Grippia

Grippia longirostris (Wiman 1929, 1-1.5m long, Early Triassic) was a small basal ichthyosaur with possibly, a short rostrum, despite its name. Once considered the most basal ichthyosaur, other taxa, like Thaisaurus have taken that place. Grippia was the first ichthyopterygian to be described from the Lower Triassic. Derived from a sister to Shastasaurus, Grippia was a sister to Utatsusaurus. Both were basal to Mikadocephalus.

The nares are essentially dorsal in orientation and elliptical. This is not a primitive trait, but one restricted to this clade. There are at least two rows of tiny maxillary teeth. The teeth are bulbous posteriorly and pointed anteriorly. The posterior dorsal vertebrae remain long, with height/length ratio of about 1/2.

Maisch MW 2010. Phylogeny, systematics, and origin of the Ichthyosauria - the state of the art. Palaeodiversity 3: 151-214.

Mazin J-M 1981. Grippia longirostris Wiman, 1929, un Ichthyopterygia primitif du Trias inférieur du Spitsberg. Bulletin du Muséum National d’Histoire Naturelle 4:317–340.

McGowan 1996. A new and typically Jurassic ichthyosaur from the Upper Triassic of British Columbia. Canadian Journal of Earth Sciences. 33 (1): 24–32. doi:10.1139/e96-003

Motani R 2000. Skull of Grippia longirostris: no contradiction with a diapsid affinity for the Ichthyopterygia. Palaeontology 43:1-14.

Motani R, Minoura N and Ando T 1998. Ichthyosaur relationships illuminated by new primitive skeletons from Japan. Nature, 393:255–257.

Wiman C 1929. Eine neue Reptilien-Ordnung aus der Trias Spitzbergens. Bulletin of the Geological Institutions of the University of Upsala 22: 183–196.

Young CC and Dong ZM 1972. On the aquatic reptiles of the Triassic in China. Vertebrate Paleontology Memoire 9:1-34

wiki/Grippia

Marine Younginiformes

Enaliosauria

Sauropterygia

Placodontia

Thalattosauriformes