Jeholopterus

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Jeholopterus Fossil range: Middle Jurassic?
Skeletal reconstruction of Jeholopterus ningchengensis.
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Order: Pterosauria Suborder: Rhamphorhynchoidea Family: Anurognathidae Genus: Jeholopterus Wang et al., 2002
Binomial name
Jeholopterus ninchengensis Wang et al., 2002

Jeholopterus was a small anurognathid pterosaur from the Daohugou Beds of northeastern China (of uncertain age, possibly Middle Jurassic or Early Cretaceous), preserved with hair and skin impressions, and named after its place of discovery, Jehol in China.

The type, and only known, species is Jeholopterus ninchengensis, based on a nearly complete specimen (IVPP V12705) from the Daohugou beds of Ningcheng County in the Neimongol (Inner Mongolia) Autonomous Region of China.^[1] The specimen is crushed into a slab and counterslab pair, so that parts of the specimen are preserved on one side of a split stone and some on the other. This includes exsquisite preservation of carbonized skin fibers and, arguably, "hair" or "protofeathers." The fibers are preserved around the body of the specimen in a "halo." Wing tissue is preserved, though its extent is questionable, including the points of attachment to the legs (or if it attached to the legs at all).

As an anurognathid, Jeholopterus is notable for its unusual skull, which was wider than it was long, with a very broad mouth. The wings of Jeholopterus show evidence that they attatched to the ankle, according to Wang et al., who also argue that it had a short tail, a feature seen in other anurognathids but unusual for "rhamphorhynchoid" pterosaurs. Wang et al. used the presence of a fringe of hair in the region the tail would be to infer the presence of a short tail. However, a subsequent study by Dalla Vecchia argued that gleaning any information about the tail is impossible, given that the tail is "totally absent" in the fossil.^[2]

By manipulating downloaded images in the computer art program Photoshop, David Peters (2003) reported that he discovered an unusual suite of soft-tissue remains, including a horse-like tail Peters speculated may have been used as a fly sweeper/distractor, as well as a long fly lure (similar to that of the anglerfish) protruding from the head, and a fin or series of fins along the back. Peters also reported that he had found "rattlesnake-like fangs", and these, along with what he described as a rattle-snake-like mandible, buttressed palate, "surgically-sharp" unguals, robust limbs and other characters suggested that Jeholopterus was a vampire pterosaur adapted to plunging fangs into tough hide, then rotating the skull forward locking the fangs beneath the hide to improve adhesion. The small teeth of the lower jaw would not have penetrated but squeezed the wound like a pliers.^[3] Prominent pterosaur researcher Chris Bennett has described Peters' findings as "fantasy" and has attempted to debunk his methodology.^[4]

On the contrary, however, when looking at the crushed, flattened, and disfigured holotype skull of Jeholopterus (see above), it is difficult to determine much accuracy from features aside from general shapes of some of the larger bones. The skull is preserved in dorsal view, so that the palate (and thus the precise arrangeemnt, shape, and size of the teeth) are ambiguous at best, as well as obscuring details of the palate, shape, and aspect of the cranial bones when seen from the side. This is a caution for all skeletal reconstructions made from crushed specimens. Furthermore, it is questionable to use even high quality photos when manipulating images for the sake of finding out features such as impressions of soft tissue,^[4] which Peters uses to argue for the presence of the long crown.^[3]

An example lies in a single, explicit feature: A bone identified by Peters as a portion of a singularly long tooth has in fact the appearance of either 1) two juxtaposed teeth, lying one atop the other, 2) a long bone broken at the end, or 3) a single tooth broken along the crown. However, in the third possibility, the end is very clean, and teeth of a reptilian nature tend to fracture more cleanly, and it is unlikely this is a broken tooth. This leaves the first two possibilities. With even three possibilities and no means to explicitly, or personally, examine the material to eliminate any of them, it seems questionable to raise the probability of any one of them other the others. Certainly, it might be logical to even dismiss the long-fang concept, though this, too, must await personal examination by a commenter.

[edit] References

[edit] External links

• Discussion of the validity and uses of computer tracing techniques, from the Dinosaur Mailing List