 In 1999 the Chilean finds were named as a second species, "Leedsichthys notocetes", the "Southern Sea Monster".However, Liston later concluded that the presumed distinguishing traits of this species, depressions on the gill rakers, were artefacts caused by erosion; "Leedsichthys notocetes" would be a junior synonym of "Leedsichthys problematicus".The fossil remains of "Leedsichthys" have been found in the Callovian of England and northern Germany, the Oxfordian of Chile, and the Callovian and upper Kimmeridgian of France.