Phylogenetic relationships within the Callicebus cupreus species group (Pitheciidae: Primates): Biogeographic and taxonomic implications.

The genus Callicebus (Thomas, 1903) is one of the most diverse of Neotropical primate genera and the only extant member of the Callicebinae subfamily. It has a widespread distribution from Colombia to Brazil, Bolivia, Peru and northern Paraguay. Coat colouring and colour pattern vary substantially within the genus, and this has led to the description of numerous species and subspecies, as well as numerous species groups. However, a lack of molecular phylogenetic analyses on the genus means that phylogenetic relationships and biogeographic history of species are poorly understood. Here, we examined phylogenetic relationships and patterns of diversification within the Callicebus cupreus species Group (sensu Kobayashi, 1995) using complete mitochondrial DNA cytochrome b gene sequence. Analyses indicate that the Callicebus cupreus Group underwent recent and extensive diversification. The common ancestor appears to have emerged some 2.3 million years ago (Ma) from a centre of origin in the western Amazon region, followed by diversification of the group between about 1.5 and 1.2Ma. Phylogenetic analyses were able to recover most previously described species (including the recently described Colombian endemic Callicebus caquetensis). However, there are some notable inconsistences between the obtained phylogeny and current taxonomy. Some previously recognized taxa were not separated by our data (e.g., Callicebus caligatus and Callicebus dubius), while currently unrecognized species diversity was uncovered within C. cupreus in the form of two divergent lineages: one of which exhibited greater phylogenetic similarity to species from the C. moloch Group. Based on the present study, we challenge current taxonomic arrangements for the C. cupreus species Group and call for a thorough taxonomic revision within the genus Callicebus.

Contiguous distribution of two species of Cebus monkeys in El Tuparro National Park, Colombia.

The geographic distribution of two congeneric monkeys (Cebus albifrons and C. apella) was studied in El Tuparro National Park in the llanos of eastern Colombia. Extensive trips were undertaken by land and river to collect 268 precisely located groups of these two species. The distributions of these monkeys were generally mutually exclusive and parapatric, contrasting with their known sympatry in closed-canopy rainforest farther to the south. The replacement of one species by the other was abrupt along the northern water courses in the park; however, the two species' ranges partially overlapped and contained islands of sympatry towards the southern parts of the park, where forests are more extensive. Along the rivers, C. albifrons was found in seasonally inundated forests and woodlands that were seldom entered by C. apella. Such inundatable vegetation was extensive in downriver sites in the typically flat llanos geography of this part of Colombia. Although some differential use of habitat was demonstrated, many forests containing the two species seemed essentially identical so that historical precedence, competition, or both may also be posited to partially explain the distributions, although this remains to be demonstrated.

Aspects of the ranging pattern in a group of wild woolly monkeys (Lagothrix lagothricha).

A group of woolly monkeys (Lagothrix lagothricha), studied for 1,800 hr from June 1984 until September 1987 in the eastern Colombian Amazon, used a home range of about 760 ha, 90% of which overlapped the ranges of three other groups. Home range use varied throughout the year, correlating in part with variations in fruit production. The home range exhibited a nonexclusive "core area" in the floristically most diverse part of the home range, although the majority of the home range was entered at a much lower frequency. Within the study area woolly monkeys occurred at a density of 5.5 individuals/km2. The average day range was 2,880 m, and the average straight line distance between sleeping sites was 896 m. Day ranges differed significantly across months, but the only significant correlation tested was a positive relation with time spent "moving" in the activity budget. Comparisons with three other Amazonian sites where woolly monkeys have been studied reveal considerable variation. Soil fertility, plant community differences, and other factors seem to influence ranging patterns. © 1996 Wiley-Liss, Inc.

Callicebus torquatus is not a white-sand specialist.

The hypothesis of Kinzey and Gentry [Primate Ecology: Problem Oriented Field Studies. New York, John Wiley & Sons, 1979] that Callicebus torquatus may be specialized for living in vegetation on white sand was evaluated by reviewing all observations I made of this species, where the substrate had been noted, and including some collection sites of J. Hernández Camacho. There was no evidence for the white-sand hypothesis. Instead, Callicebus torquatus was found to prefer upland and flooded forests that are tall and well stratified, and growing on many soil types, including white sand. © 1994 Wiley-Liss, Inc.

SOME EVOLUTIONARY TENDENCIES OF NEOTROPICAL PRIMATES: Algunas tendencias evolutivas de los primates neotropicales

The evolution of neotropical primates has occurred isolated from other primates of the world, resulting in a distinct evolutionary history. Various characteristics of neotropical primates (Platyrrhini) are quite distinct from those of the Old World (Catarrhini), including the dental formula, the position of cranial plates, the anatomy of the auditory apparatus, much less average body weights, much less terrestrial adaptation, prehensile tails for some, and conservative phenotypes. Additionally monogamous forms of platyrrhini share a tendency for rapid chromosome evolution with one monogamous group of catarrhines (Hylobatids or gibbons). The phyletic history of the platyrrhine monkeys seems to contrast with that of the catarrhine inasmuch as there was a very early division (Miocene) of the New World monkeys into groups that exist today, whereas the appearance of Old World primate family groups seemed to have occurred much more recently in the Plio-Pleistocene. Some of these tendencies can be explained hypothetically, looking at ecological characteristics suggested for the new continent while other tendencies are perhaps the result of random evolutionary pathways taken during the course of evolution such as genetic drift and founder effect. Nevertheless there is still much work to be done to be able to recognize the singularities of the Platyrrines and to appreciate the details of their evolution.

La evolución de los primates neotropicales ha transcurrido aislada o de forma independiente a la de otros primates del mundo, porque poseen una historia evolutiva diferente. Hay varias características de los primates neotropicales (Platirrinos) que son bien distintas a las del viejo mundo (Catarrinos), incluyendo la fórmula dental, el arreglo de las placas craneales, la anatomía del aparato auditivo, pesos corporales menores, una menor adaptación a comportamientos terrestres, algunos poseen colas prensiles y baja diferenciación fenotípica. Formas monógamas de platirrinos comparten una tendencia de evolución cromosómica rápida con un grupo monógamo de Catarrinos (los Hilobátidos o gibones). La historia filogenética de platirrinos, contrasta con la de catarrinos debido a una división filética antigua (mioceno) de los primates del nuevo mundo en dos grupos, con características filogenéticas expresadas en las especies actuales. En contraste, la diferenciación de catarrinos con características que se pueden identificar en especies actuales no sucedió sino hasta el Plio-Pleistoceno. Algunas de estas tendencias, pueden ser explicadas hipotéticamente teniendo en cuenta las características ecológicas planteadas en el nuevo continente; otras tendencias tal vez son el resultado de caminos evolutivos tomados al azar durante la evolución del grupo o, como resultado tanto de deriva genética como de un efecto fundador. Sin embargo, queda mucho trabajo para reconocer la totalidad de las singularidades de los platirrinos y poder apreciar los detalles de su evolución.