Mosasaur Marine Dinosaur Vertebra Cretaceous Period, 70 million years B.P. A natural Mosasaur articulated vertebra, consisting of six individual vertebrae with some original matrix. 482 grams, 22.5 cm (8 7/8 in.). From the lower phosphorus limestone beds of the Khouribga Basin, Maastrichtian level, Morocco, North Africa. Private Shropshire, UK collection. [No Reserve]