Simiolus is an extinct genus of dendropithecid primates. It was described by Mary Leakey and Richard Leakey in 1987, and the type species is S. enjiessi, which existed during the Miocene of Kenya. The species epithet is a phonetic pun on the acronym NGS. A new species, S. andrewsi, also from the middle Miocene of Kenya, was described by Terry Harrison in 2010. In November 2018, scientists reported the discovery of the smallest known ape, Simiolus minutus, which weighed approximately 8 lb (3.6 kg), and lived about 12.5 million years ago in Kenya in East Africa.