Octodontidae
Encyclopedia
The Octodontidae are a family
of rodent
s, restricted to south-western South America
. Thirteen species of octodontid are recognised, arranged in nine genera
. The best known species is the Degu
, Octodon degus.
Octodontids are medium sized rodents, ranging from 12 centimetre in body length. They have long, silky, fur, which is typically brownish in color, and often paler on the underside. The name 'octodont' derives from the wear pattern of their teeth, which resembles a figure 8. Most are nocturnal, social, burrowing animals, though the Degu is largely diurnal. They are herbivorous
, eating tuber
s, bulbs, and cactus
es.
Some authors have suggested that the octodontids should be reclassified in the order
Lagomorpha
, but this has not been supported by further analyses (e.g. Opazo, 2005). Older literature includes the tuco-tuco
s in the family, as the subfamily Ctenomyinae, but these animals are normally now treated as a separate family, the Ctenomyidae. Two of the genera now included in this family, Salinoctomys and Pipanacoctomys, have only recently been described. There is some evidence that evolution within the family may have resulted from polyploidy
. The red viscacha rat, Tympanoctomys barrerae, is tetraploid, with 102 chromosome
s, and the recently described golden viscacha rat Pipanacoctomys aureus has 92.
Members of the genus Aconaemys
are referred to as rock rat
s, and members of genus Octodon
are all called degus, though the name Degu on its own implies O. degu. The single member of Spalacopus, S. cyanus, is called the Coruro
. Members of the other genera are called viscacha rat
s: note, however, that viscacha
s are not octodontids - they are members of the chinchilla
family Chinchillidae
.
Ameghino, 1891 (Andean Rock Rats).
Genus Octodon
Bennett, 1832 (Degus).
Genus Octodontomys Palmer, 1903.
Genus Octomys Thomas, 1920.
Genus Pipanacoctomys
Mares et al., 2000.
Genus Salinoctomys Mares et al., 2000.
Genus Spalacopus Wagler, 1832.
Genus Tympanoctomys Yepes, 1942.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, restricted to south-western South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. Thirteen species of octodontid are recognised, arranged in nine genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. The best known species is the Degu
Degu
The degu is a small caviomorph rodent that is endemic to central Chile.It is sometimes referred to as the brush-tailed rat, and is also called the common degu, to distinguish it from the other members of the genus Octodon. Other members are also called degus, but they are distinguished by...
, Octodon degus.
Octodontids are medium sized rodents, ranging from 12 centimetre in body length. They have long, silky, fur, which is typically brownish in color, and often paler on the underside. The name 'octodont' derives from the wear pattern of their teeth, which resembles a figure 8. Most are nocturnal, social, burrowing animals, though the Degu is largely diurnal. They are herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, eating tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...
s, bulbs, and cactus
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
es.
Some authors have suggested that the octodontids should be reclassified in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Lagomorpha
Lagomorpha
The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families, the Leporidae , and the Ochotonidae...
, but this has not been supported by further analyses (e.g. Opazo, 2005). Older literature includes the tuco-tuco
Tuco-tuco
The tuco-tucos are members of a group of rodents that belong to the family Ctenomyidae. The tuco-tucos belong to a single genus: Ctenomys, but they include some 60 different species. The relationships among the species are debated by taxonomists. Their closest relatives are degus and other...
s in the family, as the subfamily Ctenomyinae, but these animals are normally now treated as a separate family, the Ctenomyidae. Two of the genera now included in this family, Salinoctomys and Pipanacoctomys, have only recently been described. There is some evidence that evolution within the family may have resulted from polyploidy
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
. The red viscacha rat, Tympanoctomys barrerae, is tetraploid, with 102 chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s, and the recently described golden viscacha rat Pipanacoctomys aureus has 92.
Members of the genus Aconaemys
Aconaemys
Aconaemys is a genus of rodent in the Octodontidae family.It contains the following species:* Chilean Rock Rat * Porter’s Rock Rat * Sage's Rock Rat - References :...
are referred to as rock rat
Rock rat
The term rock rat has been used for several different types of rodents:*Members of the family Muridae:**The genus Zyzomys in the subfamily Murinae**The genus Aethomys in the subfamily Murinae.*Members of the family Nesomyidae:...
s, and members of genus Octodon
Octodon
Octodon is a genus of octodontid rodents, of which the best-known member is the degu O. degus. The full list of species is:* O. bridgesi, Bridge's Degu, found in Argentina and Chile...
are all called degus, though the name Degu on its own implies O. degu. The single member of Spalacopus, S. cyanus, is called the Coruro
Coruro
The Coruro is a species of rodent in the family Octodontidae. It is monotypic within the genus Spalacopus. The species is endemic to central Chile, where it has been found in a wide variety of habitats, from coastal to montane. It is fossorial and lives in colonies....
. Members of the other genera are called viscacha rat
Viscacha Rat
The viscacha rat , or mountain viscacha rat, is a species of rodent in the family Octodontidae. It is endemic to Chile and Argentina.It is the only living species within the genus Octomys...
s: note, however, that viscacha
Viscacha
Viscachas or vizcachas are rodents of two genera in the family Chinchillidae. They are closely related to chinchillas, and look similar to rabbits...
s are not octodontids - they are members of the chinchilla
Chinchilla
Chinchillas are crepuscular rodents, slightly larger and more robust than ground squirrels, and are native to the Andes mountains in South America. Along with their relatives, viscachas, they make up the family Chinchillidae....
family Chinchillidae
Chinchillidae
The family Chinchillidae contains the chinchillas, viscachas, and their fossil relatives. They are restricted to southern and western South America, often in association with the Andes. They are large rodents, weighing from to , with strong hind legs and large ears...
.
List of species
Genus AconaemysAconaemys
Aconaemys is a genus of rodent in the Octodontidae family.It contains the following species:* Chilean Rock Rat * Porter’s Rock Rat * Sage's Rock Rat - References :...
Ameghino, 1891 (Andean Rock Rats).
- Species Aconaemys fuscus (Waterhouse, 1842) (Chilean Rock Rat). Andes of Chile and Argentina.
- Species Aconaemys porteri Thomas, 1917. Andes of Chile and Argentina.
- Species Aconaemys sagei (Pearson, 1984) (Sage's Rock Rat). Andes of Chile and Argentina.
Genus Octodon
Octodon
Octodon is a genus of octodontid rodents, of which the best-known member is the degu O. degus. The full list of species is:* O. bridgesi, Bridge's Degu, found in Argentina and Chile...
Bennett, 1832 (Degus).
- Species Octodon bridgesi Waterhouse, 1844 (Bridges' Degu). Andes of Chile and Argentina.
- Species Octodon degus (Molina, 1782) (Degu). Western Chile.
- Species Octodon lunatus Osgood, 1943 (Moon-toothed Degu). Western Chile.
- Species Octodon pacificus Hutterer, 1994 (Isla Mocha Degu). Isla Mocha, off western Chile.
Genus Octodontomys Palmer, 1903.
- Species Octodontomys gliroides (Gervais & D'Orbigny, 1844). Andes of northwestern Argentina, extreme northeastern Chile and western Bolivia.
Genus Octomys Thomas, 1920.
- Species Octomys mimax Thomas, 1920 (Mountain Viscacha-Rat). Andes of Argentina.
Genus Pipanacoctomys
Pipanacoctomys
The Golden Vizcacha Rat ' is the single species of the genus Pipanacoctomys of the rodent family Octodontidae. This animal is tetraploid and has 4x = 2n = 92 chromosomes...
Mares et al., 2000.
- Species P. aureus Mares et al., 2000 (Golden Viscacha-Rat). Catamarca Prov., Argentina.
Genus Salinoctomys Mares et al., 2000.
- Species Salinoctomys loschalchalerosorum Mares et al., 2000 (Los Chalchaleros' Viscacha-Rat). La Rioja Prov., Argentina.
Genus Spalacopus Wagler, 1832.
- Species Spalacopus cyanus (Molina, 1782) (Coruro). Western Chile.
Genus Tympanoctomys Yepes, 1942.
- Species Tympanoctomys barrerae (Lawrence, 1941) (Plains Viscacha-Rat or Red Viscacha-Rat). Scattered localities in western Argentina.
External links
- Deguworld.com - The Internet's Degu Expert, providing information, a forum and advice on raising your Degus.
- http://www.chez.com/rodent/Octodontidae/Octodontidae.html
- http://www.degutopia.co.uk
- DeguCage.com - Learn all about your degus