Stylopathes columnaris (Duchassaing, 1870)

Fig. 29, 30

Arachnopathes columnaris Duchassaing, 1870: 23.

Antipathes (Arachnopathes) columnaris: Pourtales, 1874: 46, pl. 9, fig. 8; 1878: 209.

Antipathes columnaris: Pourtales, 1880: 117, pl. 3, fig. 3; Opresko, 1974: 101–115 (em parte, ver fig. 12).

Parantipathes columnaris: Brook, 1889: 141 (listed as “ Parantipathes?”); Silberfeld, 1909: 28.

Stylopathes columnaris: Opresko, 2006: 112–118, figs 1–3.

Type and type locality. USNM 77114 (neotype): Caribbean Sea, 16º34’58.8”N, 80º54’57.6”W, 183 m.

Material examined. Brazil, off Rio Grande do Norte, Bacia Potiguar. 4º46’59.999”S, 36º10’59.999”W; depth: 423–461 m. Programa de Caracterização da Bacia Potiguar, PETROBRAS, Date: 05/2011 (MOUFPE—CNI 829, 1 specimen).

Diagnosis. “Corallum monopodial and pinnulated, mostly to the third and fourth order. Primary pinnules on stem arranged primarily in three (rarely four) rows; two lateral and one or two on the anterior side of the stem, and also in verticillate groupings of three or four—one from each row. Lateral primary pinnules longer and more extensively subpinnulated than anterior primaries. Secondary pinnules arranged primarily in verticils of three (rarely four), and sometimes singly or in subopposite pairs. Tertiary and higher order pinnules, when present, occurring singly, in pairs or in verticils. Cylindrical, reticulated worm run present along posterior side of stem. Subpinnulation of lateral pinnules generally not covering worm run. Tertiary and higher order pinnules usually more extensively developed on outer lateral margins of corallum, especially in older colonies. Spines small, conical, inclined distally, especially near distal end of the pinnules and subpinnules and becoming less distally inclined towards the proximal end. Spines up to about 0.1 mm tall near the distal end of the pinnules and decreasing to 0.05 mm or less at the proximal end; arranged in irregular rows, with members of each row spaced 0.10–0.25 mm apart. Spines on the side of the axis containing the polyps slightly longer than those on the opposite side. Polyps 0.6–0.9 mm in transverse diameter; and arranged in a single series (8–10 per centimeter) primarily on the distal or lateral sides of the pinnules” (Opresko, 2006).

Description of Brazilian specimen. Colony (MOUFPE—CNI 829) 11.3 cm tall, and 3.5 cm wide. The lowest two centimeters of the stem without pinnulation (Fig. 29a). Corallum sparsely branched to the 1st order. Pinnules organized in 3 rows; two lateral and one anterior row. Number of primary pinnules per centimeter between 9 and 10, spacing between primary pinnules 3 mm in each row. Length of primary lateral pinnules between 12 and 18 mm, Primary anterior pinnules poorly developed and hardly visible, usually without or with few secondary pinnules in whorls of 2 or 3. Length of anterior pinnules between 5 and 11 mm. Secondary pinnules on primary lateral pinnules occurring in verticils of 3 or 4 subpinnules Secondary pinnules may be confused with primaries mainly in the region proximal to the main axis of the coral, where the “worm run” is present (Fig. 29b). Length of secondary pinnules between 5 and 10 mm; number of secondary pinnules per lateral primary between 5 and 8. Tertiary pinnules present. Spines conical and inclined toward the distal end of the pinnule (Fig. 29 c-d). Spines near the distal portion of the pinnule reaching up to 0.096 mm, most common being 0.048 –0.072 mm. Distance between the spines, mainly 0.1– 0.03 mm on a pinnule 0.12 mm in diameter. Polyps not visualized (lost tissue).

Remarks. The spines of the Brazilian specimen are relatively smaller than those reported in Opresko (2006), where the length of the spines varies between 0.05–0.1 mm at the proximal end of the primary pinnules, compared to 0.03–0.06 mm in the material described herein. Species of the genus usually tend to form a tube along the main axis of the colony through the anastomosis of the central pinnules, which may house a polychaete. This structure may be termed a “worm run” or path for polychaetes (Opresko, 2006). In spite of having the typical formation of the tunnel, this colony did not keep the polychaete among its pinnules. Wagner (2011) and Pettibone (1991) cite Bayerpolynoe floridensis Pettibone, 1991 as a compulsory commensal for S. columnaris. The species, as Antipathes. columnaris, has previously been recorded for Brazil, for the state of Pará (Opresko, 1974).

Distribution. Caribbean Sea (Opresko, 2006), Gulf of Mexico (Opresko, 2009); IndoPacific, off New Zeland (Van Pesch, 1914; Cairns et al., 2009), Southwestern Atlantic, Brazil, off Pará, mouth of Amazon River (Opresko, 1974) and off Rio Grande do Norte, Bacia Potiguar (this work) (Fig. 30); from 62 m (Opresko, 2009) to 984 m depths (Van Pesch, 1914).