Eudimorphodon
Encyclopedia
Eudimorphodon was a pterosaur
that was discovered in 1973 by Mario Pandolfi near Bergamo
, Italy
and described the same year by Rocco Zambelli. The nearly complete skeleton was retrieved from shale
deposited during the Late Triassic
(mid to late Norian
stage), making Eudimorphodon the oldest pterosaur then known. It had a wingspan of about 100 centimetres (3.3 ft) and at the end of its long bony tail may have been a diamond-shaped flap like in the later Rhamphorhynchus
. If so, the flap may have helped it steer while maneuvering in the air. Eudimorphodon is known from several skeletons, including juvenile specimens.
Eudimorphodon showed a strong differentiation
of the teeth, hence its name, which is derived from ancient Greek
for "true dimorphic tooth". It also possessed a large number of these teeth, a total of 110 of them densely packed into a jaw only six centimeters long. The front of the jaw was filled with fangs, per side four in the upper jaw, two in the lower jaw, that rather abruptly gave way to a line of smaller multipointed teeth, 25 in the upper jaw, 26 in the lower jaw, most of which had five cusps, others three or even four.
The morphology of the teeth are suggestive of a piscivorous diet, which has been confirmed by preserved stomach contents containing the remains of fish of the genus Parapholidophorus
. Young Eudimorphodon had slightly differing dentition with fewer teeth and may have had a more insectivorous diet. The top and bottom teeth of Eudimorphodon came into direct contact with each other when the jaws were closed, especially at the back of the jaw. This degree of dental occlusion is the strongest known among pterosaurs. The teeth were multi-cusped, and tooth wear shows that Eudimorphodon was able to crush or chew its food to some degree. Wear along the sides of these teeth suggests that Eudimorphodon also fed on hard-shelled invertebrates.
s, archosauriformes
, or prolacertiformes
.
Within the standard hypothesis that the Dinosauromorpha
are the pterosaurs' close relatives within an overarching Ornithodira, Eudimorphodon is also unhelpful in establishing relationships within Pterosauria between early and later forms because then its multicusped teeth should be considered highly derived, compared to the simpler single-cusped teeth of Jurassic pterosaurs, and a strong indicator that Eudimorphodon is not closely related to the ancestor of later pterosaurs. Instead it is believed to be a member of a specialized off branch from the main "line" of pterosaur evolution, the Campylognathoididae
.
, E. ranzii, was first described by Zambelli in 1973. It is based on holotype
MCSNB 2888. The specific name honours Professor Silvio Ranzi. A second species, E. rosenfeldi, was named by Dalla Vecchia in 1995 for two specimens found in Italy
. However, further study by Dalla Vecchia found that these actually represented a distinct genus, which he named Carniadactylus
in 2009. One additional species is still currently recognized: E. cromptonellus, described by Jenkins and colleagues in 2001. It is based on a juvenile specimen with a wing span of just 24 centimeters, MGUH VP 3393, found in the early nineties in Greenland
. Its specific name honors Professor Alfred W. Crompton; the name is a diminutive
because the exemplar is so small.
In 1986
fossil jaw fragments containing multicusped teeth were found in Dockum Group
rocks in western Texas
. One fragment, apparently from a lower jaw, contained two teeth, each with five cusps. Another fragment, from an upper jaw, also contained several multi-cusped teeth. These finds are very similar to Eudimorphodon and may be attributable to this genus, although without better fossil remains it is impossible to be sure.
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...
that was discovered in 1973 by Mario Pandolfi near Bergamo
Bergamo
Bergamo is a town and comune in Lombardy, Italy, about 40 km northeast of Milan. The comune is home to over 120,000 inhabitants. It is served by the Orio al Serio Airport, which also serves the Province of Bergamo, and to a lesser extent the metropolitan area of Milan...
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and described the same year by Rocco Zambelli. The nearly complete skeleton was retrieved from shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
deposited during the Late Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
(mid to late Norian
Norian
The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...
stage), making Eudimorphodon the oldest pterosaur then known. It had a wingspan of about 100 centimetres (3.3 ft) and at the end of its long bony tail may have been a diamond-shaped flap like in the later Rhamphorhynchus
Rhamphorhynchus (animal)
Rhamphorhynchus , "beak snout", is a genus of long-tailed pterosaurs in the Jurassic period. Less specialized than contemporary, short-tailed pterodactyloid pterosaurs such as Pterodactylus, it had a long tail, stiffened with ligaments, which ended in a characteristic diamond-shaped vane...
. If so, the flap may have helped it steer while maneuvering in the air. Eudimorphodon is known from several skeletons, including juvenile specimens.
Dentition and diet
Heterodont
The anatomical term heterodont refers to animals which possess more than a single tooth morphology. For example, members of the Synapsida generally possess incisors, canines , premolars, and molars. The presence of heterodont dentition is evidence of some degree of feeding/hunting specialization...
of the teeth, hence its name, which is derived from ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
for "true dimorphic tooth". It also possessed a large number of these teeth, a total of 110 of them densely packed into a jaw only six centimeters long. The front of the jaw was filled with fangs, per side four in the upper jaw, two in the lower jaw, that rather abruptly gave way to a line of smaller multipointed teeth, 25 in the upper jaw, 26 in the lower jaw, most of which had five cusps, others three or even four.
The morphology of the teeth are suggestive of a piscivorous diet, which has been confirmed by preserved stomach contents containing the remains of fish of the genus Parapholidophorus
Parapholidophorus
Parapholidophorus is an extinct genus of prehistoric bony fish.-See also:* Prehistoric fish* List of prehistoric bony fish...
. Young Eudimorphodon had slightly differing dentition with fewer teeth and may have had a more insectivorous diet. The top and bottom teeth of Eudimorphodon came into direct contact with each other when the jaws were closed, especially at the back of the jaw. This degree of dental occlusion is the strongest known among pterosaurs. The teeth were multi-cusped, and tooth wear shows that Eudimorphodon was able to crush or chew its food to some degree. Wear along the sides of these teeth suggests that Eudimorphodon also fed on hard-shelled invertebrates.
Phylogeny and classification
Despite its great age Eudimorphodon has few primitive characteristics making the taxon of little use in attempting to ascertain where pterosaurs fit in the reptile family tree. Basal traits though, are the retention of pterygoid teeth and the flexibility of the tail, which lacks the very long stiffening vertebral extensions other long-tailed pterosaurs possess. Paucity of early pterosaur remains has ensured that their evolutionary origins continues to be a persiseant mystery with some experts suggesting affinities to dinosaurDinosaur
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...
s, archosauriformes
Archosauriformes
Archosauriformes is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Late Permian...
, or prolacertiformes
Prolacertiformes
Prolacertiformes were an order of archosauromorph reptiles that lived during the Permian and Triassic Periods...
.
Within the standard hypothesis that the Dinosauromorpha
Dinosauromorpha
Dinosauromorpha is the name of a clade of archosaurs that includes the closest relatives of dinosaurs, and the order Dinosauria itself. Basal forms include Saltopus, Marasuchus, the perhaps identical Lagosuchus, the lagerpetonids Lagerpeton from the Ladinian of Argentina and Dromomeron from the...
are the pterosaurs' close relatives within an overarching Ornithodira, Eudimorphodon is also unhelpful in establishing relationships within Pterosauria between early and later forms because then its multicusped teeth should be considered highly derived, compared to the simpler single-cusped teeth of Jurassic pterosaurs, and a strong indicator that Eudimorphodon is not closely related to the ancestor of later pterosaurs. Instead it is believed to be a member of a specialized off branch from the main "line" of pterosaur evolution, the Campylognathoididae
Campylognathoididae
Campylognathoididae is a group of early "rhamphorhynchoid" pterosaurs named after Campylognathoides, that lived in the Late Jurassic. The family Campylognathoididae was named in 1967 by Oskar Kuhn, originally as the subfamily Campylognathoidinae....
.
Discovery and species
Eudimorphodon currently includes two species. The type speciesType species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, E. ranzii, was first described by Zambelli in 1973. It is based on 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...
MCSNB 2888. The specific name honours Professor Silvio Ranzi. A second species, E. rosenfeldi, was named by Dalla Vecchia in 1995 for two specimens found in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. However, further study by Dalla Vecchia found that these actually represented a distinct genus, which he named Carniadactylus
Carniadactylus
Carniadactylus is a genus of pterosaur which existed in Europe during the Late Triassic period. The genus contains a single species, Carniadactylus rosenfeldi.-Description:...
in 2009. One additional species is still currently recognized: E. cromptonellus, described by Jenkins and colleagues in 2001. It is based on a juvenile specimen with a wing span of just 24 centimeters, MGUH VP 3393, found in the early nineties in Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
. Its specific name honors Professor Alfred W. Crompton; the name is a diminutive
Diminutive
In language structure, a diminutive, or diminutive form , is a formation of a word used to convey a slight degree of the root meaning, smallness of the object or quality named, encapsulation, intimacy, or endearment...
because the exemplar is so small.
In 1986
1986 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-Pterosaurs:...
fossil jaw fragments containing multicusped teeth were found in Dockum Group
Dockum Group
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...
rocks in western Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. One fragment, apparently from a lower jaw, contained two teeth, each with five cusps. Another fragment, from an upper jaw, also contained several multi-cusped teeth. These finds are very similar to Eudimorphodon and may be attributable to this genus, although without better fossil remains it is impossible to be sure.
In popular culture
- Eudimorphodon was featured in an episode of Animal ArmageddonAnimal ArmageddonAnimal Armageddon is an American paleontology-based documentary television miniseries that originally aired from to on Animal Planet. All the prehistoric scenes are created 100% in Lightwave...
, where it was described as a seagull-like creature, feeding on fish and carrion.