Callibella humilis

2.

Black-crowned Dwarf Marmoset

Callibella humilis

French: Ouistiti nain / German: Schwarzkronen-Seidenaffchen / Spanish: Titi de corona negra Other common names: Dwarf Marmoset, Roosmalens’s Dwarf Marmoset

Taxonomy. Callithrix humilis van Roosmalen et al., 1998, Brazil, Amazonas, west bank of the lower Rio Aripuana, 1 km S of Nova Olinda, 41 km SW of Novo Aripuana, Amazonas State, Brazil.

No subspecies are recognized, but there is some slight differentiation in color from the population living near the Rio Atininga, which has a more orange-ocherous underside, and the juveniles’ white lateral crown streaks are retained into maturity. Callibella is quite distinct from other marmosets (Cebuella and Mico) in both its cranial and postcranial morphology. Monotypic.

Distribution. Brazilian Amazon in a tiny area (c.b—6° S, 60° W) between the E bank of the Rio Madeira and the W bank of the lower Rio Aripuana, S to a little beyond 6° S and W to the Rio Atininga or Rio Manicoré.

Descriptive notes. Head—-body 16-17 cm, tail 22-24 cm; weight 150-185 g. The Black-crowned Dwarf Marmoset is evenly dark olive-brown above with an orangeyellow to golden to grayish yellow underside, including inner surfaces of limbs. The crown is black, and the face is mostly unpigmented except for a blackish circumocular zone, with white “eyebrows” extending back to the temples. Pinnae are bare, except for white tufts arising from their center. The tail is almost black with no, or at most very faint, rings.

Habitat. Disturbed primary or secondary terra firma forest near plantations, fields, and tree gardens; undisturbed primary forest and seasonally inundated riparian forest (igapo). A survey on the left bank of the Rio Aripuana, focusing particularly on the Black-crowned Dwarf Marmoset,failed to find them along 120-km census route either in undisturbed primary forest or igapo; however, surveys on the Rio Atininga and its major tributaries to the west found them in undisturbed primary forest and igapo.

Food and Feeding. Although very little is known, diets of the Black-crowned Dwarf Marmoset includes fruits, small animal prey (especially insects), and, of particular significance, exudates. They share a morphological and behavioral specialization for exudativory with the Pygmy Marmoset (Cebuella pygmaea). They gouge tree trunks and branches to stimulate flow of exudates—notably, in one group observed, gum of the pioneer tree Didymopanax morototon: (Araliaceae). They feed on ripe fruits of Spondias mombin and Tapirira guianensis (both Anacardiaceae), Rollinia mucosa (Annonaceae), Inga edulis and Inga ingoides (both Fabaceae), Artocarpus heterophyllus (Moraceae), palm fruits, Astrocaryum vulgare, (Areceaceae) and wild cacao (Theobroma speciosum and 1. manriae, Sterculiceae).

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List. Although not presently endangered, the Black-crowned Dwarf Marmoset has one of the smallest distributions of any Neotropical primate, and a total population of likely no more than a few thousand individuals. It is not threatened by hunting.

Bibliography. Aguiar & Lacher (2003, 2009), Ford & Davis (2009), Rylands et al. (2009), van Roosmalen & van Roosmalen (2003), van Roosmalen et al. (1998).