Stupendemys
Name:
Stupendemys
(Astonishing turtle).
Phonetic: Stu-pen-dem-iss.
Named By: R. C. Wood - 1970.
Classification: Chordata, Reptilia, Anapsida,
Testudines, Pleurodira, Pelomedusoidea, Podocnemididae.
Species: S. geographicus
(type), S. souzai.
Diet: Probable omnivore. Current thinking is that Stupendemys
would eat plants, animals, almost anything organic that would fit in
its mouth.
Size: Preserved length of carapace of largest
individual 1.8 meters long. Estimated length of shell up to
3.3 meters long.
Known locations: Venezeula - Urumaco Formation
and Brazil - Solim�es Formation.
Time period: Messinian of the Miocene to Zanclean of
the Pliocene.
Fossil representation: Remains of two species,
including the carapace.
Stupendemys
was a genus of pleurodiran turtle, a type better known as a
side-necked turtle. Side necked turtles acquired their name because
their necks are so long that the only way they could fit under the
shell was to fold their necks into one side. The preserved length of
the largest known Stupendemys carapace (the upper
shell) is one
hundred and eighty centimetres long, and has been estimated to be as
much as three hundred and thirty centimetres long in the living
animal. With the addition of the long neck Stupendemys
would have
been even longer than the famously huge Archelon,
a giant sea
turtle that lived earlier in the late Cretaceous period.
Unlike
Archelon, Stupendemys was a
freshwater turtle, and one that
inhabited the river systems and lakes of Northern South America around
the boundary of the late Miocene and early Pliocene. The huge size of
Stupendemys might be a response to the predatory
threats living in
South America which included giant crocodiles
such as Mourasuchus,
Gryposuchus
and particularly the caiman-like Purussaurus.
Additional
remains of Stupendemys shells now found have
revealed that male
Stupendemys grew two enlarged spikes from the front
of the shell that
pointed forwards alongside each side of the neck. These spikes have
wear patterns on them that seem to indicate that they were used in
combat between rival males. The larger the spikes grew, the more
advantage they would have in combat, and may have also served as
display for impressing females.
Large
pleurodiran turtles seemed to have been very common in the river
systems of South America during the Cenozoic, with another example
being Carbonemys,
a pleurodiran with a shell one hundred and
seventy-two centimetres long that lived in South America not long after
the dinosaurs went extinct.
Further reading
- Stupendemys geographicus, the world's largest
turtle. -
Breviora 436:1-31. - R. C. Wood. - 1976.
- A cintura p�lvica do quel�nio Stupendemys
(Podocnemididae,
Podocnemidinae) proveniente do Mioceno superior-Plioceno do Estado
do Acre, Brasil [The pelvic girdle of quel�nio Stupendemys
(Podocnemididae, Podocnemidinae) coming from the upper
Miocene-Pliocene of the State of Acre, Brazil]. - Acta
Geologica Leopoldensia, 20(45):47-50. - J. Bocquentin
& E. Guilherme - 1997.
- Stupendemys souzai sp. nov. (Pleurodira,
Podocnemididae)
from the Miocene-Pliocene of the Solim�es Formation, Brazil. -
Revista Brasileira de Paleontologia 9(2): 187-192. - Jean
Bocquentin & Janira Melo - 2006.
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