Janusaurus

Janusaurus; Temporal range: Tithonian; ~150–146 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Holotype skull
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Subclass:	Diapsida
Order:	†Ichthyosauria
Family:	†Ophthalmosauridae
Genus:	†Janusaurus; Roberts et al., 2014
Binomial name
	†Janusaurus lundi; Roberts et al., 2014

Janusaurus is an extinct genus of ophthalmosaurid ichthyosaur from the Upper Jurassic Slottsmøya Member, Agardhfjellet Formation of Central Spitsbergen. The holotype consists of a partial skull and postcrania, and would have belonged to an individual measuring 3–4 m (9.8–13.1 ft) long.^[2] In 2019, Janusaurus was synonymized with Arthropterygius, though maintained as a separate species, by Nikolay Zverkov and Natalya Prilepskaya,^[3] although this synonymy was objected to later that same year by Lene Delsett and colleagues, who maintained that they were sufficiently different to warrant separate genera.^[4]