Anatomy of the Nervous of Forearm and Hand of Cebus libidinosus (Rylands, 2000)

Comparative anatomy of the Sapajus sp. (bearded capuchin) hand with comments on tool use in a parallel evolution with the hominid pathway

Introduction: Bearded capuchins display a wide variety of manipulatory skills and make routine use of tools in both captivity and the wild. The efficient handling of objects in this genus has led several investigators to assume near-human thumb movements, despite a lack of anatomical studies. Methods: Here, we performed an anatomical analysis of muscles and bones in the capuchin hand. Sapajus morphological traits were quantitatively compared with those of humans, chimpanzees, gorillas, and baboons. Results: The comparative analysis indicated that the Sapajus hand is more similar to that of baboons and least similar to that of humans according to the muscles, bones, and three-dimensional data. Furthermore, these findings suggest that bearded capuchins lack true thumb opponency. Regarding manipulatory skills, they display rather primitive hand traits, with limited resources for precision grasping using the opponens pollicis. Discussion: These findings suggest that bearded capuchins' complex use of tools depends more heavily on their high cognitive abilities than on a versatile hand apparatus. These findings offer crucial insights into the evolution of primate cognition.

Comparative anatomical study of the leg's nerves of Cebus (barbed capuchins) with baboons, chimpanzees and modern humans

The anatomical comparative studies among the primates are important for the investigation of ethology, evolution, taxonomy, and comprehension of tools by hominoids. Especially the anatomical knowledge of Cebus contributes to conservation of the species, and to development of surgical procedures and clinical treatments of these animals, as they frequently are victims of automobile accidents. Recent anatomical studies came to a wrong conclusion regarding behavioral traits of Cebus, ascribed to few data available in previous literature. Therefore, to provide anatomical data and to support the other sciences related to anatomy, and to develop surgical and/or clinical procedures, we described the nerves of the legs of Cebus foccusing on their position and trajectory, as wll as innerved muscles, and compared these results with those of humans and other primates. Eight adult capuchin specimens were used for this study. The anatomical comparative study of the leg's nerves of Cebus demonstrated that, in general, structural organization of the nerves is similar among the four primates analyzed here (Cebus, chimpanzees, baboons and humans), which might be attributed to the fact that the all four primates have similar body structures. However, nerve trajectory and muscles innervation in Cebus was more similar to baboons.

Comparative anatomy of the thigh nerves of Cebus libidinosus (Rylands et al., 2000)

Non-human primates have constituted an important group among animals subjected to various studies. Ethological, evolutionary and paleontological studies have revealed changes in anatomical structures linked to the evolution of primates, considered in studies on the comparative anatomy between Cebus libidinosus and other neotropical monkeys or those from the Old World, and the detailed knowledge on their anatomy may represent an important factor for their preservation and protection when the animals are brought to veterinary clinics after accidents or illnesses. In terms of veterinary importance, sometimes these animals arrive in the veterinary medical clinics after accidents, needing surgery or clinical treatment, but the little data available on anatomy has impaired the correct proceedings. The main justification for studies on C. libidinosus, is due to little information about the anatomy related to C. libidinosus in Brazilian and worldwide scientific literature. In this study, the distribution, enervation and path of the femoral and sciatic nerves of the pelvic limb (thigh) of C. libidinosus were studied and these results were compared with literature on the anatomy of humans, chimpanzees and baboons. In general, the enervation model of the four primates is identical, but in specific terms, the differences in enervations indicate evolution convergence closer to the branch of baboons in the evolutionary tree, and these data corroborate other comparative studies in relation to the same primates to vessels, muscles and nerves. In conclusion, the nerve organization in the thigh of C. libidinosus is identical to baboon, chimpanzee and homo, but more similar to baboon. The specific differences found indicate an ancient phylogenic origin to C. libidinosus and baboons (data corroborated by other studies).

History, citoarchitecture and neurophysiology of human and non human primates' parietal lobe: A review

This strict localizationism had and still has its importance for the development of Neurosciences, since the analysis of changes in mental processes resulting from brain damage became the basis for understanding the brain organization. The human parietal cortex is a highly differentiated structure, consisting of citoarchitectonically defined subareas that are connected to other cortical and subcortical areas. Patients with lesions in the parietal cortex develop various types of neuropsychological manifestations, depending on the specific location of the lesion and the corresponding hemisphere and these lesions in this lobe do not cause modal specific disturbances. The establishment of homologies between the parietal region in humans and primates can be of great contribution in trying to unravel the various functions and complexity of this area.