Ancylus
| Ancylus | ||||||||||
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River cap snail ( Ancylus fluviatilis ) |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Ancylus | ||||||||||
| OV Müller , 1774 |
The genus Ancylus belongs to the family of plate snails (Planorbidae) and is a genus of freshwater snails that occurs in several species in the area of the western Palearctic in rivers and lakes. It is characterized by a cap or bowl-shaped shell and measures a maximum of 11 mm shell length in adulthood .
The genus Ancylus was the eponymous genus for the family of the Ancylidae (former "family of river cap snails"), which has now been dissolved as a systematic category . By far the best known species of the genus is the river cap snail Ancylus fluviatilis , which is the only one that is also widespread in Central Europe. The other representatives of the genus and also the genus Ancylus itself do not have traditional German names.
biology
The biology of the species Ancylus fluviatilis is by far the best studied .
distribution
The genus Ancylus is distributed more or less continuously over large parts of Europe (including some Atlantic islands) to the Caspian Sea and the Transcaucasian region, in some areas of North and Northeast Africa and in some isolated areas in southern Arabia and Turkestan .
The Ancylussee (a former freshwater lake as the predecessor of today's Baltic Sea) takes its name from the fossil-frequent occurrence of the species Ancylus fluviatilis .
Systematics
The external system is explained under Planorbidae . According to current knowledge , ancylus is a monophyletic taxon and, together with other genera ( Ferrissia , Gundlachia , Laevapex , Hebetancylus ), belongs to the Ancylini tribe .
The internal systematics of the genus Ancylus and the delimitation from other genera has not yet been completely resolved, despite many morphological and molecular genetic studies. In the 19th and 20th centuries in particular, well over 100 different names were given to the various forms of this externally very variable genus, which, however, have been referred to as a continuously merging group of forms since the morphological and taxonomic revision by Hubendick (1970). Molecular genetic studies have shown that within the (so far supposedly uniform) species Ancylus fluviatilis at least four highly divergent genetic lines can be found, each of which must have its own species status based on the genetic distance, but has not yet been named in terms of nomenclature.
The following classification into seven species largely follows a traditional concept and has only been partially checked by molecular genetic methods. Three of the species are endemic to Lake Ohrid on the Balkan Peninsula. Their molecular genetic position with one another and with other species of the genus Ancylus has been analyzed in more detail: According to this, they were split off from the other species over two million years ago. Two other species are endemic to the Atlantic islands of the Azores and Madeira ; How long ago they split off from the other Ancylus species is still unknown.
- Ancylus aduncus AAGould, 1847, a species endemic to Madeira
- Ancylus fluviatilis O. F. Müller , 1774, the (common) river cap snail , which is distributed over large parts of Europe and also in neighboring areas (Morocco, Hoggar Mountains, Tunisia, Yemen and western Saudi Arabia). This morphologically and probably also ecophysiologically diverse “species” is to be interpreted as a species group which, according to molecular genetic studies, is composed of at least four clearly separated species in the European range alone.
- Ancylus lapicidus Hubendick, 1960, an endemic species living in Lake Ohrid
- Ancylus regularis Brown, 1973, a species found in the highlands of Ethiopia to over 2000 m above sea level
- Ancylus scalariformis Stankovic & Radoman, 1953, an endemic species living in Lake Ohrid
- Ancylus striatus Quoy & Gaimard, 1834, an endemic species from the Azores
- Ancylus tapirulus Polinski, 1929, an endemic species living in Lake Ohrid.
Individual evidence
- ↑ Albrecht, C., Kuhn, K., Streit, B .: A molecular phylogeny of Planorboidea (Gastropoda, Pulmonata): Insights from enhanced taxon sampling. Zoologica Scripta 36: 27-39 (2007).
- ^ Soldiersko, EV, Starobogatov, YI: Genus Ancylus Müller, 1774 (Gastropoda, Planorbidae). Ruthenica 14: 37-56 (2004)
- ↑ Hubendick, B .: Studies on Ancylidae, the Palearctic and Oriental species and form groups. In: Acta Zool . 5: 5-52 (1970)
- ^ Pfenninger, M., Staubach, S., Albrecht, C., Streit, B, Schwenk, K .: Ecological and morphological differentiation among cryptic evolutionary lineages in freshwater limpets of the nominal form-group Ancylus fluviatilis (OF Müller, 1774) . Mol. Ecol. 12, 2731-2745 (2003)
- ↑ Albrecht, C., Trajanovski, S., Kuhn, K., Streit, B., Wilke, T .: Rapid evolution of an ancient lake species flock: Freshwater limpets (Gastropoda: Ancylidae) in the Balkan lake Ohrid. - Organisms, Diversity & Evolution 6: 294-307 (2006)
- ^ David S. Brown: Fresh Water Snails of Africa and their Medical Importance . 2nd ed., Taylor & Francis 1994.