Data for: Menstrual cycle in four New World primates: Poeppig’s woolly monkey (Lagothrix poeppigii), red uakari (Cacajao calvus), large-headed capuchin (Sapajus macrocephalus) and nocturnal monkey (Aotus nancymaae)

Genital organs from 33 Aotus namcymaae, 29 Poeppig’s woolly monkeys (Lagothrix poepigii), 21 red uakaris (Cacajao calvus) and 11 large-headed capuchins (Sapajus macrocephalus) were histologically analyzed in order to describe the endometrial changes related to the ovarian cycle. Recorded ovarian parameter included number and diameter of the largest antral follicle and CL. Recorded uterine variables include the density of endometrial glands, hemosiderin and fibrin measured and ranked from 0 to 5, according to the average number of target structures counted in random 1-mm2 fields at 100X.