What the Dark Wing Rhamphorhynchus Tells Us

When the “Darkwing” Specimen of Rhamphorhynchus (Goldfuss 1831, von Meyer 1846, Frey and Tischlinger 2002, JME SOS 4785) appeared, it looked like all of our arguments about wing shape in pterosaurs were finally over. And that’s how it was promoted. In this specimen (Fig. 1) the wing membrane is clearly delineated, layered and undoctored.

Figure 1. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb reconnected to their natural positions.

First Take – The Traditional Hypothesis
Tischlinger and Frey (2002) made no attempt at restoring the broken, folded and mutilated pieces of the specimen, as shown above. Rather they interpreted the soft tissue behind the elbow (in orange above) as a continuation of the wing membrane despite the obvious differences in texture and the separate layers each appears on, while ignoring what would happen if the wing were extended into the flying position  (Fig. 1). Moreover there is a sharp right angle between the wing membrane and the schmootz lateral to the tibia, not the smooth curve predicted by the deep chord/attached to the ankle wing hypothesis.

Second Take – The Heretical Hypothesis
If you put this “Humpty”  back together again (which is ridiculously easy to do) and extend the wing into the flying position it becomes more than clear that the key portions of the wing membrane behind the elbow and wrist were not preserved/exposed. So it doesn’t tell us what the Zittel wing has told us for several decades. Posterior to the elbow the pterosaur wing had a narrow chord and was stretched between the elbow and wingtip with a small fuselage fillet extending back to the femur.


References
Elgin RA, Hone DWE and Frey E 2010. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica in press. doi: 10.4202/app.2009.0145
Goldfuss A 1831. Beiträge zur Kenntnis vershiedener Reptilien der Vorwelt. Nova Acta Academiae Leopoldinae Carolinae, Breslau and Bonn, 15: 61-128.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Tischlinger H and Frey E 2002. Ein Rhamphorhynchus (Pterosauria, Reptilia) mit ungewöhnlicher Flughauterhaltung aus dem Solnhofener Plattenkalk. Archaeopteryx, 20, 1-20.
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33.Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.

wiki/Rhamphorhynchus

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