mosasaurian

from The Collaborative International Dictionary of English v.0.48

Mosasaur \Mos"a*saur\, Mosasaurian \Mos`a*sau"ri*an\, n.
   (Paleon.)
   One of an extinct order of reptiles, including {Mosasaurus}
   and allied genera. See {Mosasauria}.
   [1913 Webster]