Kunpengopterus antipollicatus reconstructed and compared

A few days ago
we looked at a new pterosaur, Kunpengopterus antipollicatus (Zhou et al. 2021; BPMC 0042; early Late Jurassic) invalidating the authors’ assertion that it had an opposed thumb. Rather, and less out-of-the-ordinary, the BPMC specimen, is like all pterosaurs and most tetrapods (the ones with hands) oriented the palms side down (in flght, medial while holding a tree trunk between them). Only digit 4, the wing finger and its metacarpal, rotates the palm side posteriorly in Longsiquama + pterosaurs for flexion in the plane of the wing (Peters 2002).

Today that same pterosaur,
Kunpengopterus antipollicatus, enters the Large Pterosaur Tree (LPT, 257 taxa) with a reconstruction (Fig. 1) we can readily compare to its sister taxon, the holotype genus, Kunpengopterus sinensis (Fig. 1).

Zhou et al. reported,
“BPMC 0042, an almost complete skeleton lacking the posterior region of the skull.”

Look more closely.
I was able to trace the crushed posterior region of the skull without seeing the specimen firsthand (Fig. 2). That’s why I have been promoting the use of DGS (digital graphic segregation) for crushed fossils like this one since 2003, apparently to no avail.

Zhou et al. 2021 also had a difficult time seeing
the proximal metatarsals. The authors took the first step toward DGS by coloring the toes, but they need to go all the way and color them in transparent colors without black outlines. Then they need to reconstruct the pes from the elements traced. The complete pes reconstruction is validated by the continuous PILs (parallel interphalangeal lines).

Zhou et al. were confident
that the BPMC skeleton was complete and unaltered, but the two feet don’t match (Fig. 4). That’s a sign that at least something was altered. This is where reconstructions (Figs. 1-4) become helpful, not only for discovery, but for sharing data at a glance. There were 12 co-authors for this paper and none were given the assignment to be the Tenth Man. The danger of that is for grad students and post-docs disagreeing with their professor risks grades, recommendations, assignments, collaborations, travel vouchers and other perks and punishments. The professors I know don’t like to be wrong. When confronted with contrary evidence some of them become silent. Others revert to middle-school name-calling. Professors and post-grads think their reputation is at stake and maybe it is. That’s why we have to have Independent Researchers who are not swayed by reputation, salary or any other influence other than the evidence.

Rarely do PhDs want to check the work of their colleagues.
There’s no pay-off because there’s no chance for discovery. They think their colleagues are accurate and cover all the bases. Given that scenario, it enters the realm of unattached amateurs to check the work of PhDs. Unfortunately and too often errors of omission, like taxon exclusion, or overlooked bits and pieces (Figs. 3, 4) are easily found by amateurs just putting forth a little more effort in areas the PhDs and their textbooks currently consider irrelevant.

Since the Zhou et al. paper touted a false hypothesis in its headline
(the opposed thumb), it should be retracted and edited to simply describe with more accuracy the very typical BPMC specimen as it is, without headline-grabbing embellishment. Otherwise this pterosaur myth, like so many others, will enter the academic universe without apology.

References
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Zhou X et al. (11 co-authors) 2021. A new darwinopteran pterosaur reveals arborealism and an opposed thumb. Current Biology (2021), https://doi.org/10.1016

BPMC = Beipiao Pterosaur Museum of China, Beipiao, Liaoning Province, China.