Istiodactylidae is a small familyofpterosaurs. This family was named in 2001 after the type genus Istiodactylus was discovered not to be a member of the genus Ornithodesmus.
| Istiodactylids
Temporal range: Early Cretaceous, 130–120 Ma
Possible Middle Jurassic record | |
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| Life restoration of Istiodactylus latidens feeding on a stegosaur corpse. | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Clade: | †Lanceodontia |
| Clade: | †Istiodactyliformes |
| Family: | †Istiodactylidae Howse, Milner & Martill, 2001 |
| Type species | |
| †Ornithodesmus latidens Hooley, 1913 | |
| Genera | |
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Remains of taxa that can be confidently assigned to Istiodactylidae have been found in the UK and China, in rocks dating from the Early Cretaceous period (BarremiantoAptian stage).[2] Arbour and Currie (2011) described Canadian Gwawinapterus beardi as a member of Istiodactylidae living in the late Cretaceous (upper Campanian stage);[3] however, Witton (2012) suggested the tooth replacement pattern in this animal does not match that of pterosaurs, suggesting that the species might be non-pterosaurian.[2] Additional research suggested that the species was in fact a fish.[4] The earliest known species might be Archaeoistiodactylus linglongtaensis, from the Middle Jurassic of China;[5] however, it also has been suggested that the holotype specimen of this species might actually be a poorly preserved specimen of Darwinopterus.[6] Hongshanopterus, a supposed istiodactylid from China, has been reclassified as a non-istiodactylid member of Ornithocheiroidea of uncertain phylogenetic placement by Witton (2012).[2]
Istiodactylids were medium-sized pterosaurs with flat, rounded jaws similar to that of a duck. They had small teeth lining their jaws, however, and this can mostly be seen in the more advanced genera such as Istiodactylus.[7]
Below is a cladogram showing the phylogenetic placement of this group within Pteranodontia from Andres and Myers (2013).[8]
| Pteranodontia |
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The cladogram below is a topology recovered by Kellner et al. (2019). In the analyses, they recovered Istiodactylidae within the more inclusive group Istiodactyliformes, and assigned both Istiodactylus and Liaoxipterus to a new subfamily called Istiodactylinae, but kept Nurhachius as a basal member.[9]
| Istiodactyliformes |
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Unlike most ornithocheiroids, istiodactylids bear physiologies suited to a terrestrial life and many of their fossils have been found in freshwater-deposits. Istiodactylids are considered to be pterosaurian equivalents to vultures: acting as the clean-up crew in their native locations. Whether or not istiodactylids could swim like most water-loving pterosaurs remains a mystery.
