Pithecia monachus E. Geoffroy, 1812

Voss, Robert S. & Fleck, David W., 2011, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 1: Primates, Bulletin of the American Museum of Natural History 2011 (351), pp. 1-81 : 46-49

Pithecia monachus E. Geoffroy, 1812

VOUCHER MATERIAL (TOTAL 5 34): Nuevo San Juan (AMNH 26841–26844; MUSM 11126–11133, 11136, 11138, 11140–11151, 11153, 11154), Orosa (AMNH 73714, 74036, 74037), Quebrada Esperanza (FMNH 88862), San Fernando (FMNH 88861), Santa Cecilia (FMNH 87002).

UNVOUCHERED OBSERVATIONS: Actiamë ( Amanzo, 2006), Choncó ( Amanzo, 2006), Itia Tëbu ( Amanzo, 2006), Jenaro Herrera ( Aquino, 1978), Reserva Comunal Tamshiyacu-Tahuayo ( Puertas and Bodmer, 1993; Heymann and Aquino, 1994), Río Orosa ( Freese et al., 1982), Río Tapiche ( Bennett et al., 2001), Río Yavarí (left bank below Angamos; Salovaara et al., 2003), Río Ya-

varí-Mirím ( Salovaara et al., 2003), Tapiche ( Jorge and Velazco, 2006).

IDENTIFICATION: Saki monkeys from the Yavarí-Ucayali interfluve were referred to Pithecia hirsuta by Hershkovitz (1979), but subsequent study of type material led Hershkovitz (1987c) to identify the same specimens as P. monachus . Although all of our material is referable to P. monachus as that taxon was briefly distinguished in Hershkovitz’s (1987c) key, the taxonomic significance of phenotypic variation among western Amazonian populations of sakis remains to be convincingly established. Because our series from Nuevo San Juan (N 5 26 adult specimens) is the largest sample available to document morphological variation within a local population of any Pithecia species , we provide a detailed description below.

The 11 adult male skins from the Río Gálvez exhibit limited variation in pelage characters. The dorsal body pelage and the pelage of the outer surfaces of the arms and legs is predominantly blackish, but the individual hairs have pale tips that produce a frosted mass effect ; specimens with long, whitish hair tips (e.g., MUSM 11126 ) appear more heavily frosted than individuals with shorter, yellowish, or brownish terminal bands ( MUSM 11142 ). The distinctive ruff or mane surrounding the head does not contrast in coloration with the rest of the body fur. The hands are distinctly paler than the arms, appearing whitish in most individuals, but the bases of the individual hairs on the hands are always dark. Most specimens also have whitish feet, but a few (e.g., MUSM 11128 , 11129 , 11145 ) have grizzled pedal fur that is not conspicuously paler than the fur of the thigh and shank .

Whereas the body pelage is long and lax, especially over the shoulders and nape (60– 100 mm), the coronal pelage (from between the ears to the brow line) is abruptly shorter (, 10 mm) and stiffer, forming a dense mat; the cheeks are densely and more or less uniformly covered by hairs that are similar in length and texture to those of the coronal pelage. This pelage of the crown and cheeks is also abruptly paler than the body fur, ranging in mass effect from whitish to yellowish or brownish gray; the individual facial hairs always have dark bases and/or dark tips, however, so even the palest faces appear finely grizzled on close inspection. The muzzle is more sparsely haired than the cheeks and crown, and the exposed skin is blackish; a small patch of blackish skin is also exposed on the center of the forehead just above the brow line in most specimens. The throat is naked and glandular, but the chest has a prominent patch of long, pale-tipped fur; the abdominal pelage is sparse and uniformly black.

The female pelage is similar to the male condition, with a few exceptions. The most obvious difference is that the transition from the long, lax nuchal fur to the shorter fur of the head is not abrupt as it is in males; instead, the cranial hairs gradually decrease in length and increase in stiffness from occiput to forehead. The coronal pelage of females is also much more chromatically variable than that of males, with some females having conspicuously pale (whitish or beige) crowns and foreheads whereas others have much darker (brownish) cranial fur; the individuals with the palest (MUSM 11141) and the darkest (MUSM 11136) cranial fur in our series are both young adults as judged by tooth wear. Although the throat of females is mostly bare, the exposed gular skin is less obviously glandular than it is in males. The pectoral tuft of long, paletipped fur is also less well developed in females than it is in males.

Head-and-body length and several osteological measurements show strong sexual dimorphism in our sample ( table 15). In general, the craniodental pattern is typical of that seen in most primates ( Schultz, 1962) with dimorphism in the facial skull (rostrum, orbits, zygoma) and the canine teeth versus monomorphism in the braincase and postcanine dentition. Three qualitative cranial traits exhibit marked variation in our sample, which we analyzed for association with age (‘‘young’’ adults versus ‘‘old’’ adults, as determined by toothwear and basicranial suture closure) and sex using Fisher’s exact test. (1) The sagittal crest (coded as present or absent) is highly significantly associated with sex and with age (p « 0.01 for both tests), being present only in males and more frequently in old adults than in young adults. (2) The mesopterygoid fossa is quite variable in its anterior extent, terminating behind the toothrows in some individuals (e.g., AMNH 268244, MUSM 11145) and penetrating deeply between the molars in others (MUSM 11127, 11128), apparently independently of age and sex. (3) The pterygoid fossae are shallow and unenclosed by bone in most individuals but more deeply excavated in others (MUSM 11133, 11142, 11145), variation that also appears to be unassociated with age or sex.

In qualitative cranial characters, the Río Gálvez sakis all agree with Hershkovitz’s (1987c: table IV) diagnosis of the Pithecia monachus group, an assemblage that includes P. aequatorialis , P. albicans , P. irrorata , and P. monachus . According to Hershkovitz, taxa within this group are distinguishable only by pelage traits. In the comparative material we examined, the distinguishing external characters of all the saki species recognized by Hershkovitz are readily apparent, at least in adult males; by his classification, our vouchers are unambiguously referable to P. monachus . By contrast, P. irrorata (which occurs south of the Amazon between the Juruá and the Tapajós; Hershkovitz, 1987c) has an almostnaked head, the exposed blackish skin of which is conspicuously set off by an encircling white-fringed ruff. Another geographically adjacent form, P. aequatorialis (which occurs north of the Amazon between the Tigre and the Napo; Bravo and Ríos, 2007; Aquino et al., 2009) has long reddish or red-based fur on the cheeks (resembling the mutton-chop whiskers of 19th-century gentlemen) and a conspicuously reddish chest. Pending a comprehensive analysis of character variation in the monachus group, these and other character differences seem sufficient to maintain the nominal taxa recognized by Hershkovitz as distinct, but whether or not these should be recognized as full species remains to be convincingly demonstrated. 15 In the event that a trinomi-

al classification is judged to better represent the situation, our material from Nuevo San Juan would be referable to the nominotypical form P. monachus monachus .

ETHNOBIOLOGY: Saki monkeys are called bëşhuidkid, a term that is perhaps etymologically analyzable as meaning ‘‘white-faced one.’’ Two subtypes are recognized by the Matses: mamu (with no meaning in Matses, but in closely related languages it means ‘‘pitch,’’ a black adhesive made of beeswax and tree latex) and bëshudu (not analyzable, except possibly the prefix bë- ‘‘face/forehead’’). The mamu variety is said to be larger, have a whiter face, whiter hands, and a bushier coat, while the bëshudu variety is said to be smaller, to have a black or darker face, less white on its hands and a thinner coat. Troops of mamu are said to be found more frequently in upland habitats far from large rivers, and bëshudu more frequently along rivers. A minority of Matses hunters do not recognize two varieties and consider mamu and bëshudu to be synonyms of bëşhuidkid. Fleck et al. (1999) discussed this ethnobiological issue in detail and summarized morphological and genetic evidence that the Matses overdifferentiate saki monkeys.

All Matses eat sakis. As with other monkeys, sakis are cooked by first singing the hair off and then boiling them; likewise, men cannot eat or touch the intestines. Children usually eat the head. The Matses believe that if they give a dog a saki monkey bone, the dog will die; therefore, they are always mindful of this when disposing of the bones.

The Matses hunt saki monkeys by listening for their grunts and calls or the noise they make rustling branches as they move through the trees, or by looking for their dropped half-eaten fruits. When a hunter with dogs encounters saki monkeys and the monkeys do not see him, he imitates their raptorwarning call, upon which all the monkeys drop to the ground. The hunter then looses his dogs, which chase the monkeys down as they run away. Hunters also run after monkeys on the ground and club them or slam them against a tree when they catch them. (Saki monkeys will bite and sometimes even kill dogs that are trying to catch them. They will also bite people, if they are not careful when grabbing them.) If saki monkeys are familiar with this trick, they will not drop to the ground when a hunter imitates their raptor-warning call.

Now that most Matses are using shotguns, hunters without dogs will often ignore saki monkeys early in the hunt because the amount of meat they have is hardly worth a shell. Likewise, if hunters have dogs but the saki monkeys will not drop to the ground, hunters will probably not shoot at them early in the hunt. If hunters encounter sakis on the way back from an unsuccessful hunt, however, they will often shoot.

Sakis in trees are shot from the ground with arrows or shotguns. When they see people, sakis will not drop to the ground but run away very fast over the tops of branches and jumping from tree to tree. Hunters may chase one down until it gets tired and then shoot it (the Matses do not usually shoot at moving targets). Sometimes a hunter will climb a tree to kill a tired-out saki monkey that he cannot shoot from the ground, but the monkey may evade the hunter by dropping to the ground and running off.

MATSES NATURAL HISTORY: Saki monkeys have a lot of hair. Their bodies are actually small, but they look big because of all the hair. Their coats look like their hair has started to go gray, like an old person’s hair. Their faces and hands are white. The tail is furry and looks big, but it does not have much meat on it and cannot be used to grab onto things. Their head hair is also long, but not on the forehead. They are strong and run very fast through the trees without falling down. They run fast on the ground as well. They run fast even with their young on their backs. Saki monkeys can drop to the ground without hurting themselves.

Saki monkeys are found in all types of habitats, in upland forest and floodplain forest, in primary forest and in blowdowns. They travel high or low in the trees.

They are found in small troops, fewer than 10 animals, or sometimes alone. The troop usually stays together to travel, feed, and sleep, though occasionally they split up to search for food. Saki monkeys wake up just before dawn. When they wake up in the morning they go ‘‘ she she she aa aa aa.’’ When they see a jaguar, they say ‘‘ waa waa waa.’’ Sometimes they feed in the same tree with woolly or uakari monkeys. The whole troop sleeps in the same tree, wherever they are when night falls [i.e., they have no permanent sleeping sites].

Saki monkeys eat mostly dicot fruits, including wesnid dëbiate [ Anacardium giganteum (Anacardiaceae) ], këku [ Couma macrocarpa (Apocynaceae) ], diden këku [ Parahancornia peruviana (Apocynaceae) ], machishte [ Rhigospira quadrangularis and? Mucoa duckei (Apocynaceae) ], mamuin [ Rheedia longifolia (Guttiferae) ], okodo mabis [undetermined sp. (Guttiferae)], moste [ Hymenaea spp. (Leguminosae) ], mannan tsipuis [ Inga spp. and? Pithecellobium (Leguminosae) ], tankada [ Parkia igneiflora , P. multijuga , and Pithecellobium auriculatum (Leguminosae) ], şhupuduşh [ Brosimum parinarioides (Moraceae) ], şhupud [ Brosimum and Poulsenia (Moraceae) ], şhannëd [? Brosimum (Moraceae) ], bin [ Castilla (Moraceae) ], dadain [ Clarisia racemosa (Moraceae) ], piuşh bëchi [ Helicostylis tomentosa and H. elegans (Moraceae) ], kuşhu tëbin [ Naucleopsis mello-barretoi and N. ternstroemiiflora (Moraceae) ], şhankuin [ Pourouma spp. (Moraceae) ], bata [ Pseudolmedia and Maquira spp. (Moraceae) ], poşhodi [ Passiflora nitida (Passifloraceae) ], mabis mabiskid [ Chrysophyllum prieurii (Sapotaceae) ], and kose [ Manilkara bidentata (Sapotaceae) ]. They eat some of the dicot fruits before they are ripe. They throw down a lot of fruits as they eat. They eat palm fruits, especially swamp-palm [ Mauritia flexuosa ] fruit and some isan [ Oenocarpus bataua ] fruit. They also eat some leaves and insects.

Tables

TABLE 15 External and Craniodental Measurements (mm) and Weights (g) of Pithecia monachus from the Yavarí- Ucayali Interfluve

	Males a	Females b
HBL	413 ± 21 (361–436) 14	390 ± 18 (362–419) 12
LT	476 ± 34 (429–521) 14	481 ± 30 (423–540) 12
HF	127 ± 6 (116–136) 14	124 ± 6 (110–132) 12
Ear	38 ± 2 (34–41) 14	37 ± 2 (32–39) 12
CIL	73.3 ± 2.2 (70.0–77.7) 13	68.4 ± 2.7 (62.3–71.7) 12
OB	44.3 ± 1.7 (41.7–47.2) 14	40.8 ± 1.4 (39.1–43.6) 12
POC	35.1 ± 1.7 (31.1–37.9) 14	35.2 ± 1.5 (32.4–37.7) 12
ZB	55.9 ± 2.2 (51.2–59.5) 14	50.7 ± 2.2 (47.2–53.7) 12
BB	43.5 ± 1.3 (41.3–45.6) 14	42.9 ± 1.6 (39.2–45.4) 12
PPL	35.1 ± 1.9 (31.8–39.2) 13	32.4 ± 1.9 (29.4–35.4) 11
LMT	24.9 ± 0.8 (23.7–26.0) 14	23.8 ± 0.8 (22.9–25.8) 12
BM1	4.8 ± 0.2 (4.5–5.2) 14	4.7 ± 0.2 (4.3–5.0) 12
M1–M1	24.1 ± 1.0 (22.2–25.5) 14	23.1 ± 1.0 (21.1–24.4) 12
I2–I2	12.5 ± 0.7 (11.7–13.7) 12	11.9 ± 0.6 (11.0–12.8) 11
Weight	2849 ± 306 (2150–3350) 14	2095 ± 335 (1640–2800) 12

a Summary statistics (mean plus or minus one standard deviation, observed range in parentheses, and sample size) for

measurements and weights of AMNH 268241, 268244; MUSM 11126, 11128–11133, 11138, 11142, 11145, 11147, 11149,

b Summary statistics (mean plus or minus one standard deviation, observed range in parentheses, and sample size) for measurements and weights of AMNH 268243; MUSM 11127, 11136, 11140, 11141, 11146, 11148, 11150, 11151, 11153, 11154.