Phylogenetic Diversity of the Cold Water Octocoral Paragorgia arborea (Linnaeus, 1758) off the East Coast of Canada

Abstract

Commonly called "bubblegum coral', Paragorgia is a genus of cold-water gorgonian coral that has a broad global distribution and is eurybathic from depths of meters to kilometers. Such ecological breadth, however, may be confounded by the presence of cryptic species. In this study the genetic distances of various Paragorgia spp. across their distribution and depth range along the Canadian mid-Atlantic margin using 18S ribosomal DNA sequences were compared. Morphometric and 18S evidence show that although appearing closely related, only one species of cold-water Paragorgia, called P. arborea, predominates in this region. However, 18S evidence from corals collected at deep depths located at one site, called the Stone Fence, indicate that a significant amount of divergence exists and other species may also be present. Such new light provides a need for further genetic testing using alternative methods (e.g. microsatellites), which could reveal new lineages that may have considerable ecological and/or taxonomic importance.

Hydrodynamic Connectivity of Habitats of Deep-Water Corals in Corsair Canyon, Northwest Atlantic: A Case for Cross-Boundary Conservation

“…Nothing is known about the reproduction or larval ecology for P. arborea. Based on population structure on the Scotian Shelf and Slope, P. arborea appears to be genetically mixed within individual sites on the western Scotian Shelf (i.e., where CCCA is situated) and thus was proposed to also have wide dispersal (Strychar et al, 2008). Regionally wide dispersal has been proposed as the reason for an absence of regional and bathymetric genetic structure for the species (Herrera et al, 2012).…”

Climate-Change Refugia for the Bubblegum Coral Paragorgia arborea in the Northwest Atlantic

“…The large, fan-shaped gorgonian octocorals of the genus Paragorgia Milne Edwards, 1857, known as 'bubblegum corals' (Figure 1), form ecologically significant habitats on hard substrates along the continental margins of eastern North America (Gass, 2002;Metaxas and Giffin, 2004;Mortensen and Buhl-Mortensen, 2004;Buhl-Mortensen and Mortensen, 2005;Gass and Willison, 2005;Leverette and Metaxas, 2005;Metaxas and Davis, 2005;Watling and Auster, 2005;Quattrini et al, 2015;Kenchington et al, 2019a), and elsewhere (Sánchez, 2005;Herrera et al, 2012;De Clippele et al, 2015;Morato et al, 2021). Of the 18 accepted species in the genus (Cordeiro et al, 2021), P. arborea (Linnaeus, 1758) and P. johnsoni Gray, 1862 are found on the continental slope off Nova Scotia, Canada, with P. arborea being the more frequently recorded (Cogswell et al, 2009;Strychar et al, 2011). In this region, both Paragorgia species are long-lived and slow-growing, attaining colony heights of 240 cm, and forming dense aggregations (Sherwood and Edinger, 2009;Watanabe et al, 2009).…”