Jeholopterus wing spread

Updated March 4, 2015 with a new orientation of the Jeholopterus hind limbs and a new tail. 

Yesterday we looked at Jeholopterus, the vampire pterosaur. I also added a dorsal view of Jeholopterus to yesterday’s post to better compare it with the AMNH animated cartoon.

Today we’ll compare long and broad Jeholopterus wings to the likely shorter wings (parts are unknown) of a sister taxon from the same formation, Daohugoupterus (Fig. 1).

Figure 1. Daohugoupterus and Jeholopterus in dorsal view to the same scale. note the much smaller wings of Daohugoupterus with a similar size skull and body. Daohugoupterus may have been the 'bumblebee" of the Daohugou Formation -- technically unable to fly, but able to fly nevertheless. A rapid wingbeat probably sustained it. By contrast, Jeholopterus had broad owl-like wings, probably requiring fewer wingbeats. Note also the placement of the orbits, lateral on the left, more forward facing on the right. Not sure how to handle the hind limb filaments other than in the pattern shown here. Filaments like these may have acted to help silence the flight of Jeholopterus by absorbing sound.

Figure 1. Daohugoupterus and Jeholopterus in dorsal view to the same scale. note the much smaller wings of Daohugoupterus with a similar size skull and body. Daohugoupterus may have been the ‘bumblebee” of the Daohugou Formation — technically unable to fly, but able to fly nevertheless. A rapid wingbeat probably sustained it. By contrast, Jeholopterus had broad owl-like wings, probably requiring fewer wingbeats. Note also the placement of the orbits, lateral on the left, more forward facing on the right. Not sure how to handle the hind limb filaments other than in the pattern shown here. Filaments like these may have acted to help silence the flight of Jeholopterus by absorbing sound.

Jeholopterus had a wing area close to 4x that of the similarly-sized Daohugoupterus. This has ramifications with regard to wing beat amplitude and frequency. In order to fly more wingbeats/second are required for the pterosaur with the smaller wings. Similar difference occur between ducks and gulls.

On the same note, I’d like to direct your attention to a PBS special on owls
available online here. While owls are distinctly different from Jeholopterus, there are some analogies, as I’m sure you’ll see after viewing the program.

Like owls,
the vampire Jeholopterus would have benefited from coming in on its dinosaurian prey quietly before making its presence known. That would have happened the moment it slid those surgically-curved claws and teeth beneath soft parts of the dinosaurian hide.

Figure 2. Wing and other extra dermal membranes surrounding Jeholopterus.

Figure 2. Wing and other extra dermal membranes surrounding Jeholopterus. Note the narrow chord wing membrane preserved on both wings, just like the Zittel wing and the Vienna Pterodactylus. On the right there are some hairy plumes, not unlike those of Longisquama, which had dorsal plumes along the midline. That cannot be demonstrated with the pterosaur crushed in the dorsoventral plane, only imagined.

The extradermal membranes of Jeholopterus (Fig. 2) have been acknowledged, but never traced and modeled to see if the fibers are similar in the front and the back and what their morphology might be. Previously I assumed these were simple fibers, but that no longer seems to be the case in every case.

Here (Fig. 2) the wing membranes have a standard shape duplicated in other pterosaurs that preserved the wing membranes well. If someone else has another take on this specimen, please let me know.

And here’s a hypothesis that can never be proven:
Tianyulong, a small contemporaneous heterodontosaurid dinosaur, had long, elevated filamentous integumentary structures apparent on the back, tail and neck. These would have been ideal passive protection from vampire pterosaurs trying to alight on its back. Relatively naked giant sauropods would have made better landing zones.

References
Cheng X, Wang X, Jiang S and Kellner AWA 2014. Short note on a non-pterodactyloid pterosaur from Upper Jurassic deposits of Inner Mongolia, China. Historical Biology (advance online publication) DOI:10.1080/08912963.2014.974038
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.
strong>Peters D 2003. The Chinese vampire and other overlooked pterosaur ptreasures. Journal of Vertebrate Paleontology 23(3): 87A.
Wang X, Zhou Z, Zhang F and Xu X 2002. A nearly completely articulated rhamphorhynchoid pterosaur with exceptionally well-preserved wing membranes and “hairs” from Inner Mongolia, northeast China. Chinese Science Bulletin 47(3): 226-230.

wiki/Jeholopterus

 

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