Marmosets

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Marmosets
Common marmoset (Callithrix jacchus)

Common marmoset ( Callithrix jacchus )

Systematics
without rank: Euarchonta
Order : Primates (Primates)
Subordination : Dry- nosed primates (Haplorrhini)
Partial order : Monkey (anthropoidea)
without rank: New World Monkey (Platyrrhini)
Family : Marmosets
Scientific name
Callitrichidae
Thomas , 1902
The pygmy marmoset is the smallest representative of the marmosets and the real monkeys at all

The marmosets or marmosets (Callitrichidae or Callitrichinae as a subfamily of the Capuchin-like (Cebidae)) are a systematic group within the New World monkeys (Platyrrhini) - but their systematic position is disputed. They are small, omnivorous primates that mainly live in South America . The family includes about 50 species in eight genera: the tamarins with the genera Leontocebus and Saguinus , the lion tamarins , the jumping tamarine and the group of marmosets which is divided into four genera.

features

Marmosets are one of the smaller primates, with the pygmy marmoset the smallest real monkey belongs to this group. They reach a head body length of 12 to 35 centimeters, the tail with 15 to 44 centimeters is always significantly longer than the body. It is long and bushy and cannot be used as a prehensile tail. The weight of these animals varies from 100 to 600 grams.

Their fur is soft and dense and, in some species, silky. Its coloration varies depending on the species, from black through various shades of brown and gray to yellow and white; certain parts of the body are often contrasting in color and tufts, tufts or beards are present. The limbs are relatively short, the hind legs are slightly longer than the front legs. The name-giving feature that distinguishes them from all other New World monkeys are the claws , which are located on the fingers and toes (with the exception of the big toe) instead of nails . These claws believed to have evolved from nails and are a common derived trait . They allow the animals to climb along vertical trunks and even forage upside down for food.

The marmoset's head is rounded, the snouts are relatively short. The face is often bare or only sparsely haired. Their tooth formula is unique among primates and is I 2- C 1- P 3- M 2, so they have a total of 32 teeth. In contrast to all other New World monkeys, the number of molars is reduced from 3 to 2, which is probably related to the dwarfism - the Jumping tamarin is the only species with three molars. Another peculiarity in the construction of the teeth is that the upper molars only have three cusps on the chewing surface - here again the Jumping tamarin is an exception, which (like all other New World monkeys) has four cusps. The tamarins show a unique specialization in the construction of the teeth, which enables them to gnaw the tree bark.

distribution and habitat

The lion tamarins are one of the marmosets that do not live in the Amazon basin

Marmosets live in the tropical forests of Central and South America . Most species occur in the Amazon basin , where their range extends from eastern Ecuador and northern Bolivia to northeastern Brazil . Exceptions are the tamarins and lion tamarins , which inhabit eastern and southeastern Brazil, and the oedipus group of tamarins , which are found in northwestern Colombia and Panama .

The habitat of these animals are forests, although they often prefer forest forms with dense undergrowth such as secondary forests or forest edges. Some species are adaptable and can also live in plantations or gardens.

Way of life

All species are diurnal; at night they sleep in tree hollows or in the thicket of plants. They live in trees and move around on all fours on horizontal branches, but they can also jump well and, thanks to their claws, climb vertical tree trunks. Your movements are generally quick and agile.

Marmosets live in groups of 2 to 15 animals. Groups consist of one or more males, one or more females and their offspring; the composition can be variable to a certain extent. Social behavior is often pronounced within the group, the animals often sleep snuggled close to each other and groom each other's fur. In an experiment, it was discovered that common marmosets exhibit altruistic tendencies. They gave conspecifics food without a reward or consideration - not even for reproductive purposes.

Marmosets communicate with each other with different sounds (with which they warn against predators, among other things), with facial expressions and body postures.

food

Marmosets are omnivores, with mostly fruits , nectar and insects forming the main component of the diet. Marmosets have specialized teeth with which they can gnaw holes in the tree bark in order to get to the tree sap. These represent an important part of their diet, especially in times when there is little fruit available. To a small extent marmosets also consume other parts of plants, small vertebrates and bird eggs.

Reproduction

Two young imperial mustache tamarins are carried by a full-grown animal

Even if there are several females in a group, usually only the dominant one breeds. In some species, this is accomplished by suppressing ovulation in the rest of the females, possibly using pheromones from the dominant animal. In the lion tamarins, on the other hand, only sexual behavior should be suppressed.

The mating behavior is variable depending on the group composition. Monogamous behavior can often be observed in captivity, i.e. the female only mates with one male. In the wild, polyandric behavior is likely to predominate , that is, the female reproduces with several males. This polyandry is a phenomenon that is rarely observed among primates.

Twice a year the female gives birth to one to three young after a gestation period of around 130 to 150 days. However, 80 percent of the offspring consists of dizygoti twins. It is believed that the female has an easier time bearing two smaller cubs than one large one. The reproductive system is unique among mammals: the twins come from separately fertilized eggs (i.e. they are dizygoti), but the placental membranes grow together, causing cell exchange between the embryos ( chimerism ). An examination of kuhl marmosets showed that they carry the different genetic material not only in blood but also in sex cells and thus do not necessarily pass on their own gametes when mating , but possibly the genetic information of their siblings. An exception to this scheme is the jumping tamarin, in which single births predominate. The reproduction rate is relatively high, the female can give birth again after five to eight months after birth.

The young animals are very large at birth, together they reach around 25 percent of the weight of the mother. The males of the group participate intensively in the rearing of the young, often also the subordinate females and the older siblings. They carry the young and occupy themselves with them and only give them to the mother to suckle. The exception is again the spring tamarin, in which the males only begin to participate in carrying after three weeks.

After a month the boys start to eat solid foods, after a few months they are completely weaned. They are sexually mature after twelve to eighteen months.

The life expectancy of marmosets in human care can be up to 28 years.

Marmosets and humans

The Lisztaffe is one of the most endangered species of marmosets

The destruction of their habitat through deforestation of the rainforests represents the greatest threat to the marmosets. As with other South American animals, the inhabitants of the Atlantic coastal forests, such as the lion tamarins, are particularly affected by the restrictions on their habitat. In addition, animals are caught in some places and made into pets ; hunting for their meat, in contrast to other New World monkeys, because of their small size, does not play a role. Because of their adaptability and because they can often live close to humans, marmosets are sometimes less endangered than larger primates. Several species of tufted monkey were able to spread in regions in eastern Brazil where they were not originally native.

Some species such as the Lisztaffe and the common marmoset are still used in animal experiments today.

Systematics

External system

The systematic position of the marmosets within the New World monkeys is controversial. Because of their unique characteristics (claws, number of molars and way of giving birth), they were compared as the Callitrichidae family to all other New World monkeys that were grouped together as Cebidae , and were considered the most primitive branch.

Morphological and molecular studies have shown that the Cebidae are a paraphyletic group in this sense , i.e. some representatives are more closely related to the marmosets than to each other. The marmosets are also not a primitive group, but highly specialized and secondarily dwarfed New World monkeys.

The position of the jumping tamarin is the biggest problem of the marmoset's internal system

It is very likely that the marmosets form a common lineage with the capuchin monkeys (Cebinae), the squirrel monkeys ( Saimiri ) and the night monkeys ( Aotus ). The relationships and the systematic classifications within this lineage are controversial. Broad systematics summarize all animals of this lineage to form a family Cebidae. Other perspectives see the marmosets a subfamily (Callitrichinae) of the Cebidae, excluding the night monkeys. Another perspective defines the Cebidae more closely (capuchin and squirrel monkeys only) and sees the night monkeys (as Aotidae) and the marmosets (Callitrichidae) as separate families. Due to the uncertain position of the night monkeys, this view is preferred here until further notice.

Internal system

Within the marmosets eight genera are distinguished: the two species of tamarins , the lion tamarins , the Goeldi , the marmosets , the marmoset , the Black Crown marmosets and pygmy marmoset , the last four are the generic group of marmosets . The Jumping tamarin shows the greatest deviations; like the other New World monkeys, it still has three molars and mainly gives birth to singles. Because of these deviations, it was often placed in its own subfamily (Callimiconinae) or even family (Callimiconidae) next to the marmosets. Molecular studies, however, consistently place it in the vicinity of the marmosets, so that the following cladogram results for the marmoset genera:

 Marmosets (Callitrichidae) 


Lion tamarin ( leontopithecus )


   

Jumping tamarin ( Callimico )


 Marmosets 

Marmosets ( Callithrix )


   


Marmoset ( Mico )


   

Black-crowned marmoset ( Callibella )



   

Pygmy marmoset ( Cebuella )






 Tamarins 

Leontocebus


   

Saguinus




The peculiarities of the Jumping tamarin can be explained by the fact that the marmosets have lost their third molar several times independently of each other and that the Jumping tamarin has switched back to singular birth as it is very unlikely that the unique reproductive behavior of tamarins and marmosets twice originated.

Today about 50 species of marmosets are distinguished:

literature

  • Thomas Geissmann : Comparative Primatology. Springer-Verlag, Berlin a. a. 2003, ISBN 3-540-43645-6 .
  • Ronald M. Nowak: Walker's Mammals of the World. 6th edition. Johns Hopkins University Press, Baltimore MD 1999, ISBN 0-8018-5789-9 .
  • Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .

Individual evidence

  1. ↑ JM Burkart, E. Fehr, C. Efferson and CP van Schaik: Other-regarding preferences in a nonhuman primate: Common marmosets provision food altruistically. In: PNAS 104 (50), 2007, 19762-19766. PDF
  2. ↑ CN Ross, JA French and G. Ortí: Germ-line chimerism and paternal care in marmosets ( Callithrix kuhlii ) . In: Proc. Natl. Acad. Sci. 104 (2007), p. 6278 online edition
  3. ↑ About Nowak (1999)
  4. ^ For example, Juan C. Opazo, Derek E. Wildman, Tom Prychitko, Robert M. Johnson, and Morris Goodman: Phylogenetic relationships and divergence times among New World monkeys (Platyrrhini, Primates). In: Molecular Phylogenetics and Evolution, 40 (1), 2006, pp. 274-280
  5. ↑ a b According to Wilson & Reeder (2005)
  6. ↑ a b According to Geissmann (2003)
  7. ^ A b Anthony B. Rylands, Eckhard W. Heymann, Jessica Lynch Alfaro, Janet C. Buckner, Christian Roos, Christian Matauschek, Jean P. Boubli, Ricardo Sampaio and Russell A. Mittermeier. 2016. Taxonomic Review of the New World Tamarins (Primates: Callitrichidae). Zoological Journal of the Linnean Society. doi: 10.1111 / zoj.12386
  8. ↑ Gregorin, R .; De Vivo, M. 2013: Revalidation of Saguinus ursula Hoffmannsegg (Primates: Cebidae: Callitrichinae). Zootaxa , 3721 (2): 172-182. doi: 10.11646 / zootaxa.3721.2.4

Web links

Commons : marmosets  - collection of images, videos, and audio files