Tanacetipathes thamnea ( Warner, 1981 )

Lima, Manuela M., Cordeiro, Ralf T. S. & Perez, Carlos D., 2019, Black Corals (Anthozoa: Antipatharia) from the Southwestern Atlantic, Zootaxa 4692 (1), pp. 1-67 : 30-33

Tanacetipathes thamnea ( Warner, 1981)

Fig. 17 , 18

Antipathes thamnea Warner, 1981: 148–151 , figs. 2–4;

Tanacetipathes thamnea: Opresko, 2001 a: 358 –361, fig. 12c; 2001b: 349. fig. 11; Loiola & Castro, 2005: 19–23, fig. 11; Opresko & Sanchez, 2005: 503–504, fig. 14; Loiola, 2007: 256–257.

Type and type locality. BMNH 1979.6.1.1–6 (syntypes): Boca de Navios , Trinidade, 30 m.

Material examined. Brazil, off Rio Grande do Norte, Bacia Potiguar , 4º43’59.988”S, 36º25’59.999”W; depth 101–108 m. Programa de Caracterização da Bacia Potiguar, PETROBRAS, Date : 05/2011 ( MOUFPE–CNI 350 , 48 specimens) .

Diagnosis. Colonies mostly 20–40 cm high, but sometimes more than 50 cm, arising from holdfast of several cm 2. Branching irregular, usually in one plane and up to five orders. Branches pinnate, primary pinnules inclined distally through about 30º and arranged in four longitudinal rows. Pairs of primary pinnules arise alternately from sides of branches with about 2 mm between pairs on the same side. Members of pairs set at about 70º to each other, one member extends on polypar side of colony, the other extends on abpolypar side. Abpolypar pinnules 8–25 mm long, polypar pinnules 4–23 mm long. Angle between abpolypar rows about 115º and between polypar rows about 100º. Secondary pinnules usually numerous, 5–10 per 10 mm of primary pinnule, mostly arising from abpolypar side of primaries. Tertiary pinnules usually borne on inner edges of longer secondaries. Occasional specimens show reduced subpinnation with only one or two secondaries at base of abpolypar primaries. Spines smooth, sub-cylindrical, inclined distally through about 37º and arranged 1–2 spine lengths apart in alternating longitudinal rows: 6–8 rows at tips of pinnules. Spines 0.05–0.09 mm long (mean = 0.11, n = 50) on abpolypar side of pinnules and 0.09–0.21 mm (mean = 0.17, n = 50) on polypar side. Difference in length between polypar and abpolypar spines diminishes towards tips of pinnules. Spines on major branches oftem longer and more closely set than on pinnules. Polyps 0.52–0.64 mm long, arranged in rows 10–17 per cm along one side of pinnules. Tentacles 0.3–0.7 mm in live material and a third to half shorter in relaxed fixed material ( Warner, 1981).

Description of Brazilian specimens. Colonies with pinnules in bottlebrush pattern, monopodial, unbranched or branched up to 2th order ( Fig. 17a ). Specimens 8 and 25 cm tall; primary pinnules usually arranged in four rows. Posterior primary pinnules longer than the anterior ones, length of posterior primary pinnules between 10 and 18 mm, but usually 14 to 16 mm; Length of anterior primary pinnules between 3 and 12 mm, but usually 9 to 11 mm. Secondary pinnules inclined toward the distal end of the primary pinnule. Number of secondary pinnules per posterior primary usually 10–15, but ranging between 7 and 20. ( Fig. 17 b–c). Length of secondary pinnules mainly between 2 and 12 mm. Tertiary pinnules scarce, usually more abundant on the abpolypar side of the posterior primary pinnule, ranging from 1 to 4 tertiaries per posterior secondary pinnule. Angle between posterior primary pinnule and anterior primary pinnule (polypar and abpolypar sides, respectively) between 55° and 70°. Angle between two anterior primary pinnules or two posterior primary pinnules (polypar/polypar sides or abpolypar/abpolypar sides, respectively) between 115° and 130°. The abpolypar side of the posterior primary pinnule have more secondary pinnules compared to the polypar side. Spines smooth or with few papillae and slightly inclined toward the distal end of the pinnule or branch ( Fig. 17d ). Distance between spines mainly between 0.12 mm and 0.18 mm. Size of the polypar spines between 0.1 mm and 0.2 mm; Abpolypar spines with size between 0.036 mm and 0.084 mm. Polyps not present (lost tissue).

Remarks. The material described here is very similar to the type series, differing only in some characteristics.

The samples from the Potiguar Basin are slightly smaller in terms of the total length of the stem (8 and 25 cm) compared to the syntypes described in Warner (1981), which have mean stem lengths between 20 and 40 cm. Warner (1981) also notes that the number of secondary pinnules per posterior primary is between 5 to 10 per 10 mm of primary pinnule, whereas it is also mentioned that a pinnule can reach up to 25 mm, and the number of secondaries per posterior primary can reach up to 25. We found colonies with more than 18 secondary pinnules per primary, the maximum number reported by Loiola & Castro (2005). In regard to the number of tertiary pinnules, Loiola & Castro (2005) reported the presence of one or two posterior tertiary pinnules per posterior secondary. In the work of Warner (1981) only the presence of a few tertiary pinnules inclined distally is described. The material studied in the present work presents from 1 to 4 tertiary pinnules per secondary, but four secondary pinnules is a rare feature in the samples, and one or two are more common, as described in Loiola & Castro (2005). The density of the primary pinnules is higher mainly in the more distal regions of the colonies, as well as in larger colonies. This is the first record of the species for the Potiguar Basin RN, Brazil. The association between T. thamnea and polychaetes of the species Parahololepidella greeffi is also recorded here.

Distribution. Atlantic Ocean: Boca de Navios, NW Trinidad ( Warner, 1981), Gulf of México ( Opresko, 2009) and Southwestern Atlantic, Brazil, off Rio Grande do Norte, Bacia Potiguar (this work), Bahia ( Loiola & Castro, 2005) and Cadeia Vitória Trindade ( Loiola & Castro, 2005) ( Fig. 18 ); from 30 m ( Warner, 1981) to 558 m depths ( Castro et al., 2006).

Figures

FIGURE 17. MOUFPE-CNI 350: Tanacetipathes thamnea (Warner, 1981). a—Corallum morphology; b—Cross section showing a cycle of pinnules; c—Cross section 158 showing one cycle of pinnules; d—Organization of spines (Abpolypar spines slightly degraded due to the specimen collection process).

FIGURE 18. Geographic distribution of Tanacetipathes thamnea (Warner, 1981). Yellow circles: records extracted from the literature (Warner, 1981; Loiola & Castro, 2005; Opresko, 2009) and based on Ocean Biogeographic Information System (OBIS). Red circle: record made in the present work.