Tanacetipathes thalassoros, Loiola, Livia L. & Castro, Clovis B., 2005

Loiola, Livia L. & Castro, Clovis B., 2005, Tanacetipathes Opresko, 2001 (Cnidaria: Antipatharia: Myriopathidae) from Brazil, including two new species, Zootaxa 1081, pp. 1-31 : 27-29

Tanacetipathes thalassoros new species

Figure 15

Material examined. Brazil: Trindade Island, about 20 ° S, 0 30 ° W, about 100 m, REVIZEE Bahia­1 ( MNRJ 3414: 1 colony—holotype); Jaseur Bank, 20 ° 36’S, 0 35 ° 51’W, about 50 m, REVIZEE Central II ( MNRJ 5148: 1 colony fragment—paratype); Doga Ressa Bank, 20 ° 57’ S, 0 34 ° 58’W, about 100 m, REVIZEE Central IV ( MNRJ 3401: 1 colony fragment—paratype).

Diagnosis. Corallum with branches arising far from the colony basis, resulting in a fan shape; posterior primary pinnules with up to 42 (more frequently 11–15) secondaries. Two to five tertiary pinnules, irregularly distributed on both proximal and distal secondary pinnules. Spines short (less than 0.14 mm), smooth or with small ornamentations. Polyps not known.

Holotype. Colony 62 cm in height, 39 cm wide, basal plate 10 mm in diameter, diameter of axis at the base 6.0 mm ( Fig. 15 a–b). Colony fan­shaped, branched up to the 6th order; lateral branches 45 ° to 90 ° with the axis, fan­shaped ( Fig. 15 a–b). Primary pinnules in 4–5 rows, in laterally alternating groups; length of anterior primaries 4–16 mm, length of posterior primaries 16–44 mm. Diameter of primaries 0.20–0.32 mm, second primary anteriors tending to be slenderer than the others; distance between adjacent (in the same row) primaries 1.6–2.0 mm ( Fig. 15 b). Six­seven primary pinnule cycles per centimeter of axis ( Fig. 15 b). Secondary pinnules along the whole length of primaries, mostly on the abpolypar side, some on the polypar, 5–11 per primary pinnule; up to 16 mm long, 0.12–0.28 mm in diameter; secondary pinnules elongated or short, independent of position (proximal or distal) ( Fig. 15 c). Tertiary pinnules usually on the abpolypar side of proximal and distal secondaries, irregularly distributed, frequently more than 5 per secondary pinnule; proximal tertiary pinnules from opposite posterior primaries occasionally can be fused ( Fig. 15 c). Spines conical, slightly compressed, smooth or with small papillae on their surfaces (both conditions are found in the same specimen); polypar and abpolypar spines slightly curved towards the distal end of pinnules; 6–8 irregular longitudinal rows (around the whole pinnule); polypar spines 0.05–0.10 mm tall, 0.03– 0.06 mm wide at base; abpolypar spines 0.03–0.07 mm tall, 0.01–0.04 mm wide at base; 4–5 spines per millimeter in a row; distance between adjacent spines in each row 0.15– 0.25 mm ( Fig. 15 d–h). Polyps badly damaged.

Variations Found in the Paratypes. Two fragments 11.8 and 13.0 cm tall, 6.8 and 1.6 cm wide, respectively, both without basal plates. Axis 1.2–1.5 mm in diameter near the base. Primary pinnules in 3–5 rows (usually 4); maximum length of anterior primaries 13– 16 mm (species average including holotype 9.20 ± 4.54 mm); maximum length of posterior primaries 27–44 mm (species average including holotype 26.00 ± 9.97 mm); diameter of primaries 0.20–0.50 mm. Secondary pinnules 5–42 per primary pinnule; maximum length 20 mm (average, including holotype, 12.20± 4.76 mm), 0.12–0.32 mm in diameter. Spines in 6–10 irregular longitudinal rows (around the whole pinnule); polypar spines 0.06–0.14 mm tall, 0.03–0.06 mm wide at base; abpolypar spines 0.03–0.06 mm tall, 0.01–0.05 mm wide at base; 4–10 spines per millimeter in a row; distance between adjacent spines in each row 0.14–0.26 mm. Polyps also badly damaged.

Etymology. The epithet thalassoros is used as a compound noun in apposition with the generic name (International Code of Zoological Nomenclature, 4th edition, 2000: article 31.2.1), derived from the words “thalassa” (Greek, sea) and “oros ” (Greek, mountain), in reference to the locations where the specimens were found.

Remarks. The arrangement and number of secondary and tertiary pinnules are very peculiar in T. thallassoros : up to 42 secondaries per primary; tertiary pinnules frequently more than 5 per secondary pinnule, irregularly distributed over proximal and distal secondaries. All the other species of Tanacetipathes have fewer secondaries per primary. The only exception is T. thamnea , in which this ratio is up to 25 per primary. However, T. thamnea has smaller and fewer tertiary pinnules, located only on the proximal secondaries, and taller polypar spines (up to 0.30 mm tall) than the new species. Also, no other species of Tanacetipathes has tertiary pinnules on the more distal secondaries as seen in T. thallassoros .

Distribution. Off Brazil: Trindade Island; Jaseur and Doga Ressa Banks (about 20 ° S—Fig. 1), in depths between 50 and 100 m.

Figures

FIGURE 15 — Tanacetipathes thalassoros n. sp. (MNRJ 3414) — Holotype: a—Colony; b—Pinnulate region of the colony; c—Transversal view, cycle of pinnules; d—Spines of the basal region of a pinnule; e— Polypar spine of the middle region of a pinnule, close view; f—Spines of the middle region of a pinnule; g—Spines of the apical region of a pinnule; h—Polypar (p) and abpolypar (ab) spines of the apical region of a pinnule, close view. Scale bars: a = 4.0 cm; b = 1.0 cm; c = 0.5 cm; d, f­g = 0.1 mm; e = 0.01 mm; h = 0.05 mm.