The
type species of
Simosaurus,
S. gaillardoti, was named by German paleontologist
Christian Erich Hermann von Meyer in 1842. In the same year, von Meyer also named
S. mougeoti. He named a third species,
S. guilelmi, in 1855. Oscar Fraas named
S. pusillus in 1881. A year later, however, it was reassigned to its own genus,
Neusticosaurus.
S. mougeoti and
S. guilelmi have more recently been considered junior synonyms of
S. gaillardoti, meaning that they represent the same species.
mark the first presence of Simosaurus'' in German deposits. The first fossils of
Simosaurus, those described by von Meyer, were found in
Lunéville, France. These were found in the upper
Muschelkalk, which dates back to the
Ladinian stage of the Middle Triassic. Material found in France includes the
holotype skull of
S. gaillardoti and a partial mandible referred to
S. mougeoti. Both were described by von Meyer. The skull, which served as the basis for the first description of
Simosaurus, has since been lost. Although initially attributed to
Simosaurus, the mandible was labeled as "
Nothosaurus mougeoti" in one of von Meyer's later papers. Additional remains of
Simosaurus were found in
Franconia and
Württemberg in Germany.
Duke William of Württemberg discovered a complete skull and sent it to von Meyer in 1842. Von Meyer named
S. guilelmi on the basis of this skull, noting that it was smaller and narrower than those of the type species. A complete skeleton first referred to
S. guilelmi has been designated the
neotype of
Simosaurus. Some German fossils have been found in the stratigrafically younger
Keuper deposits, but are very rare.
Simosaurus is present in biozones of the Muschelkalk that are distinguished by different
ammonite fauna.
Simosaurus first appears in the
nodosus biozone, where fossils of the ammonite
Ceratites nodosus are abundant. Specimens becomescommon in the slightly younger
dorsoplanus biozone, characterized by the ammonite
Ceratites dorsoplanus. ==Paleobiology==