Pliopithecoids from the Miocene of Eurasia are currently considered to be stem catarrhines on the basis of the possession of only two premolars (e.g.
(1996): Distribution and biochronology of European and Southwest Asian Miocene catarrhines. In: R.L.
The new fossil catarrhine, Saadanius hijazensis, dates from 29 million to 28 million years ago and lacks the specialized features that distinguish modern apes and Old World monkeys, suggesting that the split had not yet occurred.
As a student, Gingerich had worked with palaeontologist Elwyn Simons, who studied Aegyptopithecus, a primitive catarrhine from the early Oligocene.
Molar microwear and shearing crest development in Miocene catarrhines
. Anthropologie 42:21-35.
"Forty to 30 million years ago (Ma) neocorital portions of the brain increased in the two emerging branches of anthropoid primates - the platyrrhines (or New World monkeys) and the catarrhines
. Within the catarrhines
branch, additional marked enlargements occurred by 18-6 Ma in the lineage to the ancestors of modern hominids." Id.