Archaeoindris
Though similar to "Palaeopropithecus", "Archaeoindris" was significantly larger and more robust. "Archaeoindris" was one of the largest primates to ever evolve, and was the largest-known strepsirrhine primate, weighing an estimated . It was roughly the size of an adult male gorilla, which was first noted by Lamberton.
Evolution of primates
Molecular evidence indicates that the lineage of gibbons (family Hylobatidae) diverged from Great Apes some 18-12 million years ago, and that of orangutans (subfamily Ponginae) diverged from the other Great Apes at about 12 million years; there are no fossils that clearly document the ancestry of gibbons, which may have originated in a so-far-unknown South East Asian hominoid population, but fossil proto-orangutans may be represented by "Sivapithecus" from India and "Griphopithecus" from Turkey, dated to around 10 million years ago.