Askeptosaurus italicus (Nopcsa 1925) Middle Triassic ~225 mya, ~2 m long, was a derived from a sister to Serpianosaurus and phylogenetically preceded other thalattosauriformes, such as Anshunsaurus.

Overall larger and distinct from Serpianosaurus, the skull of Askeptosaurus was more robust with a tallerbut narrower rostrum. The nasals were completely separated laterally as the premaxilla contacted the frontal. The postorbital was a large L-shaped bone extending below the jaw line, which descended posteriorly. The lateral temporal fenestra was greatly enlarged. The jugal produced a posterior process. The slit-like upper temporal fenestra migrated anteriorly. The supratemporals were reduced to narrow strips. The palatine and ectopterygoid are separated here and the pterygoid expands to a full triangular shape.

Nopcsa F 1925. Askeptosaurus, ein neues reptil der Trias von Besano: Centralblatt für Mineralogie, Geologie und Paläontologie, p. 265-2

Kuhn E 1952. Die Triasfauna der Tessiner Kalkalpen. XVII. Askeptosaurus italicus Nopsca. Abhandlungen der Schweizerischen Paläontologischen Gesellschaft, 69, 1–73.

Kuhn-Schnyder E 1971. Über einen Schädel von Askeptosaurus italicus Nopcsa aus der Mittleren Trias des Monte San Giorgio (Kt Tessin, Schweiz). Abhandlungen des Hessischen Landesamtes für Bodenforschung, 60, 89–98

Müller J 2005. The anatomy of Askeptosaurus italicus from the Middle Triassic of Monte San Giorgio and the interrelationships of thalattosaurs (Reptilia, Diapsida). Canadian Journal of Earth Science 42: 1347–1367.

wiki/Askeptosaurus