SUBSTRATE PITTING AND BORING PATTERN OF HYRROKKIN SARCOPHAGA CEDHAGEN, 1994 (FORAMINIFERA) IN A MODERN DEEP-WATER CORAL-REEF MOUND

Colonization structures of the large parasitic foraminifer Hyrrokkin s arcophaga Cedhagen, 1994 on Lophelia pertusa, Acesta excavata and Dele ctopecten vitreus are described from a deep-water coral reef mound on the mid-Norwegian shelf at 240 to 300 m water depth. Hyrrokkin sarcoph aga is the only epibiont which is capable of attaching itself on the s oft tissue-protected coral skeleton where it tends to form clusters of 3 to 8 specimens close to the tentacles of Lophelia. The foraminifer excavates a pit up to 1.5 mm deep and etches a straight channel throug h the skeleton of the host which ends within the soft tissue. In contr ast to Lophelia, infested bivalves show a strong wound repair reaction and seal the etched channels by intense calcification. The etching is only performed by adult specimens. Substrate pitting is considered to improve the attachment strength while boring enables the parasite to secure a persistent nutrient source.