Giant sessile barnacles contribute to the construction of cold-water coral habitats south of Malta (Mediterranean Sea)

Abstract

Sessile barnacles may be important contributors to benthic communities worldwide from warm temperate to polar latitudes. Although barnacles are more often found in shallow settings, they equally occur below wave base down to bathyal depths. A case in point is represented by the presence of live populations of the thoracican cirripede Pachylasma giganteum (Philippi, 1836) associated with the lush and highly diverse deep sea cold-water coral communities (cwc) south of Malta. P. giganteum is a large cirriped (> 40 mm in height and > 30 mm in basal diameter) that is uncommon recorded in the Mediterranean Sea and the Azores region. It is relatively frequent in the Strait of Messina on circalittoral hard substrates between 80-200 m to bathyal depths (435-640 m) in the NE Atlantic where it has been found attached to scleractinians and sponges. The species is recorded as epibiont on turtles in the Aegean Sea. Finally, P. giganteum is also known as a fossil from Pleistocene palaeo-strait deposits in the Messina area (Sicily), a record which is consistent with the association of this suspension feeder with submarine topographies under the influence of strong currents.