Name:
Eudimorphodon
(True dimorphic tooth).
Phonetic: You-di-mor-fo-don.
Named By: Zambelli - 1973.
Classification: Chordata, Reptilia, Pterosauria,
Campylognathoididae.
Species: E. ranzii (type), E.
cromptonellus.
Diet: Piscivore.
Size: 1 meter wingspan.
Known locations: Greenland. Across Western Europe.
Time period: Norian of the Triassic.
Fossil representation: Several specimens.
Eudimorphodon
represents one of the earliest known
pterosaurs, and already features
that include a possibly vaned tail like that seen in Rhamphorhynchus
can be clearly seen to be established. However the tail seems to lack
stiffening tendons that can be seen in the rhamphorhynchoid group, and
may have been of little use in steering as some researchers have
speculated for the basal pterosaurs. Eudimorphodon
also has pterygoid
teeth, something not seen in later pterosaurs.
Despite
these primitive features, the exact position of Eudimorphodon
in the
evolution of pterosaurs is still unknown because no clear changing link
to their ancestors, thought to have been gliding arboreal lizards, has
been established. One thing that may actually be considered is the
possibility of what is known as 'modular evolution' as seen in the
transitional pterosaur Darwinopterus.
While
Darwinopterus links the later rhamphorhynchoid group
with the
pterodactyloid group of pterosaurs, it has shown that this change was
not gradual over the whole body, but that only one body part would
change at a time. This resulted in Darwinopterus
displaying both
primitive and advanced pterosaur body parts, with no intermediate forms
in between. If modular evolution is true for Eudimorphodon,
then it
would go some way in explaining the more primitive tail, as well as the
presence of pterygoid teeth.
Eudimorphodon
is one of the few pterosaurs where we can be absolutely certain about
its diet, due to the presence of the remains of small bony fish that
have been found inside at least one specimen. Even though some
pterosaurs would go on to different feeding strategies such as stalking
the land like storks or filter feeding for invertebrates, the
relationship between pterosaurs and fish as predator and prey would
continue all the way to the end of the Mesozoic.
A
former species of Eudimorphodon from greenland, E.
cromptonellus, has
now been renamed as a distinct genus,
Arcticodactylus.
Further reading
- Eudimorphodon ranzii gen. nov., sp. nov., uno
pterosauro Triassico. -
Rendiconti Scienze di Instituto Lombardo, B 107:27-32. - R. Zambelli -
1973.
- A diminutive pterosaur (Pterosauria: Eudimorphodontidae) from the
Greenlandic Triassic. - Bulletin Museum of Comparative Zoology
156(1):151-170. - F. A. Jenkins, N. H. Shubin, S. M. Gatesy &
K. Padian - 2001.