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

Gross anatomical description of the extrinsic and intrinsic scapular and brachial muscles of Sapajus apella (Linnaeus, 1758)

BACKGROUND

The robust brown capuchin monkey (Sapajus apella) is a South American primate with preferences for arboreal locomotion, which requires specific thoracic limb muscle adaptations. The present investigation studied the gross anatomy of the extrinsic and intrinsic scapular and brachial muscles.

METHODS

Gross dissections were performed in both thoracic limbs of four formaldehyde-fixed specimens.

RESULTS

Three rhomboideus muscles were present (capitis, cervicis, and thoracis). The trapezius muscle was divided into two parts (cervicis and thoracis). The pectoralis abdominalis and omotransversarius muscles were present. The anconeus muscle was found as an individual muscle or fused to the caput mediale of the triceps brachii muscle. The brachialis muscle had among one and two heads. The anconeus epitrochlearis was absent.

CONCLUSION

These muscles of Sapajus apella are adapted for arboreal locomotion and some terrestrial habits, since these have many similarities with other primates with a similar locomotor patterns.

Comparative analysis of origin and branches of phrenic nerve in the diaphragm of the crab-eating fox (Cerdocyon thous) and domestic dog (Canis lupus familiaris)

The crab-eating fox (Cerdocyon thous) is a canid widely distributed throughout South America, considered the only representative of the gender. There is a lack of information about anatomical aspects of the species, mainly regarded of nervous system anatomy. For clinical and surgical approaches of these animals, the domestic dog is adopted as anatomophysiological model. So, the aim of the present study was to analyse origin and branches of the phrenic nerve in the diaphragm of crab-eating fox compared to domestic dog. Four specimens of Cerdocyon thous and four of Canis lupus familiaris were used. The phrenic nerve originated from the ventral branches of the fifth (C5), sixth (C6) and seventh (C7) cervical spinal nerves. Phrenic nerves were distributed in the diaphragm as lumbocostal trunk and sternal branch (100%) in the crab-eating fox, and in costosternal trunk and lumbar branch (75%) and lumbocostal trunk and sternal branch (25%) in the domestic dog. In both species, the lumbar branch innervates the diaphragm pillars, the costal branch addresses all costal region, and the sternal branch distributes in the costal ventrolateral region and the sternal part of the diaphragm, to the left and to the right.

Comparative anatomy of the hind limb vessels of the bearded capuchins (Sapajus libidinosus) with apes, baboons, and Cebus capucinus: with comments on the vessels' role in bipedalism

Capuchin monkeys are known to exhibit sporadic bipedalism while performing specific tasks, such as cracking nuts. The bipedal posture and locomotion cause an increase in the metabolic cost and therefore increased blood supply to lower limbs is necessary. Here, we present a detailed anatomical description of the capuchin arteries and veins of the pelvic limb of Sapajus libidinosus in comparison with other primates. The arterial pattern of the bearded capuchin hind limb is more similar to other quadrupedal Cebus species. Similarities were also found to the pattern observed in the quadruped Papio, which is probably due to a comparable pelvis and the presence of the tail. Sapajus' traits show fewer similarities when compared to great apes and modern humans. Moreover, the bearded capuchin showed unique patterns for the femoral and the short saphenous veins. Although this species switches easily from quadrupedal to bipedal postures, our results indicate that the bearded capuchin has no specific or differential features that support extended bipedal posture and locomotion. Thus, the explanation for the behavioral differences found among capuchin genera probably includes other aspects of their physiology.