Planaria Bicingulata

''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. When an individual is cut into pieces, each piece has the ability to regenerate into a fully formed individual. When decapitated, they retain their memories.

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.

''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. In the United Kingdom, ''P. torva'' is a successful predator of the invasive New Zealand mud snail (''Potamopyrgus jenkinsi'').

Species

The following species are recognised in the genus ''Planaria'':

*'' Planaria adhaerens''
*'' Planaria albocingata''
*'' Planaria barroisi''
*'' Planaria bicingulata''
*'' Planaria chulunginensis''
*'' Planaria cincinata''
*'' Planaria cinerea''
*'' Planaria dagarensis''
*'' Planaria debilis''
*'' Planaria delineata''
*'' Planaria dybouskyi''
*'' Planaria flava''
*'' Planaria fontana''
*'' Planaria fuliginosa''
*'' Planaria fuliginosus''
*'' Planaria fulvifrons''
*'' Planaria fuscomaculata''
*''Planaria gigas''
*'' Planaria grubii''
*'' Planaria ignorata''
*'' Planaria incerta''
*'' Planaria kempi''
*'' Planaria lemani''
*'' Planaria lucta''
*''Planaria luteola''
*'' Planaria macrocephala''
*'' Planaria maculata''
*'' Planaria marmorosa''
*'' Planaria melanocerca''
*'' Planaria melanopunctata''
*'' Planaria melanotorquis''
*'' Planaria nesidensis''
*'' Planaria onegensis''
*'' Planaria punctatum''
*'' Planaria rosea''
*'' Planaria rothii''
*'' Planaria sabussowi''
*'' Planaria savignyi''
*'' Planaria semifasciata''
*'' Planaria simplex''
*'' Planaria sinensis''
*'' Planaria subflava''
*''Planaria torva''
*'' Planaria tremellaris''
*'' Planaria unionicola''
*'' Planaria verrucosa''
*'' Planaria wytegrensis''
*'' Planaria zeylanica''

Application of planaria in research

These invertebrates are valuable models in toxicology, neuroscience, and pharmacology, offering ethical and cost-effective alternatives to vertebrate testing. Planaria’s simple nervous system, high sensitivity to environmental changes, and well-characterized genome make them particularly useful for studying chemical toxicity, wound healing, and neuroregeneration. Their ease of maintenance in laboratory settings further enhances their appeal for research. In pharmacology and neuroscience, planaria provide a unique opportunity to study the effects of psychoactive compounds, including investigations into drug addiction and withdrawal responses. In drug delivery studies, they can be used to assess the biocompatibility and potential irritancy of pharmaceutical formulations, providing insight into their effects on biological tissues. Additionally, their remarkable ability to regenerate lost body parts makes them an important model for stem cell research, offering insights into cellular and molecular mechanisms of regeneration.

References

*Deochand, N., Costello, M. S., & Deochand, M. E. (2018). Behavioral Research with Planaria. Perspectives on behavior science, 41(2), 447–464. https://doi.org/10.1007/s40614-018-00176-w

Continenticola
Rhabditophora genera

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