Literature regulus

Ihering, 1904

Callicebus torquatus

Distribution: Rio Jurua.

Description: This nice species is easy to recognize by its white collared throat.

callicebus.nl: Vieira (1944b) identified the animals mentioned by Ihering as being C. torquatus regulus.

Ihering, H.  von (1904). O Rio Juruá. Revista do Museo Paulista 6 :412.

Thomas, 1927

Callicebus torquatus regulus subsp. n.

Type locality: Fonte-Boa, Upper Solimoes. Type in British Museum.

Distribution: Upper Solimoes.

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: Back finely grizzled brown, the hairs ringed with blackish and dull buffy. Hairs of crown, behind the black parts of the face, with rich ochraceous ends, making a coronal patch in marked contrast with the brown back. Under surface smoky blackish, the white throat patch unusually large and conspicuous. Forearms black, hands yellow; inner side of lower legs black and feet black. Tail wholly black, without any intermixture of reddish hairs.

Measurements: head and body 450mm; tail 440mm; hind foot 97mm.

Remarks: Readily recognizable by its grizzled brownish back and contrasted ochraceous crown, just as is C. t. purinus among the red-bellied forms.

Thomas, O. (1927). In the titi monkeys of the Callicebus torquatus group. Annals and Magazine of Natural History (9) 19: 509-510.

Vieira, 1944

Callicebus torquatus regulus

Locality: Fonto Boa, Upper Solimoes, not far from the Juruá.

Description: Colour on back brown-greyish, tail completely black, without mixture with reddish hairs.

Vieira, C. da C. (1944b). Nova Contribuiçao ao Conhecimento dos Mamiferos do Rio Juruá. Papeis Avulsos de Zoologia, Sao Paulo 4: 251-252.

Cruz-Lima, 1945

Callicebus torquatus regulus

Synonym: Callicebus torquatus regulus (Thomas, 1927).

Description: Back finely grizzled brown, the hairs ringed with blackish and dull buffy. Hairs of crown, behind the black parts of the face, with rich ochraceous ends, making a coronal patch in marked contrast with the brown back. Under surface smoky blackish, the white throat-patch unusually large and conspicuous. Forearms black, hands yellow; inner side of lower legs black and feet black. Tail wholly black, without any intermixture of reddish hairs (original description).

Measurements: (of the type) head and body 450mm; tail 440mm; foot 97mm.

Remarks: The Museu Nacional possesses a pair collected by Lako at the same locality as the type. The male agrees exactly with the above description; the female, however, is much lighter and more rufous, with the spot on the throat not very conspicuous and the hands with a great mixture of black hairs amongst the yellow, having also the basal half of the tail with some mixture of red hairs.

Cruz-Lima, E. da (1945). Mammals of Amazonia Vol. 1. General introduction and primates pp. 175-198.

Vieira, 1955

Callicebus torquatus regulus

Synonym: Callicebus torquatus regulus (Thomas, 1927).

Distribution: Amazonas (Alto Solimoes, Joao Pessoa, Rio Juruá).

Vieira, C. da C. (1955). Lista remissiva dos mamiferos do Brasil. Arquivos de Zoologia 8 (10): 375-379.

Cabrera, 1958

Callicebus torquatus amictus (Geoffroy, 1812)

Synonyms: Simia amicta (Humboldt, 1812), Callithrix amicta (Spix, 1823), Saguinus amictus (Lesson, 1827), Cebus torquatus (Fischer, 1829), Callicebus amictus (Elliot, 1913), Callicebus torquatus purinus (Thomas, 1927), Callicebus torquatus regulus (Thomas, 1927).

Distribution: Amazonas of Brazil, south of the Solimoes.

Remarks: The short original diagnosis of amictus, and even more the description of Spix, agrees very well with the form of torquatus that lives south of the Solimoes and that Thomas has described since under the names purinus and regulus, as the under parts were reddish or blackish, which appears to be an individual character.

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 torquatus regulus (Thomas, 1927)

Type locality: Fonté Boa, Upper Rio Solimoes, Brazil. Type in British Museum.

Distribution: Known from the type locality. Two specimens in the Rio de Janeiro Museum, collected by Lako, were from the type locality. Also recorded from Joao Pessoa on the Rio Juruá.

Description: Resembling purinus among the red-bellied group, but otherwise agreeing with the remaining, black-bellied races. Recognized by the contrast between the ochraceous crown and the finely grizzled brownish back, where the hairs are tinged alternately blackish and dull buff. Forehead black, crown with hairs are tinged alternately blackish and dull buff. Forehead black, crown with hairs dark at base, but with ochraceous tips, delimiting a sharply defined coronal patch. Under parts smoky-blackish; forearms black; hands yellow; medial aspect of hind-limbs, distal to knee, black; feet black; tail wholly black, without any intermixture of rufous hairs; pectoral patch unusually large and conspicuous. Lima refers to a female with less conspicuous pectoral patch and with some black hairs intermixed with the yellow on the hands.

Measurements: (of female type) head and body 450mm; tail 440mm; hind foot 97mm.

Remarks: Type in British Museum.

Hill, W.C.O. (1960). Primates. Comparative anatomy and taxonomy  4 (A): 98-147.

Hershkovitz, 1963

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: The northernmost race, Callicebus torquatus lugens (Humboldt) is darkest, with body or trunk deep blackish brown, throat patch or gular ruff well developed and sharply defined white or creamy. The westernmost race, medemi, is less black, browner, with gular ruff extending from ear to ear in some specimens to obsolete or absent in others, face more thinly haired, hands entirely black in some, with a more or less concealed admixture of golden hairs in others. Southward, between the Rios Putumayo and Caqueta, medemi grades into reddish, or reddish brown populations of torquatus. Here the yellow becomes dominant on the fingers (cf. ignitus Thomas) before extending over the metacarpals. In some populations (Codajáz, c.f. Lönnberg 1939) the throat patch tends to blend or become confused wit the surrounding reddish of the under surface.
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.


Hershkovitz, 1988

Callicebus torquatus regulus

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.

Peres, 1988

Callicebus torquatus torquatus

Locality: Brazil, Amazonas, Lago da Fortuna (left bank of Rio Jurua; 5°05’S, 67°10’W).

Peres, C. A. 1988. Primate community structure in western Brazilian Amazonia. Primate Conservation 9: 83-87.

Hershkovitz, 1990

Callicebus torquatus regulus

Member of the torquatus Group.

Synonym: Callicebus torquatus regulus (Thomas, 1927).

Type locality: Fonte Boa, upper Rio Solimoes, Amazonas, Brazil. Type in British Museum.

Distribution: Amazonas, Brazil, between the Rio Solimoes, lower Rio Javari, and west bank of the Rio Jurua from mouth to about 7°S.

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 above and behind ears more or less banded.

Comparisons: Distinguished from Callicebus torquatus purinus, the only other south bank representative of the species, by dark brown chest and belly; from C. t. torquatus by inner side of arms entirely blackish, throat collar well developed; from C. t. lucifer by brownish under parts and sideburns and strongly contrasted reddish crown; from lugens by paler back, side, and under parts, reddish crown; from medemi by orange hands.

Specimens examined: Total 9. Brazil – Amazonas: Fonte Boa; Rio Jurua.

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

Kobayashi, 1995

Callicebus torquatus regulus

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

Callicebus torquatus

Localities: Brazil, Amazonas, Igarape-Açu (left bank of lower Rio Urucu (4°30’S, 64°29’W); Brazil, Amazonas, Lago da Fortuna (left bank of Rio Jurua; 5°05’S, 67°10’W); Brazil, Amazonas, SM-1 (oil-drilling site between Rio Urucu and Rio Coari; 4°50’S, 65°1 6’W).


Groves, 2001

Callicebus torquatus regulus

Synonyms: Callicebus regulus (Thomas, 1927)

Distribution: From between the Rio Solimoes and the Rio Juruá.

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 regulus

Type locality: Fonte Boa, right bank of upper Rio Solimões, state of Amazonas, Brazil. Type is an adult female, skin and skull, in the British Museum of Natural History, London.

Distribution: Brazil, state of Amazonas, between the upper Rio Solimões, the lower Rio Javarí, and the left (west) bank of the Rio Juruá from mouth at the Rio Solimões to about 7º S.

Diagnostic characters: Hands orange, tail blackish, inner side of arms entirely blackish, under parts (chest and belly) except throat brown or blackish, hairs above and behind ears more or less banded, sideburns brownish, crown strongly contrasted reddish, and throat collar well developed, white. Distinguished from C. purinus by dark brown chest and belly, brownish sideburns, hairs above and behind ears more or less banded, and orange instead of white hands; from C. torquatus by inner side of arms entirely blackish, more developed white throat collar, a strongly contrasting reddish crown, and blackish instead of white feet; from C. lucifer by indistinctly banded hairs of back and sides of body, and a contrasting reddish instead of blackish crown; from C. lugens by paler back, sides of body, and under-parts, and a strongly contrasting reddish crown; and from C. medemi by orange instead of blackish hands, and contrasting reddish instead of blackish crown.

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.

Auricchio, 2010

Callicebus regulus

Localities: AM, Rio Juruá (06°00’S 68°00’W); AM, Fonte Boa (02°33’S 66°02’W).

Auricchio, P. (2010). A morphological analysis of some species of Callicebus. Neotropical Primates 17(2): 47-58.

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