Slotted snails

Slotted snails
	Fissurella volcano snail resting on a stone
Systematics
Trunk :	Molluscs (mollusca)
Class :	Snails (gastropoda)
Subclass :	Orthogastropoda
Order :	Vetigastropoda
Superfamily :	Fissure lelloidea
Family :	Slotted snails
Scientific name of the superfamily
	Fissure lelloidea
	Fleming , 1822
Scientific name of the family
	Fissurellidae
	Fleming , 1822

The keyhole limpet , keyhole limpet , Schlitznapfschnecken or Lochnapfschnecken (Fissurellidae) are a family meeresbewohnender worm that occur worldwide in cold to warm seas. As grazers , they live on algae or sessile animals.

features

Slotted snails have a flat, conical shell that is reminiscent of the shell of the limpets , which are not closely related , but they can be clearly distinguished from them by the hole that is at the tip, slightly in front or as a slot at the front end of the shell. The bowls have ribs running radially from the tip to the edge and concentric lines, which gives the bowls a net-like sculpture. Depending on the species, the housing length of the adult animal varies between 3 mm and 13 cm. The largest species is Megathura crenulata , which lives in California . An operculum is missing.

The respiratory water enters the mantle cavity under the edge of the housing at the head , flows through a pair of gills and is directed to the outside through the hole in the housing. The snails have a broad, flat foot, with which they can suck on the rocky ground like a limpet and so withstand the surf well. In some species, the mantle spreads more or less over the edge of the housing, in the largest species, the Megathura crenulata living in California , in its entirety. The snails have numerous tentacle-like appendages on the epipodium between the foot and the mantle .

The slugs have a kidney that goes back to the right kidney anlage, like the gyrian snails and the limpets, unlike the Caenogastropods , which also have only one kidney, but which develops from the left kidney anlage. This is associated with a secondary bilateral symmetry of these snails.

Way of life

The slugs live on and under rocks in the lower areas of the intertidal zone and in deeper waters, where they can firmly suck on the hard substrate and graze the growth with their radula . Most slugs are herbivores and feed on algae and detritus . Other species, especially in the genera Diodora and Emarginella , live as carnivores on sponges . Some snails of the genus Puncturella eat diatoms and detritus, while Puncturella aethiopica mainly lives on foraminifera .

In the North Sea the family is represented by the species Diodora graeca and Emarginula fissura .

Systematics

According to Bouchet & Rocroi (2005), the Fissurellidae family is the only family in the superfamily Fissurelloidea. They divide the family into three subfamilies:

Family Fissurellidae Fleming, 1822
- Subfamily Fissurellinae Fleming, 1822
- Subfamily Emarginulinae Children, 1834
  - Tribus Emarginulini Children, 1834 - Synonyms: Rimulidae, Anton, 1838; Zeidoridae Naef, 1913; Clypidinidae Golikov & Starobogatov, 1989
  - Tribus Diodorini Odhner, 1932
  - Tribus Fissurellideini Pilsbry, 1890
  - Tribus Scutini Christiaens, 1973
- Subfamily Hemitominae Kuroda, Habe & Oyama, 1971

Bouchet and Rocroi rely on studies by Keen in Moore (1960) and Christiaens (1973). and McMean (1984). According to Aktipis, Boehm and Giribet (2011), the Diodorini tribe has the status of a separate Diodorinae subfamily.

According to the classical system, the slot snails were included in the order of the adult snails (Archaeogastropoda).

literature

Peter Hayward, John S. Ryland: Handbook of the Marine Fauna of North-West Europe . Oxford University Press, Oxford 1995. 816 pages. P. 501: Fissurellidae .
Arthur William Baden Powell: New Zealand Mollusca . William Collins Publishers Ltd, Auckland (New Zealand) 1979, ISBN 0-00-216906-1
Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN 0076-2997

Web links

Commons : Common snails (Fissurellidae) - Collection of images, videos, and audio files

Fischhaus Zepkow: Family Fissurellidae - slugs

Individual evidence

↑ CM Yonge (1947): The Pallial Organs in the Aspidobranch Gastropoda and their Evolution throughout the Mollusca . Philosophical Transactions of the Royal Society B (Biological Sciences) 232 (591), pp. 443-518.
↑ J. Christiaens: Les fissurelles européennes . In: Informations de la Société belge de malacologie . 2, No. 1, 1973, pp. 3-16.
^ JH McLean: Shell reduction and loss in fissurellids: a review of genera and species in the Fissurellidea group . In: American Malacological Bulletin . 2, 1984, pp. 21-34.
↑ SW Aktipis, E. Boehm, G. Giribet (2011): Another step towards understanding the slit-limpets (Fissurellidae, Fissurelloidea, Vetigastropoda, Gastropoda): a combined five-gene molecular phylogeny. Zoologica Scripta 40, pp. 238-259.

[1] CM Yonge (1947): The Pallial Organs in the Aspidobranch Gastropoda and their Evolution throughout the Mollusca . Philosophical Transactions of the Royal Society B (Biological Sciences) 232 (591), pp. 443-518.

[Christiaens-2] J. Christiaens: Les fissurelles européennes . In: Informations de la Société belge de malacologie . 2, No. 1, 1973, pp. 3-16.

[Mclean-3] JH McLean: Shell reduction and loss in fissurellids: a review of genera and species in the Fissurellidea group . In: American Malacological Bulletin . 2, 1984, pp. 21-34.

[4] SW Aktipis, E. Boehm, G. Giribet (2011): Another step towards understanding the slit-limpets (Fissurellidae, Fissurelloidea, Vetigastropoda, Gastropoda): a combined five-gene molecular phylogeny. Zoologica Scripta 40, pp. 238-259.