The fossilised animal, thought to be at least 37 million years old, is a member of the extinct adapid
family, and was discovered in a disused quarry in Germany.
These belong either to the lemurlike adapids, the tarsierlike omomyids, or the early simians, forerunners of monkeys, apes, and humans.
Only adapids and omomyids have turned up at North American and European sites of comparable age; several African simians dating to about 40 million years ago have been discovered since 1988.
And this puts Amphipithecus smack in the midst of a long-standing debate over which lower primate gave rise to the anthropoids: adapids or another prosimian group called the omomyids, which are related to modern tarsiers.
But [even] if it is, I don't think it shows that adapids are related to anthropoids," he says.
Instead, he finds evidence that anthropoids share closer bonds with lemurlike creatures called adapids
The new fossils also shed light on whether lemurlike adapids
or tarsierlike omomyids living between 55 million and 36 million years ago qualify as simian ancestors.
Scientists divide forest-dwelling primates living 55 million to 36 million years ago into two families: the adapids, including many species resembling modern lemurs; and the omomyids, comprising several animals with anatomical ties to modern tarsiers.
Dissenters, such as Simons, view the adapids as more likely simian ancestors.