Genus Lestodelphys
The "Patagonian Opossum"
Lestodelphys Pictures
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Lestodelphys halli
(Thomas, 1921)
Names
- English: Patagonian Opossum
- Czech: vačice patagonská
- Dutch: Patagonische opossum
- German: Patagonien-Beutelratte
- Russian: ПАТАГОНСКИЙ ОПОССУМ
- Spanish: Comadrejita Patagónica
- Spanish: El Lestodelfo Patagónico
- Spanish: Lestodelfo
Etymology: The original name was "Notodelphys halli". The name "Patagonian Opossum" refers to their presence in the Patagonian steppe of Argentina." Lestodelphys" comes from the Greek prefix "Lesto" meaning "robber" which refers to its presumed predatory nature. "Halli" is named for Mr. T. H. Hall who collected many of the specimens.
Habitat
These opossums are found only in Argentina, particularly the Patagonian Pampas, Chubut, Mendoza, Neuquén, Río Negro, Santa Cruz. Opossums have been specifically found in Cabo Tres Puntas, Estancia Los Manantiales near Languineo, Pico Salamanca, and the edge of the Golfo de San Jorge.
Their population is considered critically imperiled due to the small size of their territory. They live farther south than any other living marsupial in South America or Australia. While most opossums live in tropical and neo-tropical areas, this opossum lives in temperate zones that are cold and dry.
They are probably terrestrial. Compared to arboreal opossums, their feet are stronger and tail is shorter - both making them more suited to living on the ground. The Patagonian steppe in particular is flat and mixed with bushes, shrubs and bare ground. They tend to live in areas of shrubs, grasslands and near meadows. Evolutionary History of the Marsupials and an Analysis of Osteological Characters also suggests Lestodelphys are terrestrial.
Places They Have Been Found:
- Argentina, Lihuel Calel, Lihue Calel (1 found 12/20/1986)
- Argentina, Los Lagos, Estancia Tehuel Malal, Nahuel Huapi 6 km NW (1 found 12/12/1980)
- Argentina, Lujan de Cuyo, Chacras de Coria (2 found 11/09/1969)
- Argentina, Meseta el Pedrero (1 found 04/03/1995)
- Argentina, Pampa de Agnia 30 KM MW (1 found 04/02/1992)
- Argentina, Pico Salmanca, From Owl Pellet (Found 02/19/1981)
- Argentina, Pilcaniyeu, Comallo 10 km WSW (2 found 12/10/1984)
- Argentina, Pilcaniyeu, Comallo 8 km WSW (4 found 05/16/1984)
- Argentina, Pilcaniyeu, Clemente Onelli 9 km W (19 found 11/05-06/1989)
- Argentina, Pilcaniyeu, Cerro Leones (1 found 11/28/1985)
- Argentina, Pilcaniyeu, Cerro Leones (2 found 11/28/1982)
- Argentina, Pilcaniyeu, Cerro Leones, Bariloche 16 km ENE (1 found 05/03/1977)
- Argentina, Pilcaniyeu, Cerro Leones, Bariloche 16 km ENE (1 found 11/21/1981)
Diet
Several sources, including Molecular Evolution and Adaptive Radiation, describe this opossum as primarily carnivorous. The appearance of their shortened skull, the long claws, and long canine teeth indicate a carnivorous diet. They probably live off rodents and birds. During winters in their territory they may hunt under the snow, or perhaps go into torpor like Thylamys elegans. The fat storage at the base of their tail may help them survive during lean times. Oliver Pearson (the photographer of the picture at the top of the page) reported that a 2.5 ounce (70g) Lestodelphys halli opossum ate an entire 1.2 ounce (35g) mouse - fur, bones and all - in one night.
Appearance
Size: Their head and body length is about 5.2-5.7" inches long (132-144 mm). The tail length ranges from 3.2-3.9" inches long (81-99 mm) and may store a slight amount of fat at the base of the tail. The weight may be around 2.5-2.8 ounces (70-80 grams).
Skull: They are described as having a "short, broad skull" and its appearance suggests a carnivorous diet.
Teeth: The first pair of upper incisors are the same length as the others, but set slightly apart (similar to Marmosa). The canines are described as particularly long and the molars are large.
Sex: Females are said to have 19 mammae and like many other opossums do not have a pouch. Males have orange fur in front of their throat, while females have orange around their nipples.
Ears: The length of their ear is about 0.71-0.87" inches long (18-22mm).
Feet: The length of their hind feet is 0.62-0.70" inches long (15.7-17.7mm). Their claws extend past the terminal pad, while in Marmosa it does not.
Coloring: Their color is generally dark gray-brown on their back, the sides are gray with white undersides and legs. Their face has white patches at the base of the ears and over the eyes, and the cheeks are white. See the picture above for an example.
This description about their appearance is from Walker's Mammals:
"The back is dark gray; the face is somewhat darker with no markings; the sides of the body are clear gray; and the forearms, hands, ankles, feet, and underparts are white. The cheeks, a patch over the eyes, and a patch at the posterior base of the ear are also white. There are dark shoulder and hip patches. The tail, which is furred like the body for about 20 mm at the base, then thickly covered with short, fine hairs, is dark grayish brown above and whitish below and at the tip...The ears are short, rounded, and flesh-colored."
This description about their appearance is from Mammals of the Neotropics, Volume 2:
"This small opossum resembles Marmosa elegans in general dorsal color, being gray brown, almost pearl gray (plate 2). The fur is dense and very soft. The sides are paler, and the whitish to buff venter is sharply demarcated. The cheeks and a patch over the eyes are whitish, as are the hands and feet. The tail is dark grayish brown above and whitish below. In males the fur on the front of the throat is orange, and in females the fur around the nipples is orange."
This description about their appearance is from Mammalian Species by Larry G. Marshall:
Fur is rather short, dense, fine and soft. General color is gray, dorsum is a dark gray with paler sides, shoulder and hip patches are dark. Under surface is uniformly white to bases of hairs. Cheeks and a patch over eyes are whitish. Ears are short, rounded, flesh-colored, and with a whitish patch at their bases posteriorly. Forearms, hands, ankles, and feet are pure white.
Taxonomy
This opossum is differentiated from the mouse opossums due to their feet, skull and teeth. They are more carnivorous than the opossums that eat mostly fruit and insects. Mouse opossum claws don't extend past the terminal pad like the claws of Lestodelphys. The skull and jaws are shorter, allowing for more biting power in the premolars than in Marmosa. They also have white marks on their face while mouse opossums do not.
To quote Walker's Mammals:
"In Lestodelphys the bullar floor of the skull is complete and does not have a gap between the petrous and alisphenoid components such as are found in all other genera of the Marmosidae."
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Resources
- Comadrejita Patagonica (Text in Portuguese) and The Marsupials of Argentina (Text in English)
- Evolutionary History of the Marsupials and an Analysis of Osteological Characters
- Mammals of the Neotropics, Volume 2
- Molecular Evolution and Adaptive Radiation
- Walker's Mammals
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