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Marmosa mexicanaMexican mouse opossum

By Robert Voss

Geographic Range

Marmosa mexicana occurs from eastern Mexico southward throughout much of Central America to eastern Panama, from near sea level to about 2090 m. (Gutierrez, et al., 2010; Rossi, et al., 2010)

Habitat

Marmosa mexicana (which may include more than one species; see Other Comments) occurs in a very wide range of habitats, including dry (deciduous) thorn forest, evergreen lowland forest, pine-oak woodlands, and mangroves; it is known to occur both in undisturbed situations and in secondary growth. (Alonso-Mejia and Medellin, 1992; Gutierrez, et al., 2010)

  • Range elevation
    0 to 2090 m
    0.00 to 6856.96 ft

Physical Description

Like other species of mouse opossums, Marmosa mexicana 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 usually some shade of reddish brown and the ventral fur is yellowish to orangish. Among other diagnostic traits, this species differs from other species of Marmosa by its extensive blackish facial mask, which extends well behind the eye to the base of the ear on each side of the head. This species is sexually dimorphic (males average larger than females). (Rossi, et al., 2010)

  • Sexual Dimorphism
  • male larger
  • Range mass
    35 to 99 g
    1.23 to 3.49 oz
  • Average mass
    46 (females) 63 (males) g
    oz
  • Range length
    119 to 168 mm
    4.69 to 6.61 in
  • Average length
    121 (females) 133 (males) mm
    in

Reproduction

Nothing is known about the mating system of this species.

Almost nothing has been published about reproduction that can be confidently attributed to Marmosa mexicana, but other species of Marmosa are spontaneous ovulators that give birth to highly altricial young after a short gestation (see M. robinsoni). Several descriptions of reproduction by female mouse opossums found on banana boats in the early 20th century and identified as M. mexicana (see references cited by Alonso-Mejia and Medellin, 1992) are unvouchered and might have been based on other species. Museum specimens of M. mexicana have 11 to 15 functional mammae, so average litter sizes are probably in this range. (Alonso-Mejia and Medellin, 1992; Rossi, et al., 2010)

  • Key Reproductive Features
  • iteroparous
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    2 to 13

Although parental care has not been observed in this species, females presumably nurse neonatal young, groom them, and protect them from predators, but other forms of parental investment are unknown. (Tate, 1933)

  • 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

Nothing is definitely known about the lifespan of Marmosa mexicana, but other species of Marmosa that have been studied in the wild are not thought to live much longer than one year. Captives might live longer, but no published information about captive lifespan is available. (Tate, 1933)

Behavior

There have been no published studies of behavior that can be definitely attributed to this species, but other species of Marmosa are arboreal/scansorial, nocturnal, and solitary. Alleged burrowing behavior may be based on animals found nesting in cavities excavated by other species (the forepaws of this species are conspicuously unsuited for burrowing). (Alonso-Mejia and Medellin, 1992)

Home Range

There have been no published studies of the home range of this species.

Communication and Perception

The eyes, ears, nasal turbinates (thin bones that support olfactory epithelium), and tactile hairs are well developed in this species (as in other opossums), so vision, hearing, and touch are probably important senses. Which of these are actually used for communication with other conspecifics is unknown. (Rossi, et al., 2010)

Food Habits

Little definite information is available about the food habits of this species, but its dentition is similar to that of other species of Marmosa which are known to be insectivorous and to eat fruit occasionally. Anecdotal reports suggests that it also eats, at least occasionally, bird's eggs and small vertebrates. (Alonso-Mejia and Medellin, 1992; Tate, 1933)

  • Animal Foods
  • birds
  • mammals
  • reptiles
  • eggs
  • carrion
  • insects
  • Plant Foods
  • fruit

Predation

The natural predators of this species probably include snakes, owls, and wild felids. Bones of Marmosa mexicana have been recovered from pellets of two species of owls. (Alonso-Mejia and Medellin, 1992)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Marmosa mexicana is probably a primary consumer (of fruit) and a secondary consumer (of insects). It is probably eaten by snakes, owls, and carnivorans; and it is certainly host to many species of invertebrate ecto- and endo-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).

Economic Importance for Humans: Positive

It is unlikely that this species is of any positive economic value to humans.

Economic Importance for Humans: Negative

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

Conservation Status

Marmosa mexicana is a species of Least Concern according to the IUCN Red List. Because M. mexicana is very widely distributed in a wide range of habitats including human-modified vegetation, it does not require protection. (Gutierrez, et al., 2010)

Other Comments

Until 2010 Marmosa mexicana was confused with M. zeledoni, a distinct species, so unvouchered ecological or behavioral observations from areas where these species occur sympatrically (Nicaragua, Costa Rica, and Panama) cannot be confidently associated with either species. Even as restricted by Rossi et al. (2010), M. mexicana may consist of more than one species. Two distinct mitochondrial haplotype lineages (called M. mexicana A and M. mexicana B) were identified by Gutierrez et al. (2010), who discussed the possibility that they might represent different species. (Gutierrez, et al., 2010; 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

carrion

flesh of dead animals.

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

forest

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

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

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

nocturnal

active during the night

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

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

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

References

Alonso-Mejia, A., R. Medellin. 1992. Marmosa mexicana. Mammalian Species, 421: 1-4.

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.

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.

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