The Mesenteric Filaments originate from the laterally arranged mesenteries (which increase surface area for digestion) on the internal edge of the coral oral disc or stomach and contain nematocysts. These filaments can protrude from the mouth or even from temporary opens in the side of the column (this is most clearly seen with Aiptasia sp.). Some coral species use the mesenteric filaments as a way to compete with neighbouring corals for space (see Coral Competition) and cleaning the substrate for their subsequent colonisation.
Their predominate function is for prey digestion and competition with neighbouring corals.
A study of Galaxea fascicularis found that 98.6% of prey captured by a polyp was not ingested, rather clustered into aggregates and digested externally using the mesenterial filaments. Therefore, they play a very important role in the processing of nutrients for the corals and the majority of nutrients obtained come from external digestion, rather than particles ingested and processed internally.
- (http://dx.doi.org/10.1007/s00338-008-0424-1): Roff, G., Dove, S.G., and Dunn, S.R., Mesenterial filaments make a clean sweep of substrates for coral growth, Coral Reefs, 28(1) (2008) 79.
- (http://dx.doi.org/10.1242/jeb.058354): Wijgerde, T., Diantari, R., Lewaru, M.W., Verreth, J.A.J., and Osinga, R., Extracoelenteric zooplankton feeding is a key mechanism of nutrient acquisition for the scleractinian coral Galaxea fascicularis, The Journal of Experimental Biology, 214 (2011) 3351-3357.