Elegant fat-tailed mouse opossum

Elegant fat-tailed mouse opossum[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Didelphimorphia
Family: Didelphidae
Genus: Thylamys
Species: T. elegans
Binomial name
Thylamys elegans
(Waterhouse, 1839)
Geographic range

The elegant fat-tailed mouse opossum (Thylamys elegans) is a species of opossum in the family Didelphidae and order Didelphimorphia. Its head-and-body length ranges from 106 to 121 millimeters and its average body weight is 30 grams. Its tail length ranges from 115 to 142 millimeters. Its tail is swollen (it stores fat in its tail) and has fine hairs all over it. Its dense, velvety fur varies in color, but it usually ranges from light gray to light brown. The sides are lighter, and the ventral fur is white, possibly with gray or yellow mixed in with a wide dark brown stripe down the dorsal part of the body. There is a dark patch surrounding each eye, extending towards the nose. They also have very long nasal cavities, which results in their long snouts. (Palma) In Chile, the breeding season is from September to March, producing about two litters. An elegant fat-tailed mouse opossum makes nests in various places. It is an insectivorous mammals that eats a high protein diet, mainly arthropods and their larvae, but also fruits, small vertebrates, and possibly carrion.[3] (Palma) It is an arboreal species found in Chile and perhaps Argentina, at altitudes from sea level to 2500 m.[2]

Distribution and Habitat

T. elegans inhabits the semi-arid and Mediterranean-type ecosystems that are located in Peru through central Chile. These types of ecosystems are characterized for their seasonal rainfall patterns during the months of May through August. During these months, most of the precipitation for the year occurs(about 90%). During the months when food is scarce, T. elegans uses an energy-saving behavioral mechanism called torpor. (Lima)

Climbing

In Chile, it is characteristic of most small mammals to have a very low climbing ability. The elegant fat-tailed mouse opossum, due largely to its prehensile tail and opposable thumbs on its back limbs, does not fall into this group of small Chilean mammals. T. elegans is able to quickly and effectively scale up a tree, regardless of diameter size, because it uses its tail to help climb and is able to grip the unsteady, thin branches more tightly than other mammals of similar size. This gives the opossum a slight advantage over other small mammals. (Gallardo-Santis)

Physiology

As previously noted, T. elegans utilizes the mechanism called torpor. This mechanism allows the opossum to use significantly less energy and require less food, similar to hibernation except that it is only done for a short period of time. Additionally, when water is scarce, they tend to have very concentrated urine. (Palma) It has also been found that the ratio of maximum metabolic rate (MMR) and basal metabolic rate (BMR) in these marsupials is unaffected by thermal acclimation, as it is in other mammals. T. elegans has a higher ratio than other marsupials, which are expected to have a low BMR in general.(F. Nespolo)

Reproduction

The reproductive pattern of these marsupials looks to be seasonal, occurring from mid to late winter and lasting until November or December. (Lima) Within the first year, females start to ovulate and male testis and prostate glands increase in size. (Palma) Females give birth to one or two litters, each containing eleven to thirteen offspring. (Lima)They have been reported to have approximately fifteen nipples, with only eleven to thirteen of them becoming fully functional, which determines the number of offspring. (Palma) It has been found that marsupials and eutherians have differences in the behavior and structure of sex chromosomes during the meiotic process. Marsupials have been found to have different mechanisms to associate sex chromosomes during prophase. Namely, they form a dense plate to associate the sex chromosomes, a feature that is unique to marsupials alone. (Page)

References

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[6]

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[8]

  1. ↑ Gardner, A.L. (2005). "Order Didelphimorphia". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 17. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. 1 2 Solari, S. & Teta, P. (2008). Thylamys elegans. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 28 December 2008.
  3. ↑ Eisenberg, John Frederick; Redford, Kent Hubbard (1999). Mammals of the Neotropics: The Central Neotropics: Ecuador, Peru, Bolivia, Brazil. University of Chicago Press. p. 669. ISBN 978-0-226-19542-1.
  4. ↑ F. Nespolo, Roberto. "Interplay among Energy Metabolism, Organ Mass and Digestive Enzyme Activity in the Mouse-opossum Thylamys Elegans: The Role of Thermal Acclimation." Journal of Experimental Biology 205 (2002): 2697-703. The Company of Biologists Ltd. Web. 19 Nov. 2015.
  5. ↑ Gallardo-Santis, Andrea, Javier A. Simonetti, and Rodrigo A. Vásquez. "Influence Of Tree Diameter On Climbing Ability Of Small Mammals." Journal of Mammalogy: 969-73. Print.
  6. ↑ Lima, M., N. C. Stenseth, N. G. Yoccoz, and F. M. Jaksic. "Demography and Population Dynamics of the Mouse Opossum (Thylamys Elegans) in Semi-arid Chile: Seasonality, Feedback Structure and Climate." Proceedings of the Royal Society B: Biological Sciences (2001): 2053-064. Web. 19 Nov. 2015.
  7. ↑ Page, J. "The Pairing of X and Y Chromosomes during Meiotic Prophase in the Marsupial Species Thylamys Elegans Is Maintained by a Dense Plate Developed from Their Axial Elements." Journal of Cell Science (2002): 551-60. Print.
  8. ↑ Palma, R. Eduardo. "Thylamys Elegans." Mammalian Species (1997): 1. Print.}}
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