Seasonal release of the egg capsules of Anoplodium parasita Schneider, 1858, intracoelomic turbellarian (Platyhelminthes, Rhabdocoela) symbiotic of the sea cucumber Holothuria tubulosa Gmelin, 1788 (Echinodermata, Holothuroida)
Doignon, G.; Jangoux, M.; Féral, A.; Eeckhaut, I. (2003). Seasonal release of the egg capsules of Anoplodium parasita Schneider, 1858, intracoelomic turbellarian (Platyhelminthes, Rhabdocoela) symbiotic of the sea cucumber Holothuria tubulosa Gmelin, 1788 (Echinodermata, Holothuroida), in: Féral, J.-P. et al. Echinoderm Research 2001: proceedings of the 6th European Conference on Echinoderm Research, Banyuls-sur-mer, 3-7 September 2001. pp. 261-264 In: Féral, J.-P.; David, B. (2003). Echinoderm Research 2001: Proceedings of the 6th European Conference on Echinoderm Research, Banyuls-sur-mer, 3-7 September 2001. Swets and Zeitlinger: Lisse. ISBN 90-5809-528-2. XVI, 337 pp., more |
| Available in | Authors | | Document type: Conference paper
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| Keywords | Handling > Fish handling > Dressing > Gutting
Infestation
Interspecific relationships > Symbiosis
Secretory organs > Glands > Endocrine glands > Animal reproductive organs > Gonads
Anoplodium parasita Schneider, 1858 [WoRMS]; Holothuria (Holothuria) tubulosa Gmelin, 1791 [WoRMS]; Umagillidae Wahl, 1910 [WoRMS]
MED, France, Languedoc-Roussillon, Banyuls-sur-Mer [Marine Regions]
Marine/Coastal |
| Abstract | The endosymbiotic umagillid Anoplodium parasita Schneider, 1858 (Platyhelminthes, Rhabdocoela) lives in the perivisceral coelom of the sea cucumber Holothuria tubulosa Gmelin, 1788 (Echinodermata, Holothuroida). The flatworms release their egg capsules in the coelomic cavity of their host, where they are embedded in brown bodies concentrated in the posterior part of the body, near the cloaca. The infestation of the holothurians by turbellarian egg capsules was very high: 128 out of the 202 holothurians inspected from January 1999 to July 2000 at Banyuls-sur-mer (France) contained at least 6 and up to 10,000 egg capsules (mean 1433). Quite uniform throughout the year, the number of holothuroids infested as well as the number of egg capsules found per individual drastically fall in July, the period when the gonads of holothurians are highly developed. We suggest that the release of egg capsules might be an indirect result of the spawning of the hosts. To discharge their gametes, holothurians raise their body and adhere on the substratum by their posterior end. This behaviour would cause a surpressure in the peri-cloacal coelomic area of the holothurians and consequently the expulsion of the coelomic fluids through their coelo-cloacal ducts, carrying brown bodies and egg capsules to the outside. |
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