Archaeonectrus is an extinct genus of pliosaur from the Jurassic of what is now southeastern England. The type species is Archaeonectrus (originally "Plesiosaurus") rostratus, first named by Sir Richard Owen in 1865, and renamed by N.I. Novozhilov 99 years later.
- Sepkoski, J.J. (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology 363: 1-560.
- Archaeonectrus in the Paleobiology Database