Southern range extension of Spix's saddle-back tamarin, Leontocebus fuscicollis fuscicollis, in Peru.

Peru has the highest diversity of members of the tamarin genus Leontocebus (Callitrichidae). However, for a number of taxa from this genus the distributional ranges are still not well known. In this paper we provide evidence for the extension of the southern range of Leontocebus fuscicollis fuscicollis to the right bank of the Río Abujao, south of which it is replaced by Leontocebus weddelli weddelli.

Diversidad y amenazas de los mamíferos mayores en los bosques montanos de Huánuco, Perú / Diversity and threats of larger mammals in montane forests of Huánuco, Peru

Resumen En este trabajo los mamíferos mayores que habitan en los bosques montanos del departamento de Huánuco son estudiados para determinar la diversidad de especies y el estado actual de sus poblaciones. Se realizaron censos por transecto lineal y entrevistas entre los años 2014 y 2015, en seis sitios de muestreo correspondientes a cinco provincias. De los censos y exploraciones nocturnas se obtuvieron 439 registros pertenecientes a 37 especies; de estas, 4 son endémicas de Perú y 9 se encuentran en alguna categoría de conservación de la Legislación peruana. Los órdenes más representativos correspondieron a los carnívoros y primates con 11 y 10 especies, respectivamente, mientras que los avistamientos más frecuentes fueron de Tremarctos ornatus (43 registros), Nasua nasua (34 registros) y Cuniculus paca (32 registros). Los Índices de diversidad de Shannon-Wiener y de Simpson indican a Miraflores como el sitio de muestreo con más alta diversidad (H'=3.11, 1-D=0.95). La principal amenaza para los mamíferos mayores y otros componentes de la fauna mayor es la deforestación; no obstante, la presencia de especies indicadoras de la comunidad primaria de fauna como Tremarctos ornatus, Lagothrix flavicauda y otros primates, nos indican que todavía existen fragmentos de bosque primario relativamente extensos, en particular entre los ríos Chontayacu y Crisnejas en la provincia de Marañón y entre los ríos Oso mayo y Blanco en la provincia de Puerto Inca, por lo que deben ser tomados en cuenta para su conservación.

Abstract In this work, the larger mammals that inhabit the montane forests of the department of Huánuco are studied to determine the diversity of species and the status of their populations. Linear transect censuses and interviews were conducted between 2014 and 2015 on six sampling sites corresponding to five provinces. 439 records belonging to 37 species were obtained from the censuses and nocturnal explorations. Of these species, 4 are endemic to Peru and 9 are in some conservation category of Peruvian legislation. The most representative orders corresponded to carnivores and primates with 11 and 10 species, respectively, while the most frequent sightings were of Tremarctos ornatus (43 records), Nasua nasua (34 records) and Cuniculus paca (32 records). The Shannon-Wiener and Simpson Diversity Indices indicate Miraflores as the sampling site with the highest diversity (H'=3.11, 1-D=0.95). The main threat to larger mammals and other components of the larger fauna is deforestation; however, the presence of indicator species of the primary fauna community such as Tremarctos ornatus, Lagothrix flavicauda and others primates, indicate that there are still relatively extensive fragments of primary forest, particularly between the Chontayacu and Crisnejas rivers in the province of Marañón and between the Oso mayo and Blanco rivers in the province of Puerto Inca, so they must be taken into account for their conservation.

Estado actual de Cheracebus sp. (Primates: Pitheciidae) y de su hábitat entrelos ríos Tigre y Nanay, Amazonía peruana / Current status of Cheracebus sp. (Primates: Pitheciidae) and of its habitat between the Tigre and Nanay rivers, Peruvian Amazon

Resumen Con excepción de los bosques de la cuenca del río Itaya, área de influencia de la carretera Iquitos-Nauta y cuenca media de los ríos Nanay y Tigre, no hay información sobre el estado actual de la población y hábitat de Cheracebus sp., lo que motivó el desarrollo de este estudio cuyos objetivos estuvieron orientados a obtener más información sobre el estado actual de esta especie. Para ello, de mayo a noviembre del 2019 se realizaron censos por transecto lineal en bosques de las cuencas de los ríos Itaya, Nanay y Tigre. En 1659 km de longitud recorrida se avistaron 32 grupos de Cheracebus sp., de ellos, 17 correspondieron a la cuenca del río Nanay. Grupos con cuatro individuos se avistaron con más frecuencia en la cuenca del río Nanay; la abundancia relativa y la densidad poblacional fue ligeramente mayor en la cuenca del río Itaya con 0.3 grupos/10 km y 4.2 individuos/km2. En el área de estudio, los bosques están muy perturbados desde las orillas de los ríos y quebradas hasta aproximadamente 0.7 km al interior. La baja densidad poblacional de Cheracebus sp. es consecuencia de la alta presión de caza, en particular en la cuenca del río Tigre; a ella se suma la alta perturbación de los bosques por la extracción de árboles maderables y otros recursos, lo que estaría ocasionando escasez de recursos alimenticios para éste y otros primates.

Abstract With the exception of the forests of the Itaya river basin, the area of influence of the Iquitos-Nauta highway and the middle basin of the Nanay and Tigre rivers, there is no information on the current status of Cheracebus sp. populations and habitat, which motivated this study. The objectives were aimed at obtaining more information on Cheracebus sp. and the state of its populations. Linear transect censuses were conducted from May to November 2019 in forests of the Itaya, Nanay and Tigre river basins. In 1659 km of covered length, 32 groups were sighted; of them, 17 corresponded to the Nanay river basin. Groups with four individuals were seen more frequently in the Nanay river basin; relative abundance and population density were slightly higher in the Itaya river basin with 0.3 groups/ 10 km and 4.2 individuals/ km2. In the study area, forests are highly disturbed from the banks of rivers and streams up to approximately 0.7 km inland. The low population density of Cheracebus sp. is a consequence of high hunting pressure, particularly in the Tigre river basin; added to this is the high disturbance of the forests due to the extraction of timber trees and other resources; which would be causing a shortage of food resources for this and other primates.

Diversidad y abundancia de primates en bosques de baja y alta perturbación humana de Los Chilchos, Amazonas, Perú / Diversity and abundance of primates in low and high human disturbance forests of Los Chilchos, Amazonas, Peru

En los bosques montanos de Los Chilchos habitan cinco especies de primates, cuya situación actual, tamaño de grupo y abundancia son desconocidos, información que es indispensable para el manejo y la formulación e implementación de medidas de conservación. Afín de obtener información sobre los aspectos mencionados, fueron conducidos censos por transecto lineal entre junio y julio del 2017 en bosques de baja y alta perturbación antrópica. Como resultado de los censos fueron registrados 63 grupos pertenecientes a 5 especies. De ellos, 50 grupos correspondieron a los bosques de baja perturbación, siendo Aotus miconax y Ateles belzebuth los más observados con 21 y 17 grupos, respectivamente. Grupos más grandes se observaron en Cebus yuracus (promedio 17.0±5.0 individuos) y A. belzebuth (promedio 14.5±7.2 individuos) y más pequeños en A. miconax (promedio 2.6±0.7 individuos). Con excepción de Lagothrix flavicauda, la abundancia relativa y densidad poblacional fueron más altas en bosques de baja perturbación, demostrando así el buen estado de conservación, lo que no ocurre en bosques de alta perturbación. Entre los primates, la densidad más alta fue para A. miconax con 26.23 indiv./km² y más baja para Alouatta seniculus con 3.0 indiv./km². Lagothrix flavicauda fue registrada únicamente en bosque de alta perturbación, cuya abundancia relativa fue estimada en 0.1 grupos/ 10 km.

In the montane forests of Los Chilchos five species of primates inhabit, whose current situation, group size and abundance are unknown, which are indispensable for the management and formulation and implementation of conservation measures. In order to obtain information on the mentioned aspects, censuses were conducted by linear transect between June and July 2017 in forests of low and high anthropic disturbance. As a result of the censuses, 63 groups belonging to 5 species were registered. Of these, 50 groups corresponded to low disturbance forests, being Aotus miconax and Ateles belzebuth the most observed with 21 and 17 groups, respectively. Larger groups were observed in Cebus yuracus (average 17.0 ± 5.0 individuals) and A. belzebuth (average 14.5 ± 7.2 individuals) and smaller in A. miconax (average 2.6 ± 0.7 individuals). With exception of Lagothrix flavicauda, the relative abundance and population density were higher in low-disturbance forests, demonstrating thus the good conservation status, which does not occur in high-disturbance forests. Among primates, the highest density was for A. miconax with 26.23 indiv. /km² and the lowest for Alouatta seniculus with 3.0 indiv./km². Lagothrix flavicauda was recorded only in high disturbance forest, whose relative abundance was estimated at 0.1 groups / 10 km.

Diversidad y abundancia de primates y sus amenazas en el interfluvio de los ríos Napo y Putumayo, Amazonía peruana / Diversity and abundance of primates and their threats in the interfluvium of the Napo and Putumayo rivers, Peruvian Amazonia

En el nororiente de la Amazonía peruana todavía existen áreas con escasa información sobre primates, siendo una de ellas el interfluvio entre los ríos Napo-Putumayo, lo que motivó la conducción de este estudio para determinar su diversidad y abundancia, así como identificar las amenazas para sus poblaciones. Para este propósito se realizaron censos por transectos en octubre del 2007, setiembre del 2013 y noviembre del 2014 en tres sitios de muestreo. En 1040 km de transectos recorridos fueron observados 308 grupos pertenecientes a nueve especies, siendo Leontocebus nigricollis el más común (109 grupos) y Alouatta seniculus el más escaso (16 grupos). Grupos más pequeños de Lagothrix lagothricha lagothricha (8-11 individuos) y A. seniculus (3-5 individuos) fueron observados en Tamboryacu considerado como el sitio de muestreo de mayor perturbación. Asimismo, la densidad poblacional más baja estimada para L. l. lagothricha y A. seniculus también correspondió a este sitio de muestreo con 3.8 indiv./km² y 1.6 indiv./km², respectivamente, mientras que para el resto de especies no hubo mayores diferencias entre los sitios de muestreo. Entre las actividades, la caza y extracción de madera son las principales amenazas y responsables para la escasa población de A. seniculus y l. l. lagotricha, principalmente en la cuenca del río Napo.

Within the northeastern Peruvian Amazonia remain areas with scarce information on primates, one of them being the interfluvium between the Napo and Putumayo rivers. This lack of information motivated us to conduct a study to determine the diversity and abundance of primates within the area, as well as to identify the threats, which inhibit these primate species populations. For this purpose, we conducted transect censuses in three sampling sites in October 2007, September 2013 and November 2014. In 1040 km of transect walks we observed 308 groups of nine primate species, the most common being Leontocebus nigricollis (109 groups) and the rarest being Alouatta seniculus (16 groups). Smaller groups of Lagothrix lagothricha lagothricha (8-11 individuals) and A. seniculus (3-5 individuals) were observed in Tamboryacu, a majorly disturbed sampling site. Likewise, the lowest population densities estimated for L. l. lagothricha and A. seniculus corresponded to this same sampling site with 3.8 indiv. /km² and 1.6 indiv. /km², respectively, while for the remaining species there were no major differences among the sampling sites. Among the activities, hunting and logging are the predominant threats responsible for the scarce populations of A. seniculus and l. l. lagothricha, mainly in the Napo River Basin.

Primate abundance and habitat preferences on the lower Urubamba and Tambo rivers, central-eastern Peruvian Amazonia.

We report information on population density, group size, and habitat preferences of primates along the lower Río Urubamba and in the Río Urubamba-Río Tambo interfluvium, in central-eastern Peruvian Amazonia, an area that has been little explored with regard to its primate fauna. During 425 km of transect walks in October-November 2008 and April-May 2009 totally 174 groups of nine primate species were encountered, the most common being Callicebus brunneus (45 groups), Saguinus imperator (41 groups), and Aotus nigriceps (26 groups). Group sizes were smallest for A. nigriceps and C. brunneus (mean of 2.8 and 2.9, respectively) and largest for Saimiri boliviensis (mean 15.6). Population densities were lowest for Lagothrix cana (3.3 individuals/km(2)) and highest for A. nigriceps (31.1 individuals/km(2)). Groups of C. brunneus, S. imperator, S. boliviensis, Cebus albifrons, and Cebus apella were most frequently (83 % of sightings) encountered in semi-dense or in open primary forest that included stands of bamboo (Guadua sarcocarpa) or where bamboo was a very common species.

Distribution and abundance of white-fronted spider monkeys, Ateles belzebuth (Atelidae), and threats to their survival in Peruvian Amazonia.

The white-fronted spider monkey, Ateles belzebuth, is listed as 'Endangered' according to the IUCN classification. In Peru it is found in the departments of Loreto, San Martín, Amazonas and Cajamarca, but detailed data on its geographic distribution, population densities and conservation status are scarce. In order to obtain such information, we conducted transect censuses on the Río Aushiri and Río San Antonio (right bank of Río Napo), and between the Río Curaray and the Río Arabela and Río Nashiño, respectively, and made additional explorations on the northern and southern banks of the Río Marañón. We obtained 48 sightings along 761 km of census transect. Group size and population densities were lower in an area with high hunting pressure compared to areas with medium or low hunting pressure. Besides hunting, increasing deforestation is a major threat to the survival of A. belzebuth in Peruvian Amazonia.

The range of the golden-mantle tamarin, Saguinus tripartitus (Milne-Edwards, 1878): distributions and sympatry of four tamarins in Colombia, Ecuador, and northern Peru [corrected].

A detailed understanding of the range of the golden-mantle tamarin, Saguinus tripartitus (Milne Edwards, 1878), in Amazonian Peru and Ecuador is of particular relevance, not only because it is poorly known but also because it was on the basis of its supposed sympatry with the saddleback tamarin (S. fuscicollis lagonotus) that Thorington (Am J Primatol 15:367-371, 1988) argued that it is a distinct species rather than a saddleback tamarin subspecies, as was believed by Hershkovitz (Living new world monkeys, vol I. The University of Chicago Press, Chicago, 1977). A number of surveys have been carried out since 1988 in the supposed range of S. tripartitus, in both Ecuador and Peru. Here we summarize and discuss these issues and provide a new suggestion for the geographic range of this species; that is, between the ríos Napo and Curaray in Peru and extending east into Ecuador. We also review current evidence for the distributions of Spix's black-mantle tamarin (S. nigricollis nigricollis), Graells' black-mantle tamarin (S. n. graellsi), and the saddleback tamarin (S. fuscicollis lagonotus), which are also poorly known, and examine the evidence regarding sympatry between them. We conclude that despite the existence of a number of specimens with collecting localities that indicate overlap in their geographic ranges, the fact that the four tamarins are [corrected] of similar size and undoubtedly very similar in their feeding habits militates strongly against the occurrence of sympatry among them.

Geographic distribution and demography of Pithecia aequatorialis (pitheciidae) in Peruvian Amazonia.

To study the geographic distribution and demographic characteristics of Pithecia aequatorialis in Peruvian Amazonia, we undertook surveys and transect census in three river basins (Río Itaya, Río Tigre and Río Curaray) between 2004 and 2008. A total of 123 groups of P. aequatorialis was encountered during 1623 km of transect walks. Group size was uniform among the three areas (3.4-3.6 individuals), but surprisingly, population densities were higher in the area with strong hunting pressure (Río Itaya: 7.8 ind./km(2), vs. 5.6 and 5.9 km(2) in the Río Tigre and Río Curaray basins, respectively). The most common group composition included an adult pair with one offspring. Groups with more than one adult male and/or female accounted for 35% of sightings. Our observations extend P. aequatorialis range in Peru further south to the area between the Río Tigre and Río Corrientes, but exclude the area to the north between the Río Curaray and Río Napo. These findings are in contrast to previous distribution maps. P. aequatorialis was rarely seen in interspecific association during our censuses.

Geographic distribution and possible taxonomic distinction of Callicebus torquatus populations (Pitheciidae: Primates) in Peruvian Amazonia.

Population densities of yellow-handed titi monkey (Callicebus torquatus) were estimated using transect census methods. Densities were 2.8 individuals/km(2 )in the upper Rio Itaya basin and 2.5 individuals/km(2) in the lower Rio Algodón basin. Group size varied from two to five individuals, with an average of 2.9 individuals per group at the Rio Itaya. Groups were generally composed of two adults, probably the reproductive pair, with progeny from one to three previous birth seasons. Although the Rio Itaya population is phenotypically identical to populations from the rivers Nanay and Tigre, it differs from population on the rivers Napo and Putumayo. This suggests the existence of two disjunct populations of C. torquatus in Peruvian Amazonia whose taxonomic status warrants further examination.

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.

Characteristics and use of sleeping sites in Aotus (Cebidae: Primates) in the Amazon lowlands of Peru.

In the Amazon lowlands of Peru, Aotus nancymai and A. vociferans were observed to use four different types of sleeping sites: (1) holes in the trunks and branches of dry or senescent trees; (2) concavities in polyaxial branching nodes of trees protected by dense entanglements of creepers, climbing plants, vines, and masses of diverse epiphytes; (3) complex sites among masses of epiphytes, climbers, and vines; and (4) simple sites among thickets and dense foliage. Each type is described. There was competition and sharing of sleeping holes between Aotus and other nocturnal arboreal mammals.

Population structure of Aotus nancymai (Cebidae: Primates) in Peruvian Amazon lowland forest.

Wild groups of Aotus nancymai were trapped at three sites in the Peruvian Amazon lowland forest in order to study their social structure. Data on population density, group size, sex and age composition, social organization, and population structure were analyzed and are presented here.