Primate

About: Primate is a research topic. Over the lifetime, 1250 publications have been published within this topic receiving 67388 citations. The topic is also known as: the primate order & primates.

Primate spermatogenesis: new insights into comparative testicular organisation, spermatogenic efficiency and endocrine control.

Abstract: Owing to the close phylogenetic relationship of Platyrrhini (New World monkeys) and Catarrhini (Old World monkeys) to man, nonhuman primates are often used as models for the study of male reproductive physiology and endocrinology. This review aims at providing new data and insights into comparative primate spermatogenesis, dealing specifically with quantitative aspects of germinal epithelial organisation and germ cell production, and with the roles of gonadotrophic hormones in this process. Typically, the seminiferous epithelium is composed of specific germ cell associations (spermatogenic stages). In rodents, prosimians and most Catarrhini, tubular cross sections contain a single spermatogenic stage whereas in Platyrrhini, great apes and man multi-stage tubules are present. Since Platyrrhini represent a more basal type of primate, this spermatogenic feature must have developed convergently. The primate multi-stage tubular arrangement was previously believed to be associated with low spermatogenic efficiency. However, recent studies using new methodological approaches and comparing primate species from all taxa have revealed that multistage organisation is compatible with highly efficient spermatogenesis. In fact, meta-analysis demonstrated that the efficiency of spermatogenesis in several nonhuman primate species is comparable to that of rodents which are considered as species with highly efficient germ cell production. The duration of the spermatogenic process was not related to organisation or efficiency of spermatogenesis. Sertoli cell work load was species-specific but had no impact on germ cell numbers and on the efficiency of spermatogenesis. The gonadotrophic hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH) are the primary regulators of primate testicular function. Recent studies revealed that in New World monkeys chorionic gonadotrophin (CG)--the primate pregnancy hormone--regulates testosterone production instead of LH. Receptor studies demonstrated a dual action of the closely related hormones LH and CG in primates. It is hypothesised that following the divergence of the Platyrrhini lineage from Catarrhini, the LH/CG system evolved independently with ancestral functions of the LH/CG system retained in the neotropical taxa. In summary, key spermatogenic features are preserved across all primate taxa whereas male reproductive endocrinology features appear substantially different in the neotropical primates compared to other primate lineages.

Walker's primates of the world

Abstract: From Nigeria's needle-clawed bush baby to the snub-nosed langur of Tibet, from loris to lemur, from the woolly monkey to the "naked ape," primates are among the world's most diverse-and distinctive-groups of mammals. Seventy million years of evolving primate anatomy (much of it significantly influenced by a tree-dwelling lifestyle) has resulted in such defining characteristics as stereoscopic vision, a relatively large brain, grasping hands and feet, and superior levels of dexterity and muscular coordination. Now Ronald M. Nowak offers a comprehensive guide to this fascinating and varied order of mammals. Walker's Primates of the World includes scientific and common names, the number and distribution of species, measurements and physical traits, habitat, daily and seasonal activity, population dynamics, home range, social life, reproduction, longevity, and status of threatened species. Recently extinct genera, such as the giant lemurs of Madagascar, are covered in full. Textual summaries present accurate, well-documented descriptions of the physical characteristics and living habits of primates in every part of the world. In a new introduction, noted primate conservationists Russell A. Mittermeier, Anthony B. Rylands, and William R. Konstant discuss the taxonomy and distribution of primates as well as their distinguishing characteristics, special adaptations and particularly striking features, such as sociality. They also report on conservation efforts past and future, and assess the factors, largely human-caused, that are threatening non-human primates with extinction.

Diet and Feeding Ecology of Woolly Monkeys in a Western Amazonian Rain Forest

Abstract: I investigated the diet and feeding ecology of two social groups of woolly monkeys (Lagothrix lagotricha poeppigii) in Yasuni National Park, Ecuador between April 1995 and March 1996. Woolly monkeys in Yasuni were predominantly frugivorous, with fruits comprising ca. 77% of the yearly diet; the next most common food type in the diet was insect and other animal prey. The fruit diet of woolly monkeys in Yasuni is the most diverse yet recorded for any ateline primate, including spider monkeys (Ateles), which are often regarded as ripe fruit specialists: ≥208 distinct morphospecies of fruits were consumed by woolly monkeys either during the study or during several preceding months of pilot work. Nonetheless, close to one-third of the yearly diet came from just 3 plant genera—Inga,Ficus, and Spondias—and only 20 genera each contributed to ≥1% of the diet. For one study group, the proportion of ripe fruit in the diet each month was correlated with the habitat-wide availability of this resource, a pattern evidenced by several other ateline species. However, the relationship was not apparent in the second study group. The modal party size for feeding bouts on all food types was a single monkey, and, contrary to reports for other atelines, neither feeding party size nor the total number of feeding minutes that groups spent in food patches was well predicted by patch size. Both results highlight the independent nature of woolly monkey foraging. Given that woolly monkeys and closely-related spider monkeys focus so heavily on ripe fruits, their very different patterns of social organization are intriguing and raise the question of just how their ecological strategies differ. Two important differences appear to be in the use of animal prey and in the phytochemical composition of the ripe fruits that they consume: spider monkeys rarely forage for animal prey, and woolly monkeys seldom consume the lipid-rich fruits that are an important part of spider monkey diets.