Omphalosaurus cf. O. nevadanus Merriam, 1906

Material.

MBG 1500, partial skeleton comprising a largely complete but disarticulated skull, poorly preserved cervical and dorsal vertebrae, dorsal ribs, and an unidentified bone initially interpreted as a humerus (Tichy 1995; Sander and Faber 1998).

Locality.

Dürrnberg Mountain, south of Salzburg, Bavarian Alps.

Horizon.

Lercheck Kalkstein Formation. Age: Middle Triassic (Ladinian: Fassanian).

Diagnosis.

Distinguished from other ichthyopterygians in the following features: teeth forming irregular pavement; tooth crowns irregular in shape; and enamel surface with orange-peel-like pitting.

Comments.

Tichy (1995) originally designated MBG 1500 as the holotype of a new species Omphalosaurus wolfi (Sander and Faber 1998). Subsequently, Sander and Faber (2003) argued that the purported differences between it and Omphalosaurus nevadanus do not exist. As neither the material from Nevada nor that from Bavaria is well-preserved, Sander and Faber (2003) employed open nomenclature for the specimen from the Bavarian Alps.

The phylogenetic position of Omphalosaurus remained contentious for many years (e. g., Motani 2000). Sander and Faber (2003) argued that Omphalosaurus was a highly specialized, possibly grippidian ichthyopterygian with a crushing dentition. Most recently, Qiao et al. (2022) demonstrated the close relationship between Omphalosaurus and two Early Triassic durophagous ichthyosauriforms from Anhui (China), Cartorhynchus lenticarpus and Sclerocormus parviceps.

References.

Tichy (1995), Sander and Faber (1998, 2003), Motani (2000), Qiao et al. (2022).