Omphalosaurus
Name:
Omphalosaurus
(button lizard).
Phonetic: Om-phal-o-sore-us.
Named By: J. C. Merriam - 1906.
Classification: Chordata, Reptolia,
Ichthyopterygia, Ichthyosauria.
Species: O. nevadanus
(type), O. merriami, O. nettarhynchus, O.
peyeri, O. wolfi.
Diet: Durophagus carnivore (shellfish eater).
Size: Roughly about 2 meters long.
Known locations: Germany - Lercheck Limestone
Formation, Oberer Hauptmuschelkalk Formation. Norway, Svalbard.
USA, Nevada - Prida Formation.
Time period: Anisian to Ladnian of the Triassic.
Fossil representation: Several individuals by
partial skull and post cranial remains.
Since
the genus was first named from fossils in Nevada, USA,
Omphalosaurus was usually perceived as a small and
primitive
ichthyosaur
that lived during the early Triassic. Towards the end of
the twentieth and early twenty-first centuries however questions were
raised about the genus being an ichthyosaur with notes about how the
known fossils of Omphalosaurus don’t show any
feature that are
exclusive just to the ichthyosaurs. Most of this doubt was
highlighted in a paper by Motani and published in 2000, however
since this papers by Sander and Faber in 2003, and Maisch in
2010, both describing new specimens of Omphalosaurus,
have
concluded that Omphalosaurus is a primitive
ichthyosaur.
One
thing that we can be a little more certain about Omphalosaurus
is the
diet. The teeth of Omphalosaurus are blunt and
rounded, and usually
these kinds of teeth are seen in animals that eat hard bodied items.
In reference to Omphalosaurus specifically this
would be shellfish
which would have had their hard outer shells broken up by the teeth so
that the soft inside could then be swallowed by the feeding
Omphalosaurus.
Further reading
- Preliminary note on a new marine reptile from the Middle Triassic
of Nevada. University of California Publications in Geological
Sciences 5(5):71-79. - J. C. Merriam - 1906.
- New finds of Omphalosaurus and a review of
Triassic ichthyosaur
paleobiogeography. - Palaeontologische Zeitschrift
72(1/2):149-162. - P. M. Sander & C. Faber
- 1998.
- Is Omphalosaurus ichthyopterygian? - A
phylogenetic
perspective. Journal of Vertebrate Paleontology 20(2):
295-301. - Ryosuke Motani - 2000.
- The Triassic marine reptile Omphalosaurus:
osteology, jaw
anatomy, and evidence for ichthyosaurian affinities. - Journal of
Vertebrate Paleontology Volume 23, Issue 4. - P. Martin
Sander & Christiane Faber - 2003.
- Phylogeny, systematics, and origin of the Ichthyosauria -
the state of the art. - Palaeodiversiry 3: 151-214. - M.
Maisch - 2010.
- Two Records of Omphalosaurus from the Muschelkalk - The
Reconstruction of Triassic Marine Ecosystems Based on Teeth. -
International Symposium on Paleohistology. - Tanja Wintrich &
Martin Sander - 2015.
- Preliminary report on ichthyopterygian elements from the Early
Triassic (Spathian) of Spitsbergen. - Norwegian Journal of Geology. -
Christina Ekeheien, Lene Delsett, Aubrey Roberts & Hurum Jørn -
2018.
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