A late review of Kellner et al 2010: Jeholopterus soft tissue

Kellner et al 2010
observed a deep chord wing membrane in the robust anurognathid, Jeholopterus (Figs 1–3).

Or did they?

The authors published
only the counterplate, which is why the skull and several other parts are missing (Fig 1) from every image in their paper.

Not good to omit perfectly good data on purpose. Better to combine the data (Fig 2).

Earlier
Peters 2002 interpreted the wing membrane with a shallow chord (Figs 2, 3), as in ALL other pterosaurs, using both the plate (with skull) and counterplate matched in Photoshop.

The authors reported,
“Peters (2002 argued that the wing membrane in the Chinese taxon did not reach the ankle but extended only to the elbow.

‘Argued’ implies there are two sides to this issue. Beware whenever you see this word alongside an illustration that ‘shows’ or ‘demonstrates’ an observation. In this case, Kellner et al should have reprinted the image from Peters 2002 and indicate errors.

“However, despite the fact that no trailing edge of the posterior portion of the plagiopatagium is clearly discernible, an extensive portion of soft tissue is closely associated with the tibiae.

Definition time: The plagiopatagium is the main lateral skin membrane (or “wing-to-body” or “flank” membrane) that stretches between the last digit of the forelimb, the body wall, and the hind limbs (or ankle) in flying and gliding animals like bats and flying squirrels.

Birds don’t have a plagiopatagium. Neither did pterosaurs. So no one is ever going to find anything more than a short fuselage fillet = short membrane between elbow and thigh.

Definition time: A fuselage fillet is a smoothly contoured structural transition piece where an aircraft’s wing meets the fuselage

The extensive portion of soft tissue indicated by Kellner et al are extradermal membranes = frills (Fig 3), as in Longisquama and Cosesaurus, but more frilly in owl-like Jeholopterus. Kellner et al did not recognize this possibility. Advice: follow the data.

“Apparently, Peters (2002) who based his studies on photographs, has only identified the limits of the actinopatagium, which indeed terminate at the articulation of the humerus with the radius and ulna, but the tenopatagium extends up to the ankle.”

Definition time: “the articulation of the humerus with the radius and ulna” = the elbow.

RE: “based his studies on photographs“… let’s say your radiologist did not base his/her studies on X-rays, µCT scans and other helpful images. Would that be better? Images let you trace them more precisely than the old-fashioned way with pencil and microscope.

Definition time: The tenopatagium is the innermost portion of the wing membrane, closer to the body and legs. It is characterized by being more elastic, tensile, and flexible, which allowed the pterosaur to dynamically alter its wing shape during flight.

You’ll note the tenopatagium is identified in figure 2, even though it is ragged on one side, not the other – and is better seen on the omitted plate (Fig 2), rather than the counterplate (Figs 1,2). Again, don’t omit perfectly good data.

Not how, but Why did Kellner et al find deep chord wing membranes?
Pterosaur academics are often trying to identify the deep-chord bat-wing paradigm (citations below), but it always fails to show up. Witness the statement in Kellner et al 2010, “no trailing edge of the posterior portion of the plagiopatagium is clearly discernible,” Elgin, Frey and Hone 2011 had to label narrow chord data as examples of ‘shrinkage’ in order to support the bat-wing myth.

That’s the way it is with every soft tissue pterosaur. The deep chord membrane is never present. Never = not ever.

Figure 4. Jeholopterus in dorsal view. Here the robust hind limbs, broad belly and small skull stand out as distinct from other anurognathids. Click to enlarge. ” data-image-caption=”

Figure 4. Jeholopterus in dorsal view. Here the robust hind limbs, broad belly and small skull stand out as distinct from other anurognathids. Click to enlarge.

” data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=511″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=511″ alt=”Figure 4. Jeholopterus in dorsal view. Here the robust hind limbs, broad belly and small skull stand out as distinct from other anurognathids. Click to enlarge.” class=”wp-image-17830″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=511 511w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=75 75w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=150 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg?w=768 768w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/03/jeholopterusdorsal9083.jpg 908w” sizes=”(max-width: 511px) 100vw, 511px” />

Sometimes peer-group pressure = politics
overrides the skeptical = give me evidence mindset that scientists should have. Instead they remember that their colleagues are going to someday referee each others’ submissions. That is always a consideration: stay with the consensus. Be safe.

Palmer and Dyke (2011) made similar mistakes. See link below.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Kellner AWA, Wang X, Tischlinger H, Campos DA, Hone DWE and Meng X 2010. The soft tissue of Jeholopterus (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane. Proc Royal Soc B 277: 321–329
Palmer C and Dyke G 2011. Constraints on the wing morphology of pterosaurs. Proceedings of the Royal Society B. published online 28 September 2011.
doi: 10.1098/rspb.2011.1529
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Schaller D 1985. Wing Evolution. In: Hecht M, Ostrom JH, Viohl G and Wellnhofer P, eds, The Beginning of Birds. Proceedings of the International Archaeopteryx Conference, Eichstätt 1984, (Freundes Jura Museum, Eichstätt), pp. 333–348.
Stromer E 1910. Bemerkungen zur Rekonstruktion eines Flugsaurier-Skelettes. Monatsberichte der deutschen Geologischen Gesellschaft 62, 85–91.
reptileevolution.com/pterosaur-wings.htm

A New Wing Shape for Pterosaurs?

Source: https://pterosaurheresies.wordpress.com/2026/10/24/a-late-review-of-kellner-et-al-2010-jeholopterus-soft-tissue/