Giant, 82-foot lizard fish discovered on UK beach could be largest marine reptile ever found

Ichthyosaurs had already attained massive sizes by the early portion of the Mesozoic, but it was not until the late Triassic that the largest species emerged.

The first chunk of the fossil was noticed atop a rock on the beach, indicating that a passerby had found it and set it there for others to examine, the researchers explained in the paper.

The reptile's remains are made up of a series of 12 fragments from a surangular bone, which is found in the upper portion of the lower jaw.

(Image credit: Gabriel Ugueto, CC-BY 4.0)A number of rib fragments and a coprolite, or fossilized feces, were found in the area as well, but they were not definitively attributed to the same animal.

S. sikanniensis appeared 13 million years earlier than I. severnensis and was found in British Columbia, making it unlikely that the new discovery represents another specimen of the previously known species.

They were eventually supplanted by plesiosaurs — long-necked marine reptiles that went extinct at the end of the Cretaceous, alongside all non-avian dinosaurs.