Eudimorphodon (meaning "true dimorphic tooth" in Greek) is an extinct genus of small, basal pterosaur that lived during the mid to late Norian stage of the Late Triassic around 219 to 215 million years ago. It was discovered in 1973 in the town of Cene, Italy by Mario Pandolfi and was named by Rocco Zambelli in the same year. The holotype of Eudimorphodon was a nearly complete skeleton and was retrieved from shale, a sedimentary rock. With a wingspan that only reached a metre long and a weight of no more than 10 kilograms, Eudimorphodon is considered to be one of the oldest pterosaurs known. Despite this, it has very little basal characteristics, which renders it useless when attempting to find out the place of pterosaurs in the reptile family tree. It has been suggested that the tip of its tail had a small, diamond-shaped flap similar to that of Rhamphorynchus. If Eudimorphodon truely had this flap, it likely would have been used to help the pterosaur steer through the air.
Three pairs of large openings in the skull reduced its weight. There were 58 teeth in the upper jaw and 56 in the lower.
Description[]
Only reaching a length of 1 metre and a weight of no more than 10 kilograms, Eudimorphodon was a small pterosaur. Similarly to other pterosaurs, it had four fingers on each wing, with the fourth digit attaching to the membranes of the wing and being large in size.
As its name suggests, Eudimorphodon was a heterodont, an animal that possessed more than one tooth morphology. 110 of these teeth were crammed together into the 6 centimetre long jaws, These jaws also had fangs at the front, with four per side on the upper jaw and two on the lower jaw.
Because of the shape of the teeth, Eudimorphodon was thought to have had a piscivorous diet. This was eventually confirmed after the discovering of stomach contents containing fish remains. However, younger specimens had diff erent dentition with fewer teeth and may have lived on a more insectivorous diet instead.
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. The paucity of early pterosaur remains has ensured that their evolutionary origin continues to be a mystery, with different experts suggesting affinities to dinosaurs, 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. The following phylogenetic analysis follows the topology of Upchurch et al. (2015). In 2020 however, a study upheld by Matthew G. Baron about early pterosaur interrelationships found Eudimorphodon to group with the clade Novialoidea, both within the clade called Lonchognatha.
Discovery and species[]
Eudimorphodon currently includes one species, the type species Eudimorphodon ranzii, which was first described by Zambelli in 1973. It is based on holotype MCSNB 2888. The specific name honors Professor Silvio Ranzi. A second species, Eudimorphodon 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. A third species is Eudimorphodon cromptonellus, described by Jenkins and colleagues in 2001. It is based on a juvenile specimen with a wingspan of just 24 centimeters, MGUH VP 3393, found in the early nineties in Jameson Land, Greenland. Its specific name honors Professor Alfred Walter Crompton; the name is a diminutive because the exemplar is so small. In 2015 it was named as a separate genus Arcticodactylus by Alexander Kellner. Specimen BSP 1994 I 51, in 2003 referred to a cf E. ranzii, was in 2015 by Kellner made the genus Austriadraco.
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.
Many fossils have been found that once were referred to Eudimorphodon, making Eudimorphodon represent one of the most abundant pterosaurs from Italy. Today, these have largely been made separate genera.
In The Media[]
- Eudimorphodon appeared in the video game called Dinosaur Adventure 3-D.
- Eudimorphodon made an appearance in the Animal Planet show, Animal Armageddon, where flocks of them are shown being destroyed by volcanic activity at the end of the Triassic. Unlike many of the otherals in the episode, they are shown to have survived the extinction along with the dinosaurs, like Staurikosaurus, and the mammals, like Megazostrodon.
- It can be found in Jurassic World: The Game as a VIP pterosaur in the solid gold pack.
