In a 2006 expedition to survey the reserve, scientists discovered two rare and possibly endangered species of primate in the reserve:
ursine colobus and the
olive colobus, as well as 17 rare butterfly species and the critically endangered frog species
Conraua derooi. Butterfly species include
Papilio antimachus, which has the widest wingspan in the world and
Mylothris atewa, which may be globally critically endangered. In May 2017, researchers from Rocha conducted a review of camera trap footage captured in Ghana's Atewa mountain range, they discovered the presence of
white-naped mangabeys. The unexpected finding of these primates highlights the significance of camera trap technology in uncovering and documenting the biodiversity of the region. In July 2021, a team of scientists including Dr Caleb Ofori-Boateng, a Ghanaian scientist from the CSIR-
Forestry Research Institute of Ghana (CSIR-FORIG) discovered a critically endangered frog species, named
Conraua sagyimase or the Atewa Slippery frog. These were found exclusively in the Atewa Range Forest Reserve, and it has been named after the community of Sagyimase, which has supported research on the frog. The Akan common name for the species translates to "the frog of the forest streams." Again, October 2021, two British scientists conducting research in Ghana made an extraordinary rediscovery. They found
Shelley's eagle-owl, a large and enigmatic owl species, in the Atewa Forest. Surprisingly, this bird had remained unnoticed by scientists in Ghana for nearly 150 years, adding to its elusive and mysterious nature. == The call for national park ==