Isolation and characterization of a new virus from owl monkeys: herpesvirus aotus type 3

Owl monkey kidney cell cultures yielded a viral agent 32 days after initiation of the culture. The virus was identified as a herpesvirus by physico-chemical, cultural, and morphological features. Serologically this herpesvirus was found to be unrelated to other members of this family, as well as to Herpesvirus aotus type 1 and 2. Based on these findings the name Herpesvirus aotus type 3 is suggested for this herpesvirus.     

Serum electrophoretic patterns of karyotypically defined owl monkeys (Aotus trivirgatus).

Sera were electrophoretically separated and examined from 238 karyotyped Aotus trivirgatus and 29 unkaryotyped offspring. Albumin polymorphism was observed with high frequency and found to conform to a codominant allele mode of transmission. A unique alpha globulin was identified in Karyotypes I, VII and unkaryotyped offspring, of which one parent was a Karyotype I. This alpha globulin phenotype appears to be a dominant characteristic.     

Eosinophilic myelocytoma in an owl monkey (Aotus trivirgatus)

A mass found in the anterior mediastinum at necropsy of an adult female owl monkey (Aotus trivirgatus) was morphologically consistent with an eosinophilic myelocytoma. Lymph nodes, kidneys, bone marrow, and other tissues were diffusely infiltrated by neoplastic cells. Intracellular and extracellular Charcot-Leyden crystals were present in the neoplasm.     

Breeding the owl monkey (Aotus trivirgatus) in a laboratory environment.

A breeding colony of owl monkeys (Aotus trivirgatus) established in 1972 produced 35 live infants during the first 3 years from an average daily population of 30 monogamous pairs. Initial productivity was poor, but once the breeding pairs were set up by karyotypes, reproductive performance improved. No seasonal influence on births was observed and most births occurred during daylight hours. Uterine size during gestation ranged from about 1 cm in diameter at 30 days after conception to 7--8 cm (transverse diameter) x 18--20 cm (longitudinal diameter) at 115 days after conception. The fetal head was palpable at 85 days. A gestation period of 120-140 days was estimated from extrapolation of uterine palpation data and interbirth intervals. Vaginal swabs collected from six females during two separate 1-month periods did not consistently reveal estrous cycles. An analysis of owl monkey milk showed it to contain 88.2% water, 2.16% crude protein, 2.09% fat, 7.52% lactose, and 0.36% ash.     

Two new karyotypes in the Peruvian owl monkey (Aotus trivirgatus)

The observation of remarkable karyotypic variation in owl monkeys (Aotus trivirgatus) stimulated us to study the chromosomal evolution of this New World genus. As an extension of this project, we examined the chromosome complement of a “phenotype-B” Aotus population from Peru. In addition to karyotype V(2n = 46), two new karyotypes with diploid numbers of 47 and 48 were identified. A G-band comparison of these karyotypes indicated that the chromosome number polymorphism in these Peruvian owl monkeys resulted from a single fusion or fission event involving a single metacentric and two acrocentric chromosome pairs. This mechanism is also known to be responsible for the chromosome number polymorphism in at least two other populations of phenotype B Aotus, one from Colombia and the other from Panama.     

Cardiomyopathy in captive owl monkeys (Aotus nancymae)

Dilated cardiomyopathy (DCM) was identified histopathologically in a colony of owl monkeys (Aotus nancymae) over a 15-year period. We characterized the incidence of cardiac disease echocardiographically in the colony over a 14-month period. Of 77 monkeys, 21 had systolic myocardial failure, and postmortem examination confirmed the antemortem diagnosis of DCM in eight animals. Monkeys with a questionable diagnosis at the first examination demonstrated progression of disease with time. Left ventricular end-systolic cross-sectional area and left ventricular fractional area change were the indices that most reliably discriminated between normal and diseased animals. Serum cardiac troponin I concentrations were below detectable limits in normal and diseased monkeys. The apparent high prevalence of disease in this colony precluded establishment of reference intervals for Aotus nancymae. Our study provides the first comprehensive echocardiographic evaluation of owl monkeys with cardiomyopathy.     

Visual capacities of the owl monkey (Aotus trivirgatus): temporal contrast sensitivity.

Aotus monkeys were tested in a forced-choice discrimination task to determine their ability to discriminate sinusoidally flickering lights varying in temporal frequency and luminance contrast. Under conditions of moderate light adaptation this primate is maximally sensitive to lights flickering at 10 Hz while the highest frequency they can discriminate is about 42 Hz. At very low light levels (10(-5) ft L) maximum sensitivity is for 2.2--5 Hz flicker. The highest flicker rate that could be discriminated under these conditons was about 29 Hz. In comparison to humans tested in the same situation. Aotus monkeys show relatively lower sensitivity to temporal flicker under conditions of light adaptation but relatively higher sensitivity at very low light levels.     

Pregnancy diagnosis in owl monkeys (Aotus trivirgatus): evaluation of the hemagglutination inhibition test for urinary chorionic gonadotropin.

The Subhuman Primate Pregnancy Test was evaluated as a means of detecting urinary chorionic gonadotropin to aid in pregnancy diagnosis in owl monkeys. Using radioimmunoassay, the excretion pattern of chorionic gonadotropin from pregnant owl monekys was delineated, the hormone being detected from 16 weeks prepartum until birth. By comparison, the pregnancy test kit detected chorionic gonadotropin between the fourteenth week prepartum and the last week of gestation with 94% accuracy. In a 2-year study using a simplified urine collection technique, the Subhuman Primate Pregnancy Test was shown to be a valuable procedure for diagnosing pregnancy and detecting spontaneous abortions in owl monkeys.     

Karyotypic variation in susceptibility to hemolytic anemia and idiopathic eosinophilia of owl monkeys,Aotus trivirgatus

Hematologic data gathered over a period of 4.8 years from 196 owl monkeys,Aotus trivirgatus, were analyzed to find if karyotypic differences existed. It was found that none of 30 animals of karyotypes K-I and K-VI developed hemolytic anemia, whereas 46 of 99 animals of K-II, K-III and K-IV did (p<0.005). Analysis of hemograms of normal owl monkeys showed that mean percent eosinophils varied markedly, K-I monkeys having lowest counts, 3.2%, and K-VI animals having the highest, 33%. These results establish that idiopathic eosinophilia and hemolytic anemia in this species are probably unrelated but susceptibility to both has a strong genetic component.     

Mortality causes of owl monkeys (Aotus nancymae and Aotus vociferans) in captivity

To determine the main causes of death in "owl monkeys" (Aotus nancymae and A. vociferans) in captivity, 115 necropsies were performed. According to the macroscopic findings and clinical data, results are as follow: acute lobular pneumonia (25.2%), chronic nephropathy (10.4%), acute catarrhal enteritis (8.7%), acute hemorrhagic enteritis (7%), acute toxic hepatitis (5.2%), trauma (5.2%), and others.     

Crossed renal ectopia in a squirrel monkey (Saimiri sciureus) and an owl monkey (Aotus trivirgatus)

A 5-year-old female squirrel monkey, Saimiri sciureus, died with a ceco-colonic infarct. An incidental finding was renal ectopia: The left kidney was located between the common iliac arteries posterior to the bifurcation of the aorta and to the right of the body midline. An adult owl monkey, Aotus trivirgatus, was killed in renal failure due to end-stage glomerulonephritis. Fused kidneys were located on the right side and posterior to the normal position. These are examples of crossed renal ectopia with and without fusion.     

Thyroid activity in a hypometabolic primate, the owl monkey (Aotus trivirgatus).

Serum levels of triiodothyronine (T3) and tetraiodothyronine (T4) were significantly lower in owl monkeys than in long-tailed macaques. These observations were considered to be consistent with the lower metabolic rate of the owl monkey. However, the absence of a significant difference in the levels of thyroid stimulating hormone (TSH) between the two species suggested a lower thyroid sensitivity to TSH in the owl monkeys. There was an inverse relation between levels of T3 and TSH in the owl monkeys at night and during the day.     

Electromyography of the anterior temporalis and masseter muscles of owl monkeys (Aotus trivirgatus) and the function of the postorbital septum

Anthropoids and tarsiers are distinguished from all other vertebrates by the possession of a postorbital septum, which is formed by the frontal, alisphenoid, and zygomatic bones. Cartmill [(1980) In: Evolutionary Biology of the New World Monkeys and Continental Drift. New York: Plenum, p 243-274] suggested that the postorbital septum evolved in the stem lineage of tarsiers and anthropoids to insulate the eye from movements arising in the temporal fossa. Ross [(1996) Am J Phys Anthropol 91:305-324] suggested that the septum insulates the orbital contents from incursions by the line of action of the anterior temporal muscles caused by the unique combination of high degrees of orbital frontation and convergence. Both of these hypotheses must explain why insulation of the orbital contents could not be achieved by decreasing the size of the anterior temporal musculature with a corresponding increase in size of the remaining jaw adductors, rather than evolving a postorbital septum. One possibility is that the anterior temporalis is an important contributor to vertically directed bite forces during all biting and chewing activities. Another possibility is that reduction in anterior temporal musculature would compromise the ability to produce powerful bite forces, either at the incisors or along the postcanine toothrow. To evaluate these hypotheses, electromyographic (EMG) recordings were made from the masseter muscle and the anterior and posterior portions of the temporalis muscles of two owl monkeys, Aotus trivirgatus. The EMG data indicate that anterior temporalis activity relative to that of the superficial masseter is lower during incision than mastication. In addition, activity of the anterior temporalis is not consistently higher than the posterior temporalis during incision. The data indicate relatively greater activity of anterior temporalis compared to other muscles during isometric biting on the postcanine toothrow. This may be due to decreased activity in superficial masseter and posterior temporalis, rather than elevated anterior temporalis activity. The anterior temporalis is not consistently less variable in activity than the superficial masseter and posterior temporalis. The EMG data gathered here indicate no reason for suggesting that the anterior temporal muscles in anthropoids are utilized especially for incisal preparation of hard fruits. Maintenance of relatively high EMG activity in anterior temporalis across a wide range of biting behaviors is to be expected in a vertically oriented and rostrally positioned muscle such as this because, compared to the posterior temporalis, superficial masseter and medial pterygoid, it can contribute relatively larger vertical components of force to bites along the postcanine toothrow. The in vivo data do not support this hypothesis, possibly because of effects of bite point and bite force orientation.