Dale Russell
Early research into ornithomimosaur evolution was based on comparative anatomy. In 1972, Dale Russell argued that the Jurassic "Elaphrosaurus" of Africa was an ancestral relative of ornithomimids. The descriptions of "Garudimimus" and "Harpymimus" in the revealed the existence of primitive ornithomimosaurs outside of the Ornithomimidae proper. Subsequent research and discoveries during the refined science's knowledge of ornithomimosaur evolution. In 1994, "Pelecanimimus polyodon" was described from Europe, the first known ornithomimosaur from that continent and apparently a very evolutionarily primitive taxon. From the late 1990s into the early cladistic evidence mounted against Russell's hypothesis that ornithomimosaurs were descended from a close relative of "Elaphrosaurus", and favored an ancestry close to "Pelecanimimus". Paleontologists found that within the theropod family tree, ornithomimosaurs were primitive coelurosaurs closely related to, but outside of, the maniraptorans.