Complex sentence: Welles found a larger skeleton belonging to the same species in 1964, and realized it bore crests on its skull, and therefore moved the species to the new genus "Dilophosaurus" in 1970, as "D. wetherilli".
Split into simpler sentences: Welles found a larger skeleton belonging to the same species in 1964. Realizing it bore crests on its skull, he moved the species to the new genus "Dilophosaurus" in 1970, as "D.wetherilli".