydosaurus (Fig 7) was ignored.
Fig. 4 Chlamydosaurus, the Austrlian frill-neck lizard with an erect spine and elevated tail.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/01/chlamydosaurus-bw250.jpg?w=250″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/01/chlamydosaurus-bw250.jpg?w=250″ class=”wp-image-4125″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/01/chlamydosaurus-bw250.jpg” alt=”Chlamydosaurus, the Austrlian frill-neck lizard” width=”588″ height=”365″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/01/chlamydosaurus-bw250.jpg 250w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2012/01/chlamydosaurus-bw250.jpg?w=150&h=93 150w” sizes=”(max-width: 588px) 100vw, 588px” />
Fig. 7 Chlamydosaurus, the Austrlian frill-neck lizard with an erect spine and elevated tail. From Peters 2000b.
There is a long tradition of making pterosaurs into weird monsters,
different and encumbered by various anatomical short-comings. Dr Unwin supports this tradition (Figs 1, 5). In 1983 young Kevin Padian proposed a bipedal bird-like Bauplan for Dimorphodon. This pertinent citation and study was also omitted by the authors.
Kids, this is how they play. Academics are not the little angels everyone thinks they are. Everything they write and illustrate and omit goes through their human filter.
PS
I sent Smyth a PDF of the ‘catalog’ via email over a week ago. There has been no response to date.
References
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 1995. Wing shape in pterosaurs. Nature 374, 315-316.
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.
Peters D 2011. A catalog of pterosaur pedes for trackmaker identification. Ichnos 18(2):114–141.
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].
Smyth et al (4 co-authors) 2024. Hand and foot morphology maps invasion of terrestrial environments by pterosaurs in the mid-Mesozoic. Current Biology 34, 1–14.
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Publicty
phys.org/news/2024-10-pterosaurs-tiny-tree-climbers
Source: https://pterosaurheresies.wordpress.com/2024/11/08/pterosaur-hands-and-feet-smyth-et-al-2024/
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