CLASSIFICATION AND NOMENCLATOR OF GASTROPOD FAMILIES PDF

Fenrilmaran In contrast, most of the previous overall taxonomic schemes for gastropods relied on morphological features to classify these animals, and used taxon ranks such as ordersuperorder and suborder, which are typical of classifications that are still inspired by Linnaean taxonomy. They have adopted again the common additional gastfopod above superfamily: The system encompasses both living and extinct groups, as well as some fossils whose classification as gastropods is uncertain. It is worth bearing in mind however that this taxonomy is provisional: Bouchet and Rocroi use six main clades: Further research will eventually resolve these questions. The clades are unranked. International Journal of Malacology. 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.

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Context[ edit ] Systems of classification such as this one are primarily of value to malacologists people who study mollusks and other biologists. Biological classification schemes are not merely a convenience, they are an attempt to show the actual phylogeny the evolutionary relatedness within a group of organisms. Thus a taxonomy such as this one can be seen as an attempt to elucidate part of the tree of life , a phylogenetic tree. Hausdorf, W. This system supersedes the system of Ponder and Lindberg from Subsequent revisions by other authors have been made since the publication of this paper.

In the past, the taxonomy of gastropods was largely based on the morphological characters of the taxa, such as the shell characteristics including the protoconch in shelled species, and the internal anatomy , including the structure of the radula and details of the reproductive system.

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 clades for taxa below the traditional rank of class class Gastropoda but above the rank of superfamily replacing the ranks subclass, superorder, order, and suborder , while still using the traditional Linnaean ranks for superfamilies and all taxa below the rank of superfamily i.

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 monophyly a single ancestry has not yet been tested and confirmed, or where a traditional taxon of gastropods has already been discovered to be paraphyletic 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 polyphyletic , in other words if they consist of more than one lineage. In this taxonomy valid families are recognized. 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 hypothesis.

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 ICZN.

Since the publication of this taxonomic system in , various changes have been published by other authors, for more information see changes in the taxonomy of gastropods since Main clades, groups and informal groups[ edit ] Here the information is displayed in the form of a cladogram 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.

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Classification and nomenclator of gastropod families.

Tojalabar This proposed classification has tried to integrate the results of recent molecular work by using unranked clades for taxa below the traditional rank of class class Gastropoda but above the rank of superfamily replacing the ranks subclass, superorder, order, and suborderwhile still using the traditional Linnaean ranks for superfamilies and all taxa below the rank of superfamily i. In this taxonomy valid families are recognized. Both Linnaean taxa and clades are invalid if it turns out they are polyphyleticin other words if they consist of more than one lineage. Strong in Malacologia,61 nomenclatkr From Wikipedia, the free encyclopedia. In contrast, within the Heterobranchia, for famjlies of the nudibranch groups there are six separate clades above the level of superfamily, and in the case of most of the land snailsthere are four clades above the level of superfamily. Biological classification schemes are not merely claesification convenience, they are an attempt to show the actual phylogeny the evolutionary relatedness within a group of organisms. International Journal of Malacology.

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Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)

Mauzahn Gastropods are a taxonomic class of animals which consists of snails and slugs of every kind, from the land, from freshwaterand from saltwater. This cladogram is based on the following information. Contains the Palaeozoic Neritomorpha of uncertain position and the clades Cyrtoneritimorpha and Cycloneritimorpha. Philippe Bouchet Both Linnaean taxa and clades are invalid if it turns out they are polyphyleticin other words if they consist of more than one lineage.

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