It contains one species, Issi saaneq; the full binomial name means "cold bone".

Fossils of Issi were previously assigned to the species Plateosaurus trossingensis, but new finds allowed for a reassessment of that material that showed that it possessed features thought to be exclusive to Brazilian sauropodomorphs such as Unaysaurus and Macrocollum.

On 27 July 1991, at the east coast of Greenland, on Jameson Land, in the Iron Cake site on the northern slope of the MacKnight Bjerg near the Flemingfjord, by William W. Amaral, William R. Downs, Stephen M. Gatesy, Neil H. Shubin and Niels Bonde, members of a team from Harvard University headed by Farish Jenkins, a skull was uncovered of a basal sauropodomorph.

After a CAT-scan by Marco Marzola, Filippo Rotatori and Alexandra Fernandes of the first two finds, followed by a digital deformation, it was concluded in a master's thesis by Victor Beccari that they represented a taxon new to science.

[4] In 2021, the type species Issi saaneq was named and described by Victor Beccari Dieguez Campo, Octávio Mateus, Oliver Wings, Jesper Milàn and Lars Bjørn Clemmensen.

[1] The holotype, NHMD 164741, was found in a layer of the Malmros Klint Formation of the Fleming Fjord Group, dating from the middle Norian.

The depression around the antorbital fenestra ends in front of the descending branch of the lacrimal bone.

The results of the describers' phylogenetic analyses are shown in the cladogram below:[1] Chromogisaurus Pampadromaeus Panphagia Saturnalia Guaibasaurus Pantydraco Thecodontosaurus Efraasia Plateosauravus Ruehleia Macrocollum Unaysaurus Issi Plateosaurus gracilis Plateosaurus trossingensis Riojasaurus Eucnemesaurus Massopoda