Mountain degu

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Mountain degu
Octodontomys gliroides 238516748.jpg
Humahuaca Department, Argentina
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Octodontidae
Genus: Octodontomys
Palmer, 1903
Species:
O. gliroides
Binomial name
Octodontomys gliroides
(Gervais & d'Orbigny, 1844)
Octodontomys gliroides range.svg
O. gliroides range
Synonyms [2]

The mountain degu (Octodontomys gliroides), also known as the Andean degu, [3] is a species of rodent in the family Octodontidae. It is the only species in the genus Octodontomys. [4] It is found in the foothills of the Andes in Argentina, Bolivia and Chile.

Contents

Taxonomy and etymology

The mountain degu was first described in 1844 as a member of the genus Octodon, having been given the scientific name Octodon gliroides by the French naturalists Paul Gervais and Alcide d'Orbigny. The species name, gliroides, was given due to the animal's similar appearance to that of a dormouse (gliris in Latin). [5] The etymology of the name gliroides comes from a combination of the Latin gliris, 'dormouse' with the Greek suffixes -o and eidos, which indicate "likeness of form". [6] The type locality where it was first identified is the Andes in La Paz, Bolivia. [2]

Octodontomys, a genus created in 1903 by American zoologist Theodore Sherman Palmer, comes from the Ancient Greek ὀκτώ (oktṓ), meaning 'eight', ὀδούς (odoús), meaning 'tooth', and μῦς (mûs), meaning 'mouse'. [6] The genus was created to replace the earlier-used name Neoctodon , which was already in use as a genus of beetles from an 1892 work by entomologist Ernest Marie Louis Bedel. [7] The British zoologist Oldfield Thomas had used the name Neoctodon in his 1901 description of the mountain degu (as the new species Neoctodon simonsi, named in honor of the collector Perry O. Simons), [8] which he corrected to the currently used name, Octodontomys gliroides, in his 1913 article On small mammals collected in Jujuy by Señor E. Budin. [9] Thomas noted that the species was "strikingly different" from members of Octodon, and differentiated it based on its "paler colour, whiter belly, and longer, more bushy tail". [8]

The common name "degu" is first recorded from the period between 1835 and 1845, and originates from the Mapuche word deuñ [10] or dewit. Over time, the word changed through its use in Chilean Spanish. Recorded common names for the species include long-tailed octodon and brush-tailed vizcacha rat. [11]

Phylogeny

The phylogeny and placement of O. gliroides in relation to other octodontids was originally unclear. [12] A study of mitochondrial DNA across the species' range published in 2016 solidified Octodontomys as a monophyletic group, albeit one with two distinct lineages, one of which is distributed across Bolivia and northern Chile, the other restricted to Argentina. [3] Compared to other rodents worldwide, Octodontomys has been found to have some similarities to the monophyletic dassie rat. [13] The mountain degu has a diploid chromosome number of 38 and a fundamental number of 64. [14] The 28S and 18S ribosomal RNA of the mountain degu have notably split or eliminated introns, a genetic feature shared only with the tuco-tucos. [15]

The following cladogram is adapted from work done by Rivera and colleagues in 2014. [16] The genus Octodontomys is considered, as of 2018, to be the most primitive among the octodontids. It is thought to have diverged from its sister clade, which includes the genera Octodon , Spalacopus , and Aconaemys , at a point roughly 5 to 7 million years ago. No fossils of O. gliroides are known, and all estimates of species divergence times are made based on genetic analyses. [11]

Octodontidae

Description

O. gliroides illustration by Joseph Smit, 1902 NeoctodonSimonsiSmit.jpg
O. gliroides illustration by Joseph Smit, 1902

The mountain degu is a rodent of medium size with an adult length of 200 to 380 mm (8 to 15 in), including a tail of 100 to 190 mm (4 to 7 in), and a body weight in the range of 100 to 200 grams (4 to 7 oz). The hairs are long and silky. The upper surface is greyish-brown, the chin is pure white, and the underparts are white with a grey base to the hairs. There is a tuft of white hair in front of the large ears, which are clad in short grey hair. The slender tail is bi-coloured (dark above and pale below) and has a tuft of brown or ochre hairs at the tip. Juveniles have darker fur above and greyer underparts. Their tails are brownish with a dark brown or black tufted tip. [17]

Distribution and habitat

This species is found in the mountainous areas of southwestern Bolivia, northwestern Argentina and northern Chile. [18] It has a wide altitudinal range, occurring at 200 to 300 metres (660 to 980 ft) in Jujuy Province in Argentina, and up to 4,400 metres (14,400 ft) in Potosí Department in Bolivia. As the only species of octodontid found in the higher parts of its range, it inhabits dry rocky areas with tall cacti, shrubs and herbs. [17] It is especially well suited for xeric habitats within and east of the Andes mountain range. [14]

Behaviour

A mountain degu near Yavi, Jujuy Province, Argentina Octodontomys gliroides 339329462 (cropped).jpg
A mountain degu near Yavi, Jujuy Province, Argentina

The mountain degu is a nocturnal, herbivorous rodent, being most active just after sunset. [19] It does not have any special adaptations of skull or limbs for tunnelling, but digs short burrows and lives under rocks and in caves. Its tail can be autotomised, and it can be used as a prop when climbing. It is a sociable animal and communicates by means of a range of low, medium and high-pitched gurgles, twitters and squeaks, [17] similar to the common degu and various species in genus Cavia . [20] Social groups of the mountain degu range from 2 to 4 individuals that share a burrow system together to rest and hide from predators. Female mountain degus have a smaller home range than that of males. [21] The mountain degu is notably less social than the common degu. Family groups engage in play shortly after waking from sleep, with individuals locking incisors with and riding on each other. [11] Like other octodontids, [17] the mountain degu takes dust baths, with each member of a family unit taking turns at the same location. [11]

The mountain degu feeds on the leaves and bark of shrubs, and on Acacia sheaths in the winter and on cactus fruits in the summer. It can obtain sufficient moisture from its food, particularly cactus, to satisfy its water requirements. [17]

Mountain degu young in various stages of development have been found in November, and pregnant females and young in both January and May. A gestation period of 100-109 days has been reported with a litter size of one to three pups. The pups are precocial when born, already having their eyes open and being well-furred. [19]

Relationship with humans

The mountain degu is known to host parasites that are infectious to humans, such as the Chagas disease-causing Trypanosoma cruzi . It is also parasitized by bloodsucking fleas in genus Ectinorus and lice in the genera Ferrisella . Otherwise, it has little to no societal impact, similar to other degus. [22]

Conservation

The mountain degu is common within its distribution [11] and has no known threats. The International Union for Conservation of Nature considers it to be a least-concern species because it is widely distributed, occurs in some protected areas, and can tolerate changes in its habitat. The mountain degu population is not declining at an appreciable rate, and there are no conservation actions being taken towards it. [1]

References

  1. 1 2 Weksler, M. (2016). "Octodontomys gliroides". IUCN Red List of Threatened Species . 2016: e.T15091A22240265. doi: 10.2305/IUCN.UK.2016-2.RLTS.T15091A22240265.en . Retrieved 11 November 2021.
  2. 1 2 "Octodontomys gliroides (id=1001497)". ASM Mammal Diversity Database. American Society of Mammalogists . Retrieved August 28, 2025.
  3. 1 2 Rivera, Daniela S.; Vianna, Juliana A.; Ebensperger, Luis A.; Eduardo Palma, R. (October 2016). "Phylogeography and demographic history of the Andean degu, Octodontomys gliroides (Rodentia: Octodontidae)". Zoological Journal of the Linnean Society. 178 (2): 410–430. doi:10.1111/zoj.12412.
  4. ↑ Woods, C.A.; Kilpatrick, C.W. (2005). "Genus Octodontomys". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 1572. ISBN   978-0-8018-8221-0. OCLC   62265494.
  5. ↑ Gervais, P.; d'Orbigny, A. (1844). "M. Paul Gervais communique, au nom de M. Alc. d'Orbigny et au sien, la description d'une espèce nouvelle de Mammifères Rongeurs". Extraits des procès-verbaux des séances (in French) (9). Société Philomatique de Paris: 22 – via Biodiversity Heritage Library.
  6. 1 2 Braun, Janet K.; Mares, Michael A. (1995). "The mammals of Argentina: an etymology" (PDF). Mastozoología Neotropical. 2 (2): 173–206. ISSN   0327-9383.
  7. ↑ Palmer, T.S. (1903). "Some new generic names of mammals". Science . 17: 873. doi:10.1126/science.17.439.873.a – via Biodiversity Heritage Library.
  8. 1 2 Thomas, O. (1902). "On Two new Genera of Rodents from the Highlands of Bolivia". Proceedings of the Zoological Society of London. 1902. Academic Press, [etc.]: 114–117 – via Biodiversity Heritage Library.
  9. ↑ Thomas, O. (1913). "On small mammals collected in Jujuy by Señor E. Budin". Annals and Magazine of Natural History . 11. London: Taylor and Francis: 136–143 – via Biodiversity Heritage Library.
  10. ↑ "degu". Collins English Dictionary . HarperCollins . Retrieved 2025-08-28.
  11. 1 2 3 4 5 Pérez, M Julieta; Díaz, M Mónica (2018-09-17). "Octodontomys gliroides (Rodentia: Octodontidae)". Mammalian Species. 50 (963): 74–83. doi:10.1093/mspecies/sey010. ISSN   0076-3519.
  12. ↑ Verzi, Diego H.; Olivares, A. Itatí; Morgan, Cecilia C.; Álvarez, Alicia (March 2016). "Contrasting Phylogenetic and Diversity Patterns in Octodontoid Rodents and a New Definition of the Family Abrocomidae". Journal of Mammalian Evolution. 23 (1): 93–115. doi:10.1007/s10914-015-9301-1. hdl: 11336/43822 . ISSN   1064-7554.
  13. ↑ Mares, M.A.; Ojeda, R.A. (1982). "Patterns of diversity and adaptation in South American hystricognath rodents". In Mares, M.A.; Genoways, H.H. (eds.). Mammalian Biology in South America. Pymatuning Laboratory of Ecology, University of Pittsburgh. pp. 393–432.
  14. 1 2 Honeycutt, Rodney L; Rowe, Diane L; Gallardo, Milton H (2003-03-01). "Molecular systematics of the South American caviomorph rodents: relationships among species and genera in the family Octodontidae". Molecular Phylogenetics and Evolution. 26 (3): 476–489. doi:10.1016/S1055-7903(02)00368-8. ISSN   1055-7903.
  15. ↑ Melen, G. J. (1999-06-01). "Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an `intron' bearing a hidden break site". The EMBO Journal. 18 (11): 3107–3118. doi:10.1093/emboj/18.11.3107. PMC   1171392 . PMID   10357822.
  16. ↑ Rivera, Daniela S.; Abades, Sebastian; Alfaro, Fernando D.; Ebensperger, Luis A. (2014-10-31). "Sociality of Octodontomys gliroides and other octodontid rodents reflects the influence of phylogeny". Journal of Mammalogy. 95 (5): 968–980. doi:10.1644/14-MAMM-A-057. hdl: 10533/148512 . ISSN   0022-2372.
  17. 1 2 3 4 5 James L. Patton; Ulyses F. J. Pardiñas; Guillermo D'Elía (9 March 2015). Mammals of South America, Volume 2: Rodents. University of Chicago Press. pp. 1035–1037. ISBN   978-0-226-16960-6. OCLC   904333770.
  18. ↑ Ojeda 2016, p. 548.
  19. 1 2 Ojeda 2016, p. 549.
  20. ↑ Schleich, Cristian E.; Veitl, Silke; Knotková, Ema; Begall, Sabine (2007), Begall, Sabine; Burda, Hynek; Schleich, Cristian E. (eds.), "Acoustic Communication in Subterranean Rodents" , Subterranean Rodents, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 113–127, doi:10.1007/978-3-540-69276-8_10, ISBN   978-3-540-69275-1 , retrieved 2025-01-10
  21. ↑ Ojeda 2016, pp. 542–544.
  22. ↑ Ojeda 2016, pp. 544–545.

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