Erythrocytes and erythrocyte morphologies of healthy and colony-born owl monkeys (Aotus lemurinus griseimembra)

Inadequate availability of hematological reference data seriously restricts optimal utilization of the owl monkey (Aotus lemurinus griseimembra) as an experimental model. The current study investigated erythrocytic morphology in peripheral blood of healthy, colony-born owl monkeys. The blood of the subjects contained discoid erythrocytes, poikilocytes, and showed considerable anisocytosis. Also observed were nucleated erythrocytes, erythrocytes with Howell-Jolly bodies, and reticulocyte types I, II, and III. Heinz bodies were not detected.     

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.     

Urinary enzyme concentrations in the owl monkey (Aotus nancymae)

The activity of three urinary enzymes, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and N-acetyl-β-D-glucosaminidase (NAG), was evaluated in 71 adult owl monkeys. Fifty-six animals had normal renal function, while 15 had evidence of renal dysfunction. Urinary enzyme: urinary creatinine ratios (U_E:U_Cr) were also determined. The activity for NAG was similar to that of other species, while ALP and AST were higher. Regression analyses revealed that urinary enzymes and U_E:U_Cr were significantly correlated (P ≤ 0.0001) with indices of renal damage and could identify active renal disease.     

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.     

Population densities and geographic distribution of night monkeys (Aotus nancymai and Aotus vociferans) (cebidae: Primates) in Northeastern Peru

Population densities of two species of night (or owl) monkeys (Aotus nancymai and Aotus vociferans) were estimated using transect census methods. Densities of Aotus nancymai were approximately 46.3 individuals/km² in lowland forests and 24.2 individuals/km² in highland forests. For Aotus vociferans densities were 33.0 individuals/km² in lowland forests and 7.9 individuals/km² in highland forests. A. vociferans occurs north of the Río Amazonas-Marañon and A. nancymai south of it, except for the northern enclave between the Ríos Tigre and Pastaza. The two species are nowhere sympatric. However, the two known karyotypic forms of A. vociferans occupy the same habitats throughout the Peruvian range of the species.     

Restasis® for the treatment of 'dry eye' in Aotus nancymaae

Background  This case report describes the treatment of three male owl monkeys ( Aotus nancymaae ) diagnosed with chronic dry eye with a topical cyclosporine product, Restasis^®, approved for use in humans. These owl monkeys had ocular disease resulting from procedures performed at a biotechnology company. They were moved to the Center for Neotropical Primate Research and Resources at University of South Alabama to be incorporated into the breeding colony.
Materials and methods  Schirmer tear testing was performed initially and during the course of treatment to monitor efficacy of twice daily administered Restasis^®. The goals of treatment were to reduce pain and/or distress and if possible to quantitatively increase tear production.
Results and discussion  All animals had improvements in conjunctival inflammation and had an increase in tear production.     

Puberty in the male owl monkey (Aotus trivirgatus griseimembra): A study of physical and hormonal development

In the male owl monkey (Aotus trivirgatus),the onset of puberty occurs at between 211 and 337 days (median, 313) as indicated by longitudinal measurements of plasma testosterone in six subjects. Larger rises in plasma testosterone were observed between 300 and 400 days. Pubertal increases in body weight and testicular volume are not pronounced in this species. Young animals first entered the weight range for adult males (800–1080 g) when they were between 370 and 520 days of age (median, 472). Marked growth of the subcaudal scentmarking gland occurred during puberty. The first signs of development of this gland (stiffening and discoloration of overlying hairs) were noted between 282 and 370 days (median 316), and it had attained an adult structure by 336–442 days (median, 397). These changes were androgen dependent as indicated by the fact that treatment of a prepubertal male with testosterone stimulated the subcaudal gland to develop prematurely. Hormonal and physical changes during puberty were the same whether males remained with their parents or were caged alone. There was no indication that puberty was retarded in males which had remained in their natal groups.     

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.     

Characterising a Microsatellite for DRB Typing in Aotus vociferans and Aotus nancymaae (Platyrrhini)

Non-human primates belonging to the Aotus genus have been shown to be excellent experimental models for evaluating drugs and vaccine candidates against malaria and other human diseases. The immune system of this animal model must be characterised to assess whether the results obtained here can be extrapolated to humans. Class I and II major histocompatibility complex (MHC) proteins are amongst the most important molecules involved in response to pathogens; in spite of this, the techniques available for genotyping these molecules are usually expensive and/or time-consuming. Previous studies have reported MHC-DRB class II gene typing by microsatellite in Old World primates and humans, showing that such technique provides a fast, reliable and effective alternative to the commonly used ones. Based on this information, a microsatellite present in MHC-DRB intron 2 and its evolutionary patterns were identified in two Aotus species (A. vociferans and A. nancymaae), as well as its potential for genotyping class II MHC-DRB in these primates.     

Two new species of night monkeys,genus Aotus (Cebidae,platyrrhini): A preliminary report on Aotus taxonomy

The nine allopatric species of Aotus recognized represent two natural groups distinguished by karyotype, color, and pelage patterns. Correlated with these group characters are reported differences in serum proteins and degrees of susceptibility or immunity to experimental infection with malarial parasites. The primitive gray-neck species group of Aotus contains A. brumbacki (new species), A. lemurinus (with subspecies lemurinus and griseimembra), A. trivirgatus, and A. vociferans. The derived red-neck group contains A. nancymai (new species), A. miconax. A. infulatus, and A. azarae (with subspecies azarae and boliviensis). Only the two new species are described but a key to the species and subspecies gives the diagnostic characters of each. The gray-neck group occurs almost entirely north of the Amazon, the red-neck group almost entirely south. The distributional exceptions are enclave populations resulting from river bend cutoffs. Formation of an enclave population of A. nancymai is discussed and available information on the biology of this species is reported.     

Density estimates of Panamanian owl monkeys (Aotus zonalis) in three habitat types

The resolution of the ambiguity surrounding the taxonomy of Aotus means data on newly classified species are urgently needed for conservation efforts. We conducted a study on the Panamanian owl monkey (Aotus zonalis) between May and July 2008 at three localities in Chagres National Park, located east of the Panama Canal, using the line transect method to quantify abundance and distribution. Vegetation surveys were also conducted to provide a baseline quantification of the three habitat types. We observed 33 individuals within 16 groups in two out of the three sites. Population density was highest in Campo Chagres with 19.7 individuals/km² and intermediate densities of 14.3 individuals/km² were observed at Cerro Azul. In la Llana A. zonalis was not found to be present. The presence of A. zonalis in Chagres National Park, albeit at seemingly low abundance, is encouraging. A longer‐term study will be necessary to validate the further abundance estimates gained in this pilot study in order to make conservation policy decisions. Am. J. Primatol. 72:187–192, 2010. © 2009 Wiley‐Liss, Inc.     

Disappearances of individuals from social groups have implications for understanding natal dispersal in monogamous owl monkeys (Aotus azarai)

The socially monogamous owl monkeys (Aotus spp.) live in small groups of two to five individuals. We used monthly demographic data collected from 16 social groups between 1997-2001 to estimate the age of disappearance from their natal groups and the timing of those disappearances in a population of owl monkeys (Aotus azarai azarai) in Formosa, Argentina. We applied survival analysis techniques to 48 months of observations of 47 individuals to construct age-specific probabilities of disappearance. Two-thirds of the individuals (eight of 12), for which disappearance could be well timed, disappeared at around 2 years of age. The average age at disappearance for these individuals was 29 months (+/-8), whereas the mean age of disappearance obtained from the survival analysis of censored and uncensored data was almost 3 years (mean+/-SD, 35+/-3 months). Ninety-two percent of all disappearances of adult size individuals (11 of 12) occurred around the birth season. Our data suggest that at least some individuals disperse soon after sexual maturation while others remain for up to 4 years in their natal groups.     

Mated pairs of owl monkeys (Aotus nancymaae) exhibit sex differences in response to unfamiliar male and female conspecifics

In socially monogamous species, mate‐guarding could be a reproductive strategy that benefits both males and females, especially when males contribute to parental care. By actively guarding mates, males may reduce their chances of being cuckolded, whereas females that mate‐guard may reduce the likelihood that their mates will desert them or acquire additional mates, and hence limit or reduce paternal care of offspring. Owl monkeys (Aotus spp.) are socially monogamous with biparental care of young and, hence, potential beneficiaries of mate‐guarding. We presented mated pairs of captive owl monkeys (A. nancymaae) with unfamiliar male and female conspecifics, to determine if either member of the pair exhibits intraspecific aggression toward an intruder or stays close to its mate, behaviors indicative of mate‐guarding. Male mates were more responsible for the maintenance of close proximity between mates than females. Male mates also exhibited elevated levels of behavior that signify arousal when presented with a male conspecific. These responses by mated male owl monkeys are consistent with patterns that may help prevent cuckoldry. Am. J. Primatol. 72:942–950, 2010. © 2010 Wiley‐Liss, Inc.     

Determination of vertebral heart score in three species of Spider monkey (Ateles fusciceps,A. hybridus and A. paniscus)

Background

The vertebral heart score (VHS) is a method of evaluation of cardiac size well documented in domestic mammals and in other primate species, and the aim of this study was to determine the VHS in three species of Spider monkey.

Methods

In this retrospective study, right lateral radiographs of thirty clinically well animals were reviewed and VHS determined. The species included were Ateles fusciceps (n=17), Ateles hybridus (n=8) and Ateles paniscus (n=5).

Results

The VHS was found to vary between species and was 9.73±0.81 for A. fusciceps, 10.53±0.37 for A. hybridus and 10.45±0.27 for A. paniscus.

Conclusions

The observed values appear consistent with values determined for other primate species. There was statistically significant variation noted between species, and so VHS should be considered species‐specific in this genus. The values determined may be of benefit in objectively evaluating cardiac size in the species investigated.     

Total serum creatine kinase and isozyme concentrations in the owl monkey.

Serum samples from 62 owl monkeys were analyzed to determine concentrations of creatine kinase activity and isozymes. Fifty monkeys were determined to be clinically normal, while twelve had cardiac disease. Findings showed that the data had a non-normal distribution. Based on nonparametric tests, significant differences were not observed between sexes or animals with and without cardiac disease, indicating that CK activity and isozymes are not reliable indicators of myocardial disease in the owl monkey. Reference values presented are only intended as a guide. Each laboratory should determine its own reference values.     

A comparison of non-contact, subcutaneous, and rectal temperatures in captive owl monkeys (Aotus sp.)

BACKGROUND: Three methods of body temperature measurement were compared in owl monkeys: non-contact infrared thermometry, subcutaneous transponder, and rectal probe. METHODS: Forty owl monkeys (Aotus sp.) were used. Animals were implanted with subcutaneous microchip transponders. Infrared thermometry was used at three different sites. All measurements were taken and repeated randomly. RESULTS: Infrared and subcutaneous measurements did not agree well with rectal thermometry. Subcutaneous and rectal temperatures were highly repeatable, and subcutaneous temperatures were most agreeable to rectal temperatures. CONCLUSIONS: Further investigation is needed into subcutaneous implant sites and use of different infrared thermometers in this species.