Tanacetipathes thamnea ( Warner, 1981 )

Loiola, Livia L. & Castro, Clovis B., 2005, Tanacetipathes Opresko, 2001 (Cnidaria: Antipatharia: Myriopathidae) from Brazil, including two new species, Zootaxa 1081, pp. 1-31 : 19-22

Tanacetipathes thamnea ( Warner, 1981)

Figure 11

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

Tanacetipathes thamnea: Opresko, 2001a: 358 –361, Fig. 12 c; 2001b: 349. Figure 11 Tanacetipathes paula Pérez, Costa & Opresko, 2005: 8 –12, figs. 5–8.

Material examined. Brazil: off Salvador, 13 ° 06’ S, 0 38 ° 25’ W, about 50m, REVIZEE Bahia­1 Sta. #D­0360 ( MNRJ 3411: 1 colony); off Caravelas, 18 ° 39’ S, 0 37 ° 52’ W, 65m, REVIZEE Central V Sta. #17 ( MNRJ 4864: 2 colonies); off São Matheus, 20 ° 05’ S, 0 37 ° 28’ W, 98m, REVIZEE Central I ( MNRJ 3128: 2 colonies); Jaseur Bank, 20 ° 36’ S, 0 35 ° 51’ W, about 100m, REVIZEE Central II ( MNRJ 5824, MNRJ 5138: 11 colonies); off Vitória: 20 ° 40’ S, 0 34 ° 35’ W, 100m, REVIZEE Central II Sta. #46, ( MNRJ 5139: 4 colonies); 108m, REVIZEE Central V Sta. #45 ( MNRJ 4666, MNRJ 5140, MNRJ 5141: 22 colonies); 20 ° 44’ S, 0 31 ° 49’ W, 80m, REVIZEE Central V Sta. #42 ( MNRJ 4670: 2 colonies); Almirante Saldanha Bank, 22 ° 23’ S, 0 37 ° 35’ W, 105m, REVIZEE Central I Sta. #7 ( MNRJ 3011: 2 colonies); 103m, REVIZEE Central VI ( MNRJ 5142, MNRJ 5145: 4 colonies); 240m ( MNRJ 5143, MNRJ 5144: 5 colonies).

Diagnosis. Colonies unbranched, or branching irregularly, usually in a single plane, up to 5th order ( Fig. 11 a, b). Branches pinnulate, pinnules straight or nearly so; pinnules projecting at right angles transverse to the branch or slightly inclined towards the distal end of the branch; 4–6 rows of primary pinnules. Maximum length of anterior primary pinnules 4–23 mm (average in Brazilian specimens 9.47 ± 3.55 mm), maximum length of posterior primaries 8–25 mm long (average in Brazilian specimens 15.57 ± 3.45 mm). Secondary pinnules up to 14 mm long, (maximum length average 8.06 ± 2.20 mm); up to 7 (more frequently 2–3) per anterior primary and up to 18 (more frequently 8–10) per posterior primary; secondaries on abpolypar (mostly) and polypar sides of the primary pinnules ( Fig. 11 c). Tertiary pinnules usually on the abpolypar side of the more elongate secondaries ( Fig. 11 c). Occasionally, primary pinnules with only one or two secondaries, near the proximal end of posterior primaries. Spines smooth or with small ornamentations (both conditions found in the same specimen on Brazilian material), subcylindrical, perpendicular or inclined distally; adjacent spines 1–2 spine lengths apart, arranged in alternate longitudinal rows; 6–8 rows on the distal portions of the pinnules. Polypar spines 0.09–0.30 mm tall, abpolypar spines 0.02–0.21 mm tall ( Fig. 11 d–j). Polyps 0.52–0.64 mm in transverse diameter, arranged in single rows, 10–17 per centimeter along one side of the pinnules. Tentacles 0.3–0.7 mm long in fresh material, and 1/3 to 1/2 smaller in fixed material (emended from Warner, 1981).

Remarks. The Brazilian material is similar to type specimen of Tanacetipathes thamnea Warner, 1981 , except the former colonies are branched only up to the 1st order, while the latter, up to the 5th order. Despite this difference, the branches in the type and in Brazilian specimens suggest colonies with similar appearance (see Warner, 1981: Fig. 2 ). The range in the height of polypar spines is also different: in Brazilian colonies 0.10–0.30 mm, and in the type specimen 0.09–0.21 mm. However, species of Tanacetipathes are known for showing great variations in the size of the spines, as described for T. tanacetum by Opresko (1972). Warner’s description indicates spines inclined distally in angles up to about 37°, but his illustration ( Warner, 1981: Fig. 3 ) shows such a condition only on the distal end of the pinnules. Polypar spines from the proximal end of a pinnule were either perpendicular or slightly inclined distally ( Warner, 1981: Fig. 3 ). On our specimens, the majority of proximal polypar spines are perpendicular to the axis; spines of distal portions of the pinnules are more inclined than those of proximal regions, as occurs in most species of this genus. Despite these minor discrepancies, the material herein studied was identified as T. thamnea especially due to the arrangement of secondary pinnules, unique among Tanacetipathes species. This is the first record of T. thamnea in the South Atlantic, in depths up to 240 m. The diagnosis given by Warner (1981) was emended to include variations observed in the Brazilian material, especially concerning the branching pattern, distribution of the secondary pinnules, and spines height and inclination.

We hereby propose the synonymy of Tanacetipathes paula Pérez, Costa & Opresko, 2005 , with T. thamnea . The main characters distinguishing these species would be a “more extensive subpinnulation” and “typically monopodial or only sparsely branched somewhat in a single plane” in T. thamnea ( Pérez et al., 2005) . Also, primary pinnules would be longer in T. thamnea ( Tab. 2 ).

Branching pattern unbranched or up to 5th order, usually branched up to the 6th order

in a single plane

Colonies 49 colonies, 5.2–59 cm high; largest Single colony, 83 cm high; without

specimen (59 cm) without pinnulation pinnulation near (> 25 cm) basis

near (11.5 cm) basis

However, only seven Brazilian colonies (out of 49 studied) have primary pinnules longer than 1.9 mm. The number of secondaries per primary pinnule would also be different ( Tab. 2 ). Nevertheless, an examination of the holotype of T. paula showed instances where there are a greater number of secondaries per primary. Fourteen Brazilian colonies (out of 49 studied) have only up to 9 secondaries per primary. Moreover, we evaluated diagnostic characters of T. thamnea (Brazilian specimens) and found a continuous variation in the length of primary pinnules ( Fig. 12 ) and in the number of secondaries per posterior primary pinnule ( Fig. 13 ). Also, we found significant correlations among several characteristics ( Tab. 3 ). A multiple linear regression of colony size and mean length of posterior primaries (independent variables) against number of secondaries per primary (dependent variable) showed significant results ( Tab. 4). Interestingly, the number of secondaries per primary showed a significant correlation with colony size, but length of posterior primaries did not ( Tab. 3 ). This suggests the latter character may vary due to environmental forces instead of being inherent to colony growth. Overall, it is demonstrated that differential characters of T. paula fit well within the range of variation of T. thamnea .

Variable 1 Variable 2 r P Global R = 0.66519145; F(2,46) = 18.254; p=0.000001

Independent variables Beta P

Colony size 0,576572 0,000005*

Mean length of posterior primary pinnules 0,415060 0,000511* Distribution. Atlantic: Boca de Navios, NW Trinidad ( Warner, 1981); Brazil: on the continental shelf and oceanic seamounts off northeastern and eastern Brazil (between 13º– 22º S—Fig. 1).

Figures

FIGURE 2 — Schematic draw of a colony, with some of the main terms used on descriptions and diagnosis of Tanacetipathes species.

FIGURE 3 — Transversal view of a branch, with the main terms used in the descriptions and diagnosis of the species of Tanacetipathes: P = polypar side; A = abpolypar side; 1 = first anterior primary pinnule; 2 = second anterior primary pinnule; 3 = posterior primary pinnule; 4 = polypar secondary pinnule; 5 = abpolypar secondary pinnule; 6 = polypar tertiary pinnule; 7 = abpolypar tertiary pinnule; 8 = polypar spines; 9 = abpolypar spines.

FIGURE 11 — Tanacetipathes thamnea (Warner, 1981) (MNRJ 4669): a—Colony; b—Pinnulate region of the colony; c—Transversal view, cycle of pinnules; d—Polypar (p) and abpolypar (ab) spines of the apical region of a pinnule, close view; e—Spines of the basal region of a pinnule; f—Spines of the middle region of a pinnule; g—Spines of the apical region of a pinnule; h—Polypar spines of the middle region of a pinnule, close view; i—Polypar spines of the apical region of a pinnule, close view; j—Abpolypar spines of the middle region of a pinnule, close view. Scale bars: a = 2.0 cm; b = 1.0 cm; c = 0.3 cm; d, h – i = 0.05 mm; e – g = 0.2 mm; j = 0.02.

FIGURE 12 — Length (mm) of posterior primary pinnules (mean ± standard deviation) in 49 colonies of Tanacetipathes thamnea from Brazil.

FIGURE 13 — Maximum number of secondary pinnules per posterior primary pinnule in 49 colonies of Tanacetipathes thamnea from Brazil.

Tables

TABLE 2 – Comparison of diagnostic characters of Tanacetipathes thamnea and T. paula.

Character	T. thamnea	T. paula
Length of primary pinnules	4–25 mm	up to 19 mm
Location of secondaries	polypar and abpolypar primaries	polypar and abpolypar primaries
Number of secondaries per primary	anterior up to 7 (more frequently 2–3); posterior up to 18 (more frequently 8– 10) [5–10 per 10 mm – Warner, 1981]	3–9

TABLE 3 — Pearson’s r product­moment correlation analysis of characteristics of specimens of Tanacetipathes thamnea studied. P = probability of rejection of the null hypothesis (there is not a relation between the tested variables). Number of specimens = 49. An asterisk indicates significant r values.

maximum number of secondary pinnules per posterior primary pinnule	colony size	0.522606	0.000117*
maximum number of secondary pinnules per posterior primary pinnule	mean length of posterior primary pinnules	0.340095	0.016804*
maximum number of secondary pinnules per posterior primary pinnule	maximum length of poste­ rior primary pinnules	0.285860	0.046467*
mean length of posterior primary pinnules	colony size	­0.050976	0.727956
maximum length of posterior primary pinnules	colony size	­0.130018	0.373239