Banana snails

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Banana snails
Ariolimax columbianus

Ariolimax columbianus

Systematics
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Superfamily : Arionoidea
Family : Ariolimacidae
Subfamily : Ariolimacinae
Genre : Banana snails
Scientific name
Ariolimax
Mörch , 1860

The banana snails ( Ariolimax ) from the superfamily Arionoidea are a genus of land-dwelling slugs, probably eight species , from the suborder of the land snails (Stylommatophora), which are common on the Pacific coast of North America.

features

The genus Ariolimax includes very large species of slugs that reach lengths of up to 25 cm (up to 16 cm; Schileyko ) when stretched out . The mantle is smooth and the pneumostome is well behind the center of the mantle on the right side. The phylogenetic remainder of the housing, a flat limestone plate, is completely enclosed by the mantle. The viscera extends the length of the body.

The sole of the foot is not, or is only hinted at, divided into three parts in the longitudinal direction. On the tip of the tail sits a small pit that is filled with tissue that produces mucus. The spermatic duct is long, the "ejaculative tract" in the middle is only weakly or not at all developed. The penis is very large, thin-walled with a very large edge fold and an almost terminal pore. The inner wall of the penis is covered with numerous plump folds. The penile retractor muscle is not particularly strong and inserts at the tip of the penis. The free fallopian tube is also long. The vagina, on the other hand, is short and almost cylindrical. The stem of the seminal vesicle (spermathec) is comparatively short.

The color is within the types z. T. very variable. In the genus, however, species dominate that are yellowish (to greenish). There are also more or less brown or dark brown spotted individuals. Some species are characterized by a high percentage of aphallic individuals (= without a penis). It seems that self-fertilization is particularly common here.

Reproduction

The species of the genus Ariolimax are hermaphrodites , as are all land-living lung snails. With the usually mutual fertilization, they function as both females and males. But self-fertilization is also possible and (possibly) widespread in some species of the genus. In a population of Ariolimax columbianus on Hog Island in Tomales Bay ( Marin County ), after all 400 specimens were examined, all animals were aphallic (Heath cited in Mead, 1943: p. 685). In Ariolimax columbianus the peculiar phenomenon of Apophallie was observed. During copulation, one of the sexual partners bites off the other's penis. However, this only occurs in about 5% of copulations.

Geographical distribution and ecology

The species of the genus Ariolimax live on the American west coast from southern California ( San Diego County ) to Alaska ( Sitka ). They live primarily on the ground in the moist sequoia forests that stretch along the coast of North America. However, they are also found in dry habitats, and are occasionally found in gardens and parks. They are mainly nocturnal and eat fruits and mushrooms. They play an important role in the breakdown of organic matter and the spread of seeds and spores in the coastal forest ecosystem. The seeds continue to germinate after they have passed through the snail's digestive tract.

Enemies

The two species of snakes Thamnophis ordinoides and Thamnophis elegans ssp. terrestris specialize in snails as prey. In the Pacific sequoia forests, banana snails are their main prey. Another species of snake found on the American west coast, the very rare Contia tenuis , specializes in nudibranchs as prey. Nudibranchs and banana snails are also eaten by raccoons, geese, ducks and salamanders.

Taxonomy and nomenclature

The taxon Ariolimax was established in 1860 by Otto Andreas Lowson Mörch . The type species is Limax columbianus Gould, 1851 by monotype . Currently, the genus is also divided into two subgenera Ariolimax (Ariolimax) Mörch, 1859 and Ariolimax (Meadarion) Pilsbry, 1948. Schileyko (2007) even treats Meadarion as an independent genre; more recent works do not follow it. Other authors, however, do not use sub-genres. There is also still no consensus on the number of species. In general, three to four species are recognized, recent molecular genetic studies assume up to eight species:

Trivia

The banana snail is the mascot of the University of California, Santa Cruz , but no distinction is made between the six very similar species of Ariolimax . John Travolta wore a UC Santa Cruz Banana Slug t-shirt in the movie Pulp Fiction .

The album Thirteenth Step by the progressive rock group A Perfect Circle features a banana snail on the cover side crawling over a woman's face.

In one scene of the film Coraline , a character from the film, a boy named Wyborne Lovat, called "Wybie", catches banana snails with his black cat.

supporting documents

literature

  • Bouchet, Philippe & Jean-Pierre Rocroi 2005: Part 2. Working classification of the Gastropoda. Malacologia, 47: 239-283, Ann Arbor, Michigan ISSN  0076-2997
  • Mead, Albert R. 1943: Revision of the Giant West Coast Land Slugs of the Genus Ariolimax Moerch (Pulmonata: Arionidae). American Midland Naturalist, 30 (3): 675-717, Notre Dame, Indiana JSTOR 2421208 .
  • Schileyko, Anatolij A. 2007: Treatise on Recent terrestrial pulmonate molluscs, Part 15 Oopeltidae, Anadenidae, Arionidae, Philomycidae, Succineidae, Athoracophoridae. Ruthenica, Supplement 2: 2049-2210, Moscow ISSN  0136-0027
  • Heike Reise, John MC Hutchinson: Penis-biting slugs: wild claims and confusions. Trends in Ecology & Evolution, 17 (4): 163, April 2002 PDF
  • John Pearse and Janet Leonard 2010: Banana Slug Biology. Guest lecture
  • Simroth, Heinrich 1891: Hesperarion , a new American nudibranch genus. Malakozoologische Blätter, 2 ser., 11: 109-119 Online at www.biodiversitylibrary.org
  • Pilsbry, Henry Augustus 1948: Land Mollusca of North America: (north of Mexico). Vol. 2 Part II. The Academie of Natural Sciences of Philadelphia, Monographs, 3: XLVII S., pp. 521–1113, online at Google Books (p. 710)

Individual evidence

  1. ↑ Gervais, Jennifer A., ​​Anna Traveset, Mary F. Willson 1998: The potential for seed dispersal by the banana slug ( Ariolimax columbianus ). American Midland Naturalist, 140: 103-110 JSTOR 2426993
  2. ↑ EJ Britt1, AJ Clark, and AF Bennett 2009: Dental Morphologies in Gartersnakes (Thamnophis) and Their Connection to Dietary Preferences. Journal of Herpetology, 43 (2): 252-259 doi : 10.1670 / 08-109R1.1
  3. ^ G. Allen Poynter: Possible Sharp-Tailed Snake Observation near Parksville, British Columbia. Wildlife Afield, 4 (1): 75-76 PDF  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.wildlifebc.org  
  4. ^ Otto Andreas Lowson Mörch: Contributions to the mollusc fauna of Central America. Malakozoologische Blätter, 6: 102-126 Online at www.biodiversitylibrary.org (p. 110)
  5. ↑ Pearse, JS, Leonard, JL; Breugelmans, K .; Backeljau, T. 2007: Banana slug clades and proposed taxonomy. Society of Integrative and Comparative Biology, Annual Meeting 2007 Abstract
  6. ↑ McDonnell, Rory, Timothy D. Paine, Michael J. Garmally 2009: Slugs A Guide to the Invasive and Native Fauna of California. University of California Division of Agriculture and Natural Resources, Publication 8336: 21 S., Oakland, Calif. Google Books (p. 9)
  7. ^ A b c John Pearse and Jane Leonard: All About Banana Slugs. University of California, Santa Cruz Banana Slug Genomics class, April 23, 2010 PDF (175 MB!)

annotation

  1. ↑ not to be confused with the genus Agriolimax , the earlier name for the genus of the field snails ( Deroceras )

Web links

Commons : Banana Snails  - Collection of images, videos, and audio files