Red buttocks horse monkeys

These are a descriptive for a few different minor characters in the Chinese novel Journey To The West. In Chinese this is 赤尻馬猴 (chikao mahou). They are both a species (and perhaps gendered) name as well as an actual epithet. Some of the monkeys Wukong rules over are female red-buttocks horse monkeys. Their advice to Wukong helps move the plot forward. When the Buddha is asked to determine which Sun Wukong is the real one when he is fighting his doppelganger, he lists four different monkeys: The numinous stone monkey, the arms through the back gibbon, the red buttocks horse monkey, and the sixth eared macaque. When the sixth eared macaque dies, it is said that all of his kind dies. Thus that too suggests that in a way, all of their names that the Buddha lists are species names, but also the description or name of the individuals in question.
In some translations the term in certain places is translated as "baboon" instead. However, baboons aren't native to China and I'm not so sure that they were ever supposed to be those. Due to this reason as well as the species one the name has been masculinized. However, it probably refers to female macaques.