Like other catarrhine primates, "Saadanius" was probably a tree-dweller. New World monkeys and catarrhine monkeys emerged within the simians some 35 million years ago. Old World monkeys and Hominoidea emerged within the catarrhine monkeys some 25 million years ago. They are the sister group of the Old World monkeys, together forming the catarrhine clade. Most catarrhine species show considerable sexual dimorphism and do not form a pair bond.