Fossils found in Kenya suggest that primates roamed the area more than 20 million years ago. Recent findings near Lake Turkana indicate that hominids such as Homo habilis (1.8 and 2.5 million years ago) and Homo erectus (1.8 million to 350,000 years ago) are possible direct ancestors of modern Homo sapiens, and lived in Kenya in the Pleistocene epoch. During excavations at Lake Turkana in 1984, paleoanthropologist Richard Leakey assisted by Kamoya Kimeu discovered the Turkana Boy, a 1.6-million-year-old fossil belonging to Homo erectus. Previous research on early hominids is particularly identified with Mary Leakey and Louis Leakey, who were responsible for the preliminary archaeological research at Olorgesailie and Hyrax Hill. Later work at the former site was undertaken by Glynn Isaac.