Antipathes atlantica

Antipathes atlantica Gray, 1857

Antipathes atlantica forms large colonies that are 0.5 m in height or more, and are densely branched with most branches located in a single plane like a fan (Figure 1a–c). Adjacent branches are sometimes fused together to form a net-like pattern. The terminal branches are straight or slightly curved, and typically shorter than 1 cm without becoming branched. The skeletal spines are smooth, triangular or slightly inclined distally, and are about the same width at their base as they are tall (Figure 1d–e). The spines are never bifurcated and are 40–100 µm in height. On smaller branches, the spines are arranged in axial rows with adjoining rows offset in a spiral pattern around the corallum (Figure 1d). Spine spacing is fairly even within each row, and ranges between 175–300 µm. The polyps are arranged on only one side of the corallum, are generally 0.5–1.1 mm in transverse diameter, and are spaced 1.1– 1.7 mm apart (Figure 1c). All colonies observed as part of this study were grayish white in situ (Figure 1a), however, greenish colonies have also reported for this species in other locations (Opresko et al., 2016; Opresko & Sanchez, 2005; Warner, 1981). A. atlantica has previously been reported from the Caribbean, Gulf of Mexico and Northwest Atlantic at depths ranging between 15–100 m (Cairns, Opresko et al., 1993; Opresko, 2009; Opresko et al., 2016; Opresko & Sanchez, 2005; Padilla & Lara, 2003; Sanchez, 1999; Sanchez et al., 1998; Warner, 1981, 2005). Specimens examined as part of this study were collected at depths between 55–152 m (Table 1), thereby extending the known depth range of this species.