E.(?)sachalinensis, Pervushov and colleagues considered E.amalitskii an indeterminate elasmosaurid. In a 1918 review of the geographic distribution and evolution of Elasmosaurus, Pravoslavlev provisionally assigned three other previously named species to Elasmosaurus; his taxonomic opinions have not been widely followed. One of these was E.chilensis, based on the Chilean Plesiosaurus chilensis named from a single tail vertebra by Claude Gay in 1848. Wilhelm Deecke moved chilensis to Pliosaurus in 1895, a classification which was acknowledged by Pravoslavlev. Edwin Colbert later assigned the type vertebra in 1949 to a pliosauroid, and also assigned other assigned remains to indeterminate elasmosauroids; the type vertebra was recognized as potentially belonging to Aristonectes parvidens by José O'Gorman and colleagues in 2013. Another was E.haasti, originally Mauisaurus haasti, named by James Hector in 1874 based on remains found in New Zealand. Although its validity was supported for a considerable time, M.haasti is regarded as a nomen dubium as of 2017. Pravoslavlev recognized another species from New Zealand, E.hoodii, named by Owen in 1870 as Plesiosaurus hoodii based on a neck vertebra. Welles recognized it as a nomen dubium in 1962; Joan Wiffen and William Moisley concurred in a 1986 review of New Zealand plesiosaurs. In 1949 Welles named a new species of Elasmosaurus, E.morgani. It was named from a well-preserved skeleton found in Dallas County, Texas. However, part of the specimen was accidentally thrown out during the relocation of the Southern Methodist University's paleontological collections. Welles recognized E.morganis similarity to E.platyurus in its shoulder girdle, but maintained it as a separate species due to its shorter neck and more robust rear neck vertebrae. In 1997 Carpenter reconsidered the differences between the two species, and found them sufficient to place E.morgani in its own genus, which he named Libonectes. Despite its reassignment and the loss of its material, L.morgani is often considered an archetypal elasmosaurid. Data based on these lost elements were unquestionably accepted in subsequent phylogenetic analyses, until a redescription of the surviving elements was published by Sachs and Benjamin Kear in 2015. Persson assigned another species to Elasmosaurus alongside his 1959 description of "E."helmerseni remains from Sweden, namely E.(?)gigas. It was based on Schröder's Pliosaurus(?) gigas, named in 1885 from two dorsals; one was found in Prussia, the other in Scania. While they were incomplete, Persson recognized that their proportions and the shape of their articular ends differed greatly from pliosauroids, and instead agreed well with