Gargantuan Fossil

This skeleton is enormous and ancient, approximately three million years old, found in the Bone Fields. The skeleton belonged to an eel-like, Leviathan Class super-predator dwarfing both the Sea Dragon Leviathan and Sea Emperor Leviathan, despite only being around one third of the whole skeleton. The remains consist of a huge, reptillian-esque skull and sixteen pairs of huge ribs. The skeleton is covered in flora and coral. The skull is so large that a Cyclops can fit inside its jaws. Smaller versions of its ribs can be seen in the entrance to the Lost River Junction. There is also a smaller variant of this creature's skull which can be found in the Ghost Forest.

The Precursors were also studying these remains, as evidenced by small, angular indentations on the ribcage. These samples were probably studied at the Lost River Laboratory Cache, as this was the main site in which Leviathan class bone samples are found.

Size
The skeleton is enormous. The skull itself is just under 100 metres in length, almost as long as the entire body of a Sea Dragon Leviathan. The two lower front teeth measure at 11.4 metres in height and the two upper teeth at 10.3 metres. The large, rear eye sockets measure 9.7 metres in diameter.

The skeleton that remains measures over 400 metres in length, and with the PDA estimating that it is only one third of the complete specimen, the creature would have measured between 1100 and 1300 metres.