Named By: N.I. Novozhilov - 1964.
Synonyms: Plesiosaurus rostratus.
Classification: Chordata, Reptilia, Sauropterygia, Plesiosauria, Pliosauridae?
Species: A. rostratus (type).
Size: Almost 4 meters long.
Known locations: England.
Time period: Sinemurian of the Jurassic.
Fossil representation: Almost complete.
Originally described as a species of Plesiosaurus by Richard Owen in 1865, it was identified as a distinct genus just under a hundred years later in 1964. Archaeonectrus has a slightly confusing classification due to the short neck that is around one and a half times longer than the skull. This has led to Archaeonectrus being considered to be a short necked plesiosaur or alternatively a pliosaur, the latter usually taking precedence.
- A monograph of the fossil Reptilia of the Liassic formations. Part I, Sauropterygia. - Palaeontographical Soceity Monographs 17(75):1-40. - Richard Owen - 1865.