Marmosa xerophiladryland mouse opossum

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Geographic Range

Marmosa xerophila occurs in the dry Caribbean lowlands of northwestern Venezuela and extreme northeastern Colombia. (Lopez-Fuster, et al., 2002; Rossi, et al., 2010; Thielen, et al., 1997a)

Habitat

This species inhabits dry, deciduous, thorny woodlands and cactus scrub from near sea level to about 90 meters elevation. (Lopez-Fuster, et al., 2002; Thielen, et al., 1997a)

  • Range elevation
    0 to 90 m
    0.00 to 295.28 ft

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. (Gutierrez, et al., 2010; Lopez-Fuster, et al., 2002; Rossi, et al., 2010)

  • Sexual Dimorphism
  • male larger
  • Range mass
    30 to 90 g
    1.06 to 3.17 oz
  • Average mass
    60 (males) 40 (females) g
    oz
  • Range length
    100 to 160 mm
    3.94 to 6.30 in

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. (Thielen, et al., 1997a; Thielen, et al., 2009)

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. (Thielen, et al., 1997a; Thielen, et al., 2009)

  • Breeding interval
    This species only reproduces once.
  • Breeding season
    Mating occurs in the dry season.
  • Range number of offspring
    3 to 11
  • Average number of offspring
    8
  • Average gestation period
    14 days
  • Average weaning age
    60 days
  • Average time to independence
    60 days
  • Average age at sexual or reproductive maturity (female)
    9 months
  • Average age at sexual or reproductive maturity (male)
    9 months

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. (Thielen, et al., 2009)

  • Parental Investment
  • altricial
  • 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. (Thielen, et al., 1997a)

  • Range lifespan
    Status: wild
    14 (high) months
  • Average lifespan
    Status: wild
    12 months

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'). (Thielen, et al., 1997a; Thielen, et al., 2009)

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. (Thielen, et al., 1997a)

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. (Gutierrez, et al., 2010; Thielen, et al., 1997a)

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.

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). (Thielen, et al., 1997b)

  • 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

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). (Thielen, et al., 1997b)

  • 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. (Thielen, et al., 1997b)

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. (Rossi, et al., 2010)

Contributors

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

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

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.

arboreal

Referring to an animal that lives in trees; tree-climbing.

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

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.

female parental care

parental care is carried out by females

insectivore

An animal that eats mainly insects or spiders.

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

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

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

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

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

visual

uses sight to communicate

viviparous

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

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.