Benthic richness in the Argentine continental shelf:: the role of Zygochlamys patagonica (Mollusca: Bivalvia: Pectinidae) as settlement substrate

In this study we present results on epibionts on Zygochlamys patagonica from material collected during monitoring cruises in different areas in the Argentine Sea. We update the checklist of epibiontics increasing the number of taxa from 19 to 41 and considering two species closely associated with the shells. The demosponge Iophon proximum was the most frequent and abundant epibiont (% presence and coverage). Poyldora sp. was registered as a parasite of Z. palagonica in shells from the Beagle Channel, but it did not infest scallops from the commercial beds. Zygochlamys palagonica shells constitute conspicuous hard substrate available for the settlement of sessile organisms. This fact leads to an increased benthic richness in the continental soft-bottom areas of the Argentine Sea, where scallop beds are located.