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.
the genus was first named from fossils in Nevada, USA,
Omphalosaurus was usually perceived as a small and
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,
concluded that Omphalosaurus is a primitive
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.
- 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.