Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys-A literature review

The ability of a species to withstand human impact depends on its life history characteristics, including social, ranging, and reproductive activity. The genera Lagothrix and Cacajao are more susceptible to anthropic action than small-sized primates due to their slower life histories, more restricted geographical ranges, and lower population densities. This narrative literature review aimed to gather scientific information available from the last 60 years on the reproductive biology of females of the genera Lagothrix and Cacajao. Most studies on the genus Lagothrix, mainly focused on L. lagothricha and L. l. poeppigii, present important advances on reproductive strategies, reproductive productivity, functional morphology and physiology, including seasonality, sexual cycle, gestation and fetal development in captive and free-living populations. Contrary, there is much less known about the reproductive biology of the genus Cacajao, with studies on free-living C. calvus and C. melanocephalus highlighting reproductive behavior, and basic description of the sexual cycle, gestation, and lactation. Unfortunately, the morphology of the female genital organs is only described in C. calvus, and there is still scarce information about the menstrual activity and the placenta. This literature review encourages primatologists, morphophysiologists, reproductive specialists, and ecologists to conduct comprehensive studies of these species to better understand the gaps in knowledge about reproduction, their relationship with their environment, including climatic and social variables. Understanding the integrative reproductive biology of these species will be a clue for improving the assessment of the resilience capacity of free-living populations and, consequently, establishing more appropriate management programs, and for the development of ex situ management techniques for the conservation of the species.

Anatomy of the basal nuclei of Alouatta belzebul

Abstract The basal nuclei are well-defined bodies of neurons with specific functions, located inside the white medullary center of the brain, directly involved with the motor system, participating greatly in the planning and control processes of movements. Studies on these nuclei in non-human primates are small and in the Alouatta belzebul species, nonexistent. The aim of the present study was to describe the morphology of the nuclei at the base of the brain of Alouatta belzebul. Ten male and female Alouatta belzebul brains were used, where after removal and coronal cut of the brain, the Mayland technique was performed to show the basal nuclei. There was the presence of the caudate nucleus, lentiform nucleus (this formed by the putamen, medial globus pallidus and lateral globus pallidus), claustrum and substantia nigra, which, functionally, are related to motor control. The substantia nigra is part of the midbrain and is also related to learning resulting from the effects of dopamine, responsible for activating the reward and addiction system in the telbrain and is also related to the red nucleus, which is also a midbrain nucleus. In Alouatta belzebul the red nucleus is present. It was found in the literature that degeneration of substantia nigra cells can cause Parkinson's disease in Macaca fasciculares, and because Alouatta belzebul has the same anatomical structures in the basal nuclei of the base of Macaca fasciculares, it is suggested that studies of functional evaluation of these structures should be carried out to verify whether Alouatta belzebul can be used as an experimental model for Parkinson's disease.

Reproductive biology of owl (Aotus spp.) and capuchin (Sapajus spp.) monkeys

Studies related to morpho-physiology improve the understanding of biological mechanisms in non-human primates (NHP), contributing to research in several areas, especially those of assisted reproduction and biomedicine. The genera Aotus and Sapajus are important considerations in conducting studies related to reproductive biology and biomedical research, where animals of these genera can serve as models for species with vulnerable conservation status. The reproductive functions of animals of these genera can be used in conducting studies with other NHP species, for which biological material is difficult to access. The aim in conducting the current review was to compile the scientific literature on the biology and reproductive aspects of these two genera, to provide a for a greater understanding of these topics. In addition, a systematic review of literature allows for efficient access relevant information from an extended timeframe collated in a single document. There was, therefore, a systematic search for keywords based on reproductive studies with animals in these genera conducted, and 58 articles, 12 books, and three academic theses were subsequently selected. Even though there have been advances in knowledge of the reproductive biology of animals from these genera that have occurred in recent decades, especially research conducted when these NHP were in captivity, a wide variety of areas remain to be studied so that the understanding of reproduction in these NHP can be enhanced and the knowledge gained from these studies utilized for greater understanding of reproduction of NHP in general.

Anatomia do sistema reprodutor feminino de Alouatta belzebul (Linnaeus, 1766)

RESUMO O conhecimento da anatomia de qualquer animal silvestre é de fundamental importância para sua preservação e proteção. Neste contexto, o presente estudo objetivou descrever a morfologia do sistema reprodutor feminino de Alouatta belzebul. Foram utilizados seis espécimes de A. belzebul, fêmeas, adultas, e livres de lesões. Observou-se macroscopicamente que os ovários têm características morfológicas em formato ovoides, com superfície lisa, e, na análise histológica na região de córtex, evidenciou-se folículos ovarianos em diferentes estágios de desenvolvimento. As tubas uterinas anatomicamente são finas e curvilíneas, apresentando uma camada mucosa, uma muscular e outra serosa. O útero possui formato simples, com fundo globoso, com um miométrio altamente vascularizado, sendo organizado em feixes de fibras musculares lisas. A estrutura anatômica da vagina apresentou-se como um tubo muscular longo de paredes finas, onde, na região vestibular, o óstio externo da uretra é marcado por uma papila uretral bilobada e, na região de vulva, em sua porção caudal, contatou-se um clitóris bem desenvolvido. No que concerne à análise histológica da vagina, verificou-se, em região de mucosa vaginal, um extrato basal composto por epitélio estratificado pavimentoso não queratinizado atrófico. As descrições morfológicas fornecem, de forma inédita, informações importantes relativas à anatomia macroscópica e microscópica do sistema reprodutor feminino dessa espécie.

Population estimate and morphometry of ovarian preantral follicles from three recently recognized squirrel monkey species: a comparative study

We describe morphological and morphometrical characteristics of preantral ovarian follicles from three recently recognized Saimiri species: S. macrodon, S. cassiquiarensis and S. vanzolinii; the last one a threatened species. Ovaries from four adult monkeys were evaluated: one pair from a pregnant S. macrodon, two ovarian pairs from S. cassiquiarensis females (one of them pregnant), and one left ovary from a senile S. vanzolinii, applying classical histology. Follicular preantral population was quantified and morphology and morphometry of primordial, primary and secondary follicles were evaluated. Follicular preantral population varied among species, being 347,153 in the ovaries of the S. macrodon, 270,342 and 278,376 in the ovaries of both adult non-pregnant and pregnant S. cassiquiarensis females, and 28,149 in the ovary from a senile S. vanzolinii. Most follicles were at primordial or transition stages, except for the senile S. vanzolinii female, which presented the lowest percentages of primordial and transition follicles when compared with primary and secondary ones. Most preantral follicles (>70%) were morphologically normal in the ovaries from all studied S. macrodon and S. cassiquiarensis females, but the ovary of the senile S. vanzolinii female presented a significant decrease in the percentage of normal follicles (primordial: 61%, transition: 52%, primary: 54%, and secondary: 48%). In general, follicular diameter increased significantly from primordial to transition, and subsequently from primary to secondary follicles.