New soft tissue anatomy described for pterosaur hands and feet

Hone, Lauer and Lauer 2025
described some Solnhofen pterosaurs chiefly known from hands and feet = “isolated body parts”. The authors wrote, “Here we describe a leg of a ctenochasmatid pterosaur from the Solnhofen region of southern Germany which shows exceptional preservation of the scales of the foot pad and webbing between the toes. A second specimen shows details of the hand and foot. We show that the soft tissues are remarkably consistent with those of other very distantly related pterosaurs.”

That’s a wonderful start, initially spoiled by the first line of the text, “Pterosaurs are an extinct group of archosaurian reptiles.”

Unfortunately,
pterosaurs are not archosaurs. This is an ongoing myth still taught at university. By simply adding taxa, like the lepidosaur Huehuecuetzpalli, pterosaurs have been recovered as tanystropheid lepidosaurs for the last 20 years (see the large reptile tree). This makes sense considering their laterally longer finger and toe proportions, along with a long list of other traits not found in archosaurs, but shared with tanystropheid lepidosaurs. See citations below.

Getting down to the specimens under review,
the most complete is LF (Lauer Foundation) 547 (Fig 1). So this specimen is privately held, but accessible to workers.

After phylogenetic analysis
LF 547 nested with the preazhdarchid unnamed Solnhofen specimen B St 1911 I31 (n42 in the Wellnhofer 1970 catalog). Though about 4x larger, the LF 547 specimen shares a long list of traits with the n42 specimen. The humerus, radius and ulna are relatively shorter in the LF 547 specimen, but the pteroid is longer.

The n42 specimen was not mentioned in the Hone, Lauer and Lauer text.

The authors wrote,
“LF 547 is also a pterodactyloid, based on the very elongate wing metacarpal and reduced fifth toe.”

In the large pterosaur tree (LPT) the pterodactyloid grade is recovered by convergence at least 4x. Simply adding taxa made this happen (Peters 2007). Pterosaur workers are not yet curious enough yet to do this. We have to be patient with them.

“Determining which clade this may belong to is difficult since there are few diagnostic traits based on the available elements that can be observed beyond the moderately elongate metatarsals.”

This is incorrect, as shown above. You can add partial skeletons to the LPT to find out where they nest among more completely known taxa. Currently the LPT tests 264 skeletons. Competing cladograms include only a minority fraction of this number, so taxon exclusion might be an issue here.

“However, given the complete domination of ctenochasmatoids of the pterodactyloid fauna in the Solnhofen region, we here compare it to these local species and assume that this represents a ctenochasmatoid or allied taxon.”

This is incorrect. Both the n42 and LF 547 taxa nest among the pre-azhdarchids that are rarely otherwise tested outside the LPT. If you are going to assume something in science, I guess it’s okay to confess doing so. On the other hand, the authors do not confess to omitting a long list of taxa, including the n42 specimen.

“The extensor tendon process on wing phalanx one is fully fused suggesting a relatively late ontogenetic stage for the individual.”

This is incorrect. ETP fusion is a phylogenetic trait in pterosaurs,
not an ontogenetic trait.

“There are one or two dots on the dorsal side of digit 4, and a large indeterminate patch of tissue around the base of the tibia and ventral to digit 5 is presumably part of a large heel pad of tissue. This patch extends as much as 6 mm ventral to the 5th toe.”

This may be so, but the radiating pattern is apart from the otherwise articulated pedal elements and that radiating pattern is identical to a disarticulated wing tip, including the ungual. The authors failed to identify the pedal digit 5 ungual (Fig 3).
It’s easy to miss! It is so tiny.

The authors report,
“Claw sheaths are clearly present on digits 1–4.”

Whenever that happens it’s a good sign that tiny details, like wing tip unguals,
will be preserved, as they are here.

Under ‘taxonomic identity,’
the authors ran through a long list of possible relatives and their traits rather than adding what little is know of LF 547 to their own matrix in order to let the software determine the closest relatives.

In other words, why get wordy? Just add the scores and report the results.

“Simple comparisons to the larger Solnhofern [sic] ctenochasmatoids also shows [sic] some clear differences.”

Indeed, because the LF 547 specimen is not in the ctenochasmatid clade. Cherry-picking and assuming are no longer necessary when the LPT covers all the completely known taxa. Let the software tell you. That’s why you bought it or downloaded it.

“An indeterminate azhdarchid SMNK PAL 3830 has scales preserved on the foot.”

By contrast, in the LPT the SMNK PAL 3830 specimen is a germanodactylid.

This paper made a big deal
of the minute scales prerserved on the hand and foot specimens, but missed the big phylogenetic picture due to inappropriate asumptions, lack of phylogenetic analysis and cherry-picking comparable taxa while omitting pertinent taxa.

References
Hone D, Lauer R and Lauer B 2025.  Soft tissue anatomy of pterosaur hands and feet – new information from Solnhofen region pterodactyloid specimens. Lethaia.  https://doi.org/10.18261/let.58.3.1
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-133.
Wellnhofer P 1970: Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Bayerische Akademie der Wissenschaften, Mathematisch- Wissenschaftlichen Klasse, Abhandlugen 141, 1–133.

Source: https://pterosaurheresies.wordpress.com/2025/06/26/new-soft-tissue-anatomy-described-for-pterosaur-hands-and-feet/