Dagger snails

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Dagger snails
Shiny dagger snail (Zonitoides nitidus)

Shiny dagger snail ( Zonitoides nitidus )

Systematics
Subclass : Orthogastropoda
Superordinate : Heterobranchia
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Gastrodontoidea
Family : Dagger snails
Scientific name
Gastrodontidae
Tryon , 1866

The dagger snails (Gastrodontidae) are a family from the suborder of the land snails (Stylommatophora). Most of the forms have a dagger-like love arrow, from which their German name is derived.

features

The right -hand winding cases are low-conical with wide, somewhat flattened turns. The housings are usually small (a few millimeters to about 1 cm in diameter). The mouth is usually simple, rarely with a basal tooth or a basal lamella. The housings are usually brownish to blackish, often translucent. They are usually smooth or provided with more or less irregular growth strips that can be reinforced like ribs. The crawl sole is often divided lengthways into two halves, which are separated from one another by a shallow median longitudinal groove; seldom also divided into three parts.

In the hermaphroditic genitalia, the penis is moderately long and the epiphallus is very small. The penis has an internal calcareous plate (can be reduced in some groups) and an accessory part ( arrow sack ) with a long, dagger-like love arrow (absent in some species of the genus Striatura ). The stem of the sperm library is very long and connected to the penis and free fallopian tubes by additional conductors. The free fallopian tube is long, the vagina very short or absent.

Geographical distribution, habitat and way of life

The family is Holarctic . It is also found in Central America as well as in the Canary Islands and Madeira . Some species have been anthropogenically moved to other regions (e.g. the greenhouse dagger snail Zonitoides arboreus ).

The animals usually live near water or damp places in the forest, in the leaf litter or under dead wood. Most of the species are herbivores. But there are also species that feed on other species of snail.

Taxonomy

The taxon was established in 1866 by George Washington Tryon . The family of snails (Gastrodontidae) is the nominate family of the superfamily Gastrodontoidea. The family is divided by Schileyko (2003) into the two subfamilies Gastrodontinae and Nastiinae Riedel, 1986. However, the MolluscaBase does not follow this subdivision, or rather transferred the subfamily Nastiinae to the family of shining snails (Oxychilidae).

literature

  • Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997 (hereinafter abbreviated Bouchet & Rocroi, Working classification with corresponding page number)
  • Bernhard Hausdorf: Phylogeny of the Limacoidea sensu lato (Gastropoda: Stylommatophora). Journal of Molluscan Studies, 64: 35-66, London 1998 ISSN  0260-1230

Individual evidence

  1. ↑ George Washington Tryon: Monograph of the terrestrial Mollusca of the United States. American Journal of Conchology, 2: 218-277, Philadelphia, 1866 [online at Biodiversity Heritage Library], pp. 242, 254.
  2. ↑ Gastrodontidae Tryon, 1866 MolluscaBase:
  3. ↑ Anatolij A. Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs Part 10 Ariophantidae, Ostracolethidae, Ryssotidae, Milacidae, Dyakiidae, Staffordiidae, Gastrodontidae, Zonitidae, Daudebardiidae, Parmacellidae. Ruthenica, Supplement 2 (10): 1307-1488, Moscow 2003 ISSN  0136-0027 , p. 1366.