Comparative gastrointestinal organ lengths among Amazonian primates (Primates: Platyrrhini)

ObjectivesThe morphological features of the gastrointestinal tract (GIT) in mammals reflect a species' food niche breadth and dietary adaptations. For many wild mammals, the relationship between the structure of the GIT and diet is still poorly understood, for example, the GIT for frugivorous primates is usually classified as unspecialized and homogeneous. Here, we compare the GIT structure of 13 primate species from the three families of extant platyrrhines (Atelidae, Pitheciidae, and Cebidae) in Amazonia, and discuss possible evolutionary adaptations to different diets and trophic niches.MethodsWe measured the length of the esophagus, stomach, small intestine, large intestine, cecum, colon, and rectum of the digestive tracts of 289 primate specimens. We determined the allometric relationships of the different tubular organs with the total length of the GIT as a proxy of specimen body size. Allometric parameters were used to establish the quotients of differentiation of every organ for each primate specimen.ResultsThere was a high differentiation in structure of the digestive organs among genera. Alouatta specimens clearly separated from the other genera based on dissimilarities in gastric, colonic, and rectal quotients, likely linked to the fermentation of plant contents. In contrast, all cebines (Sapajus, Cebus, and Saimiri) and Cacajao species had similar small intestine quotients, which is expected due to their high rates of animal matter consumed.ConclusionsWe show that diverse adaptations in digestive structure exist among frugivorous primates, which in turn reflect different dietary patterns within this group that may enable the geographic coexistence of different primate species

Dietas de primates no humanos del norte amazónico peruano

There are few studies describing the eating habits of non-human primates (NHPs) that provide information related to the use of food resources of the ecosystem in the Amazon Forest. The objectives of the study were (1) to determine the composition of the diet of six species of NHPs and (2) to evaluate the amplitude and diversity of their diets from the evaluation of the gastric contents of animals hunted for subsistence purposes by inhabitants of three areas of the northern Peruvian Amazon between 2012-2015. Samples of 82 primates of the species Lagothrix poeppigii (n = 30), Sapajus macrocephalus (n = 23), Pithecia monachus (n = 11), Cacajao calvus (n = 8), Cebus albifrons (n = 6) and Alouatta seniculus (n = 4). The NHPs diet consisted of a high variety of fruits, including 133 types of seeds and 39 types of arthropods. The amplitude of the niche according to the Levin Index and the Simpson Diversity Index indicate that L. poeppigii is the most generalist species in terms of fruits and arthropods, followed by C. calvus with arthropods and by S. macrocephalus in the use of fruits. On the contrary, Cebus albifrons is the most specialized species when it comes to fruits and P. monachus when it comes to arthropods.Se dispone de escasos estudios que describan los hábitos alimenticios de los primates no humanos (PNH) que permiten conocer el uso de los recursos alimenticios del ecosistema en el bosque amazónico. El estudio tuvo como objetivos (1) determinar la composición de la dieta de seis especies de PNH y (2) evaluar la amplitud y diversidad de sus dietas a partir de la evaluación de los contenidos gástricos de animales cazados con fines de subsistencia por pobladores de tres áreas del norte de la Amazonía peruana entre 2012-2015. Se trabajó con muestras de 82 primates de las especies Lagothrix poeppigii (n=30), Sapajus macrocephalus (n=23), Pithecia monachus (n=11), Cacajao calvus (n=8), Cebus albifrons (n=6) y Alouatta seniculus (n=4). La dieta de los PNH estuvo constituida por una alta variedad de frutos, entre ellos por 133 tipos de semillas y 39 tipos de artrópodos. La amplitud del nicho según el Índice de Levin y el Índice de Diversidad de Simpson indican que L. poeppigii es la especie más generalista en lo referente a frutos y artrópodos. Por el contrario, Cebus albifrons es la especie más especialista en lo que se refiere a frutos y P. monachus cuando se trata de artrópodos

Environmental and biological drivers of prevalence and number of eggs and oocysts of intestinal parasites in red howler monkeys from Central Amazonia

Host-parasite relationships can be directly affected by host’s biological aspects and environmental factors, which influence both the survival of infective forms and the incidence of parasites. However, logistical difficulties in accessing biological samples for parasitological studies makes the Amazon Forest into a poorly known region in relation to the dynamic of parasites of wild animals. Here, using 34 red howler monkeys’ biological samples donated by local subsistence hunters from two Amazon habitat types (white-water flooded forest and upland forest) as an opportune alternative, we detected four intestinal parasite taxa infecting this species (two nematodes – Trypanoxyuris sp. and Strongyloides sp., one protozoan – Entamoeba sp. –, and one not-identified trematode, the last just found for white-water flooded forest). Trypanoxyuris was the most prevalent intestinal parasite (56.5% at flooded forest and 54.5% at upland forest). There was no difference between habitat types or individual sex regarding the prevalence for any parasite taxa. On the other hand, we found a strong influence of seasonality, with increasing prevalence of all parasite taxa as the river water level increased. In terms of egg and cyst counts, we found a difference between sexes (females > males, p = 0.002) and habitat types (upland forest > white-water flooded forest, p = 0.02), and a positive relationship with river water level (p = 0.002). Although some of these parasite taxa can be shared between humans and howlers, further investigations are necessary to study the parasites taxonomy thoroughly and to assess the potential zoonotic cross-transmission of these pathogens to local people living in the Amazon. In this study, we unveiled a seasonal effect for howler monkeys’ intestinal parasites, that also might occur in other non-human primates of the Amazon. In addition, our results on periods of high risk of intestinal parasite infection are useful to estimate future impacts of climate change on host-parasite dynamics

Niche overlap between two sympatric frugivorous Neotropical primates: improving ecological niche models using closely-related taxa

Ecological niche models (ENMs) are widely used tools for predicting species geographic distribution as a function of environmental variables. The inclusion of biotic factors in the predictor suite can significantly increase the predictive power of such models, leading to a model closer to the realized niche for the species under investigation. In this study, we provide evidence of niche overlap between gray woolly monkeys (Lagothrix cana) and black-faced black spider monkeys (Ateles chamek) based on locality and ecological data covering their complete geographic range in the Amazon forests of Brazil, Peru and Bolivia. We also estimate the potential distribution of L. cana using environmental predictors, and the distribution of A. chamek as a biotic factor. Finally, we quantified current and future habitat loss and areas under legal protection. We found that only 39% of the L. cana area of occupancy is under legal protection and that the species could potentially lose up to 58% of habitat in the next 30 years. We also show that the use of a closely-related species that has a more robust dataset can improve ENMs of poorly studied, rare and/or cryptic species. The framework developed here can be applied to a wide range of sympatric species if they share similar ecological requirements. Since our focal species are the most frugivorous primates in our study region and especially vulnerable to habitat loss, the identification of highly suitable areas for both taxa can help to protect other forest-dwelling species, reducing the rate of overall biodiversity loss. © 2020, Springer Nature B.V

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions forecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosys-tem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts withdomestic dogs, these species have been threatened locally, regionally, or even across their fulldistribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths.Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae(3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data onDasypus pilo-sus(Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized,but new genetic studies have revealed that the group is represented by seven species. In thisdata paper, we compiled a total of 42,528 records of 31 species, represented by occurrence andquantitative data, totaling 24,847 unique georeferenced records. The geographic range is fromthe southern United States, Mexico, and Caribbean countries at the northern portion of theNeotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regardinganteaters,Myrmecophaga tridactylahas the most records (n=5,941), andCyclopessp. havethe fewest (n=240). The armadillo species with the most data isDasypus novemcinctus(n=11,588), and the fewest data are recorded forCalyptophractus retusus(n=33). Withregard to sloth species,Bradypus variegatushas the most records (n=962), andBradypus pyg-maeushas the fewest (n=12). Our main objective with Neotropical Xenarthrans is to makeoccurrence and quantitative data available to facilitate more ecological research, particularly ifwe integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, andNeotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure,habitat loss, fragmentation effects, species invasion, and climate change effects will be possiblewith the Neotropical Xenarthrans data set. Please cite this data paper when using its data inpublications. We also request that researchers and teachers inform us of how they are usingthese data

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data