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Coevolution between signalers and receivers has played a significant role in the diversity of animal signals and sensory systems. Platyrrhines (monkeys in the Americas) exhibit a remarkable color vision polymorphism that may have been selected by both natural and sexual selection, but sociosexual color signaling among platyrrhines has received almost no attention. Here, we study the color of reproductive skin among different reproductive classes in free‐ranging female saddleback (Leontocebus weddelli) and emperor (Saguinus imperator) tamarins, modeling color spaces, and contrasts for the different visual systems. We find that the chromatic saturation and luminance of genital color vary between reproductive classes in saddleback tamarins. Chromatic contrast between the vulva and belly is lower in the parous females (PFs) relative to adult but not currently breeding females, while achromatic contrast is higher in PFs in saddleback tamarins relative to nonparous females. However, in emperor tamarins, genital color (saturation, hue, and luminance) does not vary between reproductive classes. Overall, genital skin color variation is present in tamarins and may play a role in sexual signaling. Nevertheless, the patterns are inconsistent between species, suggesting interspecific variation. Future studies should integrate the perceiver's behavioral responses and the physical and social signaling environments into comprehensive studies of communication as well as consider the role and interaction between multiple sensory modalities. Research Highlights: Genital color (saturation and luminance) varies between reproductive classes in saddleback tamarins. Chromatic contrast between the vulva and belly is higher in nonparous females, while achromatic contrast is higher in parous females.Genital color (saturation, hue, and luminance) does not vary between reproductive classes in female emperor tamarins.Overall, genital skin color variation is present in tamarins and may play a role in sexual signaling. However, the patterns are inconsistent between species, suggesting interspecific variation. [ABSTRACT FROM AUTHOR]

Background: Acanthocephalosis is an important cause of death in captive New World primates (NWP). Once established in a colony, it is extremely difficult to treat and control, quickly spreading among NWP with a high mortality rate. This study aimed to characterize the disease associated with infection with acanthocephalans according to its epidemiological, clinical, and anatomopathological aspects in a captive NWP population. Methods: From 2010 to 2020, a Brazilian zoo had recurrent deaths of NWP associated to acanthocephalan parasitism. Clinical and pathological profiles of these animals were analyzed considering the host species, sex, age, weight, clinical signs, therapeutic protocols, and pathological findings. Results: A total of 27 deaths associated with acanthocephalosis were recorded, all lethal cases affected tamarins and lion tamarins, corresponding to 67.5% of total deaths during the course of this study. Ten animals died with no previously detected clinical signs, whereas cases with noticeable clinical signs often had apathy and progressive weight loss, resulting in cachexia. Symptomatic NWP were treated with anthelmintic protocols, antibiotics, and support therapy. However, all hospitalized animals died and had grossly detectable adult acanthocephalans in the intestinal lumen that were identified as Prosthenorchis sp., which were associated with transmural and ulcerative enteritis. Conclusions: This report revealed the impact of acanthocephalosis in a naturally infected captive colony of NWP, particularly affecting tamarins (Saguinus spp.) and lion tamarins (Leontopithecus spp.), with failed treatment and control strategies. [ABSTRACT FROM AUTHOR]

In nearly four decades our research and that of others on chemical signaling in callitrichid primates suggest a high degree of contextual complexity in both the use of signals and the response to these signals. We describe our research including observational field studies, behavioral bioassays ("playbacks"), functional imaging, and conditioning studies. Scent marking in both captivity and the wild is used for more than just territorial marking. Social contextual effects are seen in responses by subordinate females responding with ovulatory inhibition only to chemical signals from familiar dominant reproductive females. Males detect ovulation through changes in scent marks. Males responded behaviorally and hormonally to chemical signals of novel ovulating females as a function of their reproductive status (fathers, males paired with a female but not fathers, and single males). Multiple brain areas are activated in males by female chemical signals of ovulation including areas relating to memory, evaluation, and motivation. Furthermore, males can be conditioned to respond sexually to a nonsexual odor demonstrating that learning plays an important role in response to chemical signals. Male androgen and estrone levels changed significantly in response to infant chemical signals as a function of whether the males were fathers or not, whether the odors were from their own versus other infants, as well as the infant's stage of development. Chemical signals in callitrichids are providing a rich source of understanding the context and function of the chemical sensory system and its stimulation of neural, behavioral, and hormonal actions in the recipients. Highlights: We review our research for the experimental study of chemical signals in callitrichid monkeys.Chemical signals in callitrichids are contextually complex, influenced by social and reproductive contexts.Ovulatory scents activate many brain areas in male marmosets.Marmosets can be sexually conditioned to respond to arbitrary odors showing the importance of learning. [ABSTRACT FROM AUTHOR]

Background: The classification of Saguinus ursulus as a new taxon and the vulnerability of this species highlighted the need for data on its specific morphophysiological attributes. This study used ultrasound to determine the typical characteristics of pelvic‐abdominal structures and organs. Methods: Nine healthy primates of the species S. ursulus were evaluated, through ultrasound tests, to determine the morphometry of the organs of the pelvic‐abdominal cavity and the levels of ovarian activity. Results: Topography, morphology, and biometrics of the organs were described. It was observed that organs of S. ursulus are similar to those of other Neotropical primate species. However, the kidney morphology is different,the left is triangular and the right is elliptical, while the gallbladder is bilobed. Conclusion: Ultrasonography has proven to be efficient and effective for organ evaluation. The ultrasound findings are a first step toward understanding the physiology of a less‐known species. [ABSTRACT FROM AUTHOR]

Tamarins are a distinct group of small sized New World monkeys with complex phylogenetic relationships and poorly studied cytogenetic traits. In this study, we applied molecular cytogenetic analyses by fluorescence in situ hybridization with probes specific for telomeric sequences and ribosomal DNA loci after DAPI/CMA3 staining on metaphases from five tamarin species, namely Leontocebus fuscicollis, Leontopithecus rosalia, Saguinus geoffroyi, Saguinus mystax and Saguinus oedipus, with the aim to investigate the distribution of repetitive sequences and their possible role in genome evolution. Our analyses revealed that all five examined species show similar karyotypes, 2n = 46, which differ mainly in the morphology of chromosome pairs 16–17 and 19–22, due to the diverse distribution of rDNA loci, the amplification of telomeric-like sequences, the presence of heterochromatic blocks and/or putative chromosomal rearrangements, such as inversions. The differences in cytogenetic traits between species of tamarins are discussed in a comparative phylogenetic framework, and in addition to data from previous studies, we underline synapomorphies and apomorphisms that appeared during the diversification of this group of New World monkeys.

Seed dispersal distance (SDD) critically influences the survival of seedlings, spatial patterns of genetic diversity within plant populations, and gene flow among plant populations. In animal‐dispersed species, foraging behavior and movement patterns determine SDD. Direct observations of seed dispersal events by animals in natural plant populations are mostly constrained by the high mobility and low visibility of seed dispersers. Therefore, diverse alternative methods are used to estimate seed dispersal distance, but direct comparisons of these approaches within the same seed dispersal system are mostly missing.We investigated two plant species with different life history traits, Leonia cymosa and Parkia panurensis, exclusively dispersed by two tamarin species, Saguinus mystax and Leontocebus nigrifrons. We compared SDD estimates obtained from direct observations, genetic identification of mother plants from seed coats, parentage analysis of seedlings/saplings, and phenomenological and mechanistic modeling approaches.SDD derived from the different methods ranged between 158 and 201 m for P. panurensis and between 178 and 318 m for L. cymosa. In P. panurensis, the modeling approaches resulted in moderately higher estimates than observations and genotyping of seed coats. In L. cymosa, parentage analysis resulted in a lower estimate than all other methods. Overall, SDD estimates for P. panurensis (179 ± 16 m; mean ± SD) were significantly lower than for L. cymosa (266 ± 59 m; mean ± SD).Differences among methods were related to processes of the seed dispersal loop integrated by the respective methods (e.g., seed deposition or seedling distribution). We discuss the merits and limitations of each method and highlight the aspects to be considered when comparing SDD derived from different methodologies. Differences among plant species were related to differences in reproductive traits influencing gut passage time and feeding behavior, highlighting the importance of plant traits on animal‐mediated seed dispersal distance. [ABSTRACT FROM AUTHOR]

Efforts to reverse the decline of endangered golden lion tamarin monkeys have been relatively successful because the Brazilian organization dedicated to the species’ conservation (Associação Mico-Leão-Dourado, AMLD) relies on science-based computer modeling to determine the number of tamarins necessary to achieve demographic and genetic goals, and a process of strategic planning to achieve those goals. Accurate estimates of the numbers of tamarins in forest fragments are essential to evaluate progress in achieving goals and adapt strategies as necessary. In this report we present the results of a new method to survey the number of tamarins in the wild, a modification of the point transect with lures procedure. Using this method, we estimate that in 2014 there were approximately 3,700 golden lion tamarins in 41,400 hectares of Atlantic Forest. Of these, 59% are from remnant wild populations, 34% are descendants of captive-born reintroduced animals and 7% are descendants of wild translocated groups. The number of tamarins and amount of forest estimated in this survey exceeded values necessary to meet AMLD’s definition of a viable population, determined to be 2,000 tamarins in 25,000 hectares of connected and protected forest. However, the seven forest blocks and their tamarin populations are not yet adequately connected and protected. AMLD’s strategic plan to achieve a viable population of golden lion tamarins includes 12 strategies that mitigate these and other threats or contribute directly to the conservation goal. The point transect with lures survey method provides a way to evaluate progress in achieving that goal and adapt strategies as appropriate. [ABSTRACT FROM AUTHOR]

The white‐footed tamarin (Saguinus leucopus) is an endangered endemic primate of Colombia, mainly due to the deforestation of its habitat and illegal trade, which generates a high incidence of these animals in wildlife care centres. Musculoskeletal system disorders in S. leucopus are one of the most common diseases and therefore the aim of this study was to contribute to the morphologic studies with a morphometric, anatomic and radiographic description of the scapula in this species to provide a basis for medical interventions, surgical approaches, radiologic diagnoses and comparative functions of this bone. Gross dissections of each scapular region were made in eight specimens without a diagnosis of osteomuscular disease. These specimens died from natural cases in the wildlife care centres of the Corporación Autónoma Regional de Caldas (CORPORCALDAS); after necropsy their carcasses were fixed with 10% formaldehyde, 5% mineral oil and 1% phenic acid in these centres over the course of at least 1 week. X‐rays of the scapula were taken in the small animal clinic of the Universidad del Tolima, and morphometric data of the scapulae were obtained with a digital calliper. The scapula of the white‐footed tamarin was a flat triangular bone with a deep scapular notch in its cranial margin, where there was a cranial transverse scapular ligament that was absent in two specimens. The coracoid process was highly developed, medially covering the humeral joint. The dorsal margin was covered by the scapular cartilage, which was highly developed in the caudal angle. In the dorsal fourth of the caudal margin, there was a surface from which the m. teres major originated. The lateral surface had a scapular spine with a long hamatus process of the acromion until the lateral part of the humeral joint. The infraspinatus fossa was wider than the supraspinous fossa. On the costal surface, the subscapular fossa was formed by three subscapular lines and one subscapular ridge, the latter helping to form the surface for the m. teres major. In the two radiographic views, caudocranial to the scapula and dorsoventral to the thorax, the scapular spine, acromion, coracoid process, scapular incisura, supraglenoid tubercle, caudal margin, subscapular ridge, and the joints with the clavicle and the humerus could be observed. The scapula of the white‐footed tamarin presented bony reliefs that share characteristics with other primates but also with domestic mammals due to its quadrupedal locomotion, which allowed us to correlate its morphologic adaptation with its quadrupedal arboreal displacement. [ABSTRACT FROM AUTHOR]

Incomplete reproductive isolation and hybridization is relatively frequent in primates. However, no cases of hybridization between formally recognized species have been reported in tamarins (genus Saguinus), a highly specious group of Neotropical primates. Here, we provide evidence from different sources to demonstrate three cases of hybridization in captivity between species of Saguinus distributed west of the Andes (trans-Andean). To do this, we described fur color patterns, genotyped 12 microsatellite loci, sequenced the mitochondrial hypervariable region I, and generated chromosomal R bands for the three formally recognized species and the new hybrids of trans-Andean tamarins. We identified one case of interbreeding between the white-footed tamarin (Saguinus leucopus) and the cotton-top tamarin (S. œdipus) and two independent reciprocal crosses of S. leucopus and the Geoffroy's tamarin (S. geoffroyi). All these hybrids exhibit intermediate phenotypes between parental species, and genetic data are consistent with first-generation hybridization. Cytogenetic data suggest that the S. leucopus × S. œdipus hybrid is sterile, as it is a female with XY karyotype apparently affected by a condition known as gonadal dysgenesis. Trans-Andean tamarin species occur in northwest Colombia with parapatric distributions bounded by major rivers. Potential contact zones, either natural or anthropogenic, might facilitate hybridization in the wild, but this scenario remains to be assessed. Our findings warrant future studies focused on the evolutionary mechanisms of reproductive isolation in tamarins. Given the risk of hybridization, caution should be taken in management and conservation of tamarins. [ABSTRACT FROM AUTHOR]

The gross anatomy of the palmaris longus muscle in 12 specimens of Saguinus leucopus was studied by dissection. This muscle was constant and unipennate, originated in the medial epicondyle of the humerus; inserted onto flexor retinaculum and palmar aponeurosis; and innerved by the median nerve, and in one case, together with the ulnar nerve. This is the first report of double innervation for this muscle in primates. [ABSTRACT FROM AUTHOR]

Highlights • Coding of common behaviours represents reliable method of personality assessment. • Behaviour coding is not necessarily time-consuming personality assessment method. • Five observational hours per individual were sufficient for personality evaluation. • Two personality components were described for cotton-top tamarins. Abstract Individual variation in behaviour has been shown to have important ecological and evolutionary consequences. Research on animal personality has therefore received considerable attention, yet some methodological issues remain unresolved. We tested whether assessing personality by coding common behaviours is as time-consuming method as some researchers believe it to be. Altogether, 300 hours of observation were collected on 20 captive cotton-top tamarins (Saguinus oedipus). We first examined the repeatability of behavioural indices that represented the behavioural repertoire of cotton-top tamarins. We then compared the personality structures, based on different lengths of observation time, of these behavioural indices. The minimum observational time necessary to obtain a stable personality structure was 5 to 7 hours per individual. This stable structure included two components: Extraversion and Confidence, which were similar to those described in great apes, Old World monkeys, and other New World monkeys. Our findings suggest that, at least in the case of cotton-top tamarins, behavioural coding over relatively short periods of time can be used to assess personality and that longer observation periods may yield diminishing returns. [ABSTRACT FROM AUTHOR]

Primate long calls are high-amplitude vocalizations that can be critical in maintaining intragroup contact and intergroup spacing, and can encode abundant information about a call's producer, such as age, sex, and individual identity. Long calls of the wild emperor (Saguinus imperator) and saddleback (Leontocebus weddelli) tamarins were tested for these identity signals using artificial neural networks, machine-learning models that reduce subjectivity in vocalization classification. To assess whether modelling could be streamlined by using only factors which were responsible for the majority of variation within networks, each series of networks was re-trained after implementing two methods of feature selection. First, networks were trained and run using only the subset of variables whose weights accounted for ≥50% of each original network's variation, as identified by the networks themselves. In the second, only variables implemented by decision trees in predicting outcomes were used. Networks predicted dependent variables above chance (≥58.7% for sex, ≥69.2 for age class, and ≥38.8% for seven to eight individuals), but classification accuracy was not markedly improved by feature selection. Findings are discussed with regard to implications for future studies on identity signaling in vocalizations and streamlining of data analysis. [ABSTRACT FROM AUTHOR]

There is an increased interest in potential zoonotic malarias. To date, Plasmodium malariae that infects humans remains indistinguishable from Plasmodium brasilianum, which is widespread among New World primates. Distributed throughout tropical Central and South America, the Callitrichidae are small arboreal primates in which detection of natural Plasmodium infection has been extremely rare. Most prior screening efforts have been limited to small samples, the use of low-probability detection methods, or both. Rarely have screening efforts implemented a longitudinal sampling design. Through an annual mark-recapture program of two sympatric callitrichids, the emperor (Saguinus imperator) and saddleback (Saguinus fuscicollis) tamarins, whole blood samples were screened for Plasmodium by microscopy and nested PCR of the cytochrome b gene across four consecutive years (2012–2015). Following the first field season, approximately 50% of the samples collected each subsequent year were from recaptured individuals. In particular, out of 245 samples from 129 individuals, 11 samples from 6 individuals were positive for Plasmodium, and all but one of these infections was found in S. imperator. Importantly, the cytochrome b sequences were 100% identical to former isolates of P. malariae from humans and P. brasilianum from Saimiri sp. Chronic infections were detected as evidenced by repeated infections (7) from two individuals across the 4-year study period. Furthermore, 4 of the 5 infected emperor tamarins were part of a single group spanning the entire study period. Overall, the low prevalence reported here is consistent with previous findings. This study identifies two new natural hosts for P. brasilianum and provides evidence in support of chronic infections in wildlife populations. Given that callitrichids are often found in mixed-species associations with other primates and can be resilient to human-disturbed environments, they could contribute to the maintenance of P. malariae populations if future work provides entomological and epidemiological evidence indicating human zoonotic infections. [ABSTRACT FROM AUTHOR]

The study of animal sound signals can be useful in assisting conservation strategies. Understanding the vocal repertoires of endangered species and the behavioral contexts in which they are given is relevant for monitoring protocols, such as those based on automated sound recordings. The pied tamarin ( Saguinus bicolor) is at risk of extinction because of deforestation and urban growth in its restricted geographic range. Between 2012 and 2015 we studied the vocal repertoire of the species and the contexts in which different signals are emitted. We made focal recordings of eight free-living groups, two rescued individuals, and one temporarily captive group of pied tamarins in Manaus, central Brazilian Amazonia. From the 766 sounds analyzed we identified 12 distinct signals within the range of 2-11 kHz. Most signals were emitted during resting or locomotion. Less frequently emitted signals were associated with intergroup agonistic interactions, foraging, and infant-exclusive vocalizations. These results increased the known vocal repertoire of the pied tamarin providing more reliable baseline data for monitoring the species by means of automated or focal sound recordings. [ABSTRACT FROM AUTHOR]

The lack of appropriate stimuli associated with captive environments has been documented to cause several behavioural and physiological issues in captive species, including loss of natural behaviours, psychopathologies and decreased reproductive success. Providing free-ranging, naturalistic exhibits that replicate elements of a species’ natural environment is advocated as a means of promoting and preserving the natural behavioural repertoire in captive species. Exhibition of natural behaviour is considered beneficial to conservation in terms of animal health and welfare, reintroduction success, education and research. This study assessed differences in behaviour of emperor and pied tamarins housed in free-ranging and caged exhibits at Durrell Wildlife Park to determine the impact of exhibit type. Free-ranging tamarins were expected to exhibit a repertoire of behaviours more similar to that of wild tamarins based on their access to a more naturalistic and complex environment. Data was collected on a variety of behaviours, including activity, substrate use and communication, using instantaneous and one-zero sampling at 30 s intervals. Findings indicated that both free-ranging and caged tamarins exhibited natural behaviours; however, there were significant differences in mean rates of behaviours between conditions. Free-ranging tamarins exhibited significantly higher rates of locomotion (emperors: P < 0.001; pieds: P < 0.001), long calls (pieds: P = 0.019) and alarm calls (emperors: P = 0.012), and displayed competent use of the environment in terms of natural substrate use (emperors: P < 0.001; pieds: P = 0.007) and interspecific interactions. Caged tamarins exhibited significantly higher rates of affiliative (emperors: P = 0.001; pieds: P = 0.026) and agonistic (emperors: P = 0.003) intraspecific interactions and time spent in contact (emperors: P = 0.048; pieds: P = 0.043), which was largely attributed to spatial restrictions imposed by caged exhibits. This study, consistent with existing literature, indicated that the free-ranging exhibit was conducive to the expression of a behavioural repertoire more similar to that of wild tamarins. This was probably a result of the increased behavioural opportunities available in the free-ranging exhibit, highlighting their importance in promoting wild-type behaviours. However, some mean rates of behaviour were still noticeably less than those documented in wild counterparts. Methods to further promote natural behaviours in both exhibits are recommended to facilitate ex situ and in situ conservation efforts. [ABSTRACT FROM AUTHOR]

Since Darwin (), scientists have been puzzled by how behaviors that impose fitness costs on helpers while benefiting their competitors could evolve through natural selection. Hamilton's () theory of inclusive fitness provided an explanation by showing how cooperative behaviors could be adaptive if directed at closely related kin. Recent studies, however, have begun to question whether kin selection is sufficient to explain cooperative behavior in some species (Bergmüller, Johnstone, Russell, & Bshary, ). Many researchers have instead emphasized the importance of direct fitness benefits for helpers in the evolution of cooperative breeding systems. Furthermore, individuals can vary in who, when, and how much they help, and the factors that affect this variation are poorly understood (Cockburn, ; Heinsohn, ). Cooperative breeders thus provide excellent models for the study of evolutionary theories of cooperation and conflict (Cant, ). [ABSTRACT FROM AUTHOR]

Numerous animals have declining populations due to habitat loss, illegal wildlife trade, and climate change. The cotton-top tamarin (Saguinus oedipus) is a Critically Endangered primate species, endemic to northwest Colombia, threatened by deforestation and illegal trade. In order to assess the current state of this species, we analyzed changes in the population of cotton-top tamarins and its habitat from 2005 to 2012. We used a tailor-made “lure strip transect” method to survey 43 accessible forest parcels that represent 30% of the species’ range. Estimated population size in the surveyed region was approximately 2,050 in 2005 and 1,900 in 2012, with a coefficient of variation of approximately 10%. The estimated population change between surveys was -7% (a decline of approximately 1.3% per year) suggesting a relatively stable population. If densities of inaccessible forest parcels are similar to those of surveyed samples, the estimated population of cotton-top tamarins in the wild in 2012 was 6,946 individuals. We also recorded little change in the amount of suitable habitat for cotton-top tamarins between sample periods: in 2005, 18% of surveyed forest was preferred habitat for cotton-top tamarins, while in 2012, 17% percent was preferred. We attribute the relatively stable population of this Critically Endangered species to increased conservation efforts of Proyecto Tití, conservation NGOs, and the Colombian government. Due to continued threats to cotton-top tamarins and their habitat such as agriculture and urban expansion, ongoing conservation efforts are needed to ensure the long-term survival of cotton-top tamarins in Colombia. [ABSTRACT FROM AUTHOR]

Among primates, the Neotropical Callitrichid monkeys (tamarins and marmosets) exhibit a particular ability to adapt to disturbed and urbanized environments. However, little is known about physiological and health status in contrasting ecological contexts. An example of adaptation to urban environments is the white-footed tamarin ( Saguinus leucopus), an endangered species endemic to the central Andes in North West Colombia. This species was used as a model to contrast physical condition, physiological parameters and the parasite community of wild populations in rural and urban settings. Overall, the tamarins seemed to be in good body condition in both environments; however, urban tamarins exhibited overweight, elevated body mass, and higher cholesterol levels, while rural tamarins showed larger diversity and prevalence of parasites. Variation in several hematological parameters associated with altitude was also observed. Our data provide preliminary evidence of differential physiological responses to urban and rural environments in tamarins. These results may be attributed to nutritional factors, physical activity, and specific parasite-host ecological interactions in these two environments. Also, abundance and diversity of the parasite community in urban environments may be potentially constrained by habitat fragmentation and relatively fewer reservoirs. Finally, significant physiological and ecological disparities between white-footed tamarins occurring in urban and rural habitats as well as physiological response to hypoxia at higher altitudes were evidenced here. This study provides important preliminary information that will be useful to determine the ability of New World primate populations to cope with urban development and rapidly changing environments. [ABSTRACT FROM AUTHOR]

Twelve generic names have been ascribed to the New World tamarins but all are currently placed in just one: Saguinus Hoffmannsegg, 1807. Based on geographical distributions, morphology, and pelage patterns and coloration, they have been divided into six species groups: (1) nigricollis, (2) mystax, (3) midas, (4) inustus, (5) bicolor and (6) oedipus. Molecular phylogenetic studies have validated five of these groups; each are distinct clades. Saguinus inustus is embedded in the mystax group. Genetic studies show that tamarins are sister to all other callitrichids, diverging 15−13 Ma. The small-bodied nigricollis group diverged from the remaining, larger tamarins 11−8 Ma, and the mystax group diverged 7−6 Ma; these radiations are older than those of the marmosets ( Callithrix, Cebuella, Mico), which began to diversify 6−5 Ma. The oedipus group diverged from the midas and bicolor groups 5−4 Ma. We review recent taxonomic changes and summarize the history of the generic names. Taking into account the Late Miocene divergence time (11−8 Ma) between the large- and small-bodied tamarin lineages, the small size of the nigricollis group species when compared with other tamarins, and the sympatry of the nigricollis group species with the larger mystax group species, we argue that the nigricollis group be recognized as a distinct genus: Leontocebus Wagner, 1839. [ABSTRACT FROM AUTHOR]

Inequity aversion has been proposed to act as a limiting factor for cooperation, thus preventing subjects from disadvantageous cooperative interactions. While a recent study revealed that also dogs show some sensitivity to inequity, the underlying mechanisms of this behaviour are still unclear. The aim of the current study was threefold: 1) to replicate the study by Range et al. (2009, PNAS, 106, 340–345); 2) to investigate the emotional mechanisms involved in the inequity response by measuring the heart rate and 3) to explore the link between inequity aversion and cooperation in terms of behaviours shown towards the partner dog and towards the experimenter who caused the inequity. Dog tested in dyads were alternately asked to give their paw and were either equally or unequally rewarded by the experimenter. After each social test condition, we conducted food tolerance tests and free interaction tests in which the subjects’ social behaviour towards the partner and the experimenter were observed. As in the previous study, subjects refused to continue giving their paw when only the partner was rewarded, but not when both dogs were rewarded with rewards of different quality. Although subjects did not react to this quality inequity during the test, we did find reduced durations of food sharing in the subsequent tolerance test, indicating that dogs perceived the inequity but were not able to react to it in the test context. Moreover, subjects avoided their partner and the experimenter more during the free interaction time following unequal compared to equal treatment. Despite the clear behavioural reactions to inequity, we could not detect any changes in heart rate. Results suggest that inequity aversion might in fact be mediated by simple emotional mechanisms: sharing a negative experience, like inequity, might reduce future cooperation by decreasing the likelihood of proximity being maintained between partners. [ABSTRACT FROM AUTHOR]

Non-human primates housed in zoos and laboratories often exhibit reduced activity and this poses welfare concerns. We examined the effects of enclosure types of differing size and environmental complexity on the activities of two species of callitrichids. We found that cotton-top tamarins housed in an enclosure of larger size and more environmental complexity showed higher activity levels, which was mainly contributed by more feeding/foraging activity. By contrast, Goeldi’s monkeys housed in an enclosure of larger size and more environmental complexity showed lower activity levels, which was mainly contributed by less locomotory activity. In both species, off-exhibit groups housed in smaller enclosures did not show significantly less locomotory activity which would have been expected, as larger availability spaces should allow more opportunities for locomotion. Furthermore, the feeding enrichment had significant effects on increased feeding/foraging activity for both cotton-top tamarins and Goeldi’s monkeys, irrespective of enclosure type. These results suggested that environmental complexity (or application of feeding enrichment) that provided more opportunities for natural foraging could have a larger effect on overall activity levels compared with larger enclosure sizes that should provide more locomotion opportunities. More importantly, it showed that even when enclosure space and complexity were limited, increased opportunities for foraging through the application of enrichment could increase species-typical behaviours. Such inexpensive, easy to implement enrichment methods should be applied to provide more complex environments for captive non-human primates, particularly in situations where there are logistical and/or cost constraints to the modification of physical exhibits. [ABSTRACT FROM AUTHOR]

Tamarins are reported to live in small multimale-multifemale groups characterized by a single breeding female. Here we present information on the composition and genetic relatedness of individuals in 12 wild-trapped groups of Weddell's saddleback tamarins ( Saguinus weddelli) from northern Bolivia to determine if groups are best described as nuclear or extended families suggesting social monogamy or whether groups contain several unrelated same sex adults indicative of social polyandry/polygyny. Mean group size was 6.25 including an average of 2.16 adult males (range 1-4) and 2.08 adult females (1-3). No group contained only one adult male and one adult female and 25% of groups contained two parous females. We estimated the genetic relatedness among individuals using 13 polymorphic microsatellite markers. Across the population, mean relatedness was low and not significantly different among adult males versus among adult females, suggesting that both sexes disperse from their natal groups. Adults of both sexes also tended to have close same-sex adult relatives within their groups; relatedness among adult females of the same group averaged 0.31 and among adult males was 0.26. This suggests that tamarins of one or both sexes sometimes delay dispersal and remain as adults in their natal group or that emigration of same-sexed relatives into the same group may be common. Finally, parentage analyses indicated that, whereas the parents of juveniles generally were present in the group, this was not always the case. Based on these data, published reports of the presence of multiple breeding males and occasionally multiple breeding females in the same group, and the fact that less than 10% of groups in the wild contain a single adult male-adult female pair, we argue that social polyandry best characterizes the composition of tamarin groups and that monogamy is not a common mating pattern in Saguinus weddelli or other tamarin species. Am. J. Primatol. 78:298-314, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This paper is the introduction to a special issue on ''Monogamy' in Primates: Variability, Trends, and Synthesis.' The term 'monogamy' has undergone redefinition over the years, and is now generally understood to refer to certain social characteristics rather than to genetic monogamy. However, even the term 'social monogamy' is used loosely to refer to species which exhibit a spectrum of social structures, mating patterns, and breeding systems. Papers in this volume address key issues including whether or not our definitions of monogamy should change in order to better represent the social and mating behaviors that characterize wild primates; whether or not primate groups traditionally considered monogamous are actually so (by any definition); ways in which captive studies can contribute to our understanding of monogamy; and what selective pressures might have driven the evolution of monogamous and non-monogamous single female breeding systems. Am. J. Primatol. 78:283-287, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Many threatened species rely on ecotourism for conservation funding, but simultaneously suffer direct ecological impacts from ecotourism. For a range of IUCN-Redlisted terrestrial and marine bird and mammal species worldwide, we use population viability analyses to calculate the net effects of ecotourism on expected time to extinction, in the presence of other anthropogenic threats such as poaching, primary industries and habitat loss. Species for which these calculations are currently possible, for one or more subpopulations, include: orangutan, hoolock gibbon, golden lion tamarin, cheetah, African wild dog, New Zealand sealion, great green macaw, Egyptian vulture, and African penguin. For some but not all of these species, tourism can extend expected survival time, i.e., benefits outweigh impacts. Precise outcomes depend strongly on population parameters and starting sizes, predation, and ecotourism scale and mechanisms. Tourism does not currently overcome other major conservation threats associated with natural resource extractive industries. Similar calculations for other threatened species are currently limited by lack of basic population data. [ABSTRACT FROM AUTHOR]

The western black tamarin, Saguinus niger, is an endemic Brazilian primate currently classified as Vulnerable by the Brazilian environmental authorities. In this paper, we report two new records from an Amazonia-Cerrado ecotone that extend the range of the species further south to the Brazilian state of Mato Grosso. Additionally, we obtained an ecological niche model (ENM) for S. niger using eight climatic variables. The results of the ENM analysis suggest that the species is strongly associated with lowland areas where the temperature does not vary significantly among seasons. We also point out that the Araguaia, Tapirapé, and Comandante Fontoura rivers may act, along with open Cerrado formations and more seasonal climate, as southern barriers. The absence of protected areas in the southern part of its range, in combination with the intense deforestation that southeastern Amazonia faces, casts doubts on the continued presence of this and other forest-dependent species in the region. [ABSTRACT FROM AUTHOR]

ABSTRACT The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines-cotton-top tamarins ( Saguinus oedipus) and black-capped squirrel monkeys ( Saimiri boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. J. Exp. Zool. 323A: 556-566, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We analyzed DNA at 9 microsatellite loci from hair samples of 73 pied tamarins (Saguinus bicolor) located in 3 urban forest fragments and a biological reserve in the city of Manaus, Amazonas, Brazil. The forest fragments had become isolated from the continuous forest 6-15 years prior to the time of sampling. Tests for reduction in population size showed that all groups from the urban forest fragments had undergone genetic bottlenecks. Pied tamarins in this region historically formed one biological population, and the fragments were connected by high levels of gene flow. These results indicate the need to implement a conservation plan that allows for connectivity between the urban fragments, as well as protection from further constriction. Such connectivity could be achieved via the creation and protection of corridors. In addition to the current population trends explained by anthropogenic actions, the species also shows a trend of long-term demographic decline that has resulted in approximately an order of magnitude decrease and began 13 thousand years ago. [ABSTRACT FROM AUTHOR]

Early primate evolution is connected to the efficient exploitation of the terminal branch habitat. Mammals that forage in this habitat constantly encounter flexible thin branches that bend under the weight of the animals and thus form steeply inclined and declined supports. This study was aimed to gain insight into how cotton-top tamarins - a previously proposed modern analogue for a hypothetical stage in early primate evolution with prehensile autopodia - meet the specific functional demands when navigating thin, branch-like supports of different orientation. X-ray motion analysis was combined with synchronous single limb substrate reaction force measurements to discern limb mechanical adjustments. Previously reported gait parameter adjustments were confirmed for moderate support orientations, but on the steepest inclines and declines kinematic discontinuities were observed. These are interpreted to emphasize the functional roles of the forelimbs (net-braking role) and hind limbs (net-propulsive role) already established for level and moderately inclined supports. Tensile forces were exerted by the forelimbs on the steepest inclines and by the hind limbs on the steepest declines (head-first descents). Even though non-specialized small mammals have also been shown to successfully negotiate similar supports, prehensility offers advantages for foraging on thin, steeply inclined and declined terminal branches. Thus, the evolution of prehensile autopodia in small early primates likely has enhanced the exploitation of the terminal branch habitat. [ABSTRACT FROM AUTHOR]

Previous research suggests that nonhuman primates have limited flexibility in the frequency content of their vocalizations, particularly when compared to human speech. Consistent with this notion, several nonhuman primate species have demonstrated noise-induced changes in call amplitude and duration, with no evidence of changes to spectral content. This experiment used broad- and narrow-band noise playbacks to investigate the vocal control of two call types produced by cotton-top tamarins (Saguinus Oedipus). In ‘combination long calls’ (CLCs), peak fundamental frequency and the distribution of energy between low and high frequency harmonics (spectral tilt) changed in response to increased noise amplitude and bandwidth. In chirps, peak and maximum components of the fundamental frequency increased with increasing noise level, with no changes to spectral tilt. Other modifications included the Lombard effect and increases in chirp duration. These results provide the first evidence for noise-induced frequency changes in nonhuman primate vocalizations and suggest that future investigations of vocal plasticity in primates should include spectral parameters. [ABSTRACT FROM AUTHOR]

Divergence in vocalizations can reduce gene flow by serving as a premating barrier during secondary contact between previously isolated populations. In primates, vocal divergence in long calls of separated populations has been documented, yet recognition of these differences by the respective populations has seldom been studied in the field. To investigate this issue, we studied populations of two subspecies of saddle-back tamarins ( Saguinus fuscicollis nigrifrons and S. f. lagonotus) that are separated by the Amazon River in Peru. We recorded long calls of each subspecies and detected significant differences between the populations in the number of notes per call, duration of calls, and shifts in starting frequency of notes over the length of calls. In addition, a population of S. f. nigrifrons responded more overtly in measures of approach to playback of long calls of its own subspecies compared to long calls of S. f. lagonotus. These results are consistent with the hypothesis that allopatric divergence of long calls might contribute to reproductive isolation of these subspecies of saddle-back tamarins, which adds to growing evidence suggesting full species status for these taxa. Am. J. Primatol. 77:679-687, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT The genus Saguinus represents a successful radiation of over 20 species of small-bodied New World monkeys. Studies of the tamarin diet indicate that insects and small vertebrates account for ∼16-45% of total feeding and foraging time, and represent an important source of lipids, protein, and metabolizable energy. Although tamarins are reported to commonly consume large-bodied insects such as grasshoppers and walking sticks (Orthoptera), little is known concerning the degree to which smaller or less easily identifiable arthropod prey comprises an important component of their diet. To better understand tamarin arthropod feeding behavior, fecal samples from 20 wild Bolivian saddleback tamarins (members of five groups) were collected over a 3 week period in June 2012, and analyzed for the presence of arthropod DNA. DNA was extracted using a Qiagen stool extraction kit, and universal insect primers were created and used to amplify a ∼280 bp section of the COI mitochondrial gene. Amplicons were sequenced on the Roche 454 sequencing platform using high-throughput sequencing techniques. An analysis of these samples indicated the presence of 43 taxa of arthropods including 10 orders, 15 families, and 12 identified genera. Many of these taxa had not been previously identified in the tamarin diet. These results highlight molecular analysis of fecal DNA as an important research tool for identifying anthropod feeding patterns in primates, and reveal broad diversity in the taxa, foraging microhabitats, and size of arthropods consumed by tamarin monkeys. Am J Phys Anthropol 156:474-481, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Intravascular nematodes were considered the cause of death of 14 captive callitrichids. All animals were captive born at zoos in France and died with little or no premonitory signs of disease. No consistent gross lesions were observed at necropsy, although in certain cases intracardiac adult parasites were noted. The most significant histologic findings were verminous pneumonia and pulmonary endarteritis. In all cases except one, intravascular adult nematodes were observed with eggs and larvae in the lungs. Adult nematodes were obtained from 8 animals and in all cases were identified as Parastrongylus dujardini. To the authors’ knowledge, this is the first report of intravascular angiostrongylosis with primary cardiopulmonary location in callitrichids in France. [ABSTRACT FROM PUBLISHER]

This paper describes liver lobe torsion in a white-lipped tamarin ( Saguinus labiatus) and an Alaotran gentle lemur ( Hapalemur alaotrensis). Both animals had a history of acute collapse, and diagnosis was made post-mortem. To the authors' knowledge, these are the first reported cases of this pathology in non-human primates. [ABSTRACT FROM AUTHOR]

Essentially, the most effective control of plant parasitic nematodes involves the use of synthetic nematicide. However, apart from their very high cost, increased concern on the environment has necessitated a reduction in the amount of nematicides used for nematode control. In view of these, this research work was conducted to evaluate the effects of different concentrations of root extract ofTamarindus indicaandCarica papayaat different concentrationsS(100% concentration), “S/2” (50% concentration), “S/10” (10% concentration) and “S/100”(1% concentration) in the inhibition of egg hatch and mortality of larva of root-knot nematode,Meloidogyne incognita.The experiment was laid out in a completely randomised design and replicated four times. Combination of equal proportion ofT. indicaandC .papayaroot extract indicated that all the concentrations inhibited egg hatch. The standard solutionSof all the selected botanicals were more toxic and effective at (p ? 0.05) than the other concentrations. Similarly, combinations of root extracts ofT. indicaandC. papayawere the most effective of all the selected botanicals in the inhibition of egg hatch and larvae mortality, followed byT. indicaroot extracts and thenC. papayaroot extracts. [ABSTRACT FROM AUTHOR]

Saguinus leucopus is a neotropical primate, endemic and monotypic of Colombia (South America), with few studies of its anatomy, whose morphology radius this key element of this quadruped locomotion arboreal animal remains unknown. This study describes the gross functional anatomy of the radius bone of white-footed tamarin (Saguinus leucopus). The study was based on eight specimens fixed with 10% formalin and extracted their radius them, describing the main features of the bony prominences, such as muscle and ligaments attachments and neurovascular pipes. The radius of Saguinus leucopus bony presents some prominences for muscles and ligaments attachments, in addition to the synovial cartilage regions to other parts of the forelimb. The various anatomical contours of the radius of Saguinus leucopus exhibit characteristics typical particular motor functions adapted to the environment of an arboreal quadruped position. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to study the welfare of 3 captive groups of cotton-top tamarins housed in different zoological parks. Ethological observations were conducted during 1 year. In addition, fecal samples were collected and the concentrations of glucocorticoids, androgens, and progestogens were measured. Within each group, no significant differences in fecal cortisol concentrations were found between subjects. The fecal concentrations of testosterone and progesterone significantly differed depending on the sexes and ages of the tamarins. A significant association was found among hormone concentrations, exhibit dimensions, and group composition. A highly significant correlation was found between all hormones considered and the space available for each subject. Significant differences in behavioral patterns were observed among groups, including social–individual, affiliative–aggressive, and anogenital–suprapubic scent marking. Correlations between hormone measurements and behaviors were detected. In conclusion, this study confirmed the associations between some behaviors exhibited by these nonhuman primates and both cortisol and testosterone; these data also highlight the role played by progesterone in these behaviors. [ABSTRACT FROM AUTHOR]

Recent studies of spatial memory in wild nonhuman primates indicate that foragers may rely on a combination of navigational strategies to locate nearby and distant feeding sites. When traveling in large-scale space, tamarins are reported to encode spatial information in the form of a route-based map. However, little is known concerning how wild tamarins navigate in small-scale space (between feeding sites located at a distance of ≤60 m). Therefore, we collected data on range use, diet, and the angle and distance traveled to visit sequential feeding sites in the same group of habituated Bolivian saddleback tamarins ( Saguinus fuscicollis weddelli) in 2009 and 2011. For 7-8 hr a day for 54 observation days, we recorded the location of the study group at 10 min intervals using a GPS unit. We then used GIS software to map and analyze the monkeys' movements and travel paths taken between feeding sites. Our results indicate that in small-scale space the tamarins relied on multiple spatial strategies. In 31% of cases travel was route-based. In the remaining 69% of cases, however, the tamarins appeared to attend to the spatial positions of one or more near-to-site landmarks to relocate feeding sites. In doing so they approached the same feeding site from a mean of 4.5 different directions, frequently utilized different arboreal pathways, and traveled approximately 30% longer than then the straight-line distance. In addition, the monkeys' use of non-direct travel paths allowed them to monitor insect and fruit availability in areas within close proximity of currently used food patches. We conclude that the use of an integrated spatial strategy (route-based travel and attention to near-to-goal landmarks) provides tamarins with the opportunity to relocate productive feeding sites as well as monitor the availability of nearby resources in small-scale space. Am. J. Primatol. Am. J. Primatol. 76:447-459, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Comparing forelimb use across primates can improve the understanding of the mechanisms and functions of brain asymmetry. We broadened the comparative framework by investigating hand use biases across spontaneous behaviors in 11 captive emperor tamarins of 2 family groups. We found a right preference across 58% of pooled unimanual bouts and 60% of all tasks. The maximum biases for a single task were 88% right-hand use and 78% left-hand use. On an individual basis, for most tasks, 6 tamarins preferred their right hand, 2 tamarins the left, and 2 animals were ambidextrous. Only a single tamarin did not switch between left and right hand bias according to task, but displayed a consistent right-hand bias. Our accompanying review of the 2 dozen previous callitrichid hand use studies confirms this picture. Across the board, these report hand preferences for single tasks. Task specialization is found in less than half of the studies, hand specialization in less than a third, whereas population level handedness is almost never reported. Importantly, right-hand use is preponderant, but very rarely consistent across tasks or subjects. This might be attributable to the fact that often-employed simple (food-reaching) tasks may not be coupled to a specialized hemisphere and therefore not constrain forelimb use. A better understanding of what causes directional forelimb use in callitrichids and other animals is currently hampered by a lack of standardized methods including measurement criteria, task difficulty, and social setting as well as a dearth of taxonomic diversity and field studies. [ABSTRACT FROM AUTHOR]

Highlights: [•] We developed an IBM of tamarins’ movements to predict spatial patterns of seed dispersal. [•] Decision process of monkey movement during daily routine is modeled using an IBM. [•] Choice of movement depends on individual's energy and two internal thresholds. [•] The most important parameter for realistic simulations is the energy gained in feeding. [•] Implemented seed dispersal does fit empirical kernels quite well. [Copyright &y& Elsevier]

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