The only living species in the Old World monkey genus Theropithecus is the gelada.
The gelada’s scientific name is Theropithecus gelada. It is native to the Ethiopian Highlands, where it spends much of its time on steep grasslands and rocky escarpments rather than in trees. Grass can make up the great majority of its diet, an unusual specialization among primates.
Geladas are sometimes called “gelada baboons” or “bleeding-heart monkeys,” but “gelada” is the preferred common name. Their chest patch, especially prominent in females, contributes to the latter nickname. Although they resemble baboons and are close relatives within the Old World monkey family Cercopithecidae, their exact evolutionary relationship to baboons has been debated.
Theropithecus is not an extinct-only genus. Gelada is its sole surviving member, while several larger species are known from fossils, including T. brumpti, T. darti, and T. oswaldi. That fossil history is why wording that says “only species in the genus” can be misleading unless it specifies “living.”