Hydrotherosaurus "Water Beast Lizard"


Hydrotherosaurus alexandrae is an extinct genus of elasmosaurid plesiosaur, a type of aquatic reptile with a long, flexible neck and relatively small head. Hydrotherosaurus existed from the late Cretaceous (Maastrichtian, 70-65 million years). The only fossil was found in Fresno County, California. Inside the organism was the remnants  of its last meal. Nestled inside this skeleton, paleontologists found gastroliths, or stomach stones, which were probably helped anchor Hydrotherosaurus to the sea bottom to find food.

What made this organism so unique was the 60 vertebrae in its neck, which decreased as they got closer to the cranial and longer towards the trunk. In length, the organism stretched an upwards of 13 meters long.