Observations on the female internal reproductive organs of the brown howler monkey (Alouatta guariba clamitans)

Abstract

Alouatta guariba clamitans (brown howler monkey) is an endemic primate from the southeastern Brazil tropical forests, classified as near threatened by the IUCN Red List 2007. The genus Alouatta is one of the most difficult New World monkeys to breed and rear in captivity. In this study we examined the macroscopic and histological aspects of the female genital tract of wild brown howler monkeys to provide baseline information for future reproduction research. The anatomical relationship between the vagina, uterus, broad ligament, oviducts and ovaries are those of a typical primate reproductive tract. The fundic portion of the uterus is globoid, the cervix is well developed, which confers to the uterus an elongated shape, and the vagina is a long flattened channel. Histological analysis conducted in females in the follicular phase revealed large quantities of interstitial luteinized tissue in the ovaries, a stratified nonkeratinized vaginal epithelium, lack of glands in the vaginal mucosa and simple tubular endometrial glands. The observed anatomical features should be considered in the adaptation and application of assisted reproductive techniques aimed at improving captive reproduction for species conservation.

Functional morphology of the tubular genital organs in the female owl monkey (Aotus spp.)

“…The results related to uterine evaluation in this study are very similar to those reported in previous studies performed with ultrasound in A. azarai infulatus . The simplex non‐pregnant uterus was characterized by a globular fundic portion and a small cervix that protruded into the vaginal canal, which is similar to other New World primate species , but different from apes, which have the fundic portion described as flattened .…”

“…In this context, the reproductive organs develop along with the urinary system from two urogenital folds in the early embryo (i.e., each urogenital fold consists of a gonad and mesonephros). Thus, we observed that the general description of the tubular genital organs of the female owl monkey was similar to those of other New World primate species, such as the howler monkey ( Alouatta guariba clamitans ) , the red uakari ( Cacajao calvus ucayalii ) , the woolly monkey ( Lagothrix poeppigii ) , and as previously reported in the owl monkey ( Aotus trivirgatus ) . However, some aspects of the female reproductive status found in this study seem to differ from A. trivirgatus and A. azarai infulatus .…”

“…The infundibulum had a thinner tunica muscularis and a larger lumen compared to the ampulla and the isthmus. Similar observations were found in woolly monkeys [28] and red uakaris [29], although Veras et al [40] could not distinguish these segments in howler monkeys.…”

“…Changes in the thickening, number of layers, and keratinization are variations of the vaginal epithelium associated with estradiol and indicators of the estrous cycle. Changes of the vaginal epithelium have been shown in woolly monkeys , spider monkeys , red uakaris , and marmosets ; they were not observed in howler monkeys and in owl monkeys . In our study, we observed that the vaginal epithelium showed changes according the reproductive status of the female.…”

Anatomicohistological Characteristics of the Tubular Genital Organs of the Female Woolly Monkey (Lagothrix poeppigii)

“…As in the howler monkey [Veras et al., ] and in humans [Ferenczy et al., ], cyclic changes of the ciliated and secretory cells of the uterine tube epithelium have been observed. In females in the follicular phase, the ciliated cells were the dominant feature discernible in the epithelium, whereas in pregnant females and females in the luteal phase, the epithelial secretory cells were predominant throughout all areas of the epithelial surface.…”