New distribution records of Pithecia rylandsi and Pithecia mittermeieri ( Primates , Pitheciidae ) and an updated distribution map

New locations and extension of the known geographical distributions are reported for two recentlydescribed species of saki monkeys: Pithecia rylandsi and Pithecia mittermeieri. The record of P. rylandsi confirms the presence of this species further south in the state of Mato Grosso, Brazil. The new record of P. mittermeieri, which occurred in an ecotone of Amazon, Cerrado, and Pantanal biomes, is the southernmost record for the genus. Recording the distribution extension of both species is essential for their conservation, as well as to promote more studies about their ecology, behaviour, and other unknown aspects of Pithecia.

Pithecia rylandsi Marsh, 2014 occurs in the southern Amazon, in Brazil, Bolivia, and Peru.Marsh (2014) listed localities in the Pando region of northwest Bolivia, in the province of Nicolás Suárez (Bolivia), south of the Acre River, near the Peruvian and Brazilian borders (including the Tahuamanu and Nareuda rivers) and in Peru, west of the Los Amigos Conservation Concession and Los Amigos River (at least as far as the Manu Wildlife Center at the mouth of the Alto Madre de Dios River) and in a northerly direction of the Madre de Dios River.Specimens collected by J. Natterer in 1829 indicated that this species occurs in the central-west region of the Brazilian states of Rondônia and Mato Grosso, near the Bolivian border (delimited by the Mamoré-Guaporé rivers).
Pithecia mittermeieri is endemic to Brazil, and part of its distribution entails what was previously assumed to be the range of P. irorrata (Hershkovitz 1987;Marsh 2014).This species is distributed south of the Amazonas River between the Madeira and Tapajós rivers, including the drainage of the Aripuanã River, and extends into Rondônia, east of the Madeira and Mamoré Rivers, as well as the Guaporé River.Localities in Rondônia include Destacamento do Ribeirão and Pacáas Novos River, located east of the Mamoré River; specimens from both localities were collected by J. Natterer in 1829.
On 7 December 2013 one adult male of P. rylandsi was observed (15°00ʹ48ʺ S, 059°37ʹ31ʺ W) (Figure 1) and, on 3 December 2014, in the same forest fragment, two females of P. rylandsi were recorded.Both records occurred in the rural area of the Vila Bela da Santíssima Trindade municipality, in Mato Grosso, Brazil, in an area of Semi-deciduous Forest.The forest fragment was approximately 3,255 ha isolated in a matrix of agricultural and pasture lands.On 22 November 2014, in the rural municipality of Lambari D'Oeste, two subadult females of P. mittermeieri were recorded (15°11ʹ42ʺ S, 057°44ʹ43ʺ W) (Figure 2) in a savanna woodland fragment of approximately 960 ha, located in the ecotone consisting of Amazon, Cerrado, and Pantanal biomes, surrounded by cattle ranching and soybean plantations.The observation occurred during the morning (ca.11:30 am) and both females escaped when they noticed human presence.
The saki monkeys observed were identified based on their pelage pattern; the identification was later confirmed based on Marsh's (2014) revision of the genus, which stated that male Pithecia rylandsi have a bare face with very black pigmentation, predominantly gray pelage, which 1999).Another factor that could allow sakis and other primates to cross over to the opposite margins of a river is its configuration.In this context, sand banks along margins and a sinuous form of the river make this type of event possible (Ayres & Clutton-Brock 1992).
For P. mittermeieri, our record was 76 km south of the nearest known locality, which is in the municipality of Tangará da Serra, in the state of Mato Grosso (Figure 3) (Gusmão and Santos-Silva 2015) (Table 1).Currently, this new record is the southernmost record known for the genus and in an ecotone region of Amazon, Cerrado, and Pantanal biomes (Ferreira et al. 2005).
The forest fragments where both species were recorded are located in a landscape that has been significantly altered by human activities over the past few decades.Currently, these areas are composed of a homogeneous agricultural matrix, which consists of soybean plantations and livestock (Sampaio et al. 2012).This area is close to the "Arc of Deforestation", which extends from southeastern Maranhão state to southern Acre state, and has the highest deforestation rates of the entire Brazilian Amazon (Ferreira et al. 2005;Metzger 2001;Michalski et al. 2008).In this context, it is crucial to emphasize the importance of these areas (located both in Rondônia and Mato Grosso) (Table 1), for the conservation of P. mittermeieri, as they age becomes almost entirely white.On the other hand, Pithecia mittermeieri has a distinct characteristic from all other sakis: males present a bright orange ruff on the chest.We observed only two females in the fragment and identification was based on their pelage.The subadult females had very black fur around the face with lots of hair and very little stippling.Some females of P. mittermeieri are known to have very hairy faces in comparison to the females of P. rylandsi (Marsh 2014).
Our record for P. rylandsi confirms the presence of this species in the state of Mato Grosso, as the last and only record for this species in this state was made by Natterer in 1829 (Marsh 2014) (Table 1).This fact extends the distribution of this species about 34 km southeast from its previously determined southern limit in the state of Mato Grosso proposed by Marsh (2014) (Figure 3).The records of this species of saki monkey were limited to west and north of the Guaporé River (Marsh 2014), with the new record occurring in the southern part of this river, suggesting that the Guaporé River may not represent a major geographical barrier for medium-sized and large primates, as reported by Nunes (2014).During the dry season, beaches are formed in the Guaporé River over its meandering fluvial channel.Such factors may explain why the species is present on both margins of this river (Souza-Filho et al.  1. since these states present a large part of this species known distribution (Gusmão & Santos-Silva 2015).
Defining the ranges of both P. rylandsi and P. mittermeieri is critical for assessing their conservation status.Indeed, there is a lack of information about the ecology, behavior, group size, and range of both of these species.Since they currently are found in severely altered habitats, it is important to follow up sightings, like the ones herein, with intentional field studies to better understand these species.

Figure 2 .
Figure 2. A female of Pithecia mittermeieri recorded in a Savanna Woodland fragment in the rural municipality of Lambari d'Oeste in Mato Grosso, Brazil (Photo credit: Aldes Lamounier).

Figure 3 .
Figure 3.An updated distribution map of (1) Pithecia rylandsi (Primates, Pitheciidae) and (2) Pithecia mittermeieri (Primates, Pitheciidae).A. Overview of the South America, showing the area of study.B. Highlights the sites of new records for both species of Pithecia in the state of Mato Grosso in Brazil, according to published data and the present work.For locality data see Table 1.

Table 1 .
Occurrences records for Pithecia rylandsi and Pithecia mittermeieri, according to published data and the present study.