What is "phosphorosaurus"

Phosphorosaurus ("Phosphate Lizard") is an extinct genus of mosasaur from the Late Cretaceous ( Maastrichtian). Although treated as synonymous with Halisaurus in the past, recent study recognizes it as valid. Two species are known, Phosphorosaurus ortliebi from Belgium, and P. ponpetelegans from Hokkaido in Japan.