Morphological Investigation of the Female Internal Genital Organs of Marca's Marmoset (Mico marcai)

This study provides the first description of the anatomy and histology of the female internal genital organs of Mico marcai. Descriptions were based on samples collected from two free-ranging specimens. As in other species of Platyrrhini, the ovaries were oval-shaped. Histological findings suggest both females were at the beginning of the luteal phase, as shown by the presence of luteal tissue in the ovaries and the high incidence of follicular atresia. As described in other primates, branching longitudinal folds and a tunica muscularis were seen in uterine tubes in M. marcai. The tunica muscularis is responsible for the peristaltic action that carries the oocyte towards the uterus. The uterus had a collagen-rich endometrium with high numbers of simple tubular glands. Different from other primates, in M. marcai the vagina was lined with non- keratinized stratified squamous epithelium with PAS-positive vaginal fluid. Measurement of serum levels of reproductive hormones is warranted to explain histological changes in female internal genital organs of M. marcai in the different phases of the reproductive cycle.