1895 were named E.sternbergii by Williston, but were considered indeterminate by Storrs. Williston mentioned three additional Elasmosaurus species, which he would figure and describe at a later date. He again made reference to a new species of Elasmosaurus, from Kansas, in 1908. Several Russian species, based on poorly preserved vertebral remains, were assigned to Elasmosaurus by N.N. Bogolubov in 1911. One was E.helmerseni, which was first described by W.Kiprijanoff in 1882 from Maloje Serdoba, Saratov, as Plesiosaurus helmerseni. Some material from Scania, Sweden, was assigned to P. helmerseni in 1885 by H.Schröder. Vertebral and limb remains from Kursk initially assigned by Kiprijanoff to P.helmerseni were also moved by Bogolubov to the new species E.kurskensis, which he considered to be "identical with Elasmosaurus or related to it". He also named E.orskensis, based on "very large" neck and tail vertebra remains from Konopljanka, Orenburg; and E.serdobensis, based on a single neck vertebra from Maloje Serdoba. However, the validity of all these species has been questioned. Welles considered E.kurskensis as an indeterminate plesiosaur in 1962. Persson noted in a 1959 review of the Swedish "E."helmerseni material that, while the species was probably closely related to Elasmosaurus proper, it was too fragmentary for this hypothesis to be assessed; he later remarked in 1963 that, regarding the latter three species, "their generic and specific definition is questionable", although he declined to specifically label them as invalid on account of not having seen the fossil material. Similarly, in 1999, Evgeniy Pervushov, Maxim Arkhangelsky, and A.V. Ivanov considered E.helmerseni to be an indeterminate elasmosaurid. In 2000 Storrs, Archangelsky, and Vladimir Efimov concurred with Welles on E.kurskensis, and labelled E.orskensis and E.serdobensis as indeterminate elasmosaurids. Two additional Russian species were described by subsequent authors. A.N. Riabinin described a single phalanx from a flipper in 1915 as E.(?)sachalinensis; the species was named after the island of Sakhalin, where N.N. Tikhonovich found it in 1909. However, this specimen cannot be identified more specifically than an indeterminate elasmosaurid, which was followed by Persson and Pervushov and colleagues. Storrs, Arkhangelsky, and Efimov were less specific, labelling it as an indeterminate plesiosaur; this classification was followed by Alexander Averianov and V.K. Popov in 2005. Then, in 1916, P.A. Pravoslavlev named E.amalitskii from the Don River region, based on a specimen containing vertebrae, limb girdles, and limb bones. Persson considered it a valid species, and a relatively large member of the elasmosaurids; however, like