Rhamphorhynchus: Zittel wingtip ungual in higher resolution

The Zittel wing
of Rhamphorhynchus preserves a complete and unfolded pterosaur wing (brachiopatagium + propatagium). Because the specimen (B St 1880.II.8) documents a narrow-chord construction it was purposefully omitted from the earlier study by Elgin, Hone and Frey (2010) who wished all their pterosaur wings were of the invalidated and traditional deep chord variety. None are (Peters 2002). Yet the tradition continues as seen in David Attenborough videos and Bennett (2016) papers.

As a scientist,
I prefer cold hard evidence (Figs. 1-3) with regard to pterosaur wing shape. Let’s hope you do, too.

Figure 1. Zittel wing (Rhamphorhynchus) with ungual area color spectrum expanded.

Figure 1. Zittel wing (Rhamphorhynchus) with ungual area color spectrum expanded. Details in figure 2. Note the narrow chord of this nearly perfect specimen with the membrane stretched between the elbow and wingtip, not the hind limb and wing tip. This is hard evidence. This is reality.

Today
we’ll take a closer peek at the typically overlooked wing tip ungual, phalanx 5 of manual digit 4 (m4.5) that we looked at earlier in less detail. Few to no pterosaur workers and other paleontologists recognize the presence of this bone. Rarely workers (Koroljov AV 2017) consider the wing finger to be digit 5 and the pteroid digit 1. Not true (Peters 2009). Just because the wingtip claw is tiny, doesn’t mean it’s not present. You just have to look carefully and use the tools available (Photoshop) to bring it out so others can easily see it (Fig. 2).

Figure 2. Zittel wing m4.5, wingtip ungual in situ, plus with the color spectrum (image levels in Photoshop) expanded.

Figure 2. Zittel wing m4.5, wingtip ungual in situ, plus with the color spectrum (image levels in Photoshop) expanded. Yes, it gets fuzzy when it is enlarged so much, but the hook shape is readily apparent surrounded by excavation.

We nested the Zittel wing
earlier with other Rhamphorhynchus specimens in the large pterosaur tree (LPT, Fig. 3). Although ungual 4.5 is apparent (Figs. 1,2), manual digit 5 is not visible in the Zittel wing due to a ventral exposure of the specimen.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the 'dark wing' JME specimen and the MTM specimen, both in the Rhamphorhynchus muensteri clade.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the ‘dark wing’ JME specimen and the MTM specimen, both in the Rhamphorhynchus muensteri clade.

Despite having the specimen in his hands,
Bennett 2016 overlooked the ungual at the wingtip. He proximally extends the propatagium to the neck, rather than the deltopectoral crest. Worse yet, he added lots of proximal wing membrane that was never there in the Zittel wing (Fig. 3). No pterosaur documents wing membranes extending past the knee. No pterosaur documents uropatagia attaching to pedal digit 5. No pterosaur documents a propatagium extending proximally beyond the deltopectoral crest.

Figure 3. Base reconstruction of Zittel wing by Bennett 2016 where he imagined a great deal of patagium between the elbow and knee. Here the hind limbs are rotated laterally, the patagium is stretched between the elbow and wingtip. Femoral and numeral muscles are estimated. 

Figure 3. Base reconstruction of Zittel wing by Bennett 2016 where he imagined a great deal of patagium between the elbow and knee. Here the hind limbs are rotated laterally, the patagium is stretched between the elbow and wingtip. Femoral and numeral muscles are estimated.

Strictly follow your data.
Don’t enhance it with imaginary tissues. And don’t overlook real data.

References
Bennett SC 2016. New interpretation of the wings of the pterosaur Rhamphorhynchus muensteri based on the Zittel and Marsh specimens. Journal of Paleontology 89 (5):845-886. DOI: 10.1017/jpa.2015.68
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
Koroljov AV 2017. The Flight of Pterosaurs.Biol Bull Rev 7: 179. doi:10.1134/S2079086417030045
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.

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