| Istiodactylus Temporal range: Early Cretaceous |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Family: | †Istiodactylidae |
| Genus: | †Istiodactylus Howse, Milner, & Martill, 2001 |
| Type species | |
| Ornithodesmus latidens Hooley, 1913 |
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| Species | |
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I. latidens |
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| Synonyms | |
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Ornithodesmus latidens |
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Istiodactylus was a medium sized pterosaur from the Early Cretaceous period.
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In 1887 Harry Govier Seeley named the remains of a fossil pelvis discovered on the Isle of Wight, Ornithodesmus cluniculus, thinking it was a bird. In 1901 he considered that it might have been a pterosaur. In 1913 Reginald Walter Hooley named a second species, Ornithodesmus latidens, for some definitively pterosaurian material, found in the Vectis Formation. The holotype was BMNH R 0176, a partial skeleton. The specific name means "broad tooth" in Latin.
The type species of the genus Ornithodesmus, however, was in the 1980s discovered to be based on bones belonging to a dinosaur, which meant a new genus had to be named for O. latidens. This species was assigned to its own genus Istiodactylus by Stafford Howse, Andrew Milner, and David Martill in 2001. The genus name is derived from Greek istion, "sail" and daktylos, "finger", referring to the fact that the wing of pterosaurs is formed by a membrane attached to a wingfinger.
Istiodactylus was a moderately large pterosaur; its skull was 56 cm long, and its wingspan was probably in the five meter range, making it about half the size of Pteranodon. Because of the flat, rounded shape of its beak, Istiodactylus is sometimes referred to as a "duck billed pterosaur".[1] However, unlike a duck, it had small, sharp teeth, and may have eaten fish or scavenged (Howse, Milner, & Martill, 2001). The pointed leaf-shaped teeth were laterally compressed, an adaptation for slicing flesh, and closely interlocked in the frontal jaws. The skull was quite elongated, with most teeth concentrated in the blunt front part.
Howse et al. in 2001 created for Istiodactylus its own family Istiodactylidae.
In 2006 a second species, I. sinensis from China, has been named, its specific name referring to China. Its holotype is NGMC 99-07-011, a partial skeleton of a subadult individual. It was much smaller than I. latidens, its dimensions being 63% of the larger species, thus about a quarter in weight. In 2006 Lü Jun-Chang et al. concluded I. sinensis was a junior synonym of the istiodactylid Nurhachius.