Epibiosis and hyperepibiosis onPagurus bernhardus(Crustacea: Decapoda) from the west Coast of Scotland

Abstract

The presence of a diverse range of epibionts was found onPagurus bernhardusfrom the west coast of Scotland. The invertebrate species found on the shell inhabited by the crab were the hydrozoansHydractinia echinataandDycorine conferta, the cirripedsBalanus balanusandBalanus crenatus, the polychaetesHydroides norvegica,Pomatoceros triqueterandCirceis armoricana, and the molluscsHiatella arcticaandAnomia ephippium. On the crab were observed the polychaeteCirceis armoricanaand the amphipodPodoceropsis nitida. In addition, on the gastropod shells occupied byP. bernhardus, ciliate protozoan species were found attached to the hydrozoanDycorine conferta, this being hyperepibiosis. These ciliates were 6 suctorian (Conchacineta constricta,Corynophrya anisostyla,Actinocyathula homari,Actinocyathula crenata,Acineta sulcataandAcineta corophii), and one peritrich species (Zoothamniumsp.). This is the first time that this hyperepibiosis was observed. In contrast to the epibiont communities observed in previous surveys in the same sampling area, basibiont specimens withoutD. confertadid not show ciliate epibionts. The ciliate epibionts also were not present on the surface of the shell and crab in specimens withD. conferta; they only appeared in hyperepibiosis on the surface of the hydrozoan. The spatial distribution and abundance of the invertebrate epibiont species were analysed, as well as the morphology, taxonomy and distribution of the ciliate hyperepibionts.