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Paratomy is a form of asexual reproduction in animals where the organism splits in a plane perpendicular to the antero-posterior axis and the split is preceded by the "pregeneration" of the anterior structures in the posterior portion. The developing organisms have their body axis aligned, i.e., they develop in a head to tail fashion.

Budding can be considered to be similar to paratomy except that the body axes need not be aligned: the new head may grow toward the side or even point backward (e.g. Convolutriloba retrogemma an acoel flat worm).[1][2] In animals that undergo fast paratomy a chain of zooids packed in a head to tail formation may develop. Many oligochaete annelids,[3] acoelous turbellarians,[1] echinoderm larvae[4] and coelenterates[5] reproduce by this method.

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This paper has a detailed description of the changes during paratomy.[3]


  1. ^ a b Åkesson, Bertil; Robert Gschwentner; Jan Hendelberg; Peter Ladurner; Johann Müller; Reinhard Rieger (2001-12-01). "Fission in Convolutriloba longifissura: asexual reproduction in acoelous turbellarians revisited" (PDF). Acta Zoologica. 82 (3): 231–239. doi:10.1046/j.1463-6395.2001.00084.x. ISSN 1463-6395. Archived from the original (PDF) on 2016-03-04. Retrieved 2011-07-13.
  2. ^ Egger, Bernhard (December 2008). "Regeneration: rewarding, but potentially risky" (PDF). Birth Defects Research Part C: Embryo Today: Reviews. 84 (4): 257–264. doi:10.1002/bdrc.20135. ISSN 1542-9768. PMID 19067421. Retrieved 2011-07-13.
  3. ^ a b Herlant-Meewis, Henriette (1950-10-01). "Cyst-Formation in Aeolosoma Hemprichi (Ehr)". Biological Bulletin. 99 (2): 173–180. doi:10.2307/1538737. ISSN 0006-3185. JSTOR 1538737. PMID 14791418.
  4. ^ Jaeckle, William B. (1994-02-01). "Multiple Modes of Asexual Reproduction by Tropical and Subtropical Sea Star Larvae: An Unusual Adaptation for Genet Dispersal and Survival". Biological Bulletin. 186 (1): 62–71. doi:10.2307/1542036. ISSN 0006-3185. JSTOR 1542036. PMID 29283296.
  5. ^ Raikova, Ekaterina V. (1994-02-01). "Life Cycle, Cytology, and Morphology of Polypodium hydriforme, a Coelenterate Parasite of the Eggs of Acipenseriform Fishes". The Journal of Parasitology. 80 (1): 1–22. doi:10.2307/3283338. ISSN 0022-3395. JSTOR 3283338. PMID 7905920.