Gastropoda

The taxonomy of the Gastropoda as it was revised in 2005 by and  is a system for the scientific  of  s. (Gastropods are a   of animals which consists of s and s of every kind, from the land, from, and from .) The paper setting out this taxonomy was published in the journal . The system encompasses both living and extinct groups, as well as some fossils whose classification as gastropods is uncertain.

The Bouchet & Rocroi system was the first complete gastropod taxonomy that primarily employed the concept of, and was derived from research on ; in this context a clade is a "natural grouping" of organisms based upon a statistical. In contrast, most of the previous overall taxonomic schemes for gastropods relied on to classify these animals, and used  ranks such as, superorder and suborder, which are typical of classifications that are still inspired by.

In the Bouchet & Rocroi taxonomy, clades are used between the rank of and the rank of. The clades are unranked. Bouchet and Rocroi use six main clades:, , , , , and. The first three of these major clades have no nesting clades within them: the taxonomy goes immediately to the superfamily level. Within the Caenogastropoda there is one extra clade. In contrast, within the Heterobranchia, for some of the groups there are six separate clades above the level of superfamily, and in the case of most of the s, there are four clades above the level of superfamily. In some parts of the taxonomy, instead of "clade", Bouchet and Rocroi labelled groupings of taxa as a "group" or an "informal group". A clade must by definition contain only one lineage, and it was considered to be the case that these "informal groups" may either contain more than one lineage, or only contain part of a lineage. Further research will eventually resolve these questions. Since the publication of this taxonomic system in 2005, various proposals for changes have been published by other authors, for more information see.

In 2017 this taxonomy was superseded by a revised taxonomy "Revised Classification, Nomenclator and Typification of Gastropod and Monoplacophoran Families" by Philippe Bouchet & Jean-Pierre Rocroi, Bernhard Hausdorf, Andrzej Kaim, Yasunori Kano, Alexander Nützel, Pavel Parkhaev, Michael Schrödl and Ellen E. Strong in Malacologia, 2017, 61(1–2): 1–526. The authors have reverted to adopting the traditional ranks above superfamily: order, subclass, as this was preferred by many users.

Context
Systems of classification such as this one are primarily of value to s (people who study mollusks) and other s. Biological classification schemes are not merely a convenience, they are an attempt to show the actual (the  relatedness) within a group of s. Thus a taxonomy such as this one can be seen as an attempt to elucidate part of the, a.

The Bouchet & Rocroi 2005 system of gastropod was laid out in a book-length paper entitled "Classification and Nomenclator of Gastropod Families", which was published in the journal   and which was written in collaboration with J. Frýda, B. Hausdorf,, Á. Valdés and A. Warén. This system supersedes the system of. have been made since the publication of this paper.

The taxonomy set out by Bouchet & Rocroi is an attempt to get one step closer to representing this part of the. Bouchet & Rocroi's classification system is a hybrid of the pre-existing, more traditional along with some more recent far-reaching revisions which are based on molecular work and use  as, (see ). In the past, the taxonomy of gastropods was largely based on the characters of the taxa, such as the  characteristics (including the ) in shelled species, and the internal, including the structure of the  and details of the. Recent advances are based more on the characteristics of the  and. This shift in emphasis has meant that the newer taxa and their hierarchy are subject to debate, a debate that is not likely to be resolved soon.

This proposed classification has tried to integrate the results of recent molecular work by using unranked s for taxa below the traditional rank of class (class Gastropoda) but above the rank of (replacing the ranks subclass, superorder, order, and suborder), while still using the traditional  ranks for superfamilies and all taxa below the rank of superfamily (i.e., family, subfamily, tribe, genus, subgenus, and species. The clades have been given names which are similar to, or in some cases the same as, traditional Linnaean names for taxa above the level of superfamily. Whenever  (a single ancestry) has not yet been tested and confirmed, or where a traditional taxon of gastropods has already been discovered to be   (that it excludes some of its descendants) the term "group" or "informal group" has been used. Both Linnaean taxa and clades are invalid if it turns out they are, in other words if they consist of more than one lineage.

In this taxonomy 611 valid families are recognized. Of these, 202 families are exclusively, and this is indicated here with a dagger †. Superfamily names are standardized so that they all end in the suffix "-oidea", also commonly used for superorders and subclasses, replacing the "-acea" ending found especially in the older literature. Classification of families into subfamilies however is often not well resolved, and should be regarded as the best possible.

The publication Bouchet & Rocroi (2005) also includes a of  about 2400 suprageneric taxa (taxa above the level of ) of gastropods, from the subtribe to the superfamily. A full bibliographic reference is provided for each taxon, giving the name of the authority, the original publication, the date of that publication, the type genus for the taxon, its nomenclatural status, and its validity under the rules of the.

Since the publication of this taxonomic system in 2005, various changes have been published by other authors, for more information see.

Main clades, groups and informal groups
Here the information is displayed in the form of a (an evolutionary tree of descent.) It is worth bearing in mind however that this taxonomy is provisional: many of the taxa are still only known as "groups" or "informal groups", and these are very likely to be changed as more information becomes available.

This cladogram is based on the following information. The list format used below makes clear which taxa are informal groups rather than clades:


 * Paleozoic molluscs of uncertain systematic position
 * Clade
 * Clade
 * Clade
 * Clade
 * Paleozoic Neritimorpha of uncertain systematic position
 * Clade †
 * Clade
 * Clade
 * Caenogastropoda of uncertain systematic position
 * Informal group
 * Clade
 * Clade
 * Clade
 * Informal group
 * Clade
 * Clade
 * Informal group
 * Informal group
 * Clade
 * Clade
 * Clade
 * Clade
 * Group
 * Clade
 * Group
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Informal group
 * Informal group
 * Clade
 * Clade
 * Clade
 * Clade
 * Clade
 * Informal group

Taxonomy
In the following, more detailed list, indentation is used only for the ranks of superfamily and family. The clade names are not indented, but their hierarchy is indicated by the size of the font used. A clearer sense of the hierarchy of the clades can be drawn from the list immediately above this one.

molluscs of uncertain systematic position
(Existing as s only)

Uncertain position (Gastropoda or )

 * unassigned to superfamily

Basal taxa that are certainly Gastropoda
(existing as fossils only)
 * unassigned to superfamily

Clade

 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * † Family
 * † Family

Clade

 * Not assigned to a superfamily:
 * Family
 * Family
 * † Family
 * Superfamily †
 * † Family
 * † Family
 * Superfamily †
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily †
 * † Family
 * † Family
 * † Family
 * Superfamily : subsequent research has placed this superfamily in its own clade, the Neomphalina, basal to the Vetigastropoda
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily †
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family

Clade

 * Superfamily
 * Family
 * Family

Clade (= Neritopsina)
Contains the Neritomorpha of uncertain position and the clades Cyrtoneritimorpha and Cycloneritimorpha
 * Unassigned to superfamily
 * † Family
 * † Family
 * Superfamily
 * † Family
 * Superfamily
 * † Family
 * † Family
 * Superfamily
 * † Family
 * Superfamily
 * † Family

Clade

 * † Family
 * † Family

Clade

 * Superfamily
 * Family
 * † Family
 * † Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * † Family
 * Superfamily
 * Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Family
 * Superfamily
 * † Family

Clade
Contains the Caenogastropoda of uncertain systematic position, the informal group Architaenioglossa and the clades Sorbeoconcha and Hypsogastropoda
 * Caenogastropoda of uncertain systematic position
 * † Family
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * Zygopleuroid group - see
 * † Family
 * Family
 * † Family
 * † Family
 * Family
 * † Family

Informal group

 * Superfamily
 * Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * † Family

Clade

 * Not allocated to superfamily
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * † Family
 * † Family
 * Family
 * Family
 * † Family
 * † Family
 * † Family
 * Family
 * † Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * † Family
 * Family
 * † Family - If the genus  is placed in the Procerithiidae, then this family is not all fossil.
 * † Family
 * † Family
 * Family
 * Family
 * † Family - not a
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * † Family

Clade
Contains the clades Littorinimorpha, Neogastropoda and the informal group Ptenoglossa.
 * Not allocated to a superfamily
 * † Family
 * † Family
 * † Family
 * † Family

Clade

 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamliy
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * † Family
 * Family
 * Family
 * † Family
 * Family
 * † Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * † Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * † Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * † Family
 * † Family
 * Family
 * Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * † Family

Informal group

 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family

Clade

 * Unassigned to a superfamily
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family

Clade
Contains the informal groups Heterobranchia, Opisthobranchia and Pulmonata

Informal group "" (= )

 * Unassigned to a superfamily
 * Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * † Family
 * Family
 * Family
 * † Family
 * Superfamily
 * Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * † Family
 * † Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * † Family
 * Superfamily
 * Family
 * Family
 * † Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * † Family

Informal group
Contains the clades Cephalaspidea, Thecosomata, Gymnosomata, Aplysiomorpha, Sacoglossa, Umbraculida, Nudipleura and the groups Acochlidiacea and Cylindrobullida.

Clade

 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family

Clade

 * Superfamily
 * Family
 * Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family

Clade

 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family

Clade (= )

 * Superfamily
 * Family
 * Superfamily
 * Family

Group

 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family

Subclade

 * Superfamily
 * Family
 * Family
 * Family

Subclade

 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family

Group

 * Superfamily
 * Family

Clade

 * Superfamily
 * Family
 * Family

Subclade

 * Superfamily
 * Family

Subclade
Contains the clades Euctinidiacea and Dexiarchia
 * Unassigned to superfamily
 * Family

Clade (= )
Contains the subclades Gnathodoridacea and Doridacea

Subclade

 * Superfamily
 * Family

Subclade

 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily (= Phanerobranchiata Non Suctoria)
 * Family
 * Family - Aegiretidae is incorrect subsequent spelling of this family in Bouchet & Rocroi (2005). Correct is.
 * Family
 * Family
 * Family

Clade (= )
Contains the clades Pseudoeuctenidiacea and Cladobranchia

Clade ( = Doridoxida)

 * Superfamily
 * Family

Clade ( = Cladohepatica)
Contains the subclades Euarminida, Dendronotida and Aeolidida
 * Not assigned to a superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family

Subclade

 * Superfamily
 * Family
 * Family

Subclade

 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family

Subclade

 * Superfamily ( = Pleuroprocta)
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family

Informal Group
Contains the informal group Basommatophora and the clade Eupulmonata

Informal Group
Contains the clade Hygrophila
 * Superfamily
 * Family
 * Superfamily
 * Family
 * † Family

Clade

 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family

Clade
Contains the clades Systellommatophora and Stylommatophora
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family

Clade (= )

 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family

Clade
Contains the subclades Elasmognatha, Orthurethra and the informal group Sigmurethra

Subclade

 * Superfamily
 * Family
 * Superfamily
 * Family

Subclade

 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family

Informal Group

 * Superfamily
 * Family
 * † Family
 * † Family
 * † Family
 * Superfamily
 * Family
 * Family
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * † Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family


 * Superfamily
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Fossil taxa that probably belong to the superfamily Gastrodontoidea:
 * Subfamily † Archaeozonitinae
 * Subfamily † Grandipatulinae
 * Subfamily † Palaeoxestininae
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family

Informal group Sigmurethra continued
Two other superfamilies are part of the clade Sigmurethra, but they are not in the limacoid clade:
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Superfamily
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family
 * Family