Rectartemon depressus

from Wikipedia, the free encyclopedia
Rectartemon depressus
Casing of rectartemon depressus, bottom view with navel

Casing of rectartemon depressus , bottom view with navel

Systematics
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Streptaxoidea
Family : Streptaxidae
Genre : Rectartemon
Type : Rectartemon depressus
Scientific name
Rectartemon depressus
( Heynemann , 1868)

Rectartemon depressus is a predatory snail species from the Streptaxidae familythat is native to the rainforests of the Mata Atlântica in South America . It is the only known species of snail toeat strudelworms and one of their very few predators at all.

description

The pale, white to slightly greenish snail shell of Rectartemon depressus has a round, flat conical, flattened shape and reaches a diameter of up to 18.5 mm and a height of 10 mm with 6 ½ to 7 ½ convex, slowly increasing whorls Muzzle a width of 8.5 mm and a height of 7.5 mm. There is a wider navel. The case surface has rib stripes, but is smoother on the underside. The mouth of the case is only slightly sloping and cut out circular, the hem is rather thick and the upper edge is bent forward, the outer and the basal edge are slightly turned over. Usually there are bars with varices. The navel is about a quarter of the diameter. The Protoconch consists of about two and a half whorls and is clearly separated from the Teleoconch .

In contrast to the rather pale shell, the snail itself - like a number of other species in the family - has a vivid orange color.

Rectartemon depressus - like other large lung snails (in Kobelt Agnatha) of the families Streptaxidae and Daudebardiidae - has no jaws. The radula is 10 mm long and 1 mm wide. It has about 70 transverse rows with 20 or more teeth on each side in the form of a curved arch. The teeth have - similar to other predatory snails - the shape of simple curved thorns, half of which are anchored in the radula. The teeth are small in the middle, initially larger towards the outside and smaller again at the edge. There is a pointed central tooth without a tooth plate between the posterior teeth.

Spread and endangerment

Rectartemon depressus is found in the rainforests of the Mata Atlântica on the east coast of Brazil . The localities in Rio Grande do Sul include Taquara , Morro Reuter and Guaíba . Due to the severe destruction and fragmentation of the habitat through deforestation since the 20th century, the snail is one of the potentially threatened species.

nutrition

Like other predatory snails in the Streptaxidae family, Rectartemon depressus eats snails, including the invasive herbivorous species Bradybaena similaris . In addition, it is the only previously known snail species to hunt land planarians , including snail-eating species such as Obama ladislavii and other flatworms native to South America, but also the invasive species Bipalium kewense . The prey is seized with the sharp-toothed radula and devoured as a whole.

In captivity, the snail can be fed a healthy diet on a mixed diet of Bradybaena similaris and flatworms. The use of these or possible other flatworm-eating snail species for biological control of invasive flatworm species is discussed.

literature

Web links

Individual evidence