Arionidae,

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the "roundback slugs" or "round back slugs" are a

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

family of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less 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 smal ...

s, terrestrial

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusks in the superfamily

Arionoidea Arionoidea is a taxonomic group, superfamily of air-breathing land slugs, shell-less terrestrial pulmonate gastropod mollusks. Families Families within the superfamily Arionoidea include: * Arionidae * Anadenidae * Ariolimacidae * Bin ...

Distribution

The distribution of this family of slugs includes Nearctic,

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

and

Oriental The Orient is a term for the East in relation to Europe, traditionally comprising anything belonging to the Eastern world. It is the antonym of ''Occident'', the Western World. In English, it is largely a metonym for, and coterminous with, the ...

regions."Family summary for Arionidae"
AnimalBase, last change 12-06-2009, accessed 4 August 2010.

Anatomy

Unlike some slugs, European Arionidae have no keel on the back. The

caudal mucous pit The caudal mucous pit, or caudal mucous horn, is an anatomical structure on the tail end of the foot of various land snails and slugs, terrestrial pulmonate gastropod mollusks. The function of this pit is the resorption of mucus when the gast ...

is above the tip of the tail. The respiratory pore ( pneumostome) is in front of the midpoint of the

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

. The body length is up to 250 mm. The mantle covers only a part of the body and lies in the anterior part. The jaw is odontognathic, which means it is transversally ribbed.

Radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

r teeth include: central tricuspid, lateral bi- or tricuspid, marginal bicuspid, all having broad bases. Teeth are often accreted. The

digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

forms 2 loops. The heart, in relation to body axis, is titled to the left. The kidney is circular (surrounding aorta). Cephalic retractors tend to divide into separate branches attached independently to the posterior part of pallial complex. The shell is strongly reduced in places, most often completely buried in the mantle, usually of loose crystals or plate-like. Genitalia: the penis is present only in some species, epiphallus is present in nearly all of them. Male copulatory organs are generally reduced, their role being taken over by a well-developed atrium and the epiphallus that produces spermatophores. In this family, the number of

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

chromosomes lies between 21 and 30 (according to the values in this table).Barker G. M.: Gastropods on Land: ''Phylogeny, Diversity and Adaptive Morphology''. in Barker G. M. (ed.):
The biology of terrestrial molluscs
'. CABI Publishing, Oxon, UK, 2001, . 1-146, cited pages: 139 and 142. (In the reference specified as Ariononae.)

Genera

Family Arionidae has no subfamilies according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005. The type genus of the family is ''

Arion Arion (; grc-gre, Ἀρίων; fl. c. 700 BC) was a kitharode in ancient Greece, a Dionysiac poet credited with inventing the dithyramb. The islanders of Lesbos claimed him as their native son, but Arion found a patron in Periander, tyrant ...

'' Férussac, 1819 Genera within the family Arionidae include: * '' Anadenulus'' Cockerell, 1890 * ''

'' Férussac, 1819 * '' Ariunculus'' Lessona, 1881 * '' Carinacauda'' Leonard, Chichester, Richart & Young, 2011 * ''

Geomalacus ''Geomalacus'' is a genus of large air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae, the roundback slugs. Etymology The Ancient Greek word () means the Earth. The Greek word () means mollusc. Distr ...

'' Allman, 1843 * '' Gliabates'' Webb, 1959 * ''

Hemphillia ''Hemphillia'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae, the roundback slugs. The generic name ''Hemphillia'' is in honor of an American malacologist Henry Hemphill (1830–1914). ...

'' Bland & Binney, 1872Bland T. & Binney W. G. (1874). "Description of ''Hemphillia'', a new Genus of Terrestrial Mollusks". ''Annals of the Lyceum of Natural History of New York''
10208
211
Plate 9
* '' Hesperarion'' Simroth, 1891 * '' Letourneuxia'' Bourguignat, 1866 * '' Magnipelta'' Pilsbry, 1953 * ''

Prophysaon ''Prophysaon'', common name taildropper slugs, is a genus of air-breathing land slugs, terrestrial animal, terrestrial pulmonate gastropod mollusks in the family Ariolimacidae. MolluscaBase eds. (2021). MolluscaBase. Prophysaon Bland & W.G. Binne ...

'' Bland & W. G. Binney, 1873 * '' Securicauda'' Leonard, Chichester, Richart & Young, 2011 * '' Udosarx'' Webb, 1959 * '' Zacoleus'' Pilsbry, 1903Pilsbry H. A. (1903). ''Proc. Acad. nat. Sci. Philad.'' 55: 626.

Parasites

The parasites of the Arionidae slugs include the Sciomyzidae.

References

This article incorporates public domain text from the reference.

External links

Round back slugs (Arionidae)
o
weichtiere.at
{{Taxonbar, from=Q915669 Taxa named by John Edward Gray