Pygmy marmoset

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Pygmy marmoset[1][2]
Dværgsilkeabe Callithrix pygmaea.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Callitrichidae
Genus: Cebuella
Gray, 1866
Species: C. pygmaea
Binomial name
Cebuella pygmaea
Spix, 1823
Cebuella pygmaea distribution.svg
Geographic range
Synonyms
  • Callithrix pygmaea

C. p. pygmaea:

  • nigra Schinz, 1844
  • leoninus Bates, 1864

The pygmy marmoset (Cebuella pygmaea) is a small New World monkey native to rainforests of the western Amazon Basin in South America. It is notable for being the smallest monkey and one of the smallest primates in the world at just over 100 grams (3.5 oz) (Madame Berthe's mouse lemur is smaller). It is generally found in evergreen and river edge forests and is a gum-feeding specialist, or a gumivore.

About 83% of the pygmy marmoset population lives in stable troops of two to nine individuals, including a dominant male, a breeding female, and up to four successive litters of offspring. The modal size of a standard stable troop would be 6 individuals.[4] Although most groups consist of family members, some may also include 1-2 additional adult members. Members of the group communicate using a complex system including vocal, chemical, and visual signals. There are three main calling signals that depend on the distance the call needs to travel. These monkeys may also make visual displays when threatened or to show dominance. Chemical signaling using secretions from glands on the chest and genital area allow the female to indicate to the male when she is able to reproduce. The female gives birth to twins twice a year and the parental care is shared between the group.

The pygmy marmoset has been viewed as somewhat different from typical marmosets, most of which are classified in the genera Callithrix and Mico, and thus is accorded its own genus, Cebuella, within the family Callitrichidae. It is listed as Least Concern by the International Union for Conservation of Nature as it is common across its wide range and not at immediate risk of widespread decline. The biggest threats to the species are habitat loss and the pet trade.[5]

Evolution and taxonomy[edit]

There has been debate among primatologists concerning the proper genus in which to place the pygmy marmoset. An examination of the interstitial retinol binding protein nuclear gene (IRBP) in three marmoset species showed that Callithrix as constructed in the 1990s also needed to include C. pygmaea to be monophyletic, and that the times of separation of pygmaea and the argentata and jacchus species groups from one another are less than 5 million years ago, as might be expected for species of the same genus.[6] However, subsequent separation of the argentata and jacchus species groups into different genera (the argentata group having been moved to Mico) justifies maintaining a separate genus for the pygmy marmoset, as Callithrix is no longer paraphyletic.[3]

There are two subspecies described by Colin Groves of the pygmy marmoset:[1][2]

  • Cebuella pygmaea pygmaea – Northern/Western pygmy marmoset
  • Cebuella pygmaea niveiventris – Eastern pygmy marmoset

There are few morphological differences between these subspecies, as they may only differ slightly in color, and they are only separated by geographical barriers, including large rivers in Central and South America.[7]

The evolution of this species diverged in terms of body-mass from typical primates, with a high rate of body-mass reduction. This involves large decreases in pre-natal and post-natal growth rates, furthering the thought that pro-genesis played a role in the evolution of this animal.[8]

Physical description[edit]

The pygmy marmoset is the world's smallest monkey.

The pygmy marmoset is one of the world's smallest primates, and is the smallest true monkey, with a head-body length ranging from 117 to 152 millimetres (4.6 to 6.0 in) and a tail of 172 to 229 millimetres (6.8 to 9.0 in). The average adult body weight is just over 100 grams (3.5 oz) with the only sexual dimorphism of females being a little heavier.[9][10] The fur colour is a mixture of brownish-gold, grey, and black on its back and head and yellow, orange, and tawny on its underparts. Its tail has black rings and its face has flecks of white on its cheeks and a white vertical line between its eyes.[10] It has many adaptations for arboreal living including the ability to rotate its head 180 degrees and sharp claw-like nails used to cling to branches and trees.[11][12] Its dental morphology is adapted to feeding on gum, with specialised incisors that are used to gouge trees and stimulate sap flow. Its cecum is larger than usual to allow for the greater period of time gum takes to break down in the stomach.[12] The pygmy marmoset walks on all four limbs and can leap up to five meters between branches.[11][13]

Ecology[edit]

Geographic range and habitat[edit]

The pygmy marmoset can be found in much of the western Amazon Basin, in Brazil, Colombia, Ecuador, Peru, and Bolivia. The western pygmy marmoset, Cebuella pygmaea pygmaea, occurs in the state of Amazonas, Brazil, eastern Peru, southern Colombia, and north-eastern Ecuador. The eastern pygmy marmoset, C. p. niveiventris, is also found in Amazonas, but also in Acre, Brazil, eastern Peru, and northern Bolivia. The distribution of both subspecies is often limited by rivers. It typically lives in the understory of the mature evergreen forests and often near rivers.[3] Population density is correlated with food tree availability. It can be found between ground level and about 20 metres (66 ft) into the trees but generally does not enter the top of the canopy. It is often found in areas with standing water for more than three months of the year.[10]

Diet[edit]

Specialised claws allow the pygmy marmoset to cling to trees while feeding.

This monkey has a specialized diet of tree gum. It gnaws holes in the bark of appropriate trees and vines with its specialized dentition to elicit the production of gum. When the sap puddles up in the hole, it laps it up with its tongue. It also lies in wait for insects, especially butterflies, which are attracted to the sap holes. It supplements its diet with nectar and fruit.[14] A group's home range is 0.1 to 0.4 hectares (0.25 to 0.99 acres), and feeding is usually concentrated on one or two trees at a time. When those become depleted, a group moves to a new home range. Brown-mantled tamarins are generally sympatric with pygmy marmosets and often raid pygmy marmosets' gum holes.[3]

Pygmy marmosets have adapted insect-like claws, known as tegulae, to engage in a high degree of claw-clinging behaviors associated with plant exudate exploitation. Exudate is any material that oozes out of a plant, including gum, sap, resin, and latex.[15] Claw-clinging is primarily used during feeding, but also during plant exudate foraging.[13]

They are very aggressive and could kill something as big as a giraffe. Don't let these small creatures fool you.

Conservation[edit]

The pygmy marmoset, due to its extensive population size, is not thought to be at risk of large population declines. As a result, it is listed as a species of Least Concern by the International Union for Conservation of Nature. The species was originally listed on Appendix I by CITES due to wildlife trade but has since been downgraded to Appendix II. It is threatened by habitat loss in some areas of its range, and by the pet trade in others (i.e. Ecuador).[3]

Interaction between humans and the pygmy marmoset is associated with a number of behavioral changes in the animal including social play and vocalization, both of which are important to communication between animals in the species. Particularly in areas of heavy tourism, pygmy marmosets have a tendency to be less noisy, less aggressive, and less playful with other individuals. They are also pushed into higher strata of the rainforest than they would normally prefer. Tourism in areas native to the pygmy marmoset is also correlated with increased capture of the animal. Due to its small size and relatively docile nature, captured pygmy marmosets are often found in exotic pet trades.[16] Capture causes even more behavioral variations, including a decrease in both the number and the sound level of vocalizations.[17] Pygmy marmosets can also be found at local zoos, where they exist in groups.[18]

References[edit]

  1. ^ a b Groves, C.P. (2005). "Order Primates". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 132. ISBN 978-0-8018-8221-0. OCLC 62265494. 
  2. ^ a b Rylands, A. B.; Mittermeier, R. A. (2009). "The diversity of the New World primates (Platyrrhini)". In Garber, P. A.; Estrada, A.; Bicca-Marques, J. C.; Heymann, E. W.; Strier, K. B. South American Primates: Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Springer. pp. 23–54. ISBN 978-0-387-78704-6. 
  3. ^ a b c d e de la Torre, S.; Rylands, A.B. (2008). "Cebuella pygmaea". IUCN Red List of Threatened Species (IUCN) 2008: e.T41535A10493764. doi:10.2305/IUCN.UK.2008.RLTS.T41535A10493764.en. 
  4. ^ Soini, Pekka. "Ecology and Population Dynamics of the Pygmy Marmoset, Cebuella Pygmaea." Folia Primatologica 39.1-2 (1982): 1-21. Print.
  5. ^ Stella de la Torre, Charles T Snowdon, Monserrat Bejarano, Effects of human activities on wild pygmy marmosets in Ecuadorian Amazonia, Biological Conservation, Volume 94, Issue 2, July 2000, Pages 153-163, ISSN 0006-3207, doi:10.1016/S0006-3207(99)00183-4
  6. ^ Barroso, C. M. L.; Schneider, H.; Schneider, M. P. C.; Sampaio, I.; Harada, M. L.; Czelusniak, J.; Goodman, M. (1997). "Update on the phylogenetic systematics of New World monkeys: Further DNA evidence for placing the pygmy marmoset (Cebuella) within the genus Callithrix". International Journal of Primatology 18 (4): 651–674. doi:10.1023/A:1026371408379. 
  7. ^ Groves, Colin P. (2001). Primate Taxonomy. Smithsonian. 
  8. ^ Montgomery, S. H.; Mundy, N. I. (2013). "Parallel episodes of phyletic dwarfism in callitrichid and cheirogaleid primates". Journal of Evolutionary Biology 26: 810–819. doi:10.1111/jeb.12097. 
  9. ^ Nowak, R. M. (1999). Walker's Mammals of the World (6th ed.). Baltimore and London: The Johns Hopkins University Press. p. 566. ISBN 978-0-8018-5789-8. 
  10. ^ a b c Soini, P. (1982). "Ecology and population dynamics of the pygmy marmoset, Cebuella pygmaea". Folia Primatologica 39: 1–21. doi:10.1159/000156066. 
  11. ^ a b Kinzey, W. G. (1997). "Synopsis of New World primates (16 genera)". In Kinzey, W. G. New World Primates: Ecology, Evolution, and Behavior. New York: Aldine De Gruyter. pp. 169–324. 
  12. ^ a b Sussman, R. W. (2000). Primate Ecology and Social Structure. Volume 2: New World Monkeys. Needham Heights, MA: Pearson Custom Publishing. 
  13. ^ a b Jackson, C. P. (2011). "The positional behavior of pygmy marmosets (Cebuella pygmaea) in northwestern Bolivia". Primates 52 (2): 171–178. doi:10.1007/s10329-011-0237-7. PMID 21360318. 
  14. ^ Genoud, M.; Martin, R. D.; Glaser, D. (1997). "Rate of metabolism in the smallest simian primate, the pygmy marmoset (Cebuella pygmaea)". American Journal of Primatology 41 (3): 229–245. doi:10.1002/(SICI)1098-2345(1997)41:3<229::AID-AJP5>3.0.CO;2-Z. PMID 9057967. 
  15. ^ Lang, Kristina Cawthon. "Primate Factsheets: Pygmy marmoset (Callithrix pygmaea) Taxonomy, Morphology, & Ecology". Retrieved 24 September 2013. 
  16. ^ Suddath, Claire. "Pygmy Marmoset." Time.com. Time, 03 Jan. 2011. Web. 26 Sept. 2013.
  17. ^ de la Torre, S. (2000). "Effects of human activities on wild pygmy marmosets in Ecuadorian Amazonia". Biological Conservation 94 (2): 153–163. doi:10.1016/S0006-3207(99)00183-4. 
  18. ^ "Pygmy Marmoset." Sandiego Zoo. Sandiego Zoo, n.d. Web. 26 Sept. 2013.

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