Literature olallae

Lönnberg, 1939

Callicebus olallae

Locality: The Stockholm Museum has 1 specimen from “Rio Beni, La Laguna, una legua de Santa Rosa, Bolivia”.

Description: General colour almost uniformly rufous (perhaps most resembling “Sandfords brown”among the colours represented in Ridgeway’s colour standards, but not quite so bright). The anterior parts of the back are somewhat darker by means of tiny black tips to some of the hairs. The flanks and hind quarters are somewhat brighter and more rufous, but below the knee the hairs of the hind legs become somewhat tipped with black increasing on the feet, and the toes are beset with long bristly hairs, partly dark, but also some pale ones. The arms are resembling chestnut, but a little darker than the back by means of numerous tiny, black tips increasing towards the hands but the fingers look paler, because there are some bristly, brownish white hairs mixed in. The short-haired upper parts of the head look dark rufous, which is effected by means of alternating rings of orange rufous and black. A thin front-line is black and especially pronounced to the sides to small tufts. The semi-naked face is beset with short and adpressed, whitish hairs mixed with black bristles on the cheeks. The whiskers are darker than the neck by means of black tips. The ears are comparatively well covered with brownish white hairs. The fur of the body is very soft, and almost silky, differing in this respect in a remarkable degree from the corresponding general conditions f.i. in C. cupreus and allied forms. The tips of the longer hairs are very thin and attenuated. The average length of the fur on the anterior part of the back is hardly more than 4,5 cm. It is partly a little longer on the flanks and on the posterior portion of the back it increases to 5,5 or even 6cm.
The proximal 5 centimetres of the tail are like the rump, the remaining parts differ abruptly in colour, as if they belonged to another animal. They are rather brownish, which colour is affected by a mixture of pale brownish and black rings to the pairs. In consequence of this the tail looks somewhat grizzled, but there is no trace of the long whitish tips found in the cupreus-group, which give the tails of these species such a characteristic appearance.

Collectors’ measurements: Male: total length 750mm; tail 340mm; hind foot 100mm.

Skull: measurements and description of 1 specimen in the publication.

Lönnberg, E. (1939). Notes on some members of the genus Callicebus. Arkiv för Zoologi 31 (13): 1-18.

Cabrera, 1958

Callicebus brunneus

Synonyms: Callithrix brunnea (Wagner, 1842); Callithrix personatus (Gray, 1870); Callicebus brunneus (Elliot, 1913); Callicebus ollallae (sic)(Lönnberg, 1939).

Remarks: The description of C. olallae contains nothing that permits to distinguish if from C. brunneus, and its locality is that close to these that one could think of a subspecific difference.

Cabrera, A. (1958). Catálogo de los mamíferos de América del Sur. Instituto Nacional de Investigacion de la Ciencias Naturales, Ciencia Zoologica, 4 (1): 137-142.

Hill, 1960

Callicebus ollalae (sic!)

Type locality: La Laguna, Rio Beni, Bolivia. Type in Stockholm Museum.

Distribution: Known only from the type locality.

Description: Though obtained so near the type locality of C. cupreus modestus, the pelage differs so considerably that Lönnberg considered them to belong to different species, an opinion that is confirmed by cranial differences. It can scarcely be described as a further geographical race of cupreus in view of the close proximity of the habitat. Cabrera (1957), however, synonymies it with brunneus which he regards as a separate species.
General colour almost uniformly rufous (Sanford’s brown of Ridgeway, but not quite so bright).
A thin line of black hairs on forehead better developed at the sides, where they form tufts. Rest of crown dark rufous, due to alternating ringing of hairs by orange-rufous and black; anterior parts of back similar with black tips to hairs; flanks and hind-quarters brighter rufous, but distal to knee black tips reappear, increasing on the feet and toes, the latter beset with longer, bristly black hairs mixed with paler ones. Arms chestnut, the hairs with black tips increasing distally on hands, but fingers paler from inter-mixture of bristly pale-brown hairs.
Face as in C. cupreus, but whiskers darker than neck due to black-tipped hairs; ears with brownish-white hairs. Tail proximally like rump, but distal two-thirds brownish, due to annulations of pale brown and black of individual hairs giving grizzling effect; line of demarcation between basal one-third and rest very abrupt “as if they belonged to another animal”. Pale tip characteristic of tail cupreus lacking.
General character of fur softer and almost silky compared with the more wiry character in C. cupreus, modestus and other races of cupreus. Tips of longer hairs very attenuated, average length on mantle region approximately 4.5cm, but reaching 5.5 or 6.0cm on flanks and hinder parts.

Measurements: head and body 410mm; tail 340mm; foot 100mm.

Skull: see measurements and description in publication.


Hershkovitz, 1963

Callicebus moloch brunneus

Synonyms: Callithrix brunnea (Wagner, 1842); Callithrix brunnea (Wagner, 1848); Callithrix castaneoventris (Gray, 1866), Callicebus toppini (Thomas, 1914); Callicebus olallae (Lönnberg, 1939); Callicebus modestus (Lönnberg, 1939); Callicebus cupreus acreanus (Vieira, 1952); Callithrix cuprea (Goeldi and Hagman, 1904); Callicebus caligatus (Osgood – not Wagner -, 1916).

Remarks: the original description of castaneoventris, toppini, olallae, modestus and acreanus, all from the same general area, are based on vague comparisons with cupreus only. No mention was made of other related forms although Lönnberg did attempt to distinguish his modestus from his olallae described in the same paper. It is not surprising therefore, that all should prove equally distinct from cupreus and equal to each other, or brunneus, the oldest available name.

Callicebus olallae from the Rio Beni, Bolivia, was (also) disposed of by Cabrera, this time in synonymy of brunneus which he regarded as a distinct species. Judged by the description, the type and only known specimen of olallae has all the important diagnostic characters of Callicebus moloch brunneus and others which suggest intergadation with C. m. donacophilus. The name olallae, proposed in honour of its collector, was misspelled ollallae by Cabrera (1958) and ollalae by Hill (1960).


Hershkovitz, 1988

Callicebus olallae

Member of the donacophilus group.

Remarks: The Bolivian highland Callicebus modestus and Callicebus olallae. Known only from their individual type localities hardly 50km apart in the upper Yaruma-Mamoré basin, differ widely from each other and all others. In the absence of contrary evidence, each may also be regarded as an isolated relic species despite the geographic proximity to each other and to other populations of C. brunneus and C. donacophilus. Their geographic position may be analogous to that of the Peruvian Callicebus oenanthe and perhaps should be classified with it as essentially insular.

The C. donacophilus group is composed of small species; morphologically intermediate between the C. modestus and C. moloch groups, but nearer the latter.

The distribution of C. olallae, C. modestus, C. brunneus and C. donacophilus donacophilus, correlate with Brown’s single postulated refuge 22 (yungas). Present geographic distribution of prototypes of the most primitive living species C. olallae, C. modestus, C. oenanthe, C. donacophilus, and the hypothetical prototype of the C. moloch group is rooted in the southwestern portion of the generic range, well beyond the Río Solimoes Amazons flood plain.

Herskovitz, P. (1988) Origin, Speciation, and Distribution of South American Titi Monkeys, Genus Callicebus (Family Cebidae, Platyrrhini), by Philip Hershkovitz . Proceedings of the Academy of Natural Sciences of Philadelphia 140 (1): 240-272.

Hershkovitz, 1990

Callicebus olallae

Member of the donacophilus Group.

Synonyms: Callicebus olallae (Lönnberg, 1939).

Type locality: La Laguna, 5 km from Santa Rosa, Beni, Bolivia; altitude, ca. 200 m above sea level. Holotype in Royal Natural History Museum, Stockholm.

Distribution: Known only from the type locality in the upper Rio Beni drainage basin, Beni, Bolivia.

Description: Face framed with blackish, forehead reddish brown agouti; outer surface of limbs reddish brown; cheiridia dominantly blackish; sideburns not markedly contrasting in coloration with crown and forehead; blackish suborbital vibrissae conspicuous; back and sides dominantly orange, hairs with extremely broad orange median band; tail entirely dark agouti in sharp contrast with back; whitish ear tufts weak; skull as in the C. moloch group but hamular process and interpterygoid fossa less reduced than usual.

Measurements: See publication.

Comparisons: Distinguished from Callicebus brunneus by dominantly orange coloration throughout; from C. modestus and all species of Callicebus except C. oenanthe, by individual hairs of back with broad orange median band; from C. oenanthe by blackish rimmed face and absence of whitish frontal blaze; from C. donacophilus by dominantly brownish or blackish cheiridia and lack of sharp contrast between coloration of under parts and sides of body; from caligatus by orange agouti forehead, from C. moloch and C. hoffmannsi by absence of sharp contrast between sideburns and forehead and crown; from all other species by one or more of above characters.

Specimens examined: Total 1. Bolivia – Beni: La Laguna, near Santa Rosa, Rio Beni, 1 (holotype).

Hershkovitz, P. (1990). Titis, New World Monkeys of the genus Callicebus: A Preliminary Taxonomic Review. Fieldiana Zoology 55: 1-109.

Kobayashi, 1995

Callicebus olallae

Based on cranial measurements, the genus can be divided in five groups:

  • the donacophilus group (including modestus, olallae, d. donacophilus and d. pallescens)
  • the cupreus group (including caligatus, c. cupreus, c. discolor and c. ornatus)
  • the moloch group (including brunneus, h. hoffmannsi, h. baptista, moloch and cinerascens)
  • the personatus group (including p. personatus, p. nigrifrons, p. melanochir)
  • the torquatus group (including t. lucifer, t. lugens, t. medemi, t. regulus, t. purinus and t. torquatus).

The group position of C. dubius remains uncertain; C. oenanthe and C. barbarabrownae were not examined.

Kobayashi, S. (1995). A phylogenetic study of Titi Monkeys, Genus Callicebus, based on cranial measurements: 1. Phyletic groups of Callicebus. Primates 36(1): 101-120.

Anderson, 1997

Callicebus olallae

Synonyms: Callicebus olallae (Lönnberg, 1939; Hershkovitz, 1988; Kobayashi, 1990, 1991, 1995; Groves, 1993); Callicebus moloch brunneus (Hershkovitz, 1963); Callicebus moloch olallae (Emmons and Feer, 1990); Callicebus ollallae (Anderson, 1993).

Locality: Beni: La Laguna.

Remarks: The specific status of both Callicebus modestus and C. olallae needs further study. Hershkovitz
(1990) published photographs of the skull of the holotype and noted its elongation. He wrote that Callicebus modestus differs from C. brunneus “by generally paler coloration, forehead reddish brown agouti, ear tufts whitish, outer surface of limbs not blackish.” If a series of Callicebus from the Beni River
valley could be obtained and studied, a betterunderstanding of variability would be gained and the present hypothesis of specific distinctness of C. modestus and C. olallae could be tested more rigorously.

Anderson, S. (1997). Mammals of Bolivia, Taxonomy and Distribution. Bulletin of the American Museum of Natural History 231: 1-652.

Groves, 2001

Callicebus olallae

Synonyms: Callicebus olallae (Lönnberg, 1939).

Distribution: Known only form the type region.

Description: (after Hershkovitz, 1990). The most primitive of the donacophilus-group, with cranial capacity only 21% of greatest skull length. Orange-toned, hairs with a single, very broad orange band; tail dark agouti; weak white ear tufts; limbs red-brown, hands and feet blackish; conspicuous black supraorbital vibrissae.


Roosmalen et al., 2002

Callicebus olallae

Type locality: La Laguna, una legua de Santa Rosa, Río Beni, Bolivia. The holotype is an adult male, skin and skull in the Royal Natural History Museum of Stockholm, Sweden, no. A632187, collected February 1938 by A. M. Olalla (coll. no.187).

Distribution: Upper Río Beni basin, Beni, Bolivia.

Description: Facial fringe (sideburns, beard and forehead) blackish, crown reddish brown agouti; outer surface of limbs reddish brown; cheiridia dominantly blackish; blackish suborbital vibrissae conspicuous; back and limbs uniformly orange (hairs with extremely broad orange median band); tail entirely dark agouti sharply contrasting with orange back; whitish ear tufts weakly developed. Distinguished from Callicebus donacophilus by blackish facial fringe, lack of malar stripe, weakly developed whitish ear tufts, dominantly brownish or blackish cheiridia and lack of a sharp contrast between coloration of under-parts and sides of body; from Callicebus modestus by blackish facial fringe, individual hairs of back showing a broad orange median band, and lack of well-developed whitish ear tufts.

van Roosmalen, 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(Suppl.): 1-52.

Felton et al., 2006

Callicebus olallae

Locality: Puerto Santa Cruz on the Río Yacuma (14º00′S, 66º58′W)

Description: Individuals from Groups 1–3 were characterized by rufous on their back, limbs, and chest, with lighter rufous on the outside of limbs; dark brown-red forehead, sideburns, and beard; small white ear tufts; pale throat; blackish hands; creamy under parts; and a sharply contrasting blackish, uniformly coloured, tapering tail (Figs. 2 and 3). The anterior base of the tail was pale orange. The fur appeared short and spiky. The face had white hairs on the muzzle.
An examination of the holotypes suggests that Groups 1–3 were C. olallae and Groups 4 and 5 were C. modestus. In contrast to the illustration provided on page 10 of Van Roosmalen et al. (2002) the C. olallae holotype does not have a conspicuous black face ring. Our examination of the original specimens does, however, concur with the descriptions provided by Lönnberg (1939) and Hershkovitz (1990).
The pelage colour of most of the individuals of Group 6 was similar to that of Groups 1–3 (C. olallae) in that they had a rufous non-agouti back and chest, creamy under-parts, and a pale throat, although they resembled Groups 4 –5 (C. modestus) by having conspicuous white ear tufts and pale hands. One distinctly coloured individual in this group appeared lighter and possibly had grey-red agouti fur on the back. All individuals of Group 6 also had a denser layer of white hairs on the face and a whitish anterior base of the tail.
Although we can be confident that we have found individuals that are representative of the two species originally classified by Lönnberg in 1939, this does not imply that we are certain of the taxonomic distinctiveness of C. modestus and C. olallae. The identification of individuals that possessed characteristics in keeping with both C. modestus and C. olallae certainly raises questions regarding their taxonomy. There is also reason to question previous views that these species are parapatric (Hershkovitz, 1988), as no rivers or watersheds separate the populations observed in this study. It is our opinion that the proximity of the original collection site for
C. olallae, and the current known distribution of C. modestus, suggests that they share at least part of their respective geographic ranges. Nevertheless, further investigation is needed to establish whether these species may be genetically isolated by stretches of open grasslands. Similarly, variations in the composition and structure of vegetation across forest patches should be determined in order to assess possible differences in habitat preferences between the two. We concur with Anderson (1997) that further information is needed to determine the taxonomic distinctiveness of C. modestus and C. olallae.

Felton, A., Felton, A.M., Wallace, R.B. and Gómez, H. (2006). Identification, Behavioural Observations, and Notes on the Distribution of the Titi Monkeys Callicebus modestus Lönnberg, 1939 and Callicebus olallae, Lönnberg 1939. Primate Conservation 20: 41-46.

Martinez and Wallace, 2007

Callicebus olallae

Distribution: According to our observations, C. olallae is largely restricted to riverine habitats on the Yacuma River, although one group occurred 5 km east of the Maniqui River but in similar habitat. A partial preference for drier forest patches is noticeable for C. modestus, which occurred on the eastern and western sides of the Yacuma River. One C. modestus group occurred just 100 meters east of the Maniqui River, but this area was a higher and drier forest area. Overall, these data give preliminary support to the hypothesis that C. olallae is found in relatively humid and riverine forest in this patchily forested landscape; whereas C. modestus is found in relatively drier forest patches.
We determined the Beni River as the distributional western barrier for both Bolivian endemics. During 2005, WCS researchers recovered a titi monkey skin from a hunted individual from forest immediately adjacent to the Beni River on the western side. This specimen represents Callicebus aureipalatii, the new species recently described from the Madidi protected area and registered only on the western side of the Beni River (Wallace et al., 2006).
In June 2005, we observed C. modestus groups in forest immediately adjacent and on the eastern side of the Beni River. However, it is important to note that the C. modestus location around the San Marcos community was in a noticeably drier belt of forest than the majority of the relatively humid forest found immediately adjacent to the Beni River. Indeed, on several previous visits to the community we failed to register Callicebus in the more humid sectors of this forest.
The southern and southwestern limits for the two endemics occur in two broad 10 km swaths on either side of the Yucumo – Rurrenabaque road, an area characterized by lack of primary forest and low densities of wildlife related to several human settlements. Colonists who settled in these areas almost ten years ago do not report titi monkeys. In addition, no confirmed records exist for Callicebus in the Pilón Lajas Biosphere Reserve and Indigenous Territory, and indigenous people indicate that titi monkeys are not present within the reserve. These negative reports together with areas of humid forest located to the south (as observed in satellite images) suggest that these larger blocks of more humid forest represent a southern limit for the distribution of both endemic species.
We extended the known distributional limits (Hershkovitz, 1990; Anderson, 1997) for both C. olallae and C. modestus. We found groups of C. modestus between Yacuma and Maniqui Rivers, and groups of both species in the riverine forests of the Maniqui River.
Subsequently we investigated reports of the presence of C. modestus to the east of the Mamoré River (M. Herrera, pers. comm. to R. Wallace), but instead were able to verify the presence of Callicebus donacophilus at this location. Additional observations of C. donacophilus east of the Maniqui and Mamoré Rivers suggest that neither C. modestus nor C. olallae occur further east of the Maniqui River. Indeed, the San Borja region is the current known eastern distributional limit for both species.
To determine the northern limit, we extended our surveys to the relatively tall and humid Amazonian forests located south of Riberalta. Here we observed Callicebus groups that resembled species within the C. cupreus species group (van Roosmalen et al., 2002). Unfortunately, due to observation conditions, we were unable to assign species level identification to these groups. Nevertheless, we are certain that these observations do not represent either of the endemic species.
We suggest that the southern limit of this more humid forest probably represents a northern boundary for C. modestus and perhaps C. olallae although further field confirmation is recommended. In the highly fragmented forests between Santa Rosa del Yacuma and San Borja and northeast of Trinidad on the eastern side of the Mamoré River we failed to register Callicebus, and people here report not to have ever seen or heard these monkeys. Forest vegetation in these areas was very scarce and highly patchy, with relatively small and rather scattered stands of forest. In addition, forests did not have abundant canopy vines—a feature that characterized Callicebus localities in the broader southwestern Beni region.

The key result for both C. olallae and C. modestus is the extension of the eastern limit from the previously known distributional area in the Beni and Yacuma Rivers (Anderson, 1997; Felton et al., 2006). Our results also offer a preliminary northern distributional limit for both species although further work is required to establish how this limit varies for each species.
Our results show that C. olallae is restricted to riverine forests along the Yacuma and Manique Rivers, whereas C. modestus seems to occupy patches of forest in a larger area between the Beni and Maniqui Rivers. We therefore suggest that C. olallae has an extremely restricted distribution with groups almost entirely concentrated on the Yacuma River, and so far just one group registered along the Maniqui River. Nevertheless, the habitat preferences of both species need further study, particularly given that both species are absent from smaller forest patches in the region.

Description: During this study, we encountered 66 groups of Callicebus at 20 localities. Of these, 14 groups were Callicebus olallae, 31 were Callicebus modestus, 16 were Callicebus donacophilus, and for five groups we were unable to assign a species identification. These new records have dramatically increased the number of observations for the endemic species. For each species, we have identified diagnostic morphological characteristics helpful to distinguish the species in field. These features relate mainly to pelage coloration patterns.
Callicebus olallae has rather long, brown reddish body pelage. Under good light conditions, a wide orange band along each hair is visible, with the tip of the hair appearing brown. The tail is more grayish but the color does not contrast strongly with the coloration of the body fur; the base of the tail is lighter both dorsally and ventrally. White ear tufts are very conspicuous. Narrow rims of black hair that reach the ears are distinguishable around the faces of some individuals. Hands and feet are black with some white hairs visible. Another important feature is the vertically elongated form of the head with a clearly prominent and oval-shaped mouth especially noticeable in adult males. Body fur color appears more intensely red when individuals are in direct sunlight.
Direct and prolonged observations allowed us to determine critical diagnostic phenotypic traits for both C. olallae and C. modestus under a variety of lighting and weather conditions. Pelage coloration is the clearest characteristic that allows species identification in the field. For C. olallae for at least some animals we confirmed the black ring around the face originally described by Lönnberg (1939), contrasting with observations of the same species by Felton et al. (2006). The contrast between the color of the tail and body pelage is another important difference, with the basal zone conspicuously lighter in C. olallae. The longer and shaggier pelage of C. olallae was another recognizable trait. Differences in the density of white hair on the ear tufts were not considered diagnostic because observations suggested variability across phenotypes in the same groups, although this may be related to observation conditions that did not allow for the distinction of subtle features. We also noticed some distinctions in the head shape of adult males that concur with cranial measurements reported by Kobayashi (1995).

Martinez, J. and Wallace, R.B. (2007). Further Notes on the Distribution of Endemic Bolivian Titi Monkeys, Callicebus modestus and Callicebus olallaeNeotropical Primates 14(2): 47-54.

Mercado and Wallace, 2010

Callicebus olallae

Distribution: west of Beni Department, limited by the eastern margin of the Beni River. In plots of forest and the galary forests of the Ríos Yacuma y Maniquí.

Mercado, N.I. and Wallace, R.B. (2010). Distribución de primates en Bolivia y áreas prioritarias para su conservación. Tropical Conservation Science 3 (2):200-217.