Treeshrew

Last updated

Treeshrews [1]
Temporal range: Middle Eocene – Recent
Spitzhornchen.JPG
Tupaia sp.
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Grandorder: Euarchonta
Order: Scandentia
Wagner, 1855
Families
Treeshrew range.jpg
Red: Tupaiidae , Blue: Ptilocercidae , Purple: both Tupaiidae and Ptilocercidae
Treeshrew species density.jpg
The distribution and density of treeshrew species.

The treeshrews (also called tree shrews or banxrings [3] ) are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire order Scandentia, which split into two families: the Tupaiidae (19 species, "ordinary" treeshrews), and the Ptilocercidae (one species, the pen-tailed treeshrew).

Contents

Though called 'treeshrews', and despite having previously been classified in Insectivora, they are not true shrews, and not all species live in trees. They are omnivores; among other things, treeshrews eat fruit.

Treeshrews have a higher brain to body mass ratio than any other mammal, including humans, [4] but high ratios are not uncommon for animals weighing less than 1 kg (2 lb).

Among orders of mammals, treeshrews are closely related to primates, and have been used as an alternative to primates in experimental studies of myopia, psychosocial stress, and hepatitis. [5]

Name

The name Tupaia is derived from tupai , the Malay word for squirrel, [6] and was provided by Sir Stamford Raffles. [7]

Description

Dentition of Tupaia Dentition tupaia.jpg
Dentition of Tupaia
Madras treeshrew (Anathana ellioti) The Madras treeshrew (Anathana ellioti) by Davidraju img7.jpg
Madras treeshrew (Anathana ellioti)
Northern smooth-tailed treeshrew (Dendrogale murina) The northern smooth-tailed treeshrew.jpg
Northern smooth-tailed treeshrew (Dendrogale murina)
Northern treeshrew (Tupaia belangeri) Tupaia belangeri.JPG
Northern treeshrew (Tupaia belangeri)
Common treeshrew (T. glis) Stavenn Tupaia glis 00.jpg
Common treeshrew (T. glis)
Horsfield's treeshrew (T. javanica) Tupaia javanica.jpg
Horsfield's treeshrew (T. javanica)
Pygmy treeshrew (T. minor) Tupaia minor.jpg
Pygmy treeshrew (T. minor)
Pen-tailed treeshrew (1850 depiction of Ptilocercus lowii) The Zoology of the voyage of H.M.S. Samarang, under the command of Captain Sir Edward Belcher, C.B., F.R.A.S., F.G.S., during the years 1843-1846 (8338415184).jpg
Pen-tailed treeshrew (1850 depiction of Ptilocercus lowii)

Treeshrews are slender animals with long tails and soft, greyish to reddish-brown fur. The terrestrial species tend to be larger than the arboreal forms, and to have larger claws, which they use for digging up insect prey. They have poorly developed canine teeth and unspecialised molars, with an overall dental formula of 2.1.3.33.1.3.3 [8]

Treeshrews have good vision, which is binocular in the case of the more arboreal species.

Reproduction

Female treeshrews have a gestation period of 45–50 days and give birth to up to three young in nests lined with dry leaves inside tree hollows. The young are born blind and hairless, but are able to leave the nest after about a month. During this period, the mother provides relatively little maternal care, visiting her young only for a few minutes every other day to suckle them.

Treeshrews reach sexual maturity after around four months, and breed for much of the year, with no clear breeding season in most species. [8]

Behavior

Treeshrews live in small family groups, which defend their territory from intruders. Most are diurnal, although the pen-tailed treeshrew is nocturnal.

They mark their territories using various scent glands or urine, depending on the particular species.

Diet

Treeshrews are omnivorous, feeding on insects, small vertebrates, fruit, and seeds. Among other things, treeshrews eat Rafflesia fruit.

The pen-tailed treeshrew in Malaysia is able to consume large amounts of naturally fermented nectar from flower buds of the bertam palm Eugeissona tristis (with up to 3.8% alcohol content) the entire year without it having any effects on behaviour. [9] [10]

Treeshrews have also been observed intentionally eating foods high in capsaicin, a behavior unique among mammals other than humans. A single TRPV1 mutation reduces their pain response to capsaicinoids, which scientists believe is an evolutionary adaptation to be able to consume spicy foods in their natural habitats. [11]

Taxonomy

They make up the entire order Scandentia, split into the families Tupaiidae, the treeshrews, and Ptilocercidae, the pen-tailed treeshrew. The 20  species are placed in five genera.

Treeshrews were moved from the order Insectivora into the order Primates because of certain internal similarities to primates (for example, similarities in the brain anatomy, highlighted by Sir Wilfrid Le Gros Clark), and classified as a "primitive prosimian", however they were soon split from the primates and moved into their own clade. Taxonomists continue to refine the treeshrews' relations to primates and to other closely related clades.

Molecular phylogenetic studies have suggested that the treeshrews should be given the same rank (order) as the primates and, with the primates and the flying lemurs (colugos), belong to the grandorder Euarchonta. According to this classification, the Euarchonta are sister to the Glires (lagomorphs and rodents), and the two groups are combined into the superorder Euarchontoglires. [12] However, the alternative placement of treeshrews as sister to both Glires and Primatomorpha cannot be ruled out. [13] Some studies place Scandentia as sister of the Glires, which would invalidate Euarchonta: It is this organization that is shown in the tree diagram below. [14] [13]

Euarchontoglires

Scandentia (treeshrews)

Glires

Lagomorpha (rabbits, hares, pikas)

Rodentia (rodents)

Primatomorpha

Several other arrangements of these orders have been proposed in the past, and the above tree is only a well-favored proposal. [15] Although it is known that Scandentia is one of the most basal Euarchontoglire clades, the exact phylogenetic position is not yet considered resolved: It may be a sister of Glires, Primatomorpha, [16] or Dermoptera, or separate from and sister to all other Euarchontoglires. [17] [18] Shared short interspersed nuclear elements (SINEs) offer strong evidence for scandentia belonging to the euarchonta group: [19]

Euarchontoglires
Glires

Lagomorpha (rabbits, hares, pikas)

Rodentia (rodents)

Euarchonta

Order Scandentia

The 23  species are placed in four genera, which are divided into two families. The majority are in the "ordinary" treeshrew family, Tupaiidae, but one species, the pen-tailed treeshrew, is different enough to warrant placement in its own family, Ptilocercidae; the two families are thought to have separated 60 million years ago. [20] The former Tupaiidae genus Urogale was disbanded in 2011 when the Mindanao treeshrew was moved to Tupaia based on a molecular phylogeny. [20]

Family Tupaiidae
Family Ptilocercidae

Fossil record

The fossil record of treeshrews is poor. The oldest putative treeshrew, Eodendrogale parva , is from the Middle Eocene of Henan, China, but the identity of this animal is uncertain. Other fossils have come from the Miocene of Thailand, Pakistan, India, and Yunnan, China, as well as the Pliocene of India. Most belong to the family Tupaiidae; one fossil species described from the Oligocene of Yunnan is thought to be closer to the pen-tailed treeshrew. [21]

Named fossil species include Prodendrogale yunnanica , Prodendrogale engesseri , and Tupaia storchi from Yunnan, Tupaia miocenica from Thailand, Palaeotupaia sivalicus from India [22] and Ptilocercus kylin from Yunnan. [21]

Related Research Articles

<span class="mw-page-title-main">Placentalia</span> Infraclass of mammals in the clade Eutheria

Placental mammals are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less developed young which are then nurtured for a period inside the mother's pouch. Placentalia represents the only living group within Eutheria, which contains all mammals more closely related to placentals than to marsupials.

<span class="mw-page-title-main">Colugo</span> Family of mammals

Colugos are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur and the Philippine flying lemur. These two species make up the entire family Cynocephalidae and order Dermoptera.

<span class="mw-page-title-main">Euarchontoglires</span> Superorder of mammals

Euarchontoglires, synonymous with Supraprimates, is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, lagomorphs, treeshrews, primates, and colugos.

<span class="mw-page-title-main">Euarchonta</span> Mammal grandorder containing treeshrews, colugos, and primates

The Euarchonta are a proposed grandorder of mammals: the order Scandentia (treeshrews), and its sister Primatomorpha mirorder, containing the Dermoptera or colugos and the primates.

<span class="mw-page-title-main">Glires</span> Clade of rodents and lagomorphs

Glires is a clade consisting of rodents and lagomorphs. The hypothesis that these form a monophyletic group has been long debated based on morphological evidence. Two morphological studies, published in 2001 and 2003, strongly support the monophyly of Glires. In particular, the 2003 study reported the discovery of fossil material of basal members of Glires, particularly the genera Mimotona, Gomphos, Heomys, Matutinia, Rhombomylus, and Sinomylus. Their description, in 2005, helped to bridge the gap between more typical rodents and lagomorphs. Data published in 2001, based on nuclear DNA, supported Glires as a sister of Euarchonta to form Euarchontoglires, but some genetic data from both nuclear and mitochondrial DNA have been less supportive. A study, published in 2007, investigating retrotransposon presence/absence data unambiguously supports the Glires hypothesis. Studies published in 2011 and 2015 place Scandentia as a sister clade of the Glires, invalidating Euarchonta as a clade.

<span class="mw-page-title-main">Mammal classification</span> Taxonomy of mammals

Mammalia is a class of animal within the phylum Chordata. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provide useful recent compendiums. Many earlier ideas from Linnaeus et al. have been completely abandoned by modern taxonomists, among these are the idea that bats are related to birds or that humans represent a group outside of other living things. Competing ideas about the relationships of mammal orders do persist and are currently in development. Most significantly in recent years, cladistic thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics.

The Archonta are a now-abandoned group of mammals, considered a superorder in some classifications, which consists of these orders:

<span class="mw-page-title-main">Madras treeshrew</span> Species of mammal

The Madras treeshrew, also known as the Indian treeshrew, is a species of treeshrew in the monotypic genus Anathana found in the hill forests of central and southern India. The genus name is derived from the Tamil name of moongil anathaan and the species name is after Sir Walter Elliot of the Indian Civil Services in Madras.

<span class="mw-page-title-main">Northern treeshrew</span> Species of mammal

The northern treeshrew is a treeshrew species native to Southeast Asia.

<span class="mw-page-title-main">Northern smooth-tailed treeshrew</span> Species of mammal

The northern smooth-tailed treeshrew is a species of treeshrew in the family Tupaiidae found in Cambodia, Thailand, and Vietnam. Their diet primarily consists of invertebrates but rarely includes fruits and plants.

<span class="mw-page-title-main">Pen-tailed treeshrew</span> Species of mammal

The pen-tailed treeshrew is a treeshrew of the family Ptilocercidae native to southern Thailand, the Malay Peninsula, Borneo, and some Indonesian islands.

<span class="mw-page-title-main">Pygmy treeshrew</span> Species of mammal

The pygmy treeshrew is a treeshrew species within the family Tupaiidae. It is native to Thailand, Malaysia and Indonesia. The generic name is derived from the Malay word tupai meaning squirrel or small animals that resemble squirrels.

<span class="mw-page-title-main">Large treeshrew</span> Species of mammal

The large treeshrew is a treeshrew species within the Tupaiidae. It is native to Sumatra and adjacent small islands, as well as in the lowlands and hills of Borneo.

<span class="mw-page-title-main">Mindanao treeshrew</span> Species of mammal

The Mindanao treeshrew, also called the Philippine tree shrew, is a species of treeshrew endemic to the Mindanao region in the Philippines. It was formerly considered the only member of the genus Urogale, but that genus was merged into Tupaia when the species was found to nest within the latter genus in a molecular phylogeny. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.

<i>Tupaia</i> (mammal) Genus of mammals

Tupaia is a treeshrew genus in the family Tupaiidae that was first described by Thomas Stamford Raffles in 1821. The name of this genus derives from the Malay word tupai meaning squirrel or small animal resembling a squirrel.

<span class="mw-page-title-main">Tupaiidae</span> Family of mammals

Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. The family contains three living genera and 19 living species. The family name derives from tupai, the Malay word for treeshrew and also for squirrel which tupaiids superficially resemble. The former genus Urogale was disbanded in 2011 when the Mindanao treeshrew was moved to Tupaia based on a molecular phylogeny.

<span class="mw-page-title-main">Primatomorpha</span> Order of mammals

Primatomorpha is a proposed mirorder of mammals containing the orders Dermoptera and Primates. Primatomorpha is sister to Scandentia, together forming the Euarchonta.

Tupaia miocenica is a fossil treeshrew from the Miocene of Thailand. Known only from a single tooth, an upper first or second molar, it is among the few known fossil treeshrews. With a length of 3.57 mm, the tooth is large for a treeshrew. At the back lingual corner, the tooth shows a small cusp, the hypocone, that is separated from the protocone in front of it by a narrow valley. The condition of the hypocone distinguishes this species from various other treeshrews. In addition, the presence of a well-developed but simple mesostyle is distinctive.

References

  1. ↑ Helgen, K.M. (2005). "Order Scandentia". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 104–109. ISBN   978-0-8018-8221-0. OCLC   62265494.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. ↑ Rines, George Edwin, ed. (1920). "Tree-shrew"  . Encyclopedia Americana .
  4. ↑ "an article on Tupaia belangeri". The Genome Institute. Washington University. Archived from the original on 1 June 2010.
  5. ↑ Cao, J.; Yang, E.B.; Su, J.-J.; Li, Y.; Chow, P. (2003). "The tree shrews: Adjuncts and alternatives to primates as models for biomedical research" (PDF). Journal of Medical Primatology. 32 (3): 123–130. doi:10.1034/j.1600-0684.2003.00022.x. PMID   12823622. S2CID   16910445 . Retrieved 1 January 2012.
  6. ↑ Nowak, R.M. (1999). Walker's Mammals of the World . Baltimore, MD: Johns Hopkins University Press. p.  245. ISBN   978-0-8018-5789-8.
  7. ↑ Craig, John (1849). A new universal etymological technological, and pronouncing dictionary of the English Language.
  8. 1 2 Martin, Robert D. (1984). Macdonald, D. (ed.). The Encyclopedia of Mammals . New York, NY: Facts on File. pp.  440–445. ISBN   978-0-87196-871-5.
  9. ↑ Moscowicz, Clara (2008). "Tiny tree shrew can drink you under the table". NBC News .
  10. ↑ Wiens F, Zitzmann A, Lachance MA, Yegles M, Pragst F, Wurst FM; et al. (2008). "Chronic intake of fermented floral nectar by wild treeshrews". Proc Natl Acad Sci U S A. 105 (30): 10426–31. Bibcode:2008PNAS..10510426W. doi: 10.1073/pnas.0801628105 . PMC   2492458 . PMID   18663222.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ↑ "See Why Tree Shrews Are Only the Second Known Mammal to Seek Spicy Food". nationalgeographic.com. Archived from the original on August 27, 2018. Retrieved 2018-08-26.
  12. ↑ Janecka, Jan E.; Miller, Webb; Pringle, Thomas H.; Wiens, Frank; Zitzmann, Annette; Helgen, Kristofer M.; Springer, Mark S.; Murphy, William J. (2 November 2007). "Molecular and genomic data identify the closest living relatives of the Primates". Science. 318 (5851): 792–794. Bibcode:2007Sci...318..792J. doi:10.1126/science.1147555. PMID   17975064. S2CID   12251814.
  13. 1 2 Zhou, Xuming; Sun, Fengming; Xu, Shixia; Yang, Guang; Li, Ming (1 March 2015). "The position of tree shrews in the mammalian tree: Comparing multi-gene analyses with phylogenomic results leaves monophyly of Euarchonta doubtful". Integrative Zoology. 10 (2): 186–198. doi:10.1111/1749-4877.12116. ISSN   1749-4877. PMID   25311886.
  14. ↑ Meredith, Robert W.; Janečka, Jan E.; Gatesy, John; Ryder, Oliver A.; Fisher, Colleen A.; Teeling, Emma C.; Goodbla, Alisha; Eizirik, Eduardo; Simão, Taiz L. L. (28 October 2011). "Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammal diversification". Science. 334 (6055): 521–524. Bibcode:2011Sci...334..521M. doi:10.1126/science.1211028. ISSN   0036-8075. PMID   21940861. S2CID   38120449.
  15. ↑ Pettigrew, J.D.; Jamieson, B.G.; Robson, S.K.; Hall, L.S.; McAnally, K.I.; Cooper, H.M. (1989). "Phylogenetic relations between microbats, megabats, and primates" (PDF). Philosophical Transactions of the Royal Society B. Mammalia: Chiroptera and Primates. 325 (1229): 489–559. Bibcode:1989RSPTB.325..489P. doi:10.1098/rstb.1989.0102. PMID   2575767.
  16. ↑ Lin, J.; Chen, G.; Gu, L.; Shen, Y.; Zheng, M.; Zheng, W.; Hu, X.; Zhang, X.; Qiu, Y.; Liu, X.; Jiang, C. (2014). "Phylogenetic affinity of tree shrews to Glires is attributed to fast evolution rate". Molecular Phylogenetics and Evolution. 71: 193–200. doi:10.1016/j.ympev.2013.12.001. PMID   24333622.
  17. ↑ Foley, Nicole M.; Springer, Mark S.; Teeling, Emma C. (19 July 2016). "Mammal madness: Is the mammal tree of life not yet resolved?". Philosophical Transactions of the Royal Society B. 371 (1699): 20150140. doi:10.1098/rstb.2015.0140. ISSN   0962-8436. PMC   4920340 . PMID   27325836.
  18. ↑ Kumar, Vikas; Hallström, Björn M.; Janke, Axel (1 April 2013). "Coalescent-based genome analyses resolve the early branches of the Euarchontoglires". PLOS ONE. 8 (4): e60019. Bibcode:2013PLoSO...860019K. doi: 10.1371/journal.pone.0060019 . ISSN   1932-6203. PMC   3613385 . PMID   23560065.
  19. ↑ Kriegs, Jan Ole; Churakov, Gennady; Jurka, Jerzy; Brosius, Jürgen; Schmitz, Jürgen (2007-02-20). "Evolutionary history of 7SL RNA-derived SINEs in Supraprimates". Trends in Genetics. 23 (4): 158–161. doi:10.1016/j.tig.2007.02.002. PMID   17307271.
  20. 1 2 Roberts, T.E.; Lanier, H.C.; Sargis, E.J.; Olson, L.E. (2011). "Molecular phylogeny of treeshrews (Mammalia: Scandentia) and the timescale of diversification in Southeast Asia". Molecular Phylogenetics and Evolution. 60 (3): 358–372. doi:10.1016/j.ympev.2011.04.021. PMID   21565274.
  21. 1 2 Li, Q.; Ni, X. (2016). "An early Oligocene fossil demonstrates treeshrews are slowly evolving "living fossils"". Scientific Reports. 6 (1): 18627. Bibcode:2016NatSR...618627L. doi: 10.1038/srep18627 . PMC   4725336 . PMID   26766238.
  22. ↑ Ni, X.; Qiu, Z. (2012). "Tupaiine tree shrews (Scandentia, Mammalia) from the Yuanmou Lufengpithecus locality of Yunnan, China". Swiss Journal of Palaeontology. 131: 51–60. doi: 10.1007/s13358-011-0029-0 . S2CID   85271080.
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