 The history of Kritosaurus took another turn in 1990 , when Jack Horner and David B. Weishampel once again separated Gryposaurus , citing the uncertainty associated with the latter 's partial skull . Horner in 1992 described two more skulls from New Mexico that he claimed belonged to Kritosaurus and showed that it was quite different from Gryposaurus , but the following year Adrian Hunt and Spencer G. Lucas put each skull in its own genus , creating Anasazisaurus and Naashoibitosaurus . 
