Family Clavulariidae

Scleranthelia rugosa (Pourtalès), 1867

var. rugosa (Pourtalès), 1867

Sarcodictyon rugosum, Pourtalès , 1867:113.

var. musiva Studer, 1878

Scleranthelia musiva Studer, 1878b:634, Plate 1 fig. 4

Remarks. This octocoral is the only encrusting species recorded in the South Atlantic Bight. The two growth forms of Scleranthelia rugosa differ mainly in the expanse of the stolon between calyces. Growth form rugosa resembles a “network” of individual calyces interconnected by band-like stolons (up to 2mm in width), where form musiva may encrust dead octocoral axes, shells or substrate with more sheet-like coenenchyme. Both forms have sclerites mainly in the form of large (up to 1 mm) flat plates that fit closely together in mosaic fashion, and somewhat cylindrical calyces that widen near the base, taking the shape of a cone. Thorny stars and rods are present in the anthocodia. The rugosa specimen examined for this work was encrusting on a dark rock which made the translucent white coenenchyme very visible, but the musiva specimen was encrusted on a piece of pale shell hash and well camouflaged. Bayer (1981b) does not recognize these two forms as separate species but they are cataloged in the USNM as such. This species is probably not found within safe SCUBA diving limits. The S. rugosa rugosa specimen examined for this work was collected in a manned submersible.

Atlantic distribution: form rugosa - South Carolina to Martinique, Guyana, 100-550 m; form musiva – New York to Guyana, Gulf of Mexico, Caribbean, 70-300 m (type recorded off Havana at 493 m) (Deichmann 1936; Bayer 1981(b); NMNH records).

Figure 4. Plate sclerite of Scleranthelia rugosa var. musiva (USNM 54856). Scale bar = 100 µm. Image courtesy FM Bayer/Smithsonian Institution.

Figure 1. Scleranthelia rugosa var. rugosa, preserved specimen (USNM 94530), encrusting a rock. Calyx base is approximately 4 mm in diameter.

Figure 2. Scleranthelia rugosa var. musiva, preserved specimen (USNM 55450), encrusting shell hash.

Figure 3. Scleranthelia rugosa var. musiva, preserved specimen (USNM 55107). SEM image was taken at 36x by FM Bayer/Smithsonian Institution.