846


Journal of Paleontology 89(5):845–869


NHMW, Naturhistorisches Museum Wien, Vienna, Austria; SNSD-MMG, Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Germany; and YPM, Peabody Museum of Natural History, Yale University, New Haven, U.S.A.


Literature review


One of the most important specimens preserving evidence as to the structure of the pterosaur wing is the Zittel wing of Rham- phorhynchus muensteri (BSP 1880 II 8; Fig. 1.1) from the Upper Jurassic Solnhofen Limestone at Wintershof, an isolated left wing skeletonwith a seemingly undamaged impression of the patagium exposed in ventral view, which based on the catalog number was probably acquired by the museum in 1880. Zittel (1882) soon described the specimen, beginning with the following:


“This glorious fossil was found on the Winterberg near Eichstädt and purchased through the agency of the kind Herrn Geistlichen Rathes [Raymund] Schlecht for the local


State Museum. The solid, 2 cm. thick slab contains the left flight-organ in completely undisturbed condition, the wing membrane is not torn or broken, but is imprinted in impec- cable sharpness fromits extreme tip to the attachment to the trunk. It differs sharply from the surrounding rock mass by somewhat lighter coloring and even more from the yellow- colored bones. Although its margin, as seen clearly even now, was very clearly demarcated, the finder was not satisfied with the breaking off of the rock, which covered the wing membrane initially, but also scraped and smoothed the surroundings thereof, apparently with the intention thereby to bring out the patagiumeven sharper.” (Zittel, 1882, p. 52; translated from the original German)


Zittel went on to note 8–10 prominent longitudinal folds and a pattern of fine, almost straight, raised longitudinal strips (Längsstreifen, also referred to as erhabenen Streifen) that nearly paralleled the wing phalanges in the lateral part of the patagium and became progressively more anteroposteriorly angled in the medial parts. He noted that some of the strips were larger than surrounding ones and compared them to ossified tendons. The wing was compared to that of gliding lizards (Draco spp.) and bats, and though it was noted that the Rhamphorhynchus wing differed significantly from both, it was suggested that the raised longitudinal strips were functionally comparable to the elastic fibers in bat wings. Six months earlier, Marsh (1882) had described another


specimen of Rhamphorhynchus muensteri (YPM 1778; Fig. 2) with excellent preservation of parts of both wing membranes and the tail vane,which had been found in the Solnhofen Limestone at Eichstätt in 1873.Marsh purchased the specimenwhile atwork on


the American Pteranodon materials, but delayed publishing until finished with Pteranodon. The patagia of the specimen were only briefly described as being partially folded and having a smooth surface with delicate striae that were interpreted as wrinkles, and the membrane was interpreted as similar to that of bats. Subsequently, additional wing specimens of Rham-


phorhynchus muensteri from the Solnhofen Limestone at Eichstätt and Schernfeld were described. Wanderer (1908)


described the Dresden specimen (SNSD-MMG BaJ 2210), which preserves an impression of the right wing in ventral view, and stated that it agreed with Zittel’s description in all details, though the impression distal to the first interphalangeal joint of the wingfinger was covered by a thin layer of matrix that could not be prepared away. Ammon (1909) briefly described a specimen (BSP AS I 772; MB.R. 69/2191b) that preserves impressions of both wings with the distal part of the patagium of one wing detached from wing phalanx 4. Döderlein (1929a) described a specimen (BSP 1907 I 37) that preserves traces of the patagium and the tail vane, and noted fine parallel raised strips, closely spaced at 25–35 per 10mm. Following Zittel (1882), Döderlein interpreted the strips as elastic fibers. Meanwhile, Short (1914) interpreted the pterosaur patagium as bat-like, elastic, and extensible, a view that was later shared by Bramwell and Whitfield (1974). Wellnhofer (1975) presented a review of the structure of the


wings of Rhamphorhynchus basedonthe ~20specimens then known to preserve traces of soft tissues, and observed that the fact that naturally articulated forelimbs commonly occur as isolated specimens or as part of otherwise disarticulated specimens indi- cates that the patagium was much more resistant to decay than most soft tissues and so must have been coarse, leathery, and tough. Wellnhofer referred to the parts of the patagium as the propatagiumanterior to the armand forearmand controlled by the pteroid bone, the chiropatagium posterior to the arm, forearm, and wingfinger and attaching to the side of the body but not the hind- limb, and the uropatagiumposterior to the hindlimb and attaching to pedal digit V. He provided the first measurements of the raised longitudinal strips of the Zittel wing (referring to it as BSP AS I 771 because the original number was misplaced inWorldWar II and had not yet been recovered; O. Rauhut, personal commu- nication, 2012), stating that their width was ~0.05mm and that theywere spaced very evenly in the taut patagiumat 0.2mmapart so that they were 18–20 fibers per 5mm. Wellnhofer followed Zittel in interpreting the raised longitudinal strips as elastic fibers that reinforced the patagium without limiting its elasticity, and although he did not comment on the distribution of the fibers, his life reconstruction of Rhamphorhynchus suggests that he thought they were present throughout the chiropatagium. Schaller (1985) presented a theoretical review of wing


evolution and introduced many new terms including tenopata- gium, which he defined as a formlabile tensile flight-membrane, and actinopatagium, which he defined as a formstabile self-cambering ray-structured flight-membrane. He interpreted the wings of the rhamphorhynchoid Sordes as representing the archetypal pterosaur pattern with a propatagium anterior to the arm and forearm, a tenopatagial plagiopatagium posterior to the arm and forearm and attaching to the side of the body and hindlimb, an actinopatagial dactylopatagium posterior to the wingfinger and lateral to the plagiopatagium, and a uropatagium posterior to the hindlimb and attaching to pedal digit V. Schaller argued that in derived pterosaurs (e.g., Rhamphorhynchus, Pterodactylus) the entire membrane behind the forelimb (equivalent to the chiropatagium of Wellnhofer, 1975) was actinopatagial and free of the hindlimb, and included a tongue- like, flap-controlling actuator behind the elbow. He termed this derived membrane a brachiopatagium and viewed it as a self-supporting, self-cambering structure. Most of Schaller’s


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