Sigmodontinae

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Sigmodontinae
Cotton rat (Sigmodon hispidus)

Cotton rat ( Sigmodon hispidus )

Systematics
Order : Rodents (Rodentia)
Subordination : Mouse relatives (Myomorpha)
Superfamily : Mice-like (Muroidea)
Eumuroida
Family : Burrowers (Cricetidae)
Subfamily : Sigmodontinae
Scientific name
Sigmodontinae
Wagner , 1843
Rice rat ( Oryzomys palustris )

The Sigmodontinae are a subfamily of the rodent family of the burrowers (Cricetidae). They are one of the three subfamilies into which the New World mice are divided. Of these three, they are the most species-rich (with around 400 species) and the only one that has its distribution center in South America .

features

Sigmodontinae are a diverse group, they have occupied different ecological niches and accordingly developed different body shapes. In addition to species that resemble mice or rats , there are also vole , mole , gerbil and shrew-like representatives. The length of the body of the head varies from 6 to 30 centimeters, the length of the tail from 3 to 33 centimeters and the weight from 7 to 450 grams, depending on the species. The length of the fur and the color are variable, but in most species the upper side is gray or brown, the undersides are usually lighter, often whitish. They differ from other New World mice in, among other things, the morphology of the penis and the structure of the hind feet.

distribution and habitat

Sigmodontinae occur on the American continent, their range extends from the central USA to Tierra del Fuego . However, they reach the greatest biodiversity in South America, in North and Central America there are relatively few representatives, for example some species of rice rats or cotton rats . They have populated almost every habitat in their area of ​​distribution and occur in rain and dry forests as well as in deserts, steppes and grasslands, but also in high mountains up to 6000 meters above sea level.

Way of life

The way the Sigmodontinae lives are just as different as the body shapes and habitats. Most of the species are soil dwellers, but there are also tree dwelling, underground burrowing and semi-aquatic (partly in water) representatives. Most are active all year round, in the cooler regions they can fall into a torpor . Depending on the species, they can be active during the day, at dusk or at night . Most species use shelters, such as crevices in the rock, caves in the ground, hollow tree trunks or burrows that they have dug themselves or have taken over from other animals. They often make a nest out of leaves and other plant material. In addition to solitary species, there are also species that live in groups.

Many species are herbivores that consume grasses, seeds, fruits, mushrooms, tubers, lichens and other vegetable matter. In addition, there are also representatives who partly or almost entirely feed on animal food (such as insects, earthworms, tadpoles, crustaceans, small vertebrates and bird eggs). These include, for example, the cotton rats and the fish rats .

Reproduction

Sigmodontinae are very fertile animals. The breeding season extends over several months even in cooler regions; in the tropics it can last all year round. Females usually have several litters a year and can become pregnant again just a few hours after birth. The gestation period is relatively short at 20 to 30 days, the litter size is often three to five young animals, but can be up to 13. The young animals are weaned after one to four weeks and sexual maturity occurs after one to several months.

To compensate for the high birth rate, mortality is high and life expectancy is low. Sigmodontinae have numerous natural enemies, such as predators , snakes , birds of prey and owls . Few animals live more than 1 year in the wild; five years are possible in human care.

Systematics

In the past, all New World mice were grouped under the scientific name Sigmodontinae , today they are divided into three subfamilies, in addition to the Sigmodontinae these are the Neotominae and the Tylomyinae .

The internal system of the Sigmodontinae has not been fully clarified. In the approach used here, based on Wilson & Reeder (2005), they are divided into eight tribes as well as some genera that cannot be assigned to any tribus and are therefore listed as incertae sedis .

Individual evidence

  1. ↑ Pablo Rodrigues Gonçalves & João Alves de Oliveira: An integrative appraisal of the diversification in the Atlantic forest genus Delomys (Rodentia: Cricetidae: Sigmodontinae) with the description of a new species. Zootaxa, 3760, 1, pp. 1–38, 2014 doi : 10.11646 / zootaxa.3760.1.1
  2. ↑ a b c d e f g h i j k Marcelo Weksler, Alexandre Reis Percequillo, Robert S. Voss: Ten new genera of oryzomyine rodents (Cricetidae: Sigmodontinae). In: American Museum Novitates. No. 3537, 2006, ISSN  0003-0082 , pp. 1-29, online .
  3. ↑ Percequillo, AR; Weksler, M .; Costa, LP (2011). A new genus and species of rodent from the Brazilian Atlantic Forest (Rodentia: Cricetidae: Sigmodontinae: Oryzomyini), with comments on oryzomyine biogeography. Zoological Journal of the Linnean Society. 161 (2): 357-390. doi: 10.1111 / j.1096-3642.2010.00643.x .
  4. ^ A b Ronald H. Pine, Robert M. Timm & Marcelo Weksler: A newly recognized clade of trans-Andean Oryzomyini (Rodentia: Cricetidae), with description of a new genus. Journal of Mammalogy, 93, 3, pp. 851-870, 2012
  5. ↑ Machado et al .: Molecular phylogenetic position of endangered Wilfredomys within Sigmodontinae (Cricetidae) based on mitochondrial and nuclear DNA sequences and commen ts on Wiedomyini. Zootaxa 3986 (4): 421 - 434, doi: 10.11646 / zootaxa.3986.4.2

literature

  • Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. Johns Hopkins University Press, Baltimore MD et al. 1999, ISBN 0-8018-5789-9 .
  • Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .

Web links

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