Marmosa xerophila

Geographic Range

Marmosa xerophila occurs in the dry Caribbean lowlands of northwestern Venezuela and extreme northeastern Colombia.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

This species inhabits dry, deciduous, thorny woodlands and cactus scrub from near sea level to about 90 meters elevation.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• scrub forest scrub forest

Physical Description

Like other species of mouse opossums , Marmosa xerophila is a small, pouchless marsupial with large, membranous ears; prominent eyes; a mask of dark fur surrounding the eyes; and a long, slender, prehensile tail. The dorsal fur is pale yellowish- to grayish-brown, the ventral fur is usually whitish, and the tail is indistinctly bicolored, darker dorsally than ventrally. It differs from its closest relative, M. robinsoni , by its slightly smaller size, paler dorsal coloration, whiter underparts, and in certain cranial characters (for example, by lacking a distinct rostral process of the premaxillae). This species is sexually dimorphic; males are significantly larger than females.

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

• Sexual Dimorphism
• male larger

Reproduction

This species is a seasonal breeder that apparently reproduces only once in its lifetime. Nothing is definitely known about its social behavior, but adults are probably solitary like those of other opossums.

Marmosa xerophila is a seasonal breeder. Females give birth in the late dry season such that peak lactation and weaning occur in the rainy season when food is most abundant. The young of M. xerophila , like those of other marsupials, are very small and undeveloped at birth; they remain attached to the teats for about 23 days, after which they stay in a nest until they disperse and become independent of the mother at about 60 days. Both sexes become sexually mature at about 9 months; because adult survivorship declines rapidly after 12 months, it is assumed that most individuals are semelparous.

• Key Reproductive Features
• semelparous semelparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Females nurse the young for about 60 days. During this interval, the young remain physically attached to the teats for about 23 days, after which they remain in a nest. The males are not known to provide any parental care. No postweaning association of mother and young has been reported.

• 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

Lifespan/Longevity

Most wild adults of this species do not live to be more than a year old (the oldest individual observed in a field study seemed to have been only 14 months old). Nothing is known about longevity in captivity.

Behavior

Although the behavior of this species has not been investigated per se, the results of trapping and mark-recapture studies suggest that it is solitary, nonmigratory, nocturnal, and semiarboreal (like most other 'mouse opossums Marmosa ').

• Key Behaviors
• arboreal arboreal
• scansorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

Unknown, but population densities in a field study suggest seasonally variable population densities of 6 to 20 individuals per hectare in favorable habitat.

Communication and Perception

Communication in this species has not been studied, but sexually mature males have a well developed gular (or "sternal") gland that probably has some social-marking function.

The eyes, ears, nasal turbinates (thin bones that support olfactory epithelium), and tactile hairs (vibrissae) are well developed in this species (as in other opossums ), so vision, hearing, and touch are presumably important senses.

• Communication Channels
• chemical chemical

• Other Communication Modes
• scent marks scent marks

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

Food Habits

The diet of this species (as inferred from feces collected in a long-term field study) mostly consists of insects, but cactus fruits are also eaten and may be a seasonally important source of calories. The presence of stamens and pollen in feces suggests that Marmosa xerophila may also feed on nectar (as some other mouse opossums are known to do).

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods

• Animal Foods
• insects
• terrestrial non-insect arthropods

• Plant Foods
• fruit
• nectar
• flowers

Predation

Nothing is known about the predators of this species, but cats , owls , and snakes are probably important.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

This species is both a primary consumer (of fruits) and a secondary consumer (of arthropods ),it is almost certainly the prey of other vertebrates (e.g., snakes , owls , cats ), and it hosts an unknown number of internal and external parasites. Probable ectoparasites include species of Arachnida ( Acari : mites) and Insecta ( Siphonaptera : fleas). Probable endoparasites include species of Acanthocephala (spiny-headed worms), Cestoda (tapeworms), Digenea (flukes), and Nematoda (roundworms).

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

There are no known benefits that Marmosa xerophila provides to humans, but because it is insectivorous it might contribute to the control of pest species near human settlements.

Economic Importance for Humans: Negative

There are no known adverse effects of Marmosa xerophila on humans.

Conservation Status

Other Comments

Marmosa xerophila is one of only two species of the genus Marmosa that occurs in semi-arid habitats (the other is M. simonsi ). Phylogenetic analyses of cytochrome-b sequence data suggests that the closest relative of this species is M. robinsoni .

Additional Links

Encyclopedia of Life

Contributors

Robert Voss (author), American Museum of Natural History, Sharon Jansa (editor), American Museum of Natural History, Alexa Unruh (editor), Animal Diversity Web Staff.

References

Gutierrez, E., S. Jansa, R. Voss. 2010. Molecular systematics of mouse opossums (Didelphidae: Marmosa ): assessing species limits using mitochondrial DNA sequences, with comments on phylogenetic relationships and biogeography. American Museum Novitates , 3692: 1-22.

Lopez-Fuster, M., M. Salazar, R. Perez-Hernandez, J. Ventura. 2002. Craniometrics of the orange mouse opossum Marmosa xerophila (Didelphimorphia: Didelphidae) in Venezuela. Acta Theriologica , 47: 201-209.

Rossi, R., R. Voss, D. Lunde. 2010. A revision of the didelphid marsupial genus Marmosa . Part 1. The species in Tate's ' mexicana ' and ' mitis ' sections and other closely related forms. Bulletin of the American Museum of Natural History , 334: 1-81.

Tate, G. 1933. A systematic revision of the marsupial genus Marmosa . Bulletin of the American Museum of Natural History , 66: 1-250.

Thielen, D., A. Arends, S. Segnini, M. Farinas. 1997. Food availability and population dynamics of Marmosa xerophila Handley and Gordon 1979 (Marsupialia: Didelphidae). Zoocriaderos , 2(1): 1-15.

Thielen, D., A. Arends, S. Segnini, M. Farinas. 1997. Populational ecology of Marmosa xerophila Handley and Gordon 1979 (Marsupialia: Didelphidae) in a semi-arid ecosystem from northern Venezuela. Zoocriaderos , 2(1): 1-19.

Thielen, D., D. Cabello, G. Bianchi-Perez, P. Ramoni-Perazzi. 2009. Rearing cycle and other reproductive parameters of the xerophytic mouse opossum Marmosa xerophila (Didelphimorphia: Didelphidae) in the Peninsula of Paraguana. Interciencia , 34: 195-198.