Plesiosaurus was one of the first of the “antediluvian reptiles” to be discovered and excited great interest in Victorian England.
The type species of Plesiosaurus, P. dolichodeirus, was named and described by Conybeare in 1824 on the basis of a complete skeleton discovered by the early collector Mary Anning.
She found this specimen in Sinemurian (Early Jurassic)-age rocks of the lower Lias Group in December 1823. Additional fossils of Plesiosaurus were found in rocks of the Lias Group of Dorset for many years, “until the cessation of quarrying activities in the Lias Group, early in this [20th] century.”
Mary Anning (21 May 1799 – 9 March 1847) was a British fossil collector, dealer, and palaeontologist who became known around the world for important finds she made in the Jurassic marine fossil beds at Lyme Regis in Dorset, a county in Southwest England on the coast of the English Channel.
Mary Anning searched for fossils in the area’s Blue Lias cliffs, particularly during the winter months when landslides exposed new fossils that had to be collected quickly before they were lost to the sea. It was dangerous work, and she nearly lost her life in 1833 during a landslide that killed her dog.