Mico argentatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Callitrichidae

Scientific Name: Mico argentatus (Linnaeus, 1766)
Common Name(s):
English Silvery Marmoset
Callithrix argentata Hershkovitz (1977)
Taxonomic Notes: Previously in the genus Callithrix (see Rylands et al. 1993, 2000, 2008). Groves (2001, 2005) lists this species as Callithrix (Mico) argentata.

Hershkovitz (1977) believed that Mico emiliae (Thomas, 1920) - type locality, Maloca, upper Rio Curuá, (illustrated by Cruz Lima, 1945) - was a dark form of M. argentatus. Rylands et al. (1993, 2000, 2008) listed M. emiliae as a distinct species.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Rylands, A.B. & Silva Jr., J.S.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
Listed as Least Concern as this species is relatively wide ranging and adaptable, and although habitat loss is taking place within its range, there is no reason to believe that it is declining at a rate that would warrant listing in a threatened category.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Mico argentatus occurs south of the Rio Amazonas, in relatively flat, lowland forest, between the mouth of the Rio Tocantins in the east and the Rios Tapajós and Cuparí (an eastern tributary) in the west (Ferrari and Lopes Ferrari 1990; Ferrari and Lopes 1996; Vaz 2001; Pimenta and Silva Jr. 2005), extending south to the Rio Irirí as far as the lower Rio Curuá (Hershkovitz 1977). Ferrari and Lopes Ferrari (1990) (see also Ferrari 1993; Ferrari and Lopes 1996) argued that its restricted range (lowland floodplain) east of the Rio Tocantins is due to habitat differences and sympatry with the Black-handed Tamarin Saguinus niger (a wider ranging species extending between the Rio Xingu and east to the Rio Parnaíba).

Mico argentatus does not occur south of Belo Monte on the Rio Xingu (Transamazon highway) and is restricted to the north of the Tucuruí dam reservoir on the Rio Tocantins (Ferrari and Lopes Ferrari 1990; Ferrari and Lopes 1996). This restricts the range of M. argentatus well to the north of the mouth of the Rio Irirí on the eastern bank of the Xingú, with the southern limits being somewhere between the Rios Cuparí and Irirí to the west of the Rio Xingu as indicated by Hershkovitz (1977; see also Martins et al. 1988).

Ferrari (2008) pointed out that there is probably a zone of contact between M. argentatus and M. leucippe in the south-west of the formers range, but there is a gap in our knowledge of the occurrence of this genus between the Rios Teles Pires and Irirí.
Countries occurrence:
Brazil (Pará)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Can reach high densities in secondary forests and forest fragments (Ferrari 2008).

Gonçalves et al. (2003) recorded the following population densities at three sites in the west of the species' range, a short distance south of Santarém, along the Rio Tapajós:

Massafra: 9.3 individuals/km² or 1.9 groups/km²
São Benedito: 12.6 individuals/km² or 2.3 groups/km²
Tabocal: 101.1 individuals/km² or 13.3 groups/km²

These three sites were all forest fragments along the Santarém-Cuiabá highway. Gonçalves et al. (2003) also carried out a census in the Tapajós National Forest, but the densities there were too low to quantify.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:The species was found to be common near the mouth of the Rio Tapajós (Mittermeier and Coimbra-Filho 1977) in terra firma primary forests and in extensive areas of secondary growth forest (Belterra and Fordlândia, east bank of the Rio Tapajós). Between the rios Xingu and Tocantins, it is largely restricted to the dense lowland forests of the flat Tertiary/Quaternary floodplain of the Amazon, and is limited in the south by the montane and submontane forests of the Brazilian Shield (Ferrari and Lopes Ferrari 1990). Between the rios Xingu and Tapajós it ranges further south, entering mixed open forest. It has been observed in forest patches in Amazonian white-sand savanna at Alter do Chão, south of Santarém, Rio Tapajós (Albernaz and Magnusson 1999).

Sympatric in part of their range with Saguinus niger (see Veracini 1997). Ferrari (1993) indicated that S. niger has the competitive edge in forests on the relatively nutrient poor soils of the Brazilian Shield, and that M. argentatus was a “newcomer” resulting from a Holocene range expansion of the genus.

Marmosets and tamarins are distinguished from the other monkeys of the New World by their small size, modified claws rather than nails on all digits except the big toe, the presence of two as opposed to three molar teeth in either side of each jaw, and by the occurrence of twin births. They eat fruits, flowers, nectar, plant exudates (gums, saps, latex) and animal prey (including frogs, snails, lizards, spiders and insects). Marmosets have morphological and behavioural adaptations for gouging trees trunks, branches and vines of certain species to stimulate the flow of gum, which they eat, and in some species forms a notable component of the diet (Coimbra-Filho and Mittermeier 1976; Rylands 1984). They live in extended family groups of between four and 15 individuals. Mean group sizes recored by Gonçalves et al. (2003) in four localities in the west of its tnage were as follows: 1) 5.3 ±1.3; 2) 5.0 ± 0.9; 3) 5.6 ±2.1; and 3) 7.6 ±1.2. The group studied by Veracini (1997) and Tavares (Tavares and Ferrari 2002) on the Rio Curuá ranged from eight to 10 individuals. Generally, only one female per group breeds during a particular breeding season. The groups defend home ranges 10-40 ha, the size depending on availability and distribution of foods and second-growth patches. Tavares (1999) recorded a range size of 11.8 ha over 6 months.

Ecological and behavioural studies have been carried out by Veracini (1997), Tavares and Ferrari (2002) in dense lowand rain forest on the Rio Curuá at the Ferreira Pena Scientific Station at Caxiuanã, Pará., and by Albernaz and Magnusson (1999) and Corrêa (2006) in savanna forest patches at Alter do Chão, near Santarém.

Group sizes known to range from 4 to 11 individuals at Alter do Chão, near Santarém (Albernaz and Magnusson 1999; Corrêa et al. 2002; Corrêa 2006;).

Weight 273-435 g.

Threats [top]

Major Threat(s): The main threat to this species is habitat loss. There has been much forest loss within its range along the Transamazon and Santarém-Cuiabá highways, and south of the lower Rio Amazonas due to roads, logging, agro-industry and cattle-ranching. The species is not hunted, although there may be some limited use as pets.

Although apparently able to thrive in disturbed forest and forest fragments, Gonçalves et al. (2003) found that isolated remnant populations are genetically quite distinct and appear to have suffered the effects of inbreeding or genetic drift, which may be prejudicial to the long-term survival of the small (50 or less) populations, even though this species occurs in naturally fragmented forests in savannas in some parts of its range (Albernaz and Magnusson 1999; Corrêa 2006).

Conservation Actions [top]

Conservation Actions: This species is present in Tapajós National Forest (600,000 ha) and Caxiuanã National Forest (200,000 ha). It is listed on Appendix II of CITES (as Callithrix argentata).

Further research is needed on the limits of their geographical distribution, and the degree of forest loss within their known range. Soy bean cultivation, cattle ranching and logging have increased over the past decade and the impacts of these should be monitored.

Citation: Rylands, A.B. & Silva Jr., J.S. 2008. Mico argentatus. The IUCN Red List of Threatened Species 2008: e.T41520A10487535. . Downloaded on 22 September 2018.
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