Istiodactylus
Encyclopedia
Istiodactylus was a medium sized pterosaur
from the Early Cretaceous
period.
, 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". 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
.
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
from the Early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
period.
History and species
In 1887 Harry Govier Seeley named the remains of a fossil pelvis discovered on the Isle of WightIsle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
, 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
Vectis Formation
The Vectis Formation is a geological formation on the Isle of Wight, England whose strata date back to the Early Cretaceous . The Vectis Formation is composed of three geological members: the Shepherds Chine member, the Barnes High Sandstone member, and the Cowleaze Chine member...
. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
was BMNH R 0176, a partial skeleton. The specific name means "broad tooth" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
.
The type species of the genus Ornithodesmus, however, was in the 1980s discovered to be based on bones belonging to a dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
, 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.
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
was probably in the five meter range, making it about half the size of Pteranodon
Pteranodon
Pteranodon , from the Late Cretaceous geological period of North America in present day Kansas, Alabama, Nebraska, Wyoming, and South Dakota, was one of the largest pterosaur genera and had a maximum wingspan of over...
. Because of the flat, rounded shape of its beak, Istiodactylus is sometimes referred to as a "duck billed pterosaur". 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
Istiodactylidae
Istiodactylidae is a small family of pterosaurs. This family was named in 2001 after the type genus Istiodactylus was discovered not to be a member of the genus Ornithodesmus....
.
In 2006 a second species, I. sinensis from China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, 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
Nurhachius
Nurhachius was a genus of istiodactylid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China....
.
Literature
- Seeley, H. G., 1887, "On a sacrum apparently indicating a new type of bird, Ornithodesmus cluniculus Seeley from the Wealden of Brook", Quarterly Journal of the Geological Society of London 43: 206-211
- Hooley, R. W., 1913, "On the skeleton of Ornithodesmus latidens. An ornithosaur from the Wealden shales of Atherfield (Isle of Wight)", Quarterly Journal of the Geological Society, 69: 372-421
- Howse, S. C. B., Milner A. R., and Martill, D. M., 2001, "Pterosaurs". Pp. 324-335 in: Martill, D. M. and Naish, D., eds. Dinosaurs of the Isle of Wight, The Palaeontological Association
- Andres, B. and Ji Qiang, 2006, "A new species of Istiodactylus (Pterosauria, Pterodactyloidea) from the Lower Cretaceous of Liaoning, China", Journal of Vertebrate Paleontology, 26: 70-78
- Lü, J., Ji, S., Yuan, C., and Ji, Q., 2006, Pterosaurs from China, Beijing, Geological Publishing House
External links
- I. latidens at The Pterosaur Database (pdf)
- I. sinensis at The Pterosaur Database (pdf)