Limacoid clade
Encyclopedia
The limacoid clade is a taxonomic clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, semislugs and slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

s, terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod molluscs
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...

 in the informal group Sigmurethra
Sigmurethra
Sigmurethra is a taxonomic category of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This is an Informal Group which includes the majority of land snails and slugs....

.

Distribution

The original ancestral area of limacoid families is thought to be the Palearctic
Palearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...

 region and south-eastern Asia.

Typography of the name

In 1998, for the same taxon, Hausdorf used the name Limacoidea sensu lato.

The name of this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

, the limacoid clade, was written by Bouchet & Rocroi (2005) with quotation mark
Quotation mark
Quotation marks or inverted commas are punctuation marks at the beginning and end of a quotation, direct speech, literal title or name. Quotation marks can also be used to indicate a different meaning of a word or phrase than the one typically associated with it and are often used to express irony...

s like this: "limacoid clade".

Other typographical variants are used by various other authors, for example capitalizing and restricting the use of the quote marks thus: "Limacoid" clade and "Limacoid clade".

2003 taxonomy by Schileyko

The study of A. Schileyko, published in parts between 1998 and 2003, did not discuss the system that Hausdorf had proposed.

Alternative taxonomy is as follows:

Explanatory note

For this particular group of families, Bouchet & Rocroi
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

 adapted the taxonomic approach which was originally published by German malacologist Bernhard Hausdorf in 1998 in the Journal of Molluscan Studies.

Bouchet & Rocroi clearly state, on page 283:
However, in their paper, Bouchet & Rocroi (apparently accidentally) failed to show, graphically or typographically, any coverage of the limacoid clade in the taxonomic section of their paper, on pages 268-269.

Because of this omission, some authors have subsequently (mistakenly) included in the "limacoid clade" the two following superfamilies: Arionoidea
Arionoidea
Arionoidea is a taxonomic group, a superfamily of air-breathing land slugs, shell-less terrestrial pulmonate gastropod mollusks.- Families :Families within the superfamily Arionoidea include:* Arionidae* Anadenidae* Ariolimacidae* Binneyidae...

 and Helicoidea
Helicoidea
Helicoidea is a taxonomic superfamily of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Stylommatophora.-Families:There are 19 families within the superfamily Helicoidea according to Bouchet & Rocroi .* Helicidae...

. This misunderstanding was copied by Poppe & Tagaro (2006) who attempted to explain the changes within this taxonomy to the public. This same error is reproduced in various other internet sources.

Taxonomic list

The taxonomy of Bouchet and Rocroi
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

 shows the "limacoid clade" as follows:

(Families that are exclusively fossil are indicated with a dagger †)
  • Superfamily Staffordioidea
    • Family Staffordiidae
      Staffordiidae
      Staffordiidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Staffordioidea ....

  • Superfamily Dyakioidea
    • Family Dyakiidae
      Dyakiidae
      Dyakiidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Dyakioidea ....

  • Superfamily Gastrodontoidea
    Gastrodontoidea
    Gastrodontoidea is a taxonomic superfamily of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the limacoid clade.- Taxonomy:According to the taxonomy of the Gastropoda , families in this superfamily include:...

    • Family Gastrodontidae
      Gastrodontidae
      Gastrodontidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Eupulmonata ....

    • Family Chronidae
      Chronidae
      Chronidae is a family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the superfamily Gastrodontoidea within the clade Eupulmonata .- Distribution :...

    • Family Euconulidae
      Euconulidae
      Euconulidae is a taxonomic family of minute, air-breathing land snails, terrestrial pulmonate gastropod mollusks or micromollusks. This land snail family is closely allied to the Zonitidae, the glass snails.- Distribution :...

    • Family Oxychilidae
      Oxychilidae
      Oxychilidae is a taxonomic family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Gastrodontoidea.- Distribution :...

    • Family Pristilomatidae
      Pristilomatidae
      Pristilomatidae is a taxonomic family of air-breathing land snails, terrestrial gastropod mollusks in the superfamily Gastrodontoidea.According to the 2005 taxonomy of the Gastropoda by Bouchet & Rocroi these snails belong to the "limacoid clade", and Vitreinae is a synonym for Pristilomatidae,...

    • Family Trochomorphidae
      Trochomorphidae
      Trochomorphidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Eupulmonata ....

    • Fossil taxa probably belonging to the Gastrodontoidea
      • Subfamily † Archaeozonitinae
      • Subfamily † Grandipatulinae
      • Subfamily † Palaeoxestininae
  • Superfamily Parmacelloidea
    Parmacelloidea
    Parmacelloidea is a superfamily of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the clade Stylommatophora and the informal group Pulmonata...

    • Family Parmacellidae
      Parmacellidae
      Parmacellidae is a family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks within the superfamily Parmacelloidea ....

    • Family Milacidae
      Milacidae
      Milacidae is a family of air-breathing, keeled, land slugs. These are shell-less terrestrial gastropod mollusks in the superfamily Parmacelloidea.This family has no subfamilies ....

    • Family Trigonochlamydidae
  • Superfamily Zonitoidea
    • Family Zonitidae
      Zonitidae
      Zonitidae, common name the true glass snails, are a family of mostly rather small, air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Zonitoidea....

  • Superfamily Helicarionoidea
    Helicarionoidea
    Helicarionoidea is a superfamily of air-breathing land snails and semi-slugs, terrestrial pulmonate gastropod mollusks in the limacoid clade.-Families:There are three families within the superfamily Helicarionoidea:* Helicarionidae* Ariophantidae...

    • Family Helicarionidae
      Helicarionidae
      Helicarionidae is a family of air-breathing land snails or semi-slugs, terrestrial pulmonate gastropod mollusks in the superfamily Helicarionoidea.- Distribution :...

    • Family Ariophantidae
      Ariophantidae
      Ariophantidae is a taxonomic family of air-breathing land snails and semi-slugs, terrestrial pulmonate gastropod mollusks in the superfamily Helicarionoidea .- Distribution :...

    • Family Urocyclidae
      Urocyclidae
      Urocyclidae is a family of air-breathing land snails and semi-slugs, terrestrial pulmonate gastropod mollusks in the superfamily Helicarionoidea, ....

  • Superfamily Limacoidea
    Limacoidea
    Limacoidea is a taxonomic superfamily of medium-sized to large, air-breathing land slugs and snails. They are terrestrial pulmonate gastropod mollusks in the infraorder Stylommatophora ....

    • Family Limacidae
      Limacidae
      Limacidae, common name the keelback slugs, are a taxonomic family of medium-sized to very large, air-breathing land slugs, terrestrial pulmonate gastropod molluscs in the superfamily Limacoidea.- Distribution :...

    • Family Agriolimacidae
      Agriolimacidae
      Agriolimacidae is a family of small and medium sized land slugs, or shell-less snails, terrestrial pulmonate gastropod mollusks.- Distribution :Distribution of Limacidae is Holarctic, this include: Nearctic, western Palearctic and eastern Palearctic....

    • Family Boettgerillidae
    • Family Vitrinidae
      Vitrinidae
      Vitrinidae is a family of small, air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Limacoidea ....


Cladogram

A cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

 showing phylogenic relations of families in the limacoid clade:

See also

As explained in the previous section, the superfamilies Arionoidea
Arionoidea
Arionoidea is a taxonomic group, a superfamily of air-breathing land slugs, shell-less terrestrial pulmonate gastropod mollusks.- Families :Families within the superfamily Arionoidea include:* Arionidae* Anadenidae* Ariolimacidae* Binneyidae...

 and Helicoidea
Helicoidea
Helicoidea is a taxonomic superfamily of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Stylommatophora.-Families:There are 19 families within the superfamily Helicoidea according to Bouchet & Rocroi .* Helicidae...

do not belong to the limacoid clade, however they are sometimes mistakenly included in this taxon.
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