"Pliosaurus" andrewsi

"Pliosaurus" andrewsi Temporal range: Middle Jurassic, Callovian~(166.1–163.5 Ma)[1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
Two-sided view of one of the teeth from the holotype of "P." andrewsi (NHMUK PV R3891).
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Family:	†Pliosauridae
Clade:	†Thalassophonea
Genus:	†"Pliosaurus"
Species:	†"P." andrewsi
Binomial name
†"Pliosaurus" andrewsi Tarlo, 1960

"Pliosaurus" andrewsi is an extinct species of pliosaurid plesiosaurs that lived during the Callovian stage of the Middle Jurassic, in what is now England. The only known fossils of this taxon were discovered in the Peterborough Member of the Oxford Clay Formation. Other attributed specimens have been discovered in various corners of Eurasia, but these are currently seen as indeterminate or coming from other taxa. The taxonomic history of this animal is quite complex, because several of its fossils were attributed to different genera of pliosaurids, before being concretely named and described in 1960 by Lambert Beverly Tarlo as a species of Pliosaurus. However, although the taxon was found to be valid, subsequent revisions found that it is not part of this genus, and therefore a taxonomic revision must be carried out on this species.

"P." andrewsi has a skull that would have had an elongated snout capable of catching agile prey. Its teeth are round in cross section, with some longitudinal ridges on them. Unlike Pliosaurus, "P." andrewsi is among the most basal representatives of the Thalassophonea, a group of pliosaurids characterized by a short neck. "P." andrewsi would have inhabited an epicontinental (inland) sea that was around 30–50 metres (100–160 ft) deep. It shared its habitat with a variety of other animals, including invertebrates, fish, thalattosuchians, ichthyosaurs, and other plesiosaurs. At least five other pliosaurids are known from the Peterborough Member, but they were quite varied in anatomy, indicating that they would have eaten different food sources, thereby avoiding competition.