Planaria

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Planaria
Planaria torva.jpg
Planaria torva
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Platyhelminthes
Order: Tricladida
Family: Planariidae
Genus: Planaria
OF Müller, 1776
Class

Turbellarian

Planaria is a genus of planarians in the family Planariidae. Due to its excellent ability to regenerate, species of Planaria has also been used as model organisms in regeneration studies. [1] When an individual is cut into pieces, each piece has the ability to regenerate into a fully formed individual. [2] When decapitated, they retain their memories. [3]

Contents

Various species of Planaria have been widely used as model invertebrate organisms in pharmacological research, in particular in the studies of the drugs of abuse. [4] They were also proposed as models in toxicological research. [5]

Description

Currently the genus Planaria is defined as freshwater triclads with oviducts that unite to form a common oviduct without embracing the bursa copulatrix and with an adenodactyl present in the male atrium. The testes occur along the whole body. [6]

Planaria originally have habitats in dark, murky water which results in such sensitivity (Paskin et al., 2014). They are also sensitive to other stimuli such as chemical gradients, vibration, magnetic and electric fields (Deochand et al., 2018). Their central nervous system includes the anterior (head, brain and eyes) and middle (abdominal trunk and pharynx) (Deochand et al., 2018).

Diet

The food of Planaria species includes freshwater gastropods, tubificid worms, and freshwater arthropods, such as isopods of the genus Asellus and chironomid larvae. [7] In the United Kingdom, P. torva is a successful predator of the invasive New Zealand mud snail (Potamopyrgus jenkinsi). [8]

Species

The following species are recognised in the genus Planaria:

Related Research Articles

<span class="mw-page-title-main">Planarian</span> Flatworms of the Turbellaria class

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.

<i>Nereis</i> Genus of annelid worms

Nereis is a genus of polychaete worms in the family Nereididae. It comprises many species, most of which are marine. Nereis possess setae and parapodia for locomotion and gas exchange. They may have two types of setae, which are found on the parapodia. Acicular setae provide support. Locomotor setae are for crawling, and are the bristles that are visible on the exterior of the Polychaeta. They are cylindrical in shape, found not only in sandy areas, and they are adapted to burrow. They often cling to seagrass (posidonia) or other grass on rocks and sometimes gather in large groups.

<i>Dugesia</i> Genus of flatworms

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.

<span class="mw-page-title-main">Planariidae</span> Family of flatworms

Planariidae is a family of freshwater planarians.

<i>Pseudoceros</i> Genus of flatworms

Pseudoceros is a genus of the flatworms Platyhelminthes.

<span class="mw-page-title-main">Geoplanidae</span> Family of flatworms

Geoplanidae is a family of flatworms known commonly as land planarians or land flatworms.

<i>Eunice</i> (annelid) Genus of worms

Eunice is a genus in the polychaete family Eunicidae. Individuals grow to a length of between 0.5 and 300 cm. Their bodies have multiple segments. They have two eyes and five tentacles. They have well-developed sense organs and relatively large brains. Their color is dark purple-brown to red-brown with a white ring at the fourth segment. They are found in oceans and seas around the world. They have an evertible proboscis with distinctive mouthparts, some of which comprise two rows of maxilliary plates in a radula-like fashion.

<i>Bipalium</i> Genus of flatworms

Bipalium is a genus of large predatory land planarians. They are often loosely called "hammerhead worms" or "broadhead planarians" because of the distinctive shape of their head region. Land planarians are unique in that they possess a "creeping sole", a highly ciliated region on the ventral epidermis that helps them to creep over the substrate. Native to Asia, several species are invasive to the United States, Canada, and Europe. Some studies have begun the investigation of the evolutionary ecology of these invasive planarians.

<i>Doris</i> (gastropod) Genus of gastropods

Doris is a genus of sea slugs, specifically dorid nudibranchs. These animals are marine gastropod molluscs in the family Dorididae.

<span class="mw-page-title-main">Dugesiidae</span> Family of flatworms

Dugesiidae is a family of freshwater planarians distributed worldwide. The type genus is Dugesia Girard, 1850.

<i>Girardia</i> Genus of flatworms

Girardia is a genus of freshwater planarians belonging to the family Dugesiidae.

<i>Schmidtea</i> Genus of flatworms

Schmidtea is a genus of freshwater triclads. Species of the genus Schmidtea are widely used in regeneration and developmental studies.

<span class="mw-page-title-main">Dendrocoelidae</span> Family of flatworms

Dendrocoelidae is a family of freshwater tricladida flatworms that has a holarctic distribution.

Girardia tigrina, known as the brown planarian or the immigrant triclad flatworm, is a species of dugesiid native to the Americas. It has been accidentally introduced into Europe and Japan.

<i>Schmidtea polychroa</i> Species of flatworm

Schmidtea polychroa is a species of freshwater flatworm, a dugesiid triclad that inhabits the shallow mesotrophic or eutrophic waters of rivers and lakes of Europe. It is also present in North America, where it has been introduced at least in the Saint Lawrence river system. It is an animal with a limited dispersion capability.

<i>Dendrocoelum</i> Genus of flatworms

Dendrocoelum is a genus of freshwater triclad. Over one hundred species have been described.

Josef Hauser S. J. was a Hungarian zoologist and Jesuit priest.

<i>Planaria torva</i> Species of flatworms

Planaria torva is a species of planarian in the family Planariidae. When an individual is cut into pieces, each piece has the ability to regenerate into a fully formed individual.

<i>Dendrocoelum lacteum</i> Species of flatworm

Dendrocoelum lacteum, the milk-white planarian, is a freshwater planarian found in lakes and running waters in Europe, being the most widespread freshwater planarian in this continent.

<i>Cerebratulus</i> Genus of ribbon worms

Cerebratulus is a genus of nemerteans belonging to the family Lineidae.

References

  1. ↑ Mario Ivankovic; Radmila Haneckova; Albert Thommen; Markus A. Grohme; Miquel Vila-Farré; Steffen Werner; Jochen C. Rink (2019). "Model systems for regeneration: planarians". Development. 146 (17). doi: 10.1242/dev.167684 . Retrieved 21 January 2023.
  2. ↑ "Unravelling How Planaria Regenerate". Sedeer el-Showk. Retrieved 26 January 2017.
  3. ↑ Rowan Jacobsen (1 February 2024). "Brains Are Not Required When It Comes to Thinking and Solving Problems—Simple Cells Can Do It". Scientific American .
  4. ↑ Raffa, Robert B. (3 December 2008). Planaria: A Model for Drug Action and Abuse. CRC Press. doi:10.1201/9781498713597. ISBN   978-0-429-08997-8.
  5. ↑ Shah, Syed Ibrahim; Williams, Adrian C.; Lau, Wing Man; Khutoryanskiy, Vitaliy V. (1 December 2020). "Planarian toxicity fluorescent assay: A rapid and cheap pre-screening tool for potential skin irritants" (PDF). Toxicology in Vitro. 69: 105004. doi:10.1016/j.tiv.2020.105004. ISSN   0887-2333. PMID   33010358. S2CID   222159871.
  6. ↑ Ball, Ian R.; Reynoldson, T. B.; Warwick, T. (2009). "The taxonomy, habitat and distribution of the freshwater triclad Planaria torva (Platyhelminthes: Turbellaria) in Britain". Journal of Zoology. 157 (1): 99–123. doi:10.1111/j.1469-7998.1969.tb01691.x. ISSN   0952-8369.
  7. ↑ Reynoldson, T. B.; Sefton, A. D. (1976). "The food of Planaria torva (Müller) (Turbellaria-Tricladida), a laboratory and field study". Freshwater Biology. 6 (4): 383–393. doi:10.1111/j.1365-2427.1976.tb01623.x. ISSN   0046-5070.
  8. ↑ Reynoldson, T. B.; Piearce, Bronwen (1979). "Predation on snails by three species of triclad and its bearing on the distribution of Planaria torva in Britain". Journal of Zoology. 189 (4): 459–484. doi:10.1111/j.1469-7998.1979.tb03974.x. ISSN   0952-8369.


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