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Keel (slug)
Slug, or land slug, is a common name for any apparently shell-less terrestrial molluscs, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly Opisthobranchia, sea slugs and semislugs (this is in contrast to the common name ''snail'', which applies to gastropods that have a coiled shell large enough that they can fully retract their soft parts into it). Various Taxonomy (biology), taxonomic families of land slugs form part of several quite different evolutionary lineages, which also include snails. Thus, the various families of slugs are not closely related, despite a superficial similarity in the overall body form. The shell-less condition has arisen many times independently as an example of convergent evolution, and thus the category "slug" is Polyphyly, polyphyletic. Taxonomy Of the six orders of Pulmonata, two – the Onch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is dominated by a maritime climate with narrow temperature differences between seasons. The 60% smaller island of Ireland is to the west—these islands, along with over 1,000 smaller surrounding islands and named substantial rocks, form the British Isles archipelago. Connected to mainland Europe until 9,000 years ago by a landbridge now known as Doggerland, Great Britain has been inhabited by modern humans for around 30,000 years. In 2011, it had a population of about , making it the world's third-most-populous island after Java in Indonesia and Honshu in Japan. The term "Great Britain" is often used to refer to England, Scotland and Wales, including their component adjoining islands. Great Britain and Northern Ireland now constitute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semislug
Semi-slugs, also spelled semislugs, are land gastropods whose shells are too small for them to retract into, but not quite vestigial. 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.Breure A. S. H. (2010). "The rediscovery of a semi-slug: ''Coloniconcha prima'' Pilsbry, 1933 (Gastropoda, Pleurodontidae) from Hispaniola". ''Basteria'' 74(4-6): 78-86. There exist about 1,000 species of semi-slugs in comparison to about only 500 species of slugs.Burton D. W. (1982). "How to be sluggish". ''Tuatara'' 25(2): 48-63HTM Examples Semi-slugs have a worldwide distribution and have evolved in several families; genera include: * Palearctic and Nearctic ** family Parmacel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acavoidea
The Acavoidea are a taxonomic superfamily of air-breathing land snails and slugs, terrestrial pulmonate gastropod mollusks in the informal group Sigmurethra. This taxonomy was based on the study by Nordsieck, published in 1986. Taxonomy Families within the superfamily Acavoidea are as follows: *Family Acavidae Pilsbry, 1895 *Family Caryodidae Conolly, 1915 *Family Dorcasiidae Dorcasiidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Acavoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). The family Dorcasiidae has no subfamilies. ... Conolly, 1915 *Family Macrocyclidae Thiele, 1926 *Family Megomphicidae H.B. Baker, 1930 *Family Strophocheilidae Pilsbry, 1902 References Stylommatophora Gastropod superfamilies {{Heterobranchia-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
