Search

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.

The Neotropics house two guilds of large arboreal vertebrate seed predators: parrots and the pitheciin primates. Both have diets dominated by immature fruits. The possibility of members of the Pitheciinae (generaCacajao,ChiropotesandPithecia) acting as occasional seed dispersers has been mooted, but not experimentally shown. We combined primate behavioural data and seed germination data from three separate field studies in the Brazilian states of Amazonas and Pará to analyse patterns of post-consumption seed survivorship for seeds discarded by three pitheciin species (Cacajao melanocephalus ouakary,Chiropotes chiropotesandChiropotes albinasus). We then calculated the frequency of dispersal events for four species eaten byC. m. ouakary. All three primate species dropped intact seeds while feeding, and 30.7% of 674 dropped seeds germinated ex situ. Undamaged seeds from unripe and ripe samples germinated (29.3% and 42.7%, respectively), and all three primate species carried some fruits up to 20 m from the parent tree before consuming them. Potential seed-dispersal events varied from 1 (Macrolobium acaciifolium) per fruiting cycle to more than 6500 (Duroia velutina), suggesting that there are differences in dispersal potential. In summary, although they are highly specialized seed predators, these primates may also act as important dispersers for some plant species, and effective dispersal is not restricted to ripe fruits, as immature fruits removed from a tree may continue to mature and the seeds later germinate, a much-neglected aspect of dispersal ecology. The possibility that similar events occur in parrots should be experimentally investigated.

Background Although simian foamy viruses (SFV) are the only exogenous retroviruses to infect New World monkeys (NWMs), little is known about their evolutionary history and epidemiology. Previous reports show distinct SFVs among NWMs but were limited to small numbers of captive or wild monkeys from five (Cebus, Saimiri, Ateles, Alouatta, and Callithrix) of the 15 NWM genera. Other studies also used only PCR testing or serological assays with limited validation and may have missed infection in some species. We developed and validated new serological and PCR assays to determine the prevalence of SFV in blood specimens from a large number of captive NWMs in the US (n = 274) and in captive and wild-caught NWMs (n = 236) in Peruvian zoos, rescue centers, and illegal trade markets. Phylogenetic and co-speciation reconciliation analyses of new SFV polymerase (pol) and host mitochondrial cytochrome B sequences, were performed to infer SFV and host co-evolutionary histories. Results 124/274 (45.2 %) of NWMs captive in the US and 59/157 (37.5 %) of captive and wild-caught NWMs in Peru were SFV WB-positive representing 11 different genera (Alouatta, Aotus, Ateles, Cacajao, Callithrix, Cebus, Lagothrix, Leontopithecus, Pithecia, Saguinus and Saimiri). Seroprevalences were lower at rescue centers (10/53, 18.9 %) compared to zoos (46/97, 47.4 %) and illegal trade markets (3/7, 8/19, 42.9 %) in Peru. Analyses showed that the trees of NWM hosts and SFVs have remarkably similar topologies at the level of species and sub-populations suggestive of co-speciation. Phylogenetic reconciliation confirmed 12 co-speciation events (p

Morphologic, karyotypic, and molecular analyses were carried out in 25 specimens of a distinct morph of Chiropotes (henceforth termed Chiropotes sp.) obtained from a number of localities in the Brazilian Amazon. Pelage coloration clearly distinguishes the collected specimens and all other known species of this genus. A distinct karyotype was described for Chiropotes sp. It differs from C. satanas chiropotes by two pericentric inversions, and from C. satanas utahicki by three, which suggests that these taxa are reproductively isolated. Morphometric analyses did not show significant differentiation between these Chiropotes taxa. Molecular analyses confirmed the monophyly of the subfamily Pitheciinae and genera Chiropotes, Cacajao, and Pithecia (the latter appearing as the most basal lineage of the pithecine clade). The genetic distances between C. s. utahicki and Chiropotes sp. from Rio Negro were greater than those between three recognized species of Pithecia, but smaller than those between Cacajao calvus and Cacajao melanocephalus. The most appropriate name for Chiropotes sp. from Rio Negro is C. israelita. This species, C. s. chiropotes, and C. s. utahicki are allopatric. Pelage coloration, karyotype, and molecular analysis strongly indicate that C. chiropotes, C. utahicki, and Chiropotes israelita deserve species status.

It has been suggested in the literature that primates of the genus Cacajao have been restricted to flooded-forest habitats of western Amazonia since their split from the Chiropotes line in the Tertiary. It has been proposed further that the differentiation of the two species of this genus, Cacajao melanocephalus and Cacajao calvus, occurred during the Pleistocene period as a result of the fragmentation of the Amazon forest and the isolation of populations in these forest fragments or refuges. However, recent evidence has shown that at least C. melanocephalus is not dependent on flooded-forest habitats, and molecular analysis of mitochondrial DNA shows that the two species had already differentiated during the Pliocene, thus Pleistocene glaciations do not explain the speciation in Cacajao. Considering that C. melanocephalus and its closest relative, Chiropotes, inhabit terra firme forests, it is suggested that preference for flooded-forest habitats may be an apomorphy in C. calvus.

A comparative chromosomal analysis was carried out in some specimens of the three genera of the subfamily Pitheciinae (Pithecia, Chiropotes and Cacajao) using a classic cytogenetic technique (G-banding). The three genera present distinct 2n: Pithecia presents 2n=48, Chiropotes 2n=54 and Cacajao 2n=45 in the males and 2n=46 in the females. The difference in 2. found in Cacajao occurs due to a y-autosome translocation present in the male of Cacajao calvus rubicundus. Species and subspecies of the same genera show the same 2n, however the FN are different. G-banding was used to analyze the homeologies among the taxa studied and, by this mean, we observed the presence of speciesspecific chromosomes, chromosomes shared between two or among all the taxa and also chromosomes that are present in all the specimens studied. Data of this karyotypic analysis suggest that Pithecia is the most primitive among the pithecins, followed by Chiropotes, and Cacajao is the most recent one, with very rearranged karyotype.

The purpose of this study was to determine nucleotide sequences from the 5' flanking region of the epsilon-globin gene of selected platyrrhine primates and to analyze the data for phylogenetic information and estimated times of divergence. We report new sequence data for two species of New World monkeys, Callicebus torquatus and Pithecia irrorata. We analyzed these data in conjunction with homologous sequences from other primate species. The data support the hypothesis that the titi monkeys (Callicebus) and seed predators (Tribe Pitheciini) form a clade (Subfamily Pitheciinae), and also provide limited support for that subfamily being allied with the atelines. We also present estimated dates of divergence for the Callicebus and pitheciin lineages.

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.

We report here a new fossil primate from the middle Miocene of Argentina. The material consists of isolated teeth, mandibular fragments, and a talus. The fossils were collected in the Collon Cura formation at Canadon del Tordillo in Neuquen Province. An age of 15.71 ± 0.07 Ma has been reported for the Pilcaniyeu Ignimbrite, which lies just below the paleosols in which the fossils were found. This material is thus the youngest occurrence of fossil primates in Argentina (hitherto documented in the Santacrucian and older land mammal ages) but still is older than the middle Miocene platyrrhine primates from La Venta, Colombia, in particular the pitheciins Nuciruptor and Cebupithecia. The material is recognized as a new genus and species of Pitheciinae, Propithecia neuquenensis. The mesiodistally compressed, high-crowned incisors are specialized and similar to species in the tribe Pithecini and to the nonpitheciin Soriacebus (early Miocene, Patagonia). We rule out a phylogenetic relationship to the latter because of differences in molar morphology. Propithecia does, however, fit well into the pattern of pitheciin evolution, being more derived than the middle Miocene pitheciin Nuciruptor but not as much as another middle Miocene taxon, Cebupithecia. As such, this makes Propithecia the oldest taxon that can be confidently placed within this modern New World monkey subfamily. By analogy with the molar structures and diets of extant platyrrhines, Propithecia has a molar structure consistent with a variety of low-fiber diets ranging from fruit and gum to seeds. Its incisors suggest seed-eating in much the same way as extant pitheciins, like Pithecia. The talus resembles that of Callicebus, suggesting arboreal quadrupedal locomotion. Am. J. Primatol. 45:317–336, 1998. © 1998 Wiley-Liss, Inc.

A new genus and species of platyrrhine primate, Nuciruptor rubricae, are added to the increasingly diverse primate fauna from the middle Miocene of La Venta, Columbia. This species displays a number of dental and gnathic features indicating that it is related to living and extinct Pitheciinae (extant Callicebus, Pithecia, Chiropotes, Cacajao, and the Colombian middle Miocene Cebupithecia sarmientoi). Nuciruptor is markedly more derived than Callicebus but possesses a less derived mandibular form and incisor-canine complex than extant and extinct pitheciins (Cebupithecia, Pithecia, Chiropotes, and Cacajao), suggesting that it is a primitive member of the tribe Pitheciini within the larger monophyletic Pitheciinae. Nuciruptor has procumbent and moderately elongate lower incisors and low-crowned molars, suggesting that is was a seed predator, as are living pitheciins. Its estimated body size of approximately 2.0 kg places it within the size range of extant pitheciines. The dental and gnathic morphology of Nuciruptor clarifies several aspects of dental character evolution in Pitheciinae and makes it less likely that the enigmatic Mohanamico hershkovitzi (m. Miocene, Columbia) is a pitheciin.

With the sakis (Pithecia) and the bearded sakis (Chiropotes), the uakaris (Cacajao) constitute the cebid subfamily, Pitheciinae. The most recent revision recognized six Cacajao subspecies in two species, confined to the Amazon basin. Before 1970 most field information derived from 19th century travellers. Studies still lag behind those of other cebid genera. This paper summarises the known ecology of Cacajao, and identifies future research and conservation priorities. The relevance of Pleistocene refugia and metachromism in analysing its biogeography is discussed. Range size remains obscure but, with the exception of C. c. calvus, may be extensive, as all other subspecies appear to migrate in the dry season from flooded riverine forest to terra firme. Observed group size ranges from 5 to 50, indicating the operation of a fission-fusion society. Social organization appears to be multi-male and non-hierarchical. This accords with the minimal sexual dimorphism. The highly developed canines function primarily as fruit openers. Cacajao is a dietary specialist on hard-shelled fruit, and appears unique among Amazonian cebids in its dependence (at least seasonally) on riverine forests. Hunting may be a problem locally, but local taboos sometimes offer protection. They appear vulnerable to habitat disturbance. On the Rio Negro, the range of C. m. melanocephalus appears to have greatly diminished. To ensure protection of viable populations, the inferred dietary dependence on seasonal migration may require accommodation. Research priorities include the status, habitat preference, diet and social ecology of all taxa except C. c. calvus. A more complete knowledge of the biogeography of the genus would be valuable.

One hundred and forty-three sakis (Pithecia), 107 bearded sakis (Chiropotes), and 7 red uakaris (Cacajao) were studied in relation to 18 genetic loci expressed on blood through electrophoretic techniques. Eight of the 18 loci showed intrapopulational variation. The low level of genetic diversity found inPithecia could be a consequence of a decrease in populational size due to intense habitat destruction. The genetic distances between the species investigated were:Pithecia ×Chiropotes: 0.49;Pithecia ×Cacajao: 0.57;Cacajao ×Chiropotes: 0.18–0.20. These results suggest, in accordance with other data, thatChiropotes andCacajao constitute a sister group within the pithecines.

The common English name for the genus Chiropotes is currently bearded saki. We propose the use of "cuxiu" as the common name for Chiropotes species, arguing that this term not only has deeper cultural and historical roots, but would mesh with the common name currently in use over the vast majority of the genus range. Cuxiu (pronounced "coosh-e-oo") would be phylogenetically and taxonomically more appropriate, and less ambiguous, than the currently used term, and remove the implied close affiliation between Pithecia and Chiropotes . Finally, as an indigenously-derived name, it would fit with the common names in use for the other two genera in the sub-family Pitheciinae (uacari, Cacajao ; saki, Pithecia ), both of which also have indigenous origins.

White-faced saki monkeys (Pithecia pithecia) lack most of the behavioral and physical traits typical of primate monogamy [Fuentes, 1999]. 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 (

A phylogenetic assessment of Pitheciinae ( sensu Hershkovitz, 1977) is undertaken. Among the three living genera of pitheciines, Chiropotes and Cacajao share a more recent common ancestor than either does with Pithecia . Evidence for the position of pitheciines within the platyrrhine clade is weak and contradictory owing partly to the amount of parallelism within and among various platyrrhine subfamilies. Rosenberger's (1979, 1984) hypothesis that Aotus and/or Callicebus are closely related to pitheciines is not supported by a review of the cranial, dental and postcranial evidence. The evidence is weak that Alouatta and the atelines are the sister group of pitheciines as argued by Ford (1986) . An alternative view is advanced that pitheciines are an early offshoot of the platyrrhine clade. The relationships of some fossil forms to living pitheciines are considered. Cebupithecia from the Miocene of Colombia is definitely pitheciine based especially on the dentition (rounded, chisel-shaped canines) but also on postcranial evidence. However, it lacks some of the dental specializations shared by living pitheciines; therefore it is most likely a sister group of living pitheciines. Argentine Miocene Soriacebus is not a pitheciine but is convergently specialized for a diet similar to living pitheciines. Colombian Miocene Mohanamico hershkovitzi (a senior synonym of Aotus dindensis ) is possibly a very primitive pitheciine and an unlikely sister taxon to Callimico .

Six out of the 16 recognized species of fossil New World monkeys have been discussed as possible relatives of the modern callitrichines. The dental evidence for these views is examined, with emphasis on the homologies and polarities of the relevant characteristics. We conclude that there is no support for the idea that either Xenothrix or “Saimiri” bernensis are related to callitrichines, thus leaving unconfirmed the interpretation that some subfossil postcrania from the Caribbean pertain to the group. The middle Miocene La Venta forms Micodon and Mohanamico (shown not to be synonymous with Aotus dindensis) appear to be callitrichines: the first, largely on account of its very small size; and the second, by the morphology of the lower canine and canine/premolar complex. Potentially derived features shared by callitrichines and Soriacebus, an older form from Patagonia, are convergent, however. Soriacebus is referred to a new higher taxon of the Tribe Pitheciini (Subfamily Pitheciinae), Subtribe Soriacebina, distinguished from its sister-group, the monophyletic Subtribe Pitheciina, by exhibiting a more primitive morphology than the characteristic sakiuakari dentition. The La Venta Neosaimiri, an alleged intermediate between callitrichines and other platyrrhines, is autapomorphically linked with squirrel monkeys, as is another cebine from the early Miocene, Dolichocebus, once classified as a callitrichine. The fossil record thus indicates that callitrichines were in existence by the middle Miocene, but their rarity as fossils reveals little of their broader phylogenetic ties or adaptive history.

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.

This paper investigates the interrelations of some organismal and habitat parameters in two platyrrhine primate communities in French Guiana and Ecuadorian Amazonia. Fifteen habitat and organismal parameters and body weight were retained after a preliminary analysis, on the basis of frequent use and constraints reflected in anatomical specializations. The 16 parameters for 13 platyrrhine species were used for a series of principal components analyses (PCAs). All PCAs on separate or combined communities provided comparable results. The Atelinae, Ateles, Alouatta, and Lagothrix, were clustered together with Pithecia, associated with canopy, mature forest, frugivory, and (to a lesser degree) climb/suspensory locomotion. On the other hand, the three species of Cebus usually formed a loose cluster, located in the center of the cloud of species. Lastly, the Callitrichinae, involving two species of Saguinus and Cebuella, were relatively dispersed and frequently associated with liana forest, lianas, understory, and faunivory. However, Cebuella was consistently isolated and associated with liana forest, lianas, body weight, understory, and vertical supports. In this way, clusters appeared to conform to the major platyrrhine taxonomic groups, supporting the fact that basic ecological and behavioral adaptations have evolved in a phylogenetic context. In addition, the analyses revealed that body weight, forest type and layer, feeding behavior, and locomotion are the most important variables that have apparently shaped or driven the adaptive zones of extant platyrrhines.

The primate order includes two suborders, the Prosimii and the Anthropoidea (Martin 1970). The Prosimii include tarsiers, lemurs and lorises whereas the Anthropoidea include two infraorders, Catarrhini and Platyrrhini. Catarrhini are Old World primates (for example, rhesus monkeys), apes (chimpanzees, gorillas, orangutans and gibbons) and humans. The taxonomic status of the 16 genera that form the infraorder Platyrrhini (commonly known as the New World primates) has been controversial. However, both morphological studies (Ford 1986; Kay 1990; Rosenberger 1984) and molecular data (Schneider et al. 1993) agree on dividing the 16 extant platyrrhine genera into seven phyletic groups: Callitrichidae (tamarins and marmosets (Fig.1); genera Callithrix, Cebuella, Leontopithecus, Saguinus and Callimico), Pithecinae (genera Pithecia, Chiropotes, and Cacajao),Atelinae (genera Lagothrix, Brachyteles, Ateles and Alouatta), genus Cebus, genus Saimiri (squirrel monkeys), genus Aotus (owl monkeys) and genus Callicebus.

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 pitheciines, 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 subcanopy, a pattern similar to that of other southwestern Amazonian saki species, but sharply different from that of Guianan sakis (Pithecia pithecia), which use considerably lower levels of the forest. Comparisons are made between different Pithecia species to show whether and how P. albicans diverges ecologically from its congeners. © 1993 Wiley-Liss, Inc.

Since Mivart (1865), Cacajao, Chiropotes, and Pithecia have been grouped into a single taxon, which he called the subfamily Pitheciinae but which I, following Rosenberger (this issue), refer to as the living members of the tribe Pitheciini. While few today doubt the association of these three living genera, not all would place them together with Aotus and Callicebus in the subfamily Pitheciinae. This is an attempt to sort out the behavioral and morphological features of feeding and dental morphology in these taxa. Extant members of the tribe Pitheciini are adapted for sclerocarpic foraging, morphological evidence for which is found in the fossils of Soriacebus and Cebupithecia. Sclerocarpic foraging in living pitheciins is a two-stage process of seed predation involving 1) specialized features of the anterior dentition that allow removal of a hard pericarp that protects a seed or seeds, followed by 2) mastication by the posterior dentition having low cusp relief to triturate nutritious seeds of a relatively soft and uniformly pliable consistency. The dentitons of fossil pitheciins, Soriacebus and Cebupithecia, demonstrate that the hypertrophy of lower incisors plus the robustness and flaring of the canine precede development of low cusp relief on molars and premolars in the evolution of morphological features associated with sclerocarpic foraging. Features of sclerocarpic foraging are found less uniformly in the other two pitheciines, Callicebus and Aotus. © 1992 Wiley-Less, Inc.

Research conducted over the past decade has dramatically increased our knowledge of the evolutionary biology, behavior, and ecology of New World primates. Extensive field data have been collected for species from virtually all of the 16 extant genera. During this same period, the discovery of a large number of platyrrhine fossils from the Oligocene of Argentina and Bolivia, and the Miocene of Colombia, has led to a major reevaluation of the evolution and systematics of this primate group (Fleagle and Rosenberger, 1990). These specimens provide a more complete sequence from which to identify phylogenetic relationships between fossil and living forms. There is now serious doubt concerning the simple and longstanding dichotomy of New World primates into “clawed and “nonclawed taxa, and researchers have constructed a new framework for assessing the adaptive trends which characterize this important primate radiation. The papers presented in this issue of the American Journal of Physical Anthropology were originally presented on April 7, 1989, at the 58th Annual Meeting of the American Association of Physical Anthropologists in San Diego, California. The purpose of the symposium was to examine in detail the evolution of feeding adapations in each of the four subfamilies of living New World primates-Callitrichinae, Cebinae, Pitheciinae, and Atelinae. Within each paper, special attention is given to relationships between body size, diet, dental morphology, locomotor anatomy, and foraging behavior. Comparisons are made between extinct and extant taxa, as well as interspecific comparisons within subfamilies. These provide a basis for understanding the origin and function of dietary adaptations in Platyrrhini. The lead paper by Ford and Davis outlines the major issues and lines of evidence that have been used to construct the phylogenetic history of New World primates. Beginning with the argument that the traditional CallitrichidaeICebidae classification can no longer be supported, these authors review several recently proposed schemes of platyrrhine systematics. Although these schemes are in general agreement regarding the taxonomic grouping within the Callitrichinae (the marmosets and tamarins; termed Callitrichidae by some authors), and the close evolutionary relationship between the Atelinae and the saki-uakari group, the positions ofdotus, Callicebus, Saimiri, and Cebus continue to be debated. Ford and Davis also address a series of questions regarding the influence of body size (weight) on Neotropical primate foraging strategies. These authors argue that the evolutionary history of many platyrrhine lineages has been characterized by major increases andor decreases in body size. Comparisons of feeding adaptations in extant species, therefore, must consider “patterns of body size change through time,” and whether particular taxa have attained similar size through common or independent evolutionary pathways. Ford and Davis provide four alternative cladograms to account for the direction and magnitude of body weight changes in living New World monkeys and use these reconstructions to identify significant dietary, behavioral, locomotor, and ecological issues in

The axial skeleton of Cebupithecia sarmientoi is described and analyzed for its functional and phylogenetic implications. The vertebrae of the holotype of C. sarmientoi (UCMP 38762) most closely resemble those of the extant pitheciine genus Pithecia and display features associated with adaptations for clinging and leaping as in that genus. Cebupithecia has a relatively long non-prehensile tail, which is most similar in absolute dimensions and proportions to Pithecia monachus. It also shares with P. monachus a distinctive morphology of the thoracic vertebrae, specifically the presence of a bony pillar spanning the vertebral lamina and body, caudal to the pedicle, herein designated the vinculum laminum. It is proposed that many of these features are shared primitive retentions from the last common ancestor of the Cebupithecia-pitheciine clade.

A discriminant analysis was performed on 226 ceboid skulls using data on emissary foramina size and shape. The purposes of the study are to 1) measure the success with which these discriminating variables can distinguish among platyrrhine genera and 2) derive a set of classification functions which will permit the classification of new cases with unknown group membership (i.e., fossil skulls). This technique is able to correctly classify 80% of the 226 ceboid skulls. Support is given to the allocation of Chiropotes, Cacajao, and Pithecia into one morphologically unified subfamily, Pitheciinae. Alouatta, Ateles, and Lagothrix also share many similarities in emissary foramina size and shape and their inclusion into one subfamily, Atelinae, is probably warranted. The distinctiveness of Cebus in these same morphological features is apparent. Possibilities for extending this procedure to study fossil lineages in platyrrhines are discussed.

A detailed description is given of the somatic chromosomes of two specimens of Pithecia pithecia pithecia. An idiogram, constructed on the basis of metrical chromosome data, is presented and compared with those of two other members of the Pitheciinae. The possible karyological relationships within the Pitheciinae, and the cytotaxonomic position of this group within the Platyrrhini are briefly discussed.

Based on a comparison of the karyotypes of two Plathyrrhini species, Cacajao melanocephalus (Pitheciinae) and Brachyteles arachnoides (Atelinae), with those of two previously studied species, Lagothrix lagothrica (Atelinae) and C calvus rubicundus (Pitheciinae), it appears that the two Cacajao species have undergone the same number of chromosome rearrangements since they diverged from their common ancestor and that the karyotype of Brachyteles is ancestral to that of Lagothrix. The chromosomal phylogeny of these four species is proposed. A Y-autosome translocation is present in the karyotypes of the two Cacajao species.

The report begins with a key based on external characters and a tabulation of diagnostic cranial characters for separating Pithecia from Chiropotes and Cacajao of the subfamily Pitheciinae. The description of Pithecia is based on external, cranial, dental, and certain postcranial characters with particular attention to limb proportions and the femoral third trochanter. The species of Pithecia are arranged in the Pithecia pithecia group with P. p. pithecia and P. p. chrysocephala, and the Pithecia monachus group with P. m. monachus, P. m. milleri, P. irrorata irrorata, P. i. vanzolinii (new subspecies), P. aequatorialis (new species), and P. albicans. The discussion on nomenclature compares the usage of names by various authors for the different taxa. The species previously identified by Hershkovitz [Hershkovitz, 1979] as Pithecia monachus proves to be the new species P. aevuatorialis, whereas the sympatric species he called P. hirsut Spix (1823)s the same as true P. monachus É. Geoffroy (1812). Speciation among sakis is expressed, for the most part, by marked differentiation in coloration and head pelage patterns in males. Females of corresponding males diverged along the same lines but to such lesser degree that specific discrimination between them is complicated. Details of sexual dimorphism in coloration and pelage patterns are described, and those of size are documented by summaries of weights and by measurements of external, cranial, dental, and skeletal characters for each sex of each taxon. A key to the species and subspecies of Pithecia is followed by an account of each taxon that includes statements of taxonomic history or synonymy, type specimen, type locality, and geographic distribution. A full description with the addition of accounts of diagnostic characters, variation, comparisons, measurements, list of specimens examined, and other matters, is provided only or the new forms Pithecia aequatorialis and P. irrorata vanzolinii. Comparable descriptions of all taxa are contained in Volume 2 of Living New World Monkeys, currently in preparation. The gazetteer, however, includes complete data for all saki collecting and recorded localities plotted on the range maps.

The ecology of two closely related pitheciine monkeys, Cacajao calvus and Chiropotes albinasus , is reviewed, with an emphasis on their frugivorous feeding habits and the habitats they prefer. Although both consume a similar diet of young seeds of common plant taxa, they employ different foraging strategies. Chiropotes forages as a single unit in large multi-male/multi-female groups, whereas Cacajao aggregates split into parties of flexible subunits. These differences relate to their contrasting habitat preferences. Chiropotes live in the non-inundated terra firme forests and Cacajao live in the flooded varzea forests. Each habitat type is characterized by a distinctive taxonomic and spatial composition of local fruit trees, and they also contain different animal faunas. An attempt to reconstruct the evolutionary history of these monkeys is made, based upon the geomorphological evolution of the Amazoniau region.

Palmar and plantar dermatoglyphic pattern types, area and total pattern intensities (API and TPI), and pattern intensity (PI) profiles are presented for the South American genus Cacajao of the subfamily Pitheciinae. The data are based on prints from 41 bald-head uacaries (C. calvus), 9 white bald-head uacaries (C. c. calvus), and 15 black-head uacaries (C. melanocephalus). In each extremity, loops of differing orientation were the most frequent pattern type; whorls were dominant at palmar interdigital (I) area 3 in C. calvus and at both I3 and I4 in C. melanocephalus. Open fields characterized the palmar thenar and plantar proximal hypothenar, thenar, calcar, and I3 and I4. There was little evidence of significant sexual dimorphism as assessed from PI values. The genus displayed significant asymmetry at palmar I3 (P⩽0.001) and plantar distal hypothenar (P⩽0.004). There were significant group differences between C. calvus and C. c. calvus in the palmar thenar API and plantar TPIs. The combined bald-head sample of C. calvus and C. c. calvus differed from C. melanocephalus in API of palmar I4 and plantar distal thenar, I2, and distal hypothenar (marginally), and in plantar TPIs. In PI profiles, C. melanocephalus departed from the pattern shared by C. calvus and C. c. calvus in both palmar and plantar interdigital areas. As a genus, the uacaries have markedly low plantar TPI values relative to palmar values (palm-sole index > 195). Of eight comparison cebid genera, only Chiropotes, another pitheciine genus, approximated these values.

The following characteristics indicate that the skin of the silvered sakiwinki (Pithecia monachus, E. Geoffroy, 1812) is not only basically similar to other primitive cebids, but also remarkably close to that of callithricids: a thin epidermis with diminished monoamine oxidase activity; a poorly-developed dermis, paucity of elastic fibers, and scant adnexal blood supply; hair follicles arranged in linear perfect sets; grouped hairs present on the cheek; an absence of glycogen and phosphorylase in most sebaceous glands; apocrine glands present throughout most haired body regions, but totally absent from the dorsum; and poorly-differentiated eccrine glands, confined to volar friction surfaces, which are characterized by unusual glycolytic properties. Other noteworthy cutaneous traits include: concomitant epidermal and dermal pigmentation in the face and scalp; Merkel-like disks in the friction surfaces; moderately well-developed Haarscheibe, associated with large, dorsal guard hairs; small, discrete sebaceous glands throughout the dorsum; a 1:1 ratio of apocrine glands to hair follicles in the facial, gular and anogenital areas; and numerous cholinesterase-reactive nerves around eccrine but not apocrine secretory coils. Although previous comparative studies on the skin of New World monkeys suggest that the systematic designation of two familial taxa is warranted, information regarding five of the fifteen genera which comprise the families Callithricidae and Cebidae is totally lacking. Given that three of these genera (Leontopithecus, Chiropotes and Brachyteles) can no longer be obtained from animal dealers because of exportation laws, the authors were fortunate to acquire representatives of the remaining two genera. Callicebus (titi monkeys) and Pithecia (sakiwinkis). Besides defining cutaneous characteristics common to specific taxa, two earlier works by Hanson and Montagna ('62) and Perkins et al. ('68) also suggested that members of the cebid subfamilies Aotinae and Pitheciinae possess cutaneous traits that bridge an interesting gap with the callithricids. Therefore, the acquisition of these two additional aotine and pithecine genera provided the opportunity to test this hypothesis. The following, therefore, is not just another detailed manuscript regarding the skin of primates. Rather, it is an effort to define the integumental characteristics of the last obtainable New World monkey genera, and to assess those cutaneous signatures which are interfamilially common to both the callithricids and more primitive cebids. Primary emphasis is placed on the genus Pithecia; pertinent findings concerning Callicebus will be incorporated into the forthcoming and final summarization of the phylogenetic significance of the skin of New World monkeys (Perkins, '75).