Semi-slug
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Drawing of two views of Cryptella canariensis from the Canary Islands
Shell of Cryptella canariensis
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An unidentified semi-slug from Uganda
Semi-slugs, also spelled semislugs, are land gastropods whose shells are too small for them to retract into, but not quite vestigial.[1] The shell of some semi-slugs may not be easily visible on casual inspection, because the shell may be covered over with the mantle.
This is a type of gastropod that is intermediate between a slug (without an external shell) and a land snail (with a large enough shell to retract completely into).
There exist a number of gastropod families that have semi-slugs species.[2] There exist about 1000 species of semi-slugs in comparison to about only 500 species of slugs.[1]
Examples
Semi-slugs from the Neotropics:
- family Amphibulimidae: Amphibulima and Gaeotis[2]
- family Xanthonychidae: Cryptostrakon, Semiconchula and Xanthonyx[2]
- family Pleurodontidae: Coloniconcha prima[2]
- Semi-slugs do exist but are exceptional in the Camaenidae.[2]
References
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