Pterodactylus Cristatus

''Germanodactylus'' ("German finger") is a genus of germanodactylid pterodactyloid pterosaur from Upper Jurassic-age rocks of Germany, including the Solnhofen Limestone. Its specimens were long thought to pertain to '' Pterodactylus''. The head crest of ''Germanodactylus'' is a distinctive feature.

History

''G. cristatus'' is based on specimen BSP 1892.IV.1, from the Solnhofen limestone of Eichstätt, Germany. It was originally described by Plieninger in 1901 as a specimen of ''Pterodactylus kochi'', and was given its current specific name by Carl Wiman in 1925, meaning "crested" in Latin. Yang Zhongjian determined that it deserved its own genus in 1964. A second species called ''G. ramphastinus'' (in 1858 accidentally revised to ''rhamphastinus'' by Christian Erich Hermann von Meyer) was named as a distinct species long before ''G. cristatus'', described by Johann Andreas Wagner in 1851 as a species of the now deprecated genus '' Ornithocephalus''. The specific name refers to the toucan, ''ramphastinos'' in Greek. It is based on specimen BSP AS.I.745, a skeleton from the slightly younger Mörnsheimer Limestone of Daiting, Germany. Peter Wellnhofer added it to ''Germanodactylus'' in 1970, although Maisch and his coauthors have suggested that it deserves its own genus, " Daitingopterus". David M. Unwin has also referred miscellaneous limb bones and vertebrae from the somewhat older Kimmeridge Clay of Dorset, England to the genus; these finds at the time marked the earliest appearance of short-tailed pterosaurs in the fossil record.
Bennett suggested in 1996 that ''Germanodactylus'' represented adults of ''Pterodactylus'', but this has been rejected by further studies, including his own. Bennett's 2006 reappraisal of ''Germanodactylus'' found both species to be valid and included within the genus, with ''G. cristatus'' known from four specimens, including two juveniles, and ''G. rhamphastinus'' from two specimens. The genus differs from other pterosaurs by a combination of characteristics including a sharply pointed jaw tip, four to five premaxillary teeth, and eight to twelve maxillary teeth per side of the upper jaw, robust maxillary teeth that, unlike in ''Pterodactylus'', are not reduced in size farther from the tip of the jaw, a naso- antorbital fenestra twice the length of the eye socket, and various proportional differences. ''G. cristatus'' differs from "''G. rhampastinus''" by having no teeth in the tip of the jaw and fewer teeth (~13 in each side of the upper jaw and ~12 in the lower versus 16 upper and 15 lower on each side for "''G. rhamphastinus''").

Description

''Germanodactylus'' is described as being "raven-sized" in weight. ''G. cristatus'' had a 0.98 meter wingspan (3.2 ft) and a 13 centimeter (5.1 in) long skull, while "''G. rhamphastinus''" was somewhat larger, with a 1.08 meter (3.5 ft) wingspan, and a skull measuring 21 centimeters (8.3 in) long.

Head crest

''Germanodactylus'' is known for its head crest, which had a bony portion (a low ridge running up the midline of the skull) and a soft-tissue portion that more than doubled its height. The bony part does not go as far up the head in ''G. cristatus'' as in ''G. rhamphastinus''. The soft-tissue portion was not known early on, being first described in 2002 by S. Christopher Bennett. It was probably composed of cornified epidermis. ''Germanodactylus'' is the first genus for which a soft-tissue component of the crest is known, but similar structures were probably widespread among pterosaurs. Head crests like these are now known to be far more extensive in Pterosauria. Of all the pterosaurs known to date, the most basal form with such a crest is '' Austriadactylus'' and the most derived are ''Hamipterus'' and '' Tapejara''. '' Darwinopterus'' and ''Cuspicephalus'' also possess headcrests made of "fibrous" bone, demonstrating that the character is a homology, and not a homoplasy.

Classification

This genus is unspecialized compared to the pterosaurs of the Cretaceous, and has had varying placements in Pterosauria. Yang Zhongjian, who named the genus, gave it its own family Germanodactylidae. Bennett included the genus in the family Pterodactylidae, and Alexander W.A. Kellner found it to be related to ''Pterodactylus'' in his 2003 phylogenetic analysis. David M. Unwin, on the other hand, preferred to consider it a basal dsungaripteroid,Unwin, David M. (2003) "On the phylogeny and evolutionary history of pterosaurs", in ''Evolution and Palaeobiology of Pterosaurs'', 139–190.Unwin, David M. (2006). ''The Pterosaurs: From Deep Time'', 273. a group that evolved into dedicated shellfish-eaters.Unwin, David M. (2006). ''The Pterosaurs: From Deep Time'', 84–85. Maisch and co-authors considered the genus ''Germanodactylus'' to be paraphyletic, meaning the two species were not congeneric. For "''G. rhamphastinus''" the genus name "Daitingopterus" was used in a table, but the rules of the ICZN were not observed, making the new name a ''nomen nudum''. However, Maisch and his co-authors did place both ''Germanodactylus'' species in Dsungaripteroidea, like Unwin. Vidovic and Martill not only considered the contents of ''Germanodactylus'' to be paraphyletic, but they found the two species to be entirely distinct in their cladistic analysis. ''G. cristatus'' was considered the sister taxon of both Dsungaripteroidea and Azhdarchoidea, while "''G. rhamphastinus''" was sister taxon to a group they called Aurorazhdarchia. Vidovic and Martill did not initially propose a new name for "''G. rhamphastinus''", but they suggested that it might represent an adult '' Diopecephalus'', if that genus proves to be valid. However, in a subsequent paper published in 2017, Vidovic and Martill created a new genus for "''G. rhamphastinus''", '' Altmuehlopterus''.

Below is a cladogram showing the results of a phylogenetic analysis presented by Longrich, Martill, and Andres in 2018. In this analysis, they placed the species ''G. cristatus'' as the sister taxon of "''G. rhamphastinus''" within the family Germanodactylidae, and contrary to the concepts mentioned above, both of these species were recovered as closer relatives of more primitive pterosaurs, such as ''Pterodactylus'', within the group Archaeopterodactyloidea.Longrich, N.R., Martill, D.M., and Andres, B. (2018)
Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary.
''PLoS Biology'', 16(3): e2001663.

See also

* List of pterosaur genera
* Timeline of pterosaur research

References

External links

Restoration of ''G. cristatus''
at The Grave Yard-->

at The Grave Yard

{{Portal bar, Paleontology, Germany

Pterodactyloids
Late Jurassic pterosaurs of Europe
Solnhofen fauna
Taxa named by Yang Zhongjian
Fossil taxa described in 1964