Callithrix humilis

Geographic Range

Roosmalen's dwarf marmosets are endemic to the central part of the Amazonian Rain forest in Brazil. They occur in a very small area "from the west bank of the lower Rio Aripuanã, from the mouth with the Rio Madeira just SW of the town of Novo Aripuanã south at least to the village of Tucunaré on the west bank of the Rio Aripuanã, and along the east bank of the Rio Madeira south as far as the mouth of the Rio Mataurá. The southern limit for the species, in the interfluve delineated by the Rios Madeira, Mataurá and Aripuanã, is probably the headwaters of the Rios Mariepauá and Arauá" (Roosmalen and Roosmalen, 2003 p 4).

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Roosmalen's dwarf marmosets are found in disturbed primary and secondary terra firme rain forests and terra prestas forests. Roosmalen and Roosmalen explain that terra prestas are soils made by pre-Columbian farmers who mixed "decomposed organic material...and large quantities of charcoal, calcium and phosphates" near bluffs and lakes. At first, it was assumed that they only occur away from human habitations, but it seems they prefer disturbed forest areas near human inhabited areas such as plantations, gardens, and fields.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Roosmalen's dwarf marmosets are very small monkeys. They have golden to grayish yellow fur on the body with a darker almost black layer underneath. The ears and face are naked and flesh-colored, there is a triangular crown of fur on the head and white eyebrows which extend all the way to the temples, and they have a long black tail. Their coloration changes with age. They weigh from 150 to 185 grams, with females being slightly larger.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Not much is known about reproduction in Roosmalen's dwarf marmosets, but it is thought that they are very flexible, forming monogamous, polyandrous, and polygynandrous groups. Observations show that there is more than one reproductive female in a group and imply that there are obligate singleton births. Biological mothers carry young and aid is not provided by the father or any other members of the group.

• Mating System
• monogamous monogamous
• polyandrous polyandrous
• polygynous polygynous

Roosmalen's dwarf marmosets give birth to a single offspring at a time. This is different from most marmoset species, which give birth to twins. Other aspects of reproduction in Roosmalen's dwarf marmosets are not well known.

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Not much is known about the reproduction in Roosmalen's dwarf marmosets. Young are born atricial and cared for and nursed by their mother.

• Parental Investment
• altricial altricial
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• post-independence association with parents

Lifespan/Longevity

The oldest animal of this species in captivity was 36 months old and she died shortly after giving birth. Wild longevity is not reported in the literature.

Behavior

Roosmalen's dwarf marmosets occur in family groups with individuals usually numbering 6 to 8. However, groups up to 30 have been observed. No antagonistic behavior has been witnessed, nor scent marking to display the home range.

• Key Behaviors
• arboreal arboreal
• scansorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• social social
• colonial colonial

Home Range

Home range size in Roosmalen's dwarf marmosets is not reported in the literature.

Communication and Perception

Not much is known about the communication of this species, though we do know that they are social animals, living in groups of 6 to 30. Scent marking has not been observed in this species, even though it is very common in many other primate species. It is likely that vocal cues and visual communication play an important role, as they do for most primates.

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

In winter months, when fruit is scarce, Roosmalen's dwarf marmosets feed on tree gum. They cling vertically to trees with strong claw-like nails, which also allow them to cut holes in the bark and feed on saps and gums.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
  • eats sap or other plant foods

• Plant Foods
• fruit
• sap or other plant fluids

Predation

The only reported predators of Roosmalen's dwarf marmosets are domestic cats, domestic dogs, and birds of prey. It is likely that they are also preyed on by arboreal snakes and wild, arboreal felids. No predator defense had been witnessed but, as social species, they may share vigilance activities and warn each other of predator approach.

Ecosystem Roles

Roosmalen's dwarf marmosets provide a service, though probably unknowingly, to both tamarins and Parkia fruits. The tamarins who cannot gouge hole themselves, are able to feed on exudate from the holes made my Callibella individuals.

Economic Importance for Humans: Positive

There are no known benefits to humans of Roosmalen's dwarf marmosets. However, their range is believed to have one of the highest levels of primate diversity on Earth.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

It could be argued that Roosmalen's dwarf marmosets have a small negative impact on the humans in their local environment because they feed on fleshy fruits grown in gardens. However, they typically take little fruit and, as noted by Roosmalen et al. (1998), the locals do not seem to mind the small marmosets.

• Negative Impacts
• crop pest

Conservation Status

Roosmalen's dwarf marmosets are considered vulnerable by the IUCN due to their very small range and the potential for human habitat destruction in that range. No part of their range is legally protected and it is vulnerable to expanded agricultural use.

Other Comments

Roosmalen's dwarf marmosets, Callibella humilis , were previously included in the genus Callithrix and are also known as black-crowned dwarf marmosets.

Additional Links

Encyclopedia of Life

Contributors

Melissa McCullough (author), Georgia Southern University, Michelle Cawthorn (editor), Georgia Southern University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Aguiar, J., T. Lacher, Jr.. 2003. On the Morphological Distinctiveness of Callithrix Humilis van Roosmalen et al., 1998. Neotropical Primates , 11 (1): 11-18.

Roosmalen, M., T. Roosmalen, R. Mittermeier, G. de Fonseca. 1998. A New and Distinctive Species of Marmoset (Callitrichidae, Primates) from the Lower Rio Aripuana, State of Amazonas Central Brazilian Amazonia. Goeldiana , 22: 1-27. Accessed February 04, 2013 at https://library.conservation.org/Published%20Documents/1998/A%20New%20and%20Distinctive%20Species%20of%20marmoset.pdf .

Roosmalen, M., T. Roosmalen. 2003. The Description of a New Marmoset Genus, Callibella (Callitrichinae, Primates), Including its Molecular Phylogenetic Status. Neotropical Primates , 11(1): 1-12. Accessed April 24, 2013 at http://www.marcvanroosmalen.org/images/Description_of_New_Marmoset_Genus_Callibella.pdf .

2012. "

Callibella humilis (Black-crowned Dwarf Marmoset, Roosmalen's Dwarf Marmoset)

International Union for Conservation of Nature and Natural Resources. 2012. "IUCN Red List" (On-line). International Union for Conservation of Nature. Accessed February 20, 2012 at http://www.redlist.org .