|Scientific Name:||Callicebus modestus|
|Species Authority:||Lönnberg, 1939|
|Taxonomic Notes:||Kobayashi and Langguth (1999) and van Roosmalen et al. (2002) recognize five species groups – cupreus, donacophilus, moloch, personatus and torquatus. They place Callicebus modestus in the donacophilus group, along with: Callicebus donacophilus, Callicebus pallescens, Callicebus oenanthe and Callicebus olallae. Tarifa (1996), Anderson (1997) and Felton et al. (2006) suggest that the taxonomic distinctiveness between C. modestus and C. olallae needs further investigation. However, more recent field observations (Martinez and Wallace 2007) and opportunistically collected specimens (R. Wallace pers. obs.) support the taxonomic separation of C. olallae and C. modestus. Preliminary results from a scat-based genetic study show that both are clearly distinct from C. donacophilus and each other (Barreta pers. comm. to R. Wallace 2007).|
|Red List Category & Criteria:||Endangered B1ab(iii) ver 3.1|
|Assessor(s):||Veiga, L.M., Wallace, R.B. & Martinez, J.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
Listed as Endangered as the species is known from a small number of localities in southwestern Beni where its extent of occurrence (excluding savanna) is well below 5,000 km². The range is fragmented, and there is a continuing decline in habitat due to ongoing forest destruction related to agriculture and cattle ranching (likely to accelerate with the forthcoming construction of a major highway).
|Range Description:||Endemic to Bolivia with very restricted range estimated at 1,800 km² (Martinez and Wallace 2007). It occurs in the upper Río Beni basin, a tributary of the upper Rio Madeira, Beni, Bolivia. van Roosmalen et al. (2002) incorrectly indicated that the species is parapatric with Callicebus dubius along the north bank of the Río Madre de Dios, with Callicebus donacophilus along the east bank of the Río Beni and with Callicebus olallae along the west bank of the upper Río Beni (Hershkovitz 1990). However, Felton et al. (2006) and Martinez and Wallace (in press) demonstrate that the species only occurs to the east of the Río Beni, west to the Manique River in south-western Beni Department. Rowe and Martinez (2003) were unable to confirm its range as proposed by van Roosmalen et al. (2002). The geographical range of Callicebus olallae overlaps with Callicebus modestus, although transitional zones between the two taxa have yet to be confirmed and each seems to specialize on different habitat types (Felton et al. 2006; Martinez and Wallace 2007).|
Native:Bolivia, Plurinational States of
|Range Map:||Click here to open the map viewer and explore range.|
In 2002, Felton et al. (2006) conducted titi monkey surveys and interviewed local residents at four locations: Puerto Santa Cruz on the Rio Yacuma; La Laguna; Petaca; and Naranjal. Titis were relatively abundant in Naranjal, not encountered at all in Petaca (although local residents claim they occur there), and are no longer present in La Laguna (probably exterminated through hunting). Examination of the holotypes indicates that the Rio Yacuma groups were C. olallae, while two of three groups found in Naranjal were Callicebus modestus (the third appeared to combine characters from both species).
Lopez-Strauss (2007) estimated density for both C. olallae and C. modestus using calling behaviour and an adapted point-count methodology. Conservative density estimates were recorded for C. modestus between 0.9 and 12.4 groups/km² (Lopez-Strauss 2007).
|Habitat and Ecology:||This taxon occurs in relatively dry forest patches within a forest-savanna mosaic (Lonnberg 1939; Anderson 1997; Felton et al. 2006; Martinez and Wallace 2007). Two relatively large groups with 5 to 7 members were found in Naranjal. Three groups, each with two members (possibly C. olallae), were encountered at Puerto Santa Cruz, to the north of the Rio Yacuma. Martinez and Wallace (2007) and Lopez-Strauss (2007) detail average group sizes of 3 and 2.64 individuals, respectively.|
|Major Threat(s):||The main threat to this species is forest loss and habitat fragmentation. Groups surveyed by Felton et al. (2006) occurred in fragments surrounded by cattle ranches. A farmer in Naranjal reported seeing groups crossing grassland gaps (300–400 m) between patches of forest (Felton et al. 2006). There is some limited hunting for pets. The proposed major improvement to a regional road will exacerbate deforestation and is likely to increase hunting pressure (Felton et al. 2006).|
A very small part of the range of this species is included within the Beni Biosphere Reserve area (R. Wallace pers. comm.). Conservation programmes in the region include: the Greater Madidi Landscape Conservation Program in northern La Paz and south-western Beni Departments of the Wildlife Conservation Society that has lead research efforts on both Bolivian endemics since 2002; and the Asociación Boliviana para la Conservación and Conservation International who have worked with the Santa Rosa Municipality in the development of a Municipal Reserve in south-western Beni Department.
It is listed on CITES Appendix II.
Anderson, S. 1997. Mammals of Bolivia: Taxonomy and distribution. Bulletin of the American Museum of Natural History 231: 1–652.
Brown, A. D. and Rumiz, D. I. 1986. Distribucion de los primates en Bolivia. In: M. T. de Mello (ed.), A Primatologia no Brasil, pp. 335-363. Sociedade Brasileira de Primatologia, Brasília, Brazil.
Felton, A., Felton, A. M., Wallace, R. B. and Gómez, H. 2006. Identification, distribution and behavioural observations of the titi monkeys Callicebus modestus Lönnberg 1939, and Callicebus olallae Lönnberg 1939. Primate Conservation 20: 40-46.
Groves, C. P. 2001. Primate taxonomy. Smithsonian Institution Press, Washington, DC, USA.
Hershkovitz, P. 1988. Origin, speciation, and distribution of South American titi monkeys, genus Callicebus (Family Cebidae, Platyrrhini). Proceedings of the Academy of Natural Sciences of Philadelphia 140(1): 240-272.
Hershkovitz, P. 1990. Titis, New World monkeys of the genus Callicebus (Cebidae, Platyrrhini): a preliminary taxonomic review. Fieldiana: Zoology 55: 1-109.
Kobayashi, S. 1995. A phylogenetic study of titi monkeys, genus Callicebus, based on cranial measurements: I. Phyletic groups of Callicebus. Primates 36(1): 101-120.
Kobayashi, S and Langguth, A. 1999. A new species of titi monkeys, Callicebus Thomas, from north-eastern Brazil (Primates, Cebidae). Revista Brasileira de Zoologia 16(2): 531-551.
Lönnberg, E. 1939. Notes on some members of the genus Callicebus. Arkiv för Zoologi 31(A): 1-18.
Lopez, L. In prep.. Dieta y comportamiento alimenticio de dos grupos de Callicebus olallae en la estancia ganadera La Asunta, Beni, Bolivia. Undergraduate Thesis, Universidad Mayor de San Andrés.
Lopez-Strauss, H. In prep.. Estimación de Densidad y Composición de Grupos de dos primates, Callicebus olallae y Callicebus modestus, especies endémicas del sud-oeste del Departamento del Beni – Bolivia. Undergraduate Thesis, Universidad Mayor de San Andrés.
Martinez, J. and Wallace R. B. 2007. Further Notes on the Distribution of the Bolivian Endemic Titi Monkeys, Callicebus modestus and Callicebus olallae. Neotropical Primates 14(2): 47-54.
Norconk, M. A. 2007. Saki, uakaris, and titi monkeys: behavioral diversity in a radiation of primate seed predators. In: C. J. Campbell, A. Fuentes, K. C.MacKinnon, M. Panger and S. K. Bearder (eds), Primates in Perspectives, pp. 123-138. Oxford University Press, New York, USA.
Patterson, B. D. 1992. Mammals in the Royal Natural History Museum, Stockholm, collected in Brazil and Bolivia by A.M. Olalla during 1934-1938. Fieldiana: Zoology 66: 1-48.
Salazar-Bravo, J. A., Tarifa, T., Aguirre, L. F., Yensen, E. and Yates, T. L. 2003. Revised Checklist of Bolivian Mammals. Occasional Papers, Museum of Texas Tech University 220: 1-28.
Tarifa, T. 1996. Mamiferos. In: P. Ergueta and C. de Morales (eds), Libro rojo de los vertebrados de Bolivia, pp. 165-262. Centro de Datos para la conservacion-Bolivia, La Paz, Bolivia.
Van Roosmalen, M. G. M., Van Roosmalen, T. and Mittermeier, R.A. 2002. A taxonomic review of the titi monkeys, genus Callicebus Thomas, 1903, with the description of two new species, Callicebus bernhardi and Callicebus stephennashi, from Brazilian Amazonia. Neotropical Primates 10: 1-52.
Wallace, R. B. and Mercado, N. 2007. La diversidad, distribución y abundancia de primates en Bolivia: Recomendaciones preliminares para su conservación. Abstract and Presentation at the V National Biology Congress. Santa Cruz, Bolivia.
Young, B. E. 2007. Endemic species distributions on the east slope of the Andes in Peru and Bolivia. NatureServe, Arlington, Virginia, USA.
|Citation:||Veiga, L.M., Wallace, R.B. & Martinez, J. 2008. Callicebus modestus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 30 July 2015.|
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