Carychium
Bulbous dwarf horn snail ( Carychium minimum)
Carychium is a genus of tiny, land snails Haderslev to the dwarf 's horn snails ( Carychiidae ) within the lung snails ( Pulmonata ) are counted. Due to their small size, they are also ( non- systematic) called Mikrogastropoden.
Features
The dextral housing max. only 2.5 mm in size (high) and 1.5 mm wide. You are hochkonisch to spindle-shaped and have a smooth to spirally - ribbed surface. They are off-white to colorless translucent. Taxonomic features typically include the ratio of height to width of the housing, the number of turns, the amount of ribbing and the shape and position of the inner Columellarwirbels. The schalenmorphologischen characteristics show a certain degree of intraspecific variation and do not always seem to be able to clearly distinguish between different types
Dwarf horn snails are hermaphrodites seasonal, but the mating is one-sided. An animal acts than males (in the first stage of life ), an animal than females ( in later life ). In the partner who acts as females during copulation, the penis is back. The eggs have a diameter of about 0.4 mm and are therefore very large with a size of about 2 mm. Up to four generations can be produced per year.
Geographical distribution, habitat and behavior
The species of the genus Carychium are Holarctic spread. In the Palearctic the distribution area of Western Europe even as far as Japan. In the Americas the area of distribution of Canada extends to Panama. Most species have been described for Europe, North America and South East Asia ( Japan).
The dwarf 's horn snails are found in permanently wet habitats such as swamps, wet meadows, lowland forests and the shore zones of water bodies. They live in the ( permanently wet ) leaf litter in or on dead wood, and between bank vegetation of the plains to the mountains. Carychium populations are also known from Asian, European and North American caves. Due to their underground life, the kind Carychium described stygium in the Mammoth Cave in the United States.
Taxonomy and systematics
The taxon Carychium was erected in 1773 by Otto Friedrich Müller. Type species of the genus is Carychium minimum Müller, 1774 by monotype. It should be noted that the type species C. minimum OF Müller published a year after the introduction of the genus Carychium in science. Some authors taxon is divided into sub-genera:
- Carychium ( Carychium ) Müller, 1774 ( tart and fossil)
- Carychium ( Saraphia ) Risso, 1826 ( tart and fossil)
- Carychium ( Carychiella ) Strauch, 1977 ( fossil only )
- Carychium ( Carychiopsis ) Sandberger, 1872 ( fossil only )
An outline of the extant species in Carychium and Saraphia could not be confirmed molecularly and should be discarded. However, a molecular confirmation of the place -based ecological and morphological criteria definition for pure underground occurring sister group Zospeum.
On the basis of morphological features of the genus are currently being assigned about 30 extant species. The genetic study of a variety of species from the whole distribution of the genus revealed a high number (50 %) of morphologically undiscovered evolutionary lineages (or species). In particular, widespread Morphoarten showed a high intraspecific genetic variability. In malakologisch little-explored regions of the world (eg Central Asia) are expected to further discoveries.
- Genus dwarf horn snails ( Carychium OF Müller, 1773) Carychium arboreum Dourson, 2012
- Carychium Biondii Paulucci, 1882
- Carychium clappi Hubricht, 1959
- Carychium costaricanum From Martens, 1898
- Carychium cymatoplax Pilsbry, 1901
- Carychium exiguum (Say, 1822)
- Carychium exile H. C. Lea, 1842
- Carychium floridanum Clapp, 1918
- Carychium hachijoensis Pilsbry, 1902
- Carychium hellenicum Bank & Gittenberger, 1985
- Carychium ibazoricum Bank & Gittenberger, 1985
- Carychium jardineanum ( Chitty, 1853)
- Carychium mariae Paulucci, 1878
- Carychium mexicanum Pilsbry, 1891
- Bulbous dwarf horn snail ( Carychium minimum OF Müller, 1774)
- Carychium minusculum Gredler, 1887
- Carychium nannodes G. H. Clapp, 1905
- Pilsbry & Hirase Carychium nipponense, 1904
- Carychium noduliferum Reinhardt, 1877
- Carychium occidentale Pilsbry, 1891
- Carychium paganettii Zimmermann, 1925
- Carychium pessimum Pilsbry, 1902
- Carychium riparium Hubricht, 1978
- Carychium schlickumi Bush, 1977
- Carychium sibiricum Gerst Feldt, 1859
- Carychium stygium Call, 1897
- Carychium thailandicum Burch & Panha, 1998
- Carychium tianmushanense Chen, 1992
- Slender dwarf horn snail ( Carychium tridentatum ( Risso, 1826) )