Type locality: Yahuas, North of Loreto, about 2º40’S – 70º30’W, alt. 500m.
Distribution: Eastern Peruvian Amazonas.
Description: Like C. lugens Humb. (syn. Amictus, Geoff.), but the tail chestnut-rufous instead of black. Belly black, not red as in C. torquatus.
Remarks: By some accident the synonymies of the yellow-handed titis have got confused in prof. Elliot’s recent great work on the primates. He calls the red-bellied species C. torquatus, putting C. lugens and Saguinus vidua among its synonyms, while the black-bellied one he terms amictus. But a study of the original descriptions of these four animals shows that while torquatus is red-bellied, lugens, amictus, and vidua are all black-bellied and are clearly synonymous with each other, lugens being the earliest name. Its type-locality is the Upper Orinico, not Olivença, Solimoes, as stated, the latter locality being taken from Spix, whose specimen was probably C. lucifer.
Specimens of this group are very rare in collections, and the British Museum only contains six, two of each species, as follows:
C. torquatus – Adult; Rio Negro; bought in 1842; collector unknown. Head and forelimbs: Ega, Amazon; H.W. Bates
C. lugens – Young specimen from Maipures, Orinico, practically a topotype of the species; coll. G.K. Cherrie. Adult specimen; “Guiana” (no doubt incorrect); Sir R. Schomburgk.
C. lucifer – Type and paratype from Yahuas, as above.
Thomas, O. (1914). On various South-American Mammals. Annals and Magazine of Natural History (8) 13:345.
Callicebus torquatus lucifer
Distribution: Rio Iça and Loreto district.
Remarks: The British Museum has received from Herr Ehrhardt some further specimens of the beautiful monkeys of the Callicebus torquatus group, the yellow-handed Titis, and I have now had an opportunity of studying them.
In 1914 I described a monkey of this group, accepting for the time being the recognition of the red-bellied and black-bellied forms (respectively torquatus and lugens) as distinct species, to which I added a third under the name of lucifer.
But the available material now available tends to show the essential unity of all the Yellow-handed titis, and I should now propose to consider them as belonging to one species only, whose name would be C. torquatus, and to recognize among them five subspecies, each of which appears to be very constant in colour locally.
Description: Under surface and inner aspect of thighs smoky or blackish. Tail dark red; back and crown also uniformly dark reddish.
Thomas, O. (1927). In the titi monkeys of the Callicebus torquatus group. Annals and Magazine of Natural History (9) 19: 509-510.
Callicebus torquatus lucifer
Description: the representative in north Peru is reddish black.
Tate, G.H.H. (1939). The mammals of the Guiana region. Bulletin of AMNH 76: 219-220.
Callicebus torquatus lucifer
Synonym: Callicebus lucifer (Thomas, 1914).
Description: Similar to torquatus lugens but tail chestnut rufous instead of black. Belly black.
Remarks: Like lugens it is very rare, only the two specimens being known. If the specimens that Spix mentions as C. amictus really belong to this form, its geographical distribution on the upper Amazon extends to Brazilian territory.
Cruz-Lima, E. da (1945). Mammals of Amazonia Vol. 1. General introduction and primates pp. 175-198.
Callicebus torquatus lucifer (Thomas, 1914)
Synonyms: Callicebus torquatus lucifer (Thomas, 1927), Callicebus torquatus ignitus (Thomas 1927).
Distribution: North-western Brazil, north of the Solimoes and the contiguous parts of Peru and Colombia, in the drainage of the Putumayo.
Remarks: Having the abdomen reddish instead of blackish appears for us not sufficient to separate, not even sub specifically, ignitus from lucifer, as both forms were obtained in the same zone. It is interesting to note that Thomas, in the same work in which he described ignitus about a young specimen from the Rio Tonantins, only a few lines before, he considered as lucifer another specimen from the same locality. It seems to us more logical that the colour of the abdomen is subject to individual variation, than that two geographical forms live at the same locality.
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.
Callicebus torquatus lucifer (Thomas, 1914)
Type locality: Yahuas (=Yaguas), Rio Putumayo, northern Loreto, Peru. Type in British Museum.
Distribution: A rare form, only two specimens being known. Thomas (1927) gives Rio Iça and Loreto district of Peru as range. Thomas (1914) considered Olivença on the Rio Solimoes – given by Spix as locality for lugens and copied by Elliot – as within the habitat of lucifer, to which race he would assign Spix’s example.
Description: Resembling lugens rather than any of the other races, but distinguished by the rufous chestnut tail. Crown and upper parts of body uniformly dark reddish; under parts black, including medial aspect of thighs.
Hill, W.C.O. (1960). Primates. Comparative anatomy and taxonomy 4 (A): 98-147.
Callicebus torquatus torquatus (Hoffmannsegg, 1807)
Synonyms: Callithrix torquata (Hoffmannsegg, 1807); Simia amicta (Humboldt, 1812); Callithrix amictus (E. Geoffroy, 1812); Callithrix amicta (Spix, 1823); Callithrix amictus (Tschudi, 1844); Callicebus torquatus (Ihering, 1904); Callicebus torquatus (Thomas, 1914); Callicebus lucifer (Thomas, 1914); Callicebus torquatus lucifer (Thomas, 1927); Callicebus torquatus purinus (Thomas, 1927); Callicebus torquatus regulus (Thomas, 1927); Callicebus torquatus ignitus (Thomas, 1927); Callicebus torquatus torquatus (Thomas, 1927); Callicebus torquatus (Cruz Lima, 1945); Callicebus torquatus lucifer (Cabrera, 1958); Callicebus torquatus amictus (Cabrera, 1958).
Variation within the species: Individuals or populations of torquatus from the north bank of the Solimoes with uniformly reddish trunks such as the type of ignitus Thomas from the Rio Tonantins, mingle with somberly coloured ones with dark under parts such as those Thomas (1927) described and recorded as lucifer. Similarly, on the south side of the Solimoes, brightly coloured individuals of torquatus with reddish belly and thighs (purinus, Thomas) seem to be randomly distributed with brownish ones with dark bellies (regulus, Thomas). Lönnberg (1939) noted that a series of reddish torquatus from Jaburú, middle Rio Purus, south of the Solimoes, was hardly distinguishable from another from Codajáz, north of the Solimoes. He nevertheless kept them apart by recording each series under the names purinus and torquatus, respectively. Two reddish brown dark bellied specimens at hand from the Rio Nanay, Peru, on the north side of the Marañon, agree with the original description of the brownish dark-bellied regulus Thomas from south of the Solimoes.
Apparent absence of features for consistently distinguishing the populations of one side of the Solimoes from those of the other is remarkable. Cabrera (1958) rejected colour as a subspecific character but nevertheless recognized a northern Amazonian race (lucifer) and a southern race (amictus).
The possibility that Callicebus torquatus torquatus is dichromatic in some parts of its range is suggested in the above discussion. The only evidence, however, is the reference by Thomas (1927) of the occurrence of reddish (ignitus, type an immature) and blackish form (lucifer) representatives of torquatus in the same locality on the Rio Tonantins and the somewhat obscure note by Cruz Lima (1945) that a male and female from Fonteboa, type locality of regulus, represent the reddish and dark phase, respectively. Nothing is known of seasonal and age variation in colour and pelage and no differences are apparent between the sexes. Nevertheless, whether considered individually or collectively, all populations of subspecies torquatus, as recognized here, can be distinguished from medemi and lugens by their more reddish colour and by their contrastingly whitish or yellow hands or fingers, respectively.
Localities: Ampiyacu (3º1’S-71º50’W) and Upper Nanay (3º45’S-74º10’W, 3º10’S-74º55’W), Peru
Freese, C.H.; Heltne, P.G.; Castro R., N. and Whitesides, G. (1982). Patterns and Determinants of Monkey Densities in Peru and Bolivia, with Notes on Distributions. International Journal of Primatology 3(1): 53-90.
Hernandez-Camacho and Cooper, 1976
Callicebus torquatus lucifer?
Remarks: Two C. torquatus specimens from the southern bank of the lower Guamues River near Puerto Leguizamo have light-yellowish hands and distinctly ferruginous under parts (including ventral tail surface). This pattern is in contrast with the blackish under parts of typical C. t. lugens and approaches the characteristics claimed for C. t. lucifer (Thomas, 1914), a subspecies not separable from C. t. lugens according to Hershkovitz (1963).
Hernandez-Camacho, J. and Cooper, R.W. (1976). The nonhuman primates of Colombia. Neotropical Primates: Field Studies and Conservation. Pp. 47-49.
Neville et al., 1976
Localities: Mishana, Mayna river, Peru. Reported from the Samiria and Pacaya rivers, but it is possible that they were confused with Callicebus discolor.
Neville, M.; Castro, N.; Marmól A. and Revilla, J. (1976). Censusing Primate Populations in the Reserved Area of the Pacaya and Samiria Rivers, Department Loreto, Peru. Primates, 17(2): 151-181.
Kinzey et al., 1979
Callicebus torquatus torquatus
Locality: The study site is in northern Peru, near the Nanay River, 30 km southwest of Iquitos, and about 4 km south of the caserio of Mishana (see map).
Description: The pelage is rather uniformly reddish black, although the tail is blacker than the body. Two contrasting areas of colouration are a whitish to buffy coloured throat patch and yellowish hands. The throat patch does not extend like a collar around the neck, but occurs only on the ventral side of the neck. The infant animal we observed has relatively longer hair, particularly noticeable in the tail which therefore appears more “fluffy.” Otherwise the pelage of the infant is indistinguishable from that of the adults.
Kinzey, W. G.; Rosenberger, A. L.; Heisler, P. S.; Prowse, D. L. and Trilling, J. S. (1979). A Preliminary Field Investigation of the Yellow Handed Titi Monkey, Callicebus torquatus torquatus, in Northern Peru. Primates 18(1): 159-181.
Kinzey and Robinson, 1983
Locality: The study site was located about 4 km south of the Rio Nanay, 30 km southwest of Iquitos
in northeastern Peru.
Kinzey, W.G. and Robinson, J.G. (1983). Intergroup Loud Calls, Range Size, and Spacing in Callicebus torquatus. American Journal of Physical Anthropology 60:539-544.
Callicebus torquatus lucifer
Member of the torquatus group.
Hershkovitz, 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.
Hernandez-Camacho and Defler, 1989
Callicebus torquatus lucifer
Distribution: two specimens from the right margin of the lower Rio Guamués, near Puerto Asis, Putumayo, differ from the other Colombian specimens examined in having the pelage of the hands yellowish, and the under sides (including the tail) reddish, en contrast with the upper parts. This colouration approaches that of C. t. lucifer, and suggests that this subspecies can be recognized as the adjacent populations on the right bank of the Rio Putumayo. However, Hershkovitz (1963) considers lucifer to be a synonym of lugens.
Callicebus torquatus lucifer
Member of the torquatus Group.
Synonyms: Callicebus lucifer (Thomas, 1914); Callicebus torquatus ignitus (Thomas, 1927).
Type locality: Yahuas Territory, near Pebas, Loreto, Peru, about 125 m. Type in British Museum.
Distribution: North bank Rio Solimoes-Amazonas in Brazil, Colombia, Ecuador, and Peru; in Brazil between the Rios Solimoes and Japura; in Colombia between the Rios Caqueta (Japura) below mouth of Rio Caguan, and Rios Putumayo and Amazonas in the departments of Caqueta, Putumayo, and Amazonas; in Ecuador between the upper Rios Aguarico and Putumayo, Napo province; in northern Loreto, Peru, between the Rios Putumayo, Nanay, and Amazonas.
Description: Hands whitish, buffy orange to rufous with or without mixture of blackish hairs; tail blackish or with mixture of reddish; under parts except throat blackish, reddish brown, or reddish; Chest and belly brown or blackish; hairs surrounding ears uniformly blackish; hairs of back and sides brownish or reddish brown, the hairs distinctly to weakly banded.
Comparisons: Distinguished from lugens by brownish agouti upper parts; from torquatus and purinus by blackish under parts; from regulus by hairs surrounding ears uniformly blackish; and from medemi by dominantly or entirely orange hands.
Specimens examined: Total 27. Brazil – Amazonas: Rio lea, near Colombian border; Rio Tonantins (holotype of ignitus); Santa Rita. Colombia – Amazonas: Encanto, Rio Caraparana. Peru – Loreto: Apayacu; Lagarto Cocha, boca; Pebas; Rio Curarary, boca; Santa Luisa, Rio Nanay; Yahuas Territory.
Hershkovitz, P. (1990). Titis, New World Monkeys of the genus Callicebus: A Preliminary Taxonomic Review. Fieldiana Zoology 55: 1-109.
Callicebus torquatus lucifer
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.
Voss and Emmons, 1996
Locality: Colombia, Amazonas, Rio Miriti-Parana (study site on right bank, ca. 18 airline km WNW of confluence with left bank of lower Caqueta at ca. 1°11’S, 70°02’W). Peru, Loreto, Rio Ampiyacu (surveys centered at ca. 3°10’S, 71°50’W).
Callicebus torquatus lucifer
Synonym: Callicebus lucifer (Thomas, 1914)
Distribution: From between the Rio Solimoes and the Rio Caquetá.
Remarks: Almost certainly there are several species among what Hershkovitz (1990) designated as subspecies. I have little experience with this group and so leave them as subspecies of the one species, except for the strikingly distinct black-handed medemi.
Van Roosmalen et al., 2002
Callicebus lucifer (Thomas, 1914)
Type locality: Yahauas Territory, in the vicinity of Pebas, Department of Loreto, Peru. Type is an adult male, skin and skull, in the British Museum of Natural History, London.
Distribution: Interfluve delineated by the Rio Solimões and Río Napo in the south, and the Rio Japurá and Río Caquetá in the north; in Brazil between the Rios Solimões and Japurá; in Colombia between the Ríos Caquetá below mouth of Río Caguán, and Rios Putumayo and Amazonas in the departments of Caquetá, Putumayo and Amazonas; in Ecuador between the upper Ríos Aguarico and Putumayo, Napo province; and in Peru in northern Loreto, between the Ríos Putumayo, Nanay, and Amazonas. Campos et al. (1992) and De la Torre et al. (1995) report on the presence of C. torquatus, which we presume to be C. lucifer (but may, alternatively, be C. medemi) in the Cuyabeno Reserve, Río Aguarico, province of Sucumbios, in north-eastern Ecuador.
Description: Feet, tail, head, sideburns, and under parts except throat entirely blackish, hairs of back and sides of body brownish or reddish brown, the hairs distinctly to weakly banded, throat white, hands orange. Distinguished from C. lugens by brownish agouti upper parts and orange instead of white hands; from C. torquatus and C. purinus by orange instead of white hands and blackish under parts; from C. regulus by blackish (except white throat) head and hairs surrounding ears uniformly blackish, and orange hands; from C. medemi by dominantly or entirely orange instead of black hands.
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.
Heymann, et al., 2002
Description: Van Roosmalen et al. (2002) rose to species rank what were considered subspecies of Callicebus torquatus by Hershkovitz (1990). For one of these, Callicebus lucifer, orange hands are given as one of the diagnostic characters. Hershkovitz (1990) also considered orange hands as distinguishing Callicebus torquatus lucifer from Callicebus torquatus medemi. Observations made by us at different localities in north-eastern Peru, however, cast some doubt on the general validity of this character as a distinguishing feature for this taxon.
In January 1982, EHW visited Mishana on the right bank of the Río Nanay (3°52.75’S, 73°29.50’W), the site where Warren Kinzey and his co-workers carried out their field studies of titi monkeys. In the village of Mishana, a hunter was carrying a juvenile titi monkey on his shoulders. It was easily identifiable as of the Callicebus torquatus group, the most prominent character being its whitish-creamy hands. In August 2000, FEC saw an infant/young juvenile titi monkey kept as a pet in the village of Negro Urco, on the right bank of the Río Napo. The hands were white, only the tips of the hairs had some dirty-yellowish coloration, perhaps resulting from the animal walking on the earthen floor. In the forest near Negro Urco, he saw three wild titi monkeys at a distance of about 20 m. Observation of the animals with a binocular showed that the hands were whitish-creamy without any tendency towards yellow or orange. In May 2002, FEC visited Santa María on the left bank of the upper Río Nanay, where he saw a juvenile titi monkey kept as a pet. The hairs of its hands were whitish-creamy, but the tips of the hair (which were partially sticking together as if dirty) were a brownish-yellowish colour. Our observations of whitish-creamy hands, particularly of the pet in Mishana and the wild animals near Negro Urco, clearly contrast with the orange hands listed as a diagnostic or distinguishing character by Van Roosmalen et al. (2002) and Hershkovitz (1990). There are four possibilities to account for this discrepancy.
First, since the animals were juveniles, it is possible that they had not yet attained fully adult colouration. We are not aware of any information in the literature on ontogenetic changes in the colouration of titi monkeys.
Second, hand colour might be variable within species or subspecies. The individuals we have seen might represent but one variety within the populations. No information is available on the variability of hand colour within populations of titi monkeys, although Pekka Soini has observed titi monkeys with variably whitish, dirty white and yellowish hair on the hands at Mishana and in areas near to Iquitos (south of the Nanay).
Third, the titi monkeys from the Río Nanay and the Río Napo could differ from other populations of C. lucifer, and might perhaps represent a new species or subspecies. This possibility can only be explored by comparing representative specimens from the different areas.
Fourth, the titi monkeys seen by us represent idiosyncratic forms, different from all other animals of the respective population. People might have captured these animals because they were different from the rest of the population. If this were the case, one might also suspect that “collections … acquired by purchasing live and dead animals from animal dealers who sent natives into the bush” (Van Roosmalen et al., 2002, p.42) are biased towards idiosyncratic individuals which attracted the hunters’ attention. The observation of white hands in wild individuals near Negro Urco is clear evidence against such an explanation.
Under any circumstances, our observations suggests that orange hands cannot be taken as a diagnostic character of C. lucifer until more information is available on variation within and between populations and on whether or not ontogenetic changes in hand colouration do occur.
Distribution: There is also an inconsistency in the current literature with regard to the geographic distribution of C. lucifer in Peru. Hershkovitz (1990, p.83) gives the area “between the Ríos Putumayo, Nanay and Amazonas”, and Aquino and Encarnación, (1994, p.30), following Hershkovitz, state “north of the rivers Nanay and Amazonas to the Río Putumayo”. The map provided by Van Roosmalen et al. (2002), however, does not include the area between the lower Napo and the Nanay. The presence of C. lucifer at Mishana and close to Iquitos clearly indicates its distribution south of the lower Nanay, contrasting with the information provided by Hershkovitz (1990) and Aquino and Encarnación (1994). Sightings at Santa María and Negro Urco also provide clear evidence of its presence on the left bank of the upper Nanay and the right bank of the Napo. However, its presence in areas between the Napo and Nanay is less clear. It was not seen during brief surveys by FEC along the Río Chambira, an affluent of the left bank of the lower Nanay, and its affluent Río Pintoyacu. People on these rivers did not report the species to be present in the area, although they knew it from the Nanay and from the Río Mazán, an affluent of the right bank of the lower Napo. Summarizing the available information, one might suspect that C. lucifer has a patchy distribution in Peru. Kinzey and Gentry (1979) had argued that C. torquatus is restricted to white-sand forests, but this hypothesis was convincingly rejected by Defler (1994) for Callicebus (torquatus) lugens. It would be premature to speculate on any ecological or edaphic factors relating to the distribution of C. lucifer in Peru until its full distributional range and the extent to which it may be patchy are known.
Rowe and Martinez, 2003
The map included in Van Roosmalen et al. (2002) indicates that the range of C. medemi to be between the Rio Caquetá in Colombia and the Rio Aguarico in Ecuador. The titi observed on the north bank of the Rio Aguarico, Ecuador (00º41.670’S, 076º27.736’W) were reddish brown in colour and had the yellow/gold hands of C. lucifer. The range of C. lucifer must thus extend further west than described by Van Roosmalen et al. (2002), and the corresponding range of C. medemi is perhaps limited by the Rio Putamayo, which forms the border of Colombia and Ecuador. This range would be consistent with Hershkovitz (1990) and Groves (2001).
Rowe, N. and Martinez, W. (2003). Callicebus sightings in Bolivia, Peru and Ecuador. Neotropical Primates 11(1): 32-35.
Callicebus torquatus lucifer
Distribution: Callicebus torquatus is found throughout lowland Colombian Amazonia up to about 500m of altitude in Putumayo and probably about the same in Caquetá. The species has been observed on the left bank of the Guayabero River, where it was collected in 1959 by Hernandez-Camacho, In La Macarena National Park, and recently it was observed north of the Guayabero above La Cordillera de los Picachos National park. The species is known in the Vichada selva between the Vichada and Guaviare Rivers, reaching the middle Tomo River, where it probably extends to the upper Tomo, although this needs to be confirmed.
It is not found on the lower Tomo River or lower Tuparro River, nor is it found on the north bank of the lower Vichada River, contrary to the distribution map of Hershkovitz (1990). This error is due to the collection of a specimen by the English ornithologist Cherrie in about 1904 from Maipures, which evidently was a captive animal obtained in the existing village of Maipures on the left bank.
Description: The species pelage is uniformly reddish brown or blackish brown, the tail is blackish mixed with some reddish hairs; hands and feet whitish or dark brown. This pelage contrasts in all of the subspecies with a band of white hair which extends upwards from the chest and follows the neck, prolonging itself to the ears. This extension to the ears is weak in Callicebus torquatus torquatus, a subspecies not confirmed for Colombia and different from the other subspecies which have white extending to the base of the ears.
Lucifer: the pelage is basically blackish but intermixed with many hairs on the back (extending to the top of the crown) and flanks with many reddish brown hairs, giving the animal a definite reddish appearance in the sunlight.
Defler, T.R. (2004). Primates of Colombia.
Palaciosa and Peres, 2005
Locality: 10 km upriver from the mouth of the Quebradón el Ayo (1º35′ S, 69º30′W), a small clear-water tributary of the Rio Caquetá (the Rio Japurá in Brazil), Department of Amazonas.
Palaciosa, E. and Peres, C.A. (2005). Primate Population Densities in Three Nutrient-Poor Aazonian Terra Firme Forests of South-Eastern Colombia. Folia Primatologica 76:135–145.
Aquino et al., 2007
Location: Algodon River, Peruvian Amazonia (see map).
Aquino et al., 2008
Callicebus torquatus lucifer
Locality: Rio Algodon, in northern Peru is close to the border with Colombia, and located near the confluence of the Putumayo river (72°05’W/02°29’S – 72°10’W/02°37’S).
Description: General colouration dark brown. Crown with reddish brown hair; broad frontal band with dark brown hair. Facial skin light and moderately covered with short white hair. Dorsal side of trunk and neck chestnut brown; basal portion of hair lighter chestnut, terminal portion chestnut brown. Throat has a band of creamy-white hair extending laterally to the base of the ears. Ventral side of trunk light chestnut. Upper arm with chestnut brown hair, forearm blackish to black hair. Hand with short hair, basal part orange, terminal part yellow-creamy. Thigh with chestnut-brown hair; lower leg and foot with blackish hair. Tail generally blackish brown; basal portion of hair in proximal 2/3 of the tail reddish brown, terminal portion chestnut brown. Remainder of tail with blackish or brownish hair.
Remarks: Diagnosis and comparisons of subspecies of C. torquatus in Hershkovitz (1990) indicate that there is variation in fur color within subspecies. Therefore, it is possible that the differences detected in the extent and shape of white hair on the throat, the coloration of the hands, and the width of the frontal band in Callicebus observed in this study simply represent intrataxon variation. However, throat collar has been used as a diagnostic criterion to distinguish C. torquatus purinus from C. torquatus torquatus, although Hershkovitz (1990) does not mention this characteristic for the other titi monkey subspecies. Hand color is described as yellow, golden, or orange for all subspecies of C. torquatus except C. torquatus medemi, where the hands are blackish. Defler (2003) reports that the Colombian C. torquatus lugens and C. torquatus lucifer exhibit white or yellowish hands. In this study, we found consistent phenotypic differences between two disjunctive populations of C. torquatus in Peruvian Amazonia: the populations between the rivers Nanay and Tigre had a tie-like or rectangular creamy-white hair tuft on the throat, white-creamy hands, and a narrow frontal band, whereas the populations between the rivers Napo and Putumayo had a collar-like band of creamy-white hair extending laterally to the base of the ears, yellow-creamy to orange hands, and a broad frontal band. On the basis of difference in hand color of the Nanay population from other C. torquatus populations,
Heymann et al. (2002) speculated on the possible existence of a distinct taxon. Only detailed examination of additional individuals and the inclusion of genetic methods will lead to a resolution of this issue.
The Peruvian C. torquatus are separated geographically, into a population between the rivers Napo and Amazonas in the south and the Putumayo in the north, and a population between the right bank of the Rio Nanay and the left bank of the lower Rio Tigre and the Rio Pucacuro. Within these areas, the species is not distributed uniformly and seems to be restricted to forests on high and medium terraces with ‘‘varillal’’ vegetation that is dominated by plants with sclerotic and leathery leaves growing on sandy or sandy-clayey soils (Encarnacion, 1993).
The population between the rivers Nanay and Tigre is probably delimited in the north by the confluence of the Rio Pucacuro and the Quebrada Aleman, an area that also marks the distributional limit of ‘‘varillal’’ vegetation. Our observations that C. torquatus in Peru is restricted to ‘‘varillales’’ growing on white-sand soils or on sandy-clayey soils coincides with information by Kinzey and Gentry (1978). It is reinforced by (a) the lack of both ‘‘varillales’’ and C. torquatus further north of Quebrada Aleman (Aquino et al., 2000); (b) the presence of this species southward from kilometer 25 of the highway Iquitos–Nauta, coinciding with the presence of ‘‘varillales,’’ and the lack of both C. torquatus and ‘‘varillales’’ north of this point. The Peruvian populations therefore seem to be more restricted than population studied by Peres (1993) and Defler (1994, 2003) who found C. torquatus in a large variety of habitats in Brazilian and Colombian Amazonia, ranging from flooded forests (‘‘varzea’’ and ‘‘igapo’’) to tierra firme forests, although Peres (1993) does not specify characteristics of the vegetation and soils. The reasons for such differences in habitat occupation remain obscure.
In conclusion, our study indicates the need for reconsidering the geographic distribution of C. torquatus in Peru. The taxonomic status of the different Peruvian populations of C. torquatus requires further scrutiny. Future studies will have to include genetic analyses of the respective populations, and additional surveys to make a more accurate delimitation of the geographic distribution, particularly of the population south of the Rio Nanay, to reach a definite conclusion.
Aquino, R., Terrones, W. , Cornejo, F. and Heymann, E.W. (2008). Geographic distribution and possible taxonomic distinction of Callicebus torquatus populations in Peruvian Amazonia. American Journal of Primatology 70:1181-1186.
Aquino et al., 2015
Locality: the forest in the lower basin of the Río Tigre and sub basin of the Río Nanay: Alto Itaya (UTM 615679/9540649) and Huanganayacu (UTM 473383/9627228), but absent at the study site of Alto Nanay (UTM 542669/9617188) .