Terrestrial molluscs or land molluscs (mollusks) are an

ecological Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...

group that includes all

molluscs 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 taxon, extant species of molluscs are recognized. The number of fossil sp ...

that live on

land Land, also known as dry land, ground, or earth, is the solid terrestrial surface of the planet Earth that is not submerged by the ocean or other bodies of water. It makes up 29% of Earth's surface and includes the continents and various islan ...

in contrast to

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

and marine molluscs. They probably first occurred in the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

, arising from freshwater ones.

Characteristics

This group includes

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

s and

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 smal ...

s. Loss of the shell has taken place many times in different groups that are not evolutionarily closely related, and land snails and slugs are most often treated together as a single group in specialized malacological literature.Barker G. M. (ed.)
The biology of terrestrial molluscs
'. CABI Publishing, 2001, 558 pp. .Barker G. M. (ed.)
Natural enemies of terrestrial molluscs
'. CABI Publishing, 2004, 644 pp. . All terrestrial molluscs belong to the class

Gastropoda 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. ...

. However, colonization of the land took place several times during the

evolutionary Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

past, and as a result terrestrial molluscs are classified in several different, often not closely related, gastropod

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

. Terrestrial mollusks comprise about 35 thousand species, most of which belong to the order (in some sources suborder or infraorder)

Stylommatophora Stylommatophora is an orderPhilippe Bouchet, Jean-Pierre Rocroi, Bernhard Hausdorf, Andrzej Kaim, Yasunori Kano, Alexander Nützel, Pavel Parkhaev, Michael Schrödl and Ellen E. Strong. 2017. Revised Classification, Nomenclator and Typification ...

. Terrestrial molluscs occur across most of the planet, with the exception of

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

and some islands. They inhabit a wide range of ecosystems, from

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...

s and

tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless moun ...

s to

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s. In terms of survival, this group of species is currently one of the most threatened; there are more known species extinctions of terrestrial molluscs than in any other group of organisms.Cameron R. ''Slugs and snails''. HarperCollins Publishers, London, 2016, 508 pp. .

Taxonomic diversity

According to an estimate from Cameron, of the 409 existing gastropod

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

, 119 include terrestrial molluscs. Among these 119 families, 104 are

, 7 are terrestrial

pulmonates Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group include ...

other than stylommatophorans, and 8 are operculates (formerly " prosobranchs", molluscs with an operculum, a group that primarily consists of marine snails). "Prosobranchs" *

Cyclophoroidea Cyclophoroidea is a superfamily of land snails with an operculum, terrestrial gastropods within the informal group Architaenioglossa, that belongs to the clade Caenogastropoda.Bouchet, P.; Rosenberg, G.; Gofas, S. (2015). Cyclophoroidea Gray, ...

(up to 10 families in different classifications) *

Helicinidae Helicinidae is a family of small tropical land snails which have an operculum. They are terrestrial operculate gastropod mollusks in the superfamily Helicinoidea. These snails are not at all closely related to the air-breathing land snails, d ...

Proserpinellidae Proserpinellidae is a Taxonomy (biology), taxonomic family (biology), family of land snails with an operculum (gastropod), operculum, terrestrial animal, terrestrial gastropod mollusks in the superfamily Helicinoidea (according to the Taxonomy o ...

and

Proserpinidae Proserpinidae is a Taxonomy (biology), taxonomic family (biology), family of small land snails with an operculum (gastropod), operculum, gastropod mollusks in the superfamily Helicinoidea (according to the Taxonomy of the Gastropoda (Bouchet & Ro ...

(in the superfamily

Helicinoidea Helicinoidea is a taxonomic superfamily of land snails that have an operculum. In other words, they are terrestrial operculate gastropod mollusks. They are in the superfamily Neritoidea and are quite closely related to the marine and freshwa ...

) *

Pomatiidae The family Pomatiidae is a taxonomic family of small operculate land snails, terrestrial gastropod mollusks that can be found over the warmer parts of the Old World. In the older literature, this family is designated as Pomatiasidae. This famil ...

(in the superfamily

Littorinoidea Littorinoidea are a superfamily of both sea snails and land snails which have a gill and an operculum, terrestrial and marine gastropod mollusks in the clade Littorinimorpha. The terrestrial family within this group, the Pomatiidae, are ...

, which consist mainly of marine snails) * Assimineidae and

Truncatellidae Truncatellidae, common name the "looping snails", is a family of small amphibious snails, with gills and an operculum, semi-marine gastropod mollusks or micromollusks. Shell description This family of snails have small shells which lose th ...

(in the superfamily

Truncatelloidea Truncatelloidea is a superfamily of snails, gastropod mollusks in the clade Caenogastropoda.Bouchet, P. (2013). ''Truncatelloidea''. Retrieved through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=7 ...

, which consist mainly of aquatic snails; most species semi-marine) "Pulmonates" *

Amphiboloidea Amphiboloidea is a Taxonomy (biology), taxonomic superfamily of air-breathing land snails. Distribution Amphibolids are found in Indo-Pacific intertidal mangrove, saltmarsh and estuarine mudflat habitats. Taxonomy 2005 taxonomy According ...

(three families of land and semi-marine snails) * Ellobioidea (

Ellobiida Ellobiida is an order of gastropods belonging to the class Gastropoda. Families: * Ellobiidae Ellobiidae, common name the hollow-shelled snails, is a family of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in th ...

) (1-5 families in different classifications, some of the species live in

litoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal area ...

both in marine and terrestrial habitats) *

Systellommatophora The Systellommatophora (synonym Gymnomorpha) is a clade of primitive, air-breathing slugs, according to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005). They are marine and terrestrial pulmonate gastropods within the Heterobranchi ...

(3 families of land and semi-marine slugs) *

(more than 100 families of land snails and slugs)

Best known terrestrial malacologists

Oskar Boettger Oskar Boettger (german: Böttger; 31 March 1844 – 25 September 1910) was a German zoologist who was a native of Frankfurt am Main. He was an uncle of the noted malacologist Caesar Rudolf Boettger (1888–1976). From 1863 to 1866 he studied at ...

Jacques Philippe Raymond Draparnaud Jacques Philippe Raymond Draparnaud (3 June 1772, Montpellier – 2 February 1804) was a French naturalist, malacologist and botanist. Draparnaud is considered the father of malacology in France. He was professor of medicine and pathology at th ...

Wilhelm Kobelt Wilhelm Kobelt (20 February 1840 – 26 March 1916) was a German zoologist born in Alsfeld, Grand Duchy of Hesse. He specialized in the field of malacology. Kobelt is remembered for his work as curator of the Senckenberg Museum in Frankfurt am ...

Henry Augustus Pilsbry Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a centu ...

Emil Adolf Rossmässler Emil Adolf Rossmässler (''Emil Adolf Roßmäßler'', ''Emil Adolph Roßmäßler'') (March 3, 1806 in Leipzig – April 8, 1867 in Leipzig) was a German biologist. With Otto Eduard Vincenz Ule and Karl Johann August Müller, he was co-founder of t ...

* Heinrich Simroth *

Carl Agardh Westerlund Carl Agardh Westerlund (12 January 1831 – 28 February 1908 in Ronneby) was a Swedish malacologist. Biography Westerlund was born at Berga in Kalmar County, Sweden. He became a student in Uppsala University in 1853 and studied at Lund Unive ...

References

Most important literature

* Barker G. M. (ed.)
The biology of terrestrial molluscs
'. CABI Publishing, 2001, 558 pp. . * Cameron R. ''Slugs and snails''. HarperCollins Publishers, London, 2016, 508 pp. {{ISBN, 978-0-00-711301-9. Mollusc ecology Molluscs by adaptation

Characteristics

Taxonomic diversity

Best known terrestrial malacologists

See also

References

Most important literature