Aquino et al., 2008
Callicebus torquatus spp.
Locality: approximately 80km southwest of the city of Iquitos, between the area near the mouth of the Quebrada Maquizapa and the headwaters of the Rio Itaya (73°38’W/04°15’S – 74°00’W/04°09’S).
Description: General colouration intensively reddish brown. Crown with intensively reddish brown hair; narrow frontal band with black hair. Facial skin blackish and sparsely covered with short white hair. Dorsal side of trunk and neck reddish brown; basal portion of hair dark grey, terminal portion reddish brown. Throat with tie-like tuft of creamy-white hair, not extending laterally. Ventral side of trunk reddish chestnut. Upper arm with dark brown hair; forearm with black hair; hand with short creamy-white hair. Thigh and lower leg with reddish brown hair; foot with black hair. Tail generally black; basal portion of hair in proximal 2/3 of the tail reddish brown, terminal portion black; remainder of tail with black 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., 2009
Locality: source of the Río Itaya.
Remarks: the specimens of this species that live in this part of the Peruvian Amazon are coloured differently from those that live between the Rios Napo and Putumayo, therefore they do not correspond to C. torquatus lucifer, and might belong to a new species.
Aquino R.; Terrones, W.; Navarro, R.; Terrones, C. and Cornejo, F.M. (2009). Caza y estado de conservación de primates en la cuenca del río Itaya, Loreto, Perú. Revista peruana de biología 15(2): 33-39.
Aquino et al., 2014
Localities: the survey area was on both sides of the road between Iquitos and Nauta, from appr. km 16 north till appr. km 85 south and from appr. 10 km to the east, limited by the Lower Itaya and the Amazonas and appr. 20 km to the west, limited by the Reserva Nacional Allpahuayo – Mishana (RNAM), quebrada Nauta and the upper parts of the quebradas Pensión and Miraflores.
Remarks: Considering C. torquatus, this report follows Aquino et al. (2008), as the phenotypical characters described by van Roosmalen et al. (2002) for C. lucifer differ from that species, except that both populations are separated for more than 100 km.