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Aim: The central and western Amazonia underwent several landscape changes during the Quaternary. Whereas the Riverine Barrier Hypothesis is traditionally used to explain the influence of rivers on speciation, processes such as river rearrangements have been overlooked to explain the geographic distribution and evolutionary history of Amazonia biota. Here, we tested how river rearrangements influenced the evolutionary history of uakari monkeys, genus Cacajao, a primate genus primarily associated with seasonally flooded forests in central and western Amazonia. Location: Central and Western Amazonia. Taxon: The genus Cacajao, including the black uakaris (C. melanocephalus, C. ayresi, C. hosomi); and the bald‐headed uakaris (C. calvus, C. amuna, C. rubicundus, C. ucayalii, C. novaesi). Methods: We performed a continuous phylogeographic analysis using 77 cytochrome b sequences to identify the origin and dispersal of Cacajao lineages. We used genome‐wide SNP variation (ddRADseq) to investigate population structure, gene flow and demographic history in Cacajao populations and used digital elevation models to identify landscape and riverscape characteristics that may have influenced the geographic distribution of Cacajao. Results: Our continuous phylogeographic reconstruction pointed out that the ancestral Cacajao lineage occupied the flooded forests of the Solimões River, in central Amazonia, at ~1.7 Mya and descendant lineages dispersed throughout central and western Amazonia more recently. We identified gene flow in both black and bald‐headed uakari populations, even across rivers considered barriers (e.g. the Negro River). Landscape analysis showed that river rearrangements influenced the geographic distribution and population structure in Cacajao. Historical demographic analyses suggest varied scenarios of population size changes among Cacajao monkeys consistent with periods of intense dynamism in flooded habitats and the formation of non‐flooded upland forests. Main Conclusion: Our results support that the river rearrangements have shaped the geographic distribution and divergence of recently diverged Cacajao lineages. Landscape and riverscape changes, along with retractions of the flooded forests, isolated some Cacajao populations in floodplain areas. Our study also suggests that these events led to the recent changes in demographic histories in species with a restricted geographic distribution. [ABSTRACT FROM AUTHOR]

Community-based tourism is a participatory approach implemented to support the economic and social development of local communities. Here, we present the preliminary results of an initiative of primate tourism in the Mamirauá Reserve for Sustainable Development (Mamirauá SDR), Amazon rainforest, Brazil. Between January and December 2019, we monitored the sighting rate of bald uakaris (Cacajao calvus calvus) by Uakari lodge tourists aiming to identify the main variables influencing the records of this primate that could be used as a baseline for a primate-watching program. During 334 days, tourist guides provided data on 602 tourist outings, with 190 sightings of uakari groups (109 in the morning and 81 in the afternoon). These values correspond to a mean of 0.57 sightings/day and 0.32 sightings/outing while the mean number of uakaris sighted per outing was 6 individuals (± 6.6 SD; min = 1; max = 30). Uakaris were mostly traveling (55%) or feeding (35%), and less frequently resting (9%). Uakari sightings varied monthly, with 73.4% of the tourists reporting seeing uakaris at least once during their stay, while 26.6% did not. The marked seasonal variation in the water level, food availability, and the socioecological strategies of uakaris are parameters that may have facilitated the detectability of these primates by tourists in Mamirauá SDR. We concluded that primate tourism in Mamirauá SDR has a high potential to strengthen the synergism between traditional and scientific knowledge and promote social and economic benefits for local communities and new conservation actions for primates. [ABSTRACT FROM AUTHOR]

An understanding of a species' geographic distribution is essential to assess, plan, and develop strategies for its conservation. The geographic distribution of the bald uakari, Cacajao calvus, and its component subspecies has been poorly investigated, with disjunct distributions being reported in Brazil and Peru. In this study, we reveal new records of bald uakari occurrence based on multi-year surveys, a literature review, and an examination of vouchers available in six zoological collections, clarifying the geographic distribution of all subspecies. We confirm that C. c. calvus has a disjunct distribution with populations along the rios Tarauacá and Pauini, 250 km away from those on the left bank of middle Rio Juruá and lower Rio Jutaí; and 650 km from the population of the Mamirauá Sustainable Development Reserve (Mamirauá SDR). Cacajao c. rubicundus has a disjunct distribution with three isolated populations 1) inhabiting the flooded forests of the Rio Solimões and the Paraná (channel) Jacurapá, 2) the left bank of the lower Rio Jutaí; and 3) in the Auati-Paraná. Cacajao c. novaesi has the smallest geographic distribution of the bald uakaris, occurring only in the Gregório-Tarauacá interfluvium. Cacajao c. novaesi and C. c. calvus are separated by the Rio Tarauacá, which is also a significant geographic barrier for other primates, including titi and saki monkeys. We also confirm the occurrence of Cacajao c. ucayalii in Brazil in the Serra do Divisor National Park. This Peruvian subspecies has the most extensive range, with isolated populations found in areas completely separated from the lowlands. The patchy distribution of Cacajao calvus provides a unique opportunity to understand how local environmental variation may have promoted ecological flexibility for the successful establishment of isolated populations. [ABSTRACT FROM AUTHOR]

We report the rediscovery of Pithecia vanzolinii in the upper Juruá River Basin, in the State of Acre, Brazil. An individual was collected after being hunted by a local inhabitant of an extractive community in the Riozinho da Liberdade Extractive Reserve. This is the first record of this species in the last 60 years and highlights the importance of intensifying studies of this almost unknown species. [ABSTRACT FROM AUTHOR]

[Display omitted] • We revised the taxonomic classification of bald-headed uakaris, genus Cacajao. • The use of a single mitochondrial marker did not recover the shallower relationships. • ddRADseq phylogenetic analyses retrieved five lineages of bald-headed uakaris. • We proposed a taxonomic arrangement with five species of bald-headed uakaris. • A new species is described based on molecular and morphological information. Bald uakaris, genus Cacajao , are Amazonian primates currently classified as one species and four subspecies based on the patterns of pelage coloration. In this study, we test if their current taxonomy is represented by the phylogenetic relationship of the main lineages retrieved from molecular data. We included, for the first time, all bald uakari taxa in a mitochondrial (cytochrome b) and genome-wide (ddRAD) phylogenetic analyses. We also examined the pattern of pelage colouration in specimens from zoological collections. Having determined the number of lineages using Maximum Likelihood and the species tree using coalescent analyses, we test their divergence time using a Bayesian approach. While the cytochrome b analysis only recovered two clades, the ddRAD analysis supported the reciprocal monophyly of five lineages of bald uakaris, with all clades including only individuals with distinct and exclusive diagnostic phenotypic characters. We found that species diversification in Cacajao occurred during the last 300 Kya and may have been influenced by the formation of rivers and flooded forests in western Amazonia. We propose that the four bald uakari subspecies currently recognised can be upgraded to species level and we describe the white uakaris from the basin of the Rio Tarauacá as a new species. [ABSTRACT FROM AUTHOR]

White-faced saki monkeys ( Pithecia pithecia) lack most of the behavioral and physical traits typical of primate monogamy [Fuentes, ]. In order to determine if social bonds in this species reflect patterns displayed by pair-bonded groups or larger multimale-multifemale groups, we draw on 17 months of data collected on wild white-faced sakis at Brownsberg Nature Park, Suriname. We analyzed within-group social bonds for three habituated groups (one two-adult and two multiadult groups) by measuring grooming, proximity, and approach/leave patterns between adult and subadult group members. We found that both two-adult and multiadult groups showed significantly stronger social bonds between a single male-female dyad within each group (deemed 'primary dyads'). In all three groups, primary dyads were composed of the oldest adult male and a breeding female. These pairs had significantly higher levels of grooming than other within-group dyads and were also in close proximity (<1 m) more often than nonprimary dyads. Grooming in primary dyads was nonreciprocal, and consistently biased toward female investment. Grooming patterns in nonprimary dyads varied, but were often more reciprocal. Grooming and proximity of the primary dyad also changed in relation to infant development. Our results suggest that while white-faced sakis do not show behavioral and physical traits typical of monogamy or pair-bonding, social bonds are strongest between a single male-female pair. Pitheciine social systems range from small group monogamy in Callicebus to large multimale-multifemale groups in Chiropotes and Cacajao. As the middle taxon in this platyrrhine radiation, behavioral strategies of white-faced sakis provide a model for how social bonds and affiliation could be influenced by and affect the evolution of larger group size in primates. Am. J. Primatol. 73:1051-1061, 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

I observed leaping behavior in the white-faced saki (Pithecia pithecia) and the black-bearded saki (Chiropotes satanas satanas) for 15 and 10 months, respectively, as part of a larger study of positional behavior in the tribe Pitheciini. I used focal animal instantaneous sampling to observe the two species on separate islands in their natural habitat at Guri Lake, Venezuela. Leaping behavior correlates with patterns of forest use and body size, and differences between the species relate more to habitat preferences than to habitat differences per se. Pithecia usually chose vertical or highly angled supports of lower tree portions for take-off and landing, and took off from a stationary posture. Chiropotes took off from the main crown or terminal branches, gaining momentum from locomotor movement before performing a leaping take-off. Pithecia's vertical body orientation and longer leap distance allowed it to assume a mid-flight tuck to prepare for a hindlimb-first landing onto a solid support, and to absorb landing forces with its relatively longer hindlimbs. Chiropotes remained more pronograde throughout its leaps, and minimized landing forces by landing on all four limbs onto numerous flexible supports in the terminal branches. The smaller-bodied P. pithecia is specialized for vertical clinging and leaping, and exhibits behavioral and morphological parallels with other vertical clingers and leapers. The larger C. satanas is a generalized leaper that lacks morphological specializations for leaping. Pithecia's use of solid supports in the lower tree portions allows it to move quietly through the forest–one of a suite of behaviors related to predator avoidance. This example of variation within one behavioral category has implications for devising locomotor classifications and interpreting fossil remains. Am. J. Primatol. 66:369–387, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

From June 1994 to October 1995, I conducted a study of the feeding ecology of one group of black-headed uacaris (Cacajao melanocephalus melanocephalus) in Pico da Neblina National Park, Brazil, near the Venezuelan border (01°10′N to 00°26′S, 65°03′W to 66°52′W). Of a total of 429 feeding records, 89% corresponded to fruits from which black-headed uacaris ate ripe and unripe seeds, mesocarps and arils. Seeds were the single most important food item year-around, corresponding to 81% of the feeding records for fruits. Black-headed uacaris used 120 different plant species in 32 families as food. The 3 most important plant species in their diet, Micrandra spruceana, Eperua leucantha, and Hevea braziliensis (all trees), accounted for 38% of the feeding records for fruits. These species produced fruits that were protected by very hard green husks, were barochorous, did not have fleshy mesocarps, and were slow to mature, thus being available as unripe fruits for long periods. The second and third most important species in the diet of black uacaris, Eperua leucantha and Hevea braziliensis, were dominant in the forest: approximately 30% of trees ≥10 cm dbh sampled in a 2-ha botanical transect at the study site. I discuss the formation of large social groups of black-headed uacaris in Pico da Neblina National Park in light of the peculiar floristic composition of the study site. [ABSTRACT FROM AUTHOR]

Data on the ecology and diet of buffy sakis (Pithecia albicans) were obtained during a 20-month study in an entirely undisturbed terra firme forest in the upper Urucu river, Amazonas, Brazil. Groups of 3-7 sakis found in a 900-ha study plot used large home ranges (147-204 ha), which overlapped extensively with those of neighboring groups. Similar to other pitheclines, buffy sakis were primarily seed predators, relying heavily on young seeds of certain key plant families, such as the Sapotaceae and Leguminosae. Ripe fruits, ripe seeds, young leaves, flowers, and nectar were eaten to a lesser extent. Whether or not feeding, sakis spent most of their time in the canopy and subeanopy, a pattern similar to that of other southwestern Amazonian saki species, but sharply different from that of Guianan sakis (Pithecia pithecia), which use considerably tower levels of the forest. Comparisons are made between different Pithecia species to show whether and how P. albicans diverges ecologically from its congeners. [ABSTRACT FROM AUTHOR]