Hedera caerulescens (Alcyonacea : Alcyoniidae), a new genus and species of soft coral from the temperate North Atlantic: invasive in its known range?

• Published in: Invertebrate Systematics
• Main Authors: I. E. Conti-Jerpe, D. W. Freshwater
• Format: Text
• Language: English
• Published: CSIRO Publishing 2017
• Subjects: North Atlantic
• Online Access: https://doi.org/10.1071/IS16069

We describe a novel alcyoniid species of stoloniferous octocoral found off the coast of North Carolina, USA. Colonies have an encrusting morphology with pale to bright blue monomorphic polyps connected by spongy, sclerite-dense stolons that often form mats. Sclerites are colourless and sparsely tubercled. Sclerites of the stolons are predominantly spindles and rods with rare irregular fused forms, butterflies, and crosses. Polyps have a crown and points formation that consists of rods and spindles that can be curved or irregularly branched. Tentacles contain short flattened rods and rare crosses. Both the mitochondria-encoded COI-5P and mtMutS were sequenced and BLAST searches revealed no close homology with any previously sequenced species. Phylogenetic analyses of the sequence data suggested a closest relationship with species of Alcyonium Linnaeus, 1758 (Alcyoniidae) and Gersemia Marenzeller, 1877 (Nephtheidae) and supported the recognition of a new genus. This species was not previously reported in the Carolinas region despite extensive historical sampling and a recently published key to octocorals of the South Atlantic Bight. Reports and photographs from local divers suggest that this species may have been introduced in North Carolina waters ∼2002–04, where it has been found on both shipwrecks and hard bottom ledges, at 13–34 m depth.