Chrysopathes oligocrada, Loiola, Laia, 2008

Loiola, Laia, 2008, Two New Species of Chrysopathes (Cnidaria: Anthozoa: Antipatharia) from the Western Atlantic, Zootaxa 1707, pp. 49-59 : 51-54

Chrysopathes oligocrada new species ( Figs. 1–2 )

Chrysopathes sp. Opresko, 2005; de Laia Loiola, 2007 (in part).

Holotype. USNM 1104648, Gulf of Mexico, off the Yucatan Peninsula, 21°17’ N, 86°15’W, 225–250 fm (411–457 m), March 14, 1968, R/V Pillsbury sta. 587.

Other material. Paratypes ( USNM 1104649), same locality data as holotype (4 specimens). Paratypes ( UMML 7.1157), same locality data as holotype (27 specimens). Paratype, ( MNRJ 4627), Brazil, off Salvador, 13°23’S, 38°37’W, 761 m, REVIZEE Bahia-2 sta. E0499 (1 specimen).

Diagnosis. Corallum branched primarily in single plane; usually only one or two orders of branching (three orders in some colonies). Arrangement of primary pinnules as described for genus; density 18–21 per cm. Lateral pinnules mostly 7–8 mm long (to 2 cm); slightly to distinctly longer than anterior and posterior pinnules. Anteriormost primary pinnules usually with one secondary pinnule arising near base, and only on outer side. Posterior primary pinnules occasionally with single secondary pinnule. Lateral primary pinnules usually simple, very rarely with single subpinnule. Tertiary pinnules absent.

Spines simple, smooth, <0.07 mm. Spines on middle and lower parts of pinnules conical and slightly inclined distally in side view; those on distal part of pinnules appearing more strongly inclined distally and with abaxial side extending basally down axis. Abaxial side of distal spines generally 2–4 times longer than adaxial side. Polyps 1.6 to 2.4 mm in transverse diameter; in single row with about three polyps per centimeter.

Description of holotype. Height 16.5 cm high, width 15 cm ( Fig. 1 A); lower end of stem about 1.2 mm in diameter; unpinnulated part of stem 4 cm; basal plate missing. Corallum mostly with first and second order branching (one third order branch); overall branching planar with branches arising from outer sides of lower order branches. Stem extending to top of corallum; with eight branches, mostly 1.5–2 cm apart (eight per 10 cm). Largest branch 8 cm long (broken at distal end); basal diameter 0.9 mm. Branches extend upward and outward slightly (distal angle 60–70º), but curve vertically.

Primary pinnules about 3 mm apart in each row, resulting in four pinnules per centimeter in each row. Total of 21 primary pinnules per cm (18 per cm on stem and some larger branches). Lateral primary pinnules ( Fig. 1 B) usually 7–8 mm long (to 12 mm); maximum diameter 0.2 mm near base. Anterior and posterior primary pinnules to 6 mm long. Pinnules thin and very narrow walled. Distal angle of primary pinnules and branch 60–70°.

Single secondary pinnule on one or both anterior primary pinnules ( Figs. 1 B and 2E), usually absent on lateral or posterior primary pinnules except on stem. Secondary pinnules arise about 0.5 mm from base of anterior primary on outer side and extend laterally or slightly basally; secondaries on anterior primaries of opposite rows directed away from each other; secondaries on posterior primaries, when present, follow similar pattern. Secondary pinnules mostly 3–4 mm long, but some slightly longer than anterior pinnules.

Spines conical in lateral view and inclined distally on middle and lower parts of pinnules ( Figs. 2 B–D); increasingly more inclined distally towards tip of pinnule with abaxial edge flared out basally ( Fig. 2 A); abaxial edge of distal spines to four times longer than adaxial edge (e.g., 0.1 mm vs. 0.025 mm). Height of pinnular spines (from midpoint of base to apex) 0.05–0.07 mm on distal sections and 0.03–0.04 mm on middle and basal sections. Spines generally subequal in size around circumference of axis. Spines on stem and larger branches 0.03 mm. Number of rows of spines (visible in lateral view) increasing from three to four near tip to five or six along lower sections of pinnules. Distance between spines in the same row 0.15–0.3 mm. Number of rows and density of spines on larger branches and stem similar to that on pinnules.

Polyps present on some branches but in poor condition; mostly 1.6–2.0 mm in transverse diameter (to 2.4 mm) as measured from distal edge of distal lateral tentacles to proximal edge of proximal lateral tentacles. Polyp density three per centimeter. Polyps on primary pinnules arranged in single row on upper, lateral, or rarely on lower side of pinnule relative to direction of branch. Polyps on subpinnules commonly found on side facing distal section of anterior primary pinnule; thus, polyps on subpinnules in opposite rows face in same general direction.

Description of paratypes. Other specimens from Pillsbury sta. 587 similar to holotype in planar growth form of corallum; height to 20 cm, width to 15 cm, basal stem diameter to 1 mm; usually with two orders of branches. Subpinnulation typically consisting of single secondary pinnule on each anterior primary pinnule; single secondary pinnule on some posterior primaries but usually only on larger branches and stem; secondary pinnules rarely present on lateral primaries. Density of primary pinnules 18–21 per cm. Lateral primary pinnules usually only slightly longer than anterior and posterior ones; but to three or four times longer (to 2 cm). Spines on distal section of pinnules to 0.07 mm tall; 0.16–0.25 mm apart in each row; with three or four rows visible in lateral view. Polyps in poor condition; mostly 1.6 to 2.0 mm in transverse diameter.

Paratype from Brazil (MNRJ 4627) with similar pinnular density (18–21 per cm) and with only one subpinnule per primary. Colony 10.0 cm by 4.0 cm; unpinnulated section of stem 2.0 cm, basal stem diameter 0.5 mm. Lateral primary pinnules 11–17 mm long and 1.8–3.0 mm apart in each row; anterior and posterior primaries 4–9 mm; secondaries 3.0–8.0 mm long; tertiary pinnules not present. Distal pinnular spines 0.04–0.05 mm; middle and basal ones 0.02–0.03 mm; spines on stem and larger branches rarely more than 0.02 mm. Five or six irregular rows of spines visible in lateral view. Distance between spines in one row 0.12–0.27 mm; three to four spines per millimeter in each row. Polyps absent.

Comparisons. The species is similar to Chrysopathes formosa Opresko 2003 in the overall growth form of the corallum, and in the small number of secondary pinnules, but differs from that species in several ways. In C. formosa the pinnules in general are slightly longer and are spaced somewhat further apart (15–18 per cm for all rows) than in C. oligocrada . The most significant difference, however, is in the size of the spines. In C. formosa the pinnular spines are mostly 0.08–0.12 mm (to 0.16 mm tall), whereas those in C. oligocrada are not more than 0.07 mm and often less.

Etymology. The specific name is derived from the Greek oligo (few) and crada (twig), in reference to the scarcity of subpinnulation.

Distribution. The species is known from off the coast of Yucatan, Mexico at a depth of 411–457 m and from off the coast of Brazil at a depth of 761 m.

Figures

FIGURE 1. Chrysopathes oligocrada, new species, holotype, USNM 1104648: A, entire corallum; B, cross section of branch showing pinnules and subpinnules.

FIGURE 2. Chrysopathes oligocrada new species, holotype, USNM 1104648: A – D, spines on sections of pinnules, scale bars 0.1 mm; E, cross section of branch showing arrangement of pinnules and subpinnules