Terrestrial molluscs or land molluscs (mollusks) are an ecological group that includes all molluscs that live on land in contrast to freshwater and marine molluscs. They probably first occurred in the Carboniferous, arising from freshwater ones. [1]
Terrestrial molluscs or land molluscs (mollusks) are an ecological group that includes all molluscs that live on land in contrast to freshwater and marine molluscs. They probably first occurred in the Carboniferous, arising from freshwater ones. [1]
This group includes land snails and land slugs. 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. [2] [3]
All terrestrial molluscs belong to the class Gastropoda. However, colonization of the land took place several times during the evolutionary past, and as a result terrestrial molluscs are classified in several different, often not closely related, gastropod taxa. [2]
Terrestrial mollusks comprise about 35 thousand species, most of which belong to the order (in some sources suborder or infraorder) Stylommatophora.
Terrestrial molluscs occur across most of the planet, with the exception of Antarctica and some islands. They inhabit a wide range of ecosystems, from deserts and tundras to rainforests.
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. [4]
According to an estimate from Cameron, [4] of the 409 existing gastropod families, 119 include terrestrial molluscs. Among these 119 families, 104 are Stylommatophora, 7 are terrestrial pulmonates other than stylommatophorans, and 8 are operculates (formerly "prosobranchs", molluscs with an operculum, a group that primarily consists of marine snails).
"Prosobranchs"
"Pulmonates"
Gastropods, commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.
Helix is a genus of large, air-breathing land snails native to the western Palaearctic and characterized by a globular shell.
Athoracophoridae, common name the leaf-veined slugs, are a family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the infraorder Stylommatophora, the stalk-eyed snails and slugs. Many of the species have an attractive pattern on their dorsal surface which resembles the veins in a leaf, hence the common name.
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.
Limacidae, also known by their 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.
Euconulidae is a taxonomic family of minute, air-breathing land snails, terrestrial pulmonate gastropod mollusks or micromollusks in the superfamily Trochomorphoidea.
Polygyridae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea.
Monachoides incarnatus is a species of air-breathing land snail in the terrestrial pulmonate gastropod mollusk family Hygromiidae, the hairy snails and their allies.
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 small internal shell, particularly sea slugs and semi-slugs.
Milacidae is a family of air-breathing, keeled, land slugs. These are shell-less terrestrial gastropod mollusks in the superfamily Parmacelloidea.
A love dart is a sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are both formed and stored internally in a dart sac. These darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place. Darts are quite large compared to the size of the animal: in the case of the semi-slug genus Parmarion, the length of a dart can be up to one fifth that of the semi-slug's foot.
Perforatella bidentata is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Hygromiidae, the hairy snails and their allies.
Ariophantidae is a taxonomic family of air-breathing land snails and semi-slugs, terrestrial pulmonate gastropod mollusks in the superfamily Helicarionoidea.
Trochomorphidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Gastrodontoidea. Since 2017, its classification has been revised and it now belongs to the superfamily Trochomorphoidea
Gastrodontidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Gastrodontoidea.
Staffordiidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Trochomorphoidea.
Oreohelicidae is a family of small to medium-sized air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Punctoidea.
Pyramidulidae is a family of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Pupilloidea.
The sensory organs of gastropods include olfactory organs, eyes, statocysts and mechanoreceptors. Gastropods have no sense of hearing.
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly.
