Epizoanthus papillosus

Ryland, John S. & Ward, Helen, 2016, Carcinoecium-forming Epizoanthus [Hexacorallia: Zoantharia] and the biology of E. papillosus in the eastern Atlantic, with special reference to the cnidom, Zootaxa 4088 (4), pp. 489-514 : 510

Conclusions from Epizoanthus papillosus

Benthic surveys have shown that Epizoanthus papillosus is widespread and quite abundant in the seas around the British Isles, apart from the Irish Sea, English Channel and Southern Bight. It most commonly constructs carcinoecia in association with Anapagurus laevis but small, free-living colonies also occur. The latter facilitated cnidom comparisons between equivalent-sized polyps in carcinoecia and free-living colonies. As has been previously demonstrated in other zoanthids (Ryland, et al., 2004), the capsule size in some nematocyst types is correlated with polyp size (and, interestingly, may be correlated with umbrella size in Cyanea (Östman & Hydman, 1997)) . This has great relevance to the use of capsule size in taxonomy. Major differences were found between the cnidoms of carcinoecia and free-living colonies, including presence or absence (holotrichs in tentacles of freeliving colonies only), abundance (basitrichs being much more abundant in free-living colonies), and capsule size (both holotrichs and p -mastigophores being larger in free-living colonies). The differences seem probably related to method of feeding, with carcinoecia polyps less dependent on captured live prey and able to benefit from the activities of the hermit crab, but may also be to protect the pagurid itself. This demonstrated paucity of nematocyst types and abundance has a significant, negative impact on the use of cnidom characters in the taxonomy of carcinoecium-forming species of Epizoanthus .