Planarians (triclads) are free-living flatworms of the class Turbellaria, order Tricladida, which includes hundreds of species, found in freshwater, marine, and terrestrial habitats. Planarians are characterized by a three-branched intestine, including a single anterior and two posterior branches. Their body is populated by adult stem cells called neoblasts, which planarians use for regenerating missing body parts. Many species are able to regenerate any missing organ, which has made planarians a popular model in research of regeneration and stem cell biology. The genome sequences of several species are available, as are tools for molecular biology analysis.
Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals. With the exception of two acoel freshwater species, all known acoelomorphs are marine.
Dugesia is a genus of dugesiid triclads that contains some common representatives of the class Turbellaria. These common flatworms are found in freshwater habitats of Africa, Eurasia, and Australia. Dugesia is best known to non-specialists because of its regeneration capacities.
Geoplanidae is a family of flatworms known commonly as land planarians or land flatworms.
Schmidtea mediterranea is a freshwater triclad that lives in southern Europe and Tunisia. It is a model for regeneration, stem cells and development of tissues such as the brain and germline.
Continenticola is a clade that includes the land planarians (Geoplanidae) and the freshwater triclads.
Dugesiidae is a family of freshwater planarians distributed worldwide. The type genus is Dugesia Girard, 1850.
Girardia is a genus of freshwater planarians belonging to the family Dugesiidae.
Schmidtea is a genus of freshwater triclads. Species of the genus Schmidtea are widely used in regeneration and developmental studies.
Dugesia notogaea is a species of dugesiid triclad that inhabits freshwater bodies of north Queensland, Australia.
Dugesia sicula is a species of dugesiid triclad that lives in freshwater bodies of the Mediterranean Basin, where it is widely distributed. It has been reported from Sicily, Elba and Mallorca, Eivissa, Sardinia, Algeria, Tunisia, Morocco and Crete.
Geoplanoidea is a superfamily of freshwater and land triclads that comprises the species of the Geoplanidae and the Dugesiidae families.
Cura is a genus of freshwater flatworm (triclads) belonging to the family Dugesiidae.
Microplaninae is a subfamily of land planarians.
Neppia is a genus of dugesiid triclad that is found in South America, Subantarctic region, Africa, Tasmania and New Zealand.
Geoplaninae is a subfamily of land planarians endemic to the Neotropical region. Members of this family are sometimes referred to as the Neotropical land planarians. However, one species, Obama nungara has been introduced in Europe.
Bipaliinae is a subfamily of land planarians found mainly in Madagascar, the Indian subcontinent and Southeast Asia, although some species have been introduced worldwide.
Dugesia subtentaculata is a species of planarian that inhabits the freshwater of Southern France, several localities on the Iberian Peninsula, Mallorca, Morocco and Algeria.
Rhynchodeminae is a subfamily of land planarians with a worldwide distribution.
Caenoplanini is a tribe of land planarians in the subfamily Rhynchodeminae mostly found throughout the Australasian and Oceanian realms.
