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 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 ...

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate Pulmonata or pulmonates, is an informal group (previously an Order (biology), order, and before that a Class (biology), subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a Respiratory system of gastro ...

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 ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s 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 * Binneyidae ...

Distribution

The distribution of this family of slugs includes

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America ...

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-Sib ...

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 AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and pr ...

, last change 12-06-2009, accessed 4 August 2010.

Anatomy

Unlike some slugs, European Arionidae have no

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

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 animal, terrestrial pulmonate gastropod mollusc, mollusks. The function of this pit is the resor ...

is above the tip of the tail. The respiratory pore (

pneumostome The pneumostome or breathing pore is a respiratory opening of the external body anatomy of an air-breathing land slug or land snail. It is a part of the respiratory system of gastropods. It is an opening in the right side of the mantle of a ...

) 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 A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

: the penis is present only in some species,

epiphallus The reproductive system of gastropods (slugs and snails) varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly, see Mating of gastropods. In many mar ...

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

spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophore ...

s. 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, respective ...

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

s 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 In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

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. Dis ...

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

Hemphillia ''Hemphillia'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae Arionidae, common name the "roundback slugs" or "round back slugs" are a taxonomic family of air-breathing land slugs, ...

'' 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 ''Letourneuxia'' is a genus of large air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae, the roundback slugs. Species This genus is monotypic, containing the single species * ''Letourneuxia nyctelia'' (Bo ...

'' 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 The family Sciomyzidae belongs to the typical flies (Brachycera) of the order Diptera. They are commonly called marsh flies, and in some cases snail-killing flies due to the food of their larvae. Here, the Huttoninidae, Phaeomyiidae and Tetan ...

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