Citizendia
Your Ad Here

Mesogastropoda was for many years a traditional taxonomic group of snails, an order. Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos The word snail is a Common name that can be used for almost all members of the Molluscan class Gastropoda which have coiled shells in the This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used The order was composed mostly of sea snails, but it also including some land snails and freshwater snails, all of which were prosobranch gastropod mollusks. Prosobranchiagif|thumb|The shell of a Harpa species a prosobranch gastropod]] Prosobranchia used to be a large Taxonomic Subclass of Snails The class Gastropoda or the gastropods, also previously known as gasteropods, or univalves, and more commonly known as Snails Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000

This order was introduced by J. Thiele in his work from 1921, it and was used for many decades subsequently. For the 19th century chemist by the same name see Johannes Thiele (chemist.

Recent research in malacology has made it clear that Mesogastropoda was not a monophyletic taxon, and because of that, the taxon is no longer included in modern classifications. Malacology is the branch of Invertebrate Zoology which deals with the study of Mollusks the second-largest Phylum of animals in terms of described A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to Nonetheless most of the standard texts and field guides on mollusks date from the time period when this classification was still current, and therefore references to mesogastropods or Mesogastropoda are frequently encountered. A field guide Bold textis a Book designed to help the reader identify Wildlife ( Plants or Animals or other objects of natural

The lower taxa traditionally contained in Mesogastropoda are now mostly covered by in the superorder Caenogastropoda. Caenogastropoda is a very large Taxonomic group a Superorder of saltwater (and in a minor way freshwater snails ( aquatic and marine A more detailed account of the taxonomy is given in the articles on Gastropoda and Archaeogastropoda. The class Gastropoda or the gastropods, also previously known as gasteropods, or univalves, and more commonly known as Snails Archaeogastropoda is (or more accurately was a Taxonomic order of sea Snails Archeogastropoda are "primitive" marine Prosobranch

Contents

Description

There are about 30,000 species. Most are to be found in the sea, but there are also numerous species in freshwater and even a few occur on land. Their shells have no mother-of-pearl or nacre. Nacre, also known as mother of pearl, is an organic-inorganic Composite material produced by some Mollusks as an inner shell layer

Most of these snails are herbivorous, but a few are parasites or predators. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Parasitism is a type of symbiotic relationship between Organisms of different Species. The radula has seven denticles (or small teeth), which are sometimes reduced. The radula is a toothed Chitinous ribbon typically used for scraping cutting and chewing food before it enters the Esophagus.

The Mesogastropoda are, in many ways, more developed than the Archaeogastropoda. Archaeogastropoda is (or more accurately was a Taxonomic order of sea Snails Archeogastropoda are "primitive" marine Prosobranch Through torsion of the intestinal mass and a spiral movement of the body, the gill, the kidney and the osphradium (which means sensory receptor, or olfactory organ) have disappeared on the right side. A gill is an anatomical structure found in many aquatic organisms The kidneys are complicated organs that have numerous biological roles These organs exist only on the left side of the animal.

The heart consists of only one atrium and one ventricle. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic

The nervous system is also more developed than in the Archeogastropods. The nervous system is a Network of specialized cells that communicate information about an animal's surroundings and itself The ganglia are connected with different organs through nerve pathways. In Anatomy, a ganglion (pl ganglia) is a tissue mass. Neurology In neurological contexts ganglia are composed mainly of

In the Mesogastropoda, the execretory and the reproductive ducts are separated (in contrast with the most primitive prosobranchs). Many members produce egg capsules, containing one to more than 1,000 eggs.

Taxonomy

The taxonomy of the Mesogastropoda (according to ITIS) (which is no longer in use). Integrated Taxonomic Information System ( ITIS) is a partnership designed to provide consistent and reliable information on the Taxonomy of biological Species The current taxonomy (according to Ponder & Lindberg, 1997) is given under Gastropoda

Families

References

External links

© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic