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Spilocuscus rufonigerblack-spotted cuscus

By Lisa Bey

Geographic Range

Spilocuscus rufoniger, the black-spotted cuscus, is restricted to northern New Guinea. It is found in the provinces of Papua New Guinea, Morobe Province, Sattelberg (Smithsonian Institution, 1993).

Habitat

S. rufoniger inhabits tropical forests and thick scrub areas in northern New Guinea. It inhabits undisturbed forests below 1200 meters in elevation (Flannery, 1995; Nowak, 1999).

  • Range elevation
    1200 (high) m
    3937.01 (high) ft

Physical Description

S. rufoniger is the largest species of phalangerid, with females weighing between 6 and 7 kg on average (Nowak, 1999). The head and body average 70 cm in length, with the tail adding an additional 50 cm on average. Female black-spotted cuscus are larger than males of the species. Although both male and female have striking black and red coloration, their pelage is sexually dimorphic. Females have a dark saddle on their backs, whereas males have only an area of mottling or spots. Young go through a sequence of color changes as they mature. The fur of black-spotted cuscus is dense and wooly.

S. rufoniger has short snouts, and their ears are almost invisible. The head is round with a pointed snout and large eyes that are adapted for a nocturnal lifestyle. The first and second fingers are opposable to the other fingers. Their foreclaws are curved and sharply pointed for climbing. The foot is modified for grasping in that the big toe is opposed to the others. This toe is also clawless. The second and third toes are small and fused. Black-spotted cuscus have highly prehensile tails that are naked at the terminal end. The underside of the tail is striated with calluses for grasping.

Female black-spotted cuscus have four mammae. Their pouches are forward opening and well developed.

In both sexes, the frontal bones of the skull are distinctly convex and have a large sinus that does not open into the nasal cavity. The teeth of cuscus have low crowns. S. rufoniger can be distinguished from other spotted cuscus by the presence of small, peg-like premolars in front of the main premolar of their upper jaws. Cuscus have a well-developed protocone on the first upper molar. The alisphenoid and basoccipital consistently form a more extensive structure that is developed earlier in life than it is in other phalangerids (Flannery, 1995; Grzimek, 1990; Nowak, 1999).

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Average mass
    6-7 kg
    lb
  • Average length
    70 cm
    27.56 in

Development

See reproduction.

Reproduction

The mating system and behavior of this species are unknown.

Mating in S. rufoniger is not well documented or observed. Courtship is usually conducted on the limbs of trees. There is very little known about reproduction of this species (Flannery, 1995).

The female provides protection for her altricial neonates in her pouch, and nurses them. Little else is known about parental care in this species.

Lifespan/Longevity

Nothing is known about the lifespan of these animals.

Behavior

S. rufoniger is a mostly arboreal species that occasionally descends to the ground. They are thought to be mostly nocturnal, resting by day curled up exposed on a branch high in the canopy. They are slow moving and sluggish in their behavior. Individuals usually feed and nest alone and interactions between individuals are often aggressive (Flannery, 1995; Nowak, 1999).

Communication and Perception

Food Habits

There is little information about the diet of S. rufoniger. Large acorns of Lithocarpus spp. have been found with chew marks on them that are thought to be from this cuscus. Black-spotted cuscus are thought to be omnivorous, possibly feeding occasionally on small animals (Flannery, 1995).

Predation

The island habitat of S. rufoniger is free of tree-climbing predators (Nowak, 1999).

Ecosystem Roles

Because the diet of these animals is largely unknown, it is difficult to speculate on the role they play within their ecosystem.

Economic Importance for Humans: Positive

Because of its large size, S. rufoniger has long been valued by hunters for its coat and its meat. The native Papuans value the meat and use the beautiful dense fur for caps and capes (Nowak, 1999).

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no reports of negative effects on humans produced by these animals.

Conservation Status

Spilocuscus rufoniger is listed as endangered. Its limited range and colorful pelt have made it susceptible to overhunting. Habitat loss due to an expanding human population has caused the numbers of S. rufoniger to decline. Currently there are no national parks in New Guinea to help protect this species (Flannery, 1995; Nowak, 1999).

Other Comments

Historically, S. rufoniger was considered a subspecies of Spilocuscus maculates (common spotted cuscus). It has recently been reclassified as a unique species (Flannery, 1987).

Contributors

Lisa Bey (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

island endemic

animals that live only on an island or set of islands.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Flannery, T. 1995. Mammals of New Guinea. Ithaca, NY: Comstock/Cornell.

Flannery, T. 1987. The phylogenetic realtionships of living Phalangerids with a suggested new taxonomy. Surrey Beatty and Sons and the Royal Zoological Society of South Wales, 18: 35-44.

Grzimeks, B. 1990. Grzimeks Encyclopedia of Mammals. New York: McGraw-Hill Publishing Co..

Nowak, R. 1999. Walkers Mammals of the World. Baltimore, MD: The Johns Hopkins University Press.

Smithsonian Institution, 1993. "MSW Scientific Names" (On-line). Accessed September 9, 2001 at . http://www.nmnh.si.edu/cgi-bin/wdb/msw/names/query/1250.

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