Istiodactylus is an istiodactylid pterosaurian reptile from the Early Cretaceous of the United Kingdom. It was officially named in 2001 by Stafford House, Andrew Milner, and David Martell. It was one of the most specialized pterosaurs to exist, and its remains were thought to have belonged to a dromaeosaurid dinosaur, right before they were discovered to be more pterosaurian in nature.
Physiology[]
Istiodactylus was a pterosaur with with 4 legs (2 of which served as wings), 3 regular fingers on each hand (joined by an elongated 4th finger which supports the wing membrane), a small body, a short tail, and a long, toothy beak. However, it did have a few interesting traits; its beak was somewhat wide and did not taper off into a sharp point, its eyes were smaller than the already proportionally small eyes of pterosaurs such as Tropeognathus, and its teeth were smaller in size. Most of its body (excluding its beak and wings) would have been covered in a fur-like covering called pycnofibers.
Diet[]
Istiodactylus was a scavenger, feeding off of dinosaur carcasses. Its razor-sharp, interlocking teeth were used for cutting into flesh, allowing it to pull chunks of meat off a carcass.
Ecology[]
It was once speculated that Istiodactylus ate fish, due to its wide bill and interlocking teeth; however, later examinations of its skull gave rise to the notion that it scavenged carcasses like a vulture, which has been supported by many of its cranial features. Its skull was deep, which helped resist bending or snapping when the pterosaur was eating, and it had large jaw muscles, giving it a strong bite; at the same time, individual bones in the skull were slender and shallow (meaning that the skull was not built for subduing struggling prey), its teeth were short, and its eyes were smaller than those of truly predatory pterosaurs (which meant that it was not able to see prey that well or watch their every move). These skeletal features correspond with those of scavenging birds such as vultures, making Istiodactylus the perfect obligate scavenger; in fact, the pterosaur may have even acted a bit like its avian counterpart, always being the first carnivore to arrive at the carcass of a large dinosaur, but retreating from it whenever larger carnivores like Neovenator showed up to dine on it. As well as this, Istiodactylus' wings were shorter than those of sea-faring pterosaurs, which had a body plan built for soaring over long distances; along with the fact that the istiodactylid has always been found in terrestrial settings, we can assume that it was better built for taking off and landing.