Jeholopterus ninchengensis (Wang, Zhou, Zhang and Xu 2002) Middle to Late Jurassic, ~ 160 mya, [IVPP V 12705] was exquisitely preserved with wing membranes and pycnofibers on a complete and articulated skeleton (see below). Unfortunately the fragile and crushed skull was undecipherable to those who observed it first hand. Using methods described here, Peters (2003) deciphered the skull and identified the IVPP specimen of Jeholopterus as a vampire. In that hypothesis, Jeholopterus stabbed dinosaurs with its fangs, then drank their blood by squeezing the wound with its plier-like jaws while hanging on with its robust limbs and surgically sharp, curved and elongated claws. From head to toe, Jeholopterus stood apart morphologically. It was not your typical anurognathid. Derived from a sister to the CAGS specimen attributed to Jeholopterus, the holotype of Jeholopterus was a phylogenetic sister to Batrachognathus.
Distinct from the CAGS specimen, the IVPP specimen had a robust and upturned premaxilla, part of a ventrally convex jawline. The naris, antorbital fenestra and orbit were all taller. The posterior of the skull leaned forward, diminishing the lateral temporal fenestra until the quadrate was in long contact with the jugal. With this rattlesnake-like configuration, Jeholopterus could open its jaws to an amazing degree, like a rattlesnake. In dorsal view the nasals were narrower and the orbits faced further forward, enhancing stereoscopic vision. The teeth were all small and blunt, except for two large anterior maxillary fangs (22 per cent of the skull length). The ectopalatine and pterygoid were the largest among pterosaurs. They buttressed the maxillary fangs to distribute stabbing forces to the sides and backs of the jaws.
The cervicals were longer and so were the dorsals. A whip-like caudal series of 35 tiny vertebrae was the longest among anurognathids.
The scapulocoracoids were enlarged. The humerus extended nearly to the pubis. Digit I was subequal to the other two. The fingers were all capable of hyperextension. The enormous and extremely sharp claws were capable of hyperflexion. Unlike any other pterosaur, these claws could have been used side-by-side to create one insertion. Manual 4.2 was as robust as m4.1.
As in the CAGS specimen, the puboischial plate was shallower than the depth of the acetabulum. The ilium was extended further anteriorly. The hind limbs were larger and more robust. The pes was the most robust of all pterosaurs. Metatarsal V extended further than halfway down the metatarsus. Pedal 5.1 extended to p4.5. These modifications increased pedal leverage in order to drive the pedal claws deeper into the substrate (dino skin).
The long hairs that covered Jeholopterus might have been used for insulation. The dense fibers could also have kept biting insects away from its own skin while drinking blood and otherwise locked down and defenseless.
More on pterosaur wings here and here.
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