Tanacetipathes barbadensis ( Brook, 1889 )

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 : 28-30

Tanacetipathes barbadensis ( Brook, 1889)

Figs. 15 , 16

Aphanipathes barbadensis Brook, 1889: 128 , Pl. II, fig. 10; Pl. XI, fig. 4; Warner, 1981: 151–152, figs. 8–9;

Tanacetipathes barbadensis: Opresko 2001 a: 358 –361, figs. 11b e 12a; 2001b: 349; Loiola & Castro, 2005: 5–10, figs 4–5; Opresko & Sanchez 2005: 502–503, fig 13; Loiola, 2007: 256–257;

Antipathes hirta: Echeverría, 2002: 1072–1075 , figs. 5–7, tabs. 2–3 [non Tanacetipathes hirta ( Gray, 1857) ].

Type and type locality. BMNH 1886.6 .14.4.5 (holotype), Barbados, depth unknown .

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 349 , 15 specimens) .

Diagnosis. Corallum unbranched, sparsely branched, or branched to the 5th order or more; stem and branches pinnulate in a bottlebrush pattern, with up to three orders of pinnules. Primary pinnules in 4–5 (rarely 6) rows. The lower pinnules bear one or two short, simple or forked, secondary processes which are turned downwards, and situated near the base of each pinnule. The stem is 30 cm long, and the pinnules vary from 1.3 to 2.5 cm, with an average length of about 2 cm. The spines are strong, elongate, much compressed, and arranged in irregular, steep, dextrorse spirals as well as in longitudinal rows. Polypar spines mostly 0.20–0.25 mm tall, but up 0.30 mm from midpoint of base to apex, 0.03–0.08 mm wide at the base; abpolypar spines smaller, slenderer, and more distally inclined than polypar spines, 0.03–0.15 mm tall, 0.01–0.06 mm wide at the base. Six rows may be counted from one aspect of a pinnule, the members of a row being about one length apart. Polyps 0.5–0.8 mm in transverse diameter, 9–14 per centimeter, in 1 or 2 rows, with small spaces between adjacent ones (adapted from Brook, 1889 and Loiola & Castro, 2005).

Description of Brazilian specimens. Corallum monopodial unbranched or branched to the 1st order, with branches arising near the base ( Fig. 15a ). Stem and branches in a bottlebrush pattern, with pinnules in up to 6 rows. Secondary pinnules inclined towards the distal end of the primary posterior pinnules, anterior primary pinnules rarely exhibiting subpinnulation. One to four secondary pinnules per posterior primary pinnule; but usually with only 2 or 3 long secondary pinnules at the proximal end of the posterior primary pinnule ( Fig. 15 b–c). Tertiary pinnules, if present, no more than three, close to the proximal end of the secondary pinnule. Length of posterior primary pinnules variable, but generally measuring between 10 mm and 26 mm. Length of anterior primary pinnules between 3 and 12 mm. Secondary pinnules between 2 and 12 mm in length, most often close to 6 mm. Spines smooth and conical, arranged in 5 to 6 rows as viewed with an Optical Microscope (M.O.) ( Fig. 15d ). Polypar spines usually near 0.144 mm, but up to 0.216 mm; abpolypar spines with ranging from 0.048 mm to 0.084 mm. Distance between spines in a row 0.12–0.18 mm, with approximately 4 spines per millimeter in each row. Polyps not present (tissue lost).

Remarks. Tanacetipathes barbadensis ( Brook, 1889) resembles Tanacetipathes tanacetum ( Pourtalès, 1880) in the pattern of pinnulation and morphometry of the spines. Both species can be distinguished mainly by the number of secondary pinnules per posterior primary. Tanacetipathes tanacetum presents from 3 to 7, while T. barbadensis usually presents 3 or less than 3 secondary ones per posterior primary ( Loiola & Castro, 2005). The specimens of T. barbadensis studied here have primary pinnules on the lower portion of the stem shorter than those reported for the species by other investigators (up to 30 mm long in the Potiguar Basin material, compared to 60 mm reported in Opresko & Sanchez, 2005). However, the samples described in Loiola & Castro (2005), also coming from the Brazilian continental shelf, presented posterior primary pinnules up to 45 mm in length. Thus, the smaller size of the pinnules may be indicative of an intraspecific variation of the Brazilian specimens. In the western Atlantic, Tanacetipathes barbadensis has the shallowest depth distribution among species of the genus, with a bathymetric interval between 8 and 100 m. The present work is the first record of the species for the Potiguar Basin, Rio Grande do Norte. The samples studied here hosted a species of polychaete, Parahololepidella greeffi (Augener, 1918) . This species, belonging to the family Polynoidae , was also observed in association with all the specimens of the Genus Tanacetipathes described in the present work. Previously, P. greeffi had been recorded only in association with Tanacetipathes spinescens ( Gray, 1857) ( Britayev et al., 2014) . The worms were found mainly on the main axis of the coral, and had a coloration very close to that of the antipatharians. However, no changes were seen in the skeletal morphology of the corals that could be interpreted as being induced by the polychaetes.

Distribution. Atlantic Ocean: off Barbados ( Brook, 1889); Boca de Navios, NW Trinidad ( Warner, 1981); Gulf of Mexico ( Opresko, 2009) and Southwestern Atlantic, Brazil, off Rio Grande do Norte, Bacia Potiguar (this work) and Abrolhos Bank ( Loiola & Castro 2005) ( Fig. 16 ); from 8 m ( Loiola & Castro, 2005) to 346 m depths ( Opresko, 2009).

Figures

FIGURE 15. MOUFPE-CNI 349: Tanacetipathes barbadensis (Brook, 1889). a—146 Corallum morphology; b—Cross section showing one cycle of pinnules; c—Cross section showing one cycle of pinnules; d—Organization of spines.

FIGURE 16. Geographic distribution Tanacetipathes barbadensis (Brook, 1889). Yellow circles: records extracted from the literature (Brook, 1889; Warner, 1981; Loiola & Castro, 2005; Opresko, 2009) and based on Ocean Biogeographic Information System (OBIS). Red circle: record made in the present work.