''Eudimorphodon'' was a

pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the Order (biology), order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cre ...

that was discovered in 1973 by Mario Pandolfi in the town of Cene, Italy and described the same year by Rocco Zambelli. The nearly complete skeleton was retrieved from

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especia ...

deposited during the Late

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

(mid to late

Norian The Norian is a division of the Triassic Period. It has the rank of an age ( geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic ...

stage),Wellnhofer, P. (1991). "Summary of Triassic Pterosaurs." ''The Illustrated Encyclopedia of Pterosaurs.'' London, UK: Salamander Books Limited. p. 67. . making ''Eudimorphodon'' one of the oldest pterosaurs known.Cranfield, I. ''The Illustrated Directory of Dinosaurs and Other Prehistoric Creatures''. London: Salamander Books, Ltd. Pp. 280–281. It had a wingspan of about and at the end of its long bony tail may have been a diamond-shaped flap like in the later ''

Rhamphorhynchus ''Rhamphorhynchus'' (, from Ancient Greek ''rhamphos'' meaning "beak" and ''rhynchus'' meaning "snout") is a genus of long-tailed pterosaurs in the Jurassic period. Less specialized than contemporary, short-tailed pterodactyloid pterosaurs such ...

''. If so, the flap may have helped it steer while maneuvering in the air. ''Eudimorphodon'' is known from several skeletons, including juvenile specimens.

Discovery and species

''Eudimorphodon'' currently includes one species, the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

''Eudimorphodon ranzii'', which was first described by Zambelli in 1973. It is based on

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

MCSNB 2888. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

honors Professor

Silvio Ranzi Silvio () is an Italian male name, the male equivalent of Silvia. Sílvio is a variant of the name in Portuguese. It is derived from the Latin "Silvius", meaning "spirit of the wood," and may refer to: People * Silvio Berlusconi (born 1936), ...

. A second species, ''Eudimorphodon rosenfeldi'', was named by Dalla Vecchia in 1995 for two specimens found in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

. 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 Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is ...

. Its specific name honors Professor

Alfred Walter Crompton Alfred Walter "Fuzz" Crompton (born 21 February 1927 in Durban) is a South African paleontologist and zoologist. Crompton studied at the University of Stellenbosch and obtained a bachelor's degree in 1947 and a masters in 1949, in zoology. He c ...

; the name is a

diminutive A diminutive is a root word that has been modified to convey a slighter degree of its root meaning, either to convey the smallness of the object or quality named, or to convey a sense of intimacy or endearment. A ( abbreviated ) is a word-form ...

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 The Dockum is a Late Triassic (approximately late Carnian through Rhaetian, or 223–200 Ma) geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Color ...

rocks in western

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

. 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.

Description

''Eudimorphodon'' was a small pterosaur, being in length, and weighing no more than . Its fourth finger had a very large size, and attached to the membrane making up the wing. ''Eudimorphodon'' showed a strong differentiation of the teeth, hence its name, which is derived from

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

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 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 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'' is an extinct genus of prehistoric bony fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizat ...

''. ''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.Osi, A. (2010). "Feeding-related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet." ''Lethaia'', The teeth distinguish ''Eudimorphodon'', because almost all other pterosaurs either had simple teeth, or lacked them altogether. Benson ''et al.'' (2012) noticed that the teeth would have been perfect for grabbing and crushing fish.

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

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s, archosauriformes, or prolacertiformes. Within the standard hypothesis that the Dinosauromorpha are the pterosaurs' close relatives within an overarching

Ornithodira Avemetatarsalia (meaning "bird metatarsals") is a clade of diapsid reptiles containing all archosaurs more closely related to birds than to crocodilians. The two most successful groups of avemetatarsalians were the dinosaurs and pterosaurs. Din ...

, ''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 Novialoidea (meaning "new wings") is an extinct clade of macronychopteran pterosaurs that lived from the latest Early Jurassic to the latest Late Cretaceous (early Toarcian to late Maastrichtian ageBarrett, P. M., Butler, R. J., Edwards, N. P., ...

. 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 Novialoidea (meaning "new wings") is an extinct clade of macronychopteran pterosaurs that lived from the latest Early Jurassic to the latest Late Cretaceous (early Toarcian to late Maastrichtian ageBarrett, P. M., Butler, R. J., Edwards, N. ...

.Matthew G. Baron (2020). "Testing pterosaur ingroup relationships through broader sampling of avemetatarsalian taxa and characters and a range of phylogenetic analysis techniques". PeerJ. 8: e9604. doi:10.7717/peerj.9604. PMC 7512134. .

References

*Dixon, Dougal. "The Complete Book of Dinosaurs." Hermes House, 2006. *Fantastic Facts About Dinosaurs () {{Taxonbar, from=Q132577 Pterosaurs Fossils of Italy Late Triassic pterosaurs of Europe Fossil taxa described in 1973