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Any of various small, chiefly freshwater flatworms of the order Tricladida, having a soft, broad, ciliated body, a three-branched digestive cavity, and the ability to regenerate body parts.

[From New Latin Plānāria, genus name, from feminine of Late Latin plānārius, on level ground, from plānus, flat; see pelə- in Indo-European roots.]


(Animals) any free-living turbellarian flatworm of the mostly aquatic suborder Tricladida, having a three-branched intestine
[C19: from New Latin Plānāria type genus, from Late Latin plānārius level, flat; see plane1]


(pləˈnɛər i ən)

any of various free-swimming, mostly freshwater flatworms, having an undulating or sluglike motion.
[1885–60; < New Latin Planari(a) a flatworm genus (n. use of feminine of Late Latin plānārius level, on level ground; taken to mean “flat”; see plane1, -ary) + -an1]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.planarian - free-swimming mostly freshwater flatwormsplanarian - free-swimming mostly freshwater flatworms; popular in laboratory studies for the ability to regenerate lost parts
flatworm, platyhelminth - parasitic or free-living worms having a flattened body
class Turbellaria, Turbellaria - free-living flatworms
References in periodicals archive ?
Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians.
Planarians, small free-living flatworms, are especially interesting for researchers due to their remarkable ability to regenerate any lost body part through their many stem cells.
While human beings lack substantial regenerative capabilities in the CNS, many non-human species, such as amphibians, planarians, and certain fish, can repair, regenerate and remodel substantial portions of their brain and brain stem even after critical life-threatening trauma.
Several planarians are known to affect bivalve mollusks, and among them turbellarians of the orders Rhabdocoela and Prolecithophora have been detected in the mantle cavity, gills, and alimentary tract of their host.
Comparisons amongst the entire collection of 50 species will provide the necessary breadth for identifying and studying the evolutionary principles that naturally select regeneration-deficient planarians.
Currently, his interest extends to the roles of N-glycans, if any, in the regeneration of parts of the body lost using planarians and earthworms that possess high regenerative potentials.
TEHRAN (FNA)- Researchers announced the discovery of a gene zic-1 that enables stem cells to regrow a head after decapitation in flatworm planarians.
Maden said that some animals (such as hydra, planarians, and jellyfish) avoid aging or age-related death due to the ability to regenerate all organs.
That unmated females lay fewer eggs than mated females is consistent with some previous studies on geckos (Kearney & Shine 2005), salamanders (Uzzel 1964), millipedes (Enghoff 1976), and planarians (Weinzierl et al.