Cnidaria: Antipatharia) from the Northern Gulf of Mexico Dennis M

Northeast Gulf Science Volume 12 Article 2 Number 2 Number 2 10-1992 New Species of Black Coral (Cnidaria: Antipatharia) from the Northern Gulf of Mexico Dennis M. Opresko Oak Ridge National Laboratory Stephen D. Cairns Smithsonian Institution DOI: 10.18785/negs.1202.02 Follow this and additional works at: https://aquila.usm.edu/goms Recommended Citation Opresko, D. M. and S. D. Cairns. 1992. New Species of Black Coral (Cnidaria: Antipatharia) from the Northern Gulf of Mexico. Northeast Gulf Science 12 (2). Retrieved from https://aquila.usm.edu/goms/vol12/iss2/2 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf of Mexico Science by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. Opresko and Cairns: New Species of Black Coral (Cnidaria: Antipatharia) from the Nort Northeast Gulf Science Vol. 12, No. 2 October 1992 p. 93·97 NEW SPECIES OF BLACK CORAL (Cnidaria: Antipatharia) FROM THE NORTHERN GULF OF MEXICO Dennis M. Opresko Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37930 and Stephen D. Cairns Department of Invertebrate Zoology, Smithsonian Institution, Washington, D.C. 20560 ABSTRACT: A new species of black coral, Antlpathes expansa (Cnldarla: Antlpatharla) from the. northeastern Gulf of Mexico Is described. The species Is distinguished from other westem Atlantic flabellate species by having large, conical, tuberculate spines. A. expansa resembles the lndo·Paclflc species Antlpathes cancellata (Brook) but differs In having a non·retlculate corallum and slightly larger polyps. In September, 1989 the second front and posterior sides of corallum. Ter author participated in a cruise of the minal branchlets short, most 5 • 9 mm Johnson-Sea-Link I research submersible long and 0.4- 0.6 mm in diameter (0.2- 0.3 (stations 2582 - 2595) off the southeastern mm excluding spines), arranged bilateral coast of Louisiana. While the purpose of ly, but not regularly alternate or opposite; the cruise was to investigate the geomor adjacent branch lets on same or opposite phology of authigenic carbonate hard sides of branch 0.1 - 2.0 mm apart (most grounds associated with oil deposits, ly 0.5 - 1.5 mm apart), and arising from all many benthic invertebrates were also col lower order ramifications including stem. lected from depths of 183 - 353 m and Branchlets occasionally overlapping and later deposited at the National Museum anastomosing. of Natural History. Among the specimens Spines relatively long, conical, and collected were eight species of tuberculate on distal one-third to one-half Antipatharia, including one previously of surface; unequal in size around cir undescribed species. This new species is cumference of branch axis (Fig. 2); described herein. The other seven polypar spines on branchlets usually species, as well as the azooxanthellate 0.18-0.20 mm long (range: 0.14-0.23 mm), Scleractinia, collected on that cruise will 0.04 - 0.05 mm wide at center; abpolypar be reported in a separate paper (Cairns, spines mostly 0.09 · 0.13 mm long. Spines Opresko, Hopkins, and Schroeder, in on branchlets spaced about 0.28 mm prep.). apart (4-5 per mm) and in 3-4 longitudinal rows (complete spines including base) as Material Examined seen from a lateral view (with a total of JSL-1-2585, 27°44.62' N, 91 °07.9°W 6 rows around the circumference of the (off southeastern Louisiana), 129- 144m, axis). USN M 88340, holotype. Polyps in a single row, about 0.8 mm in transverse diameter (from proximal Diagnosis side of proximal lateral tentacles to distal Corallum small, generally flabellate (Fig. side of distal lateral tentacles); inter- 1a), but not strictly in one plane; occa- polypar space betwen adjacent polyps sional short branches extending out of variable, mostly 0.3 · 0.4 mm resulting in 93 Published by The Aquila Digital Community, 1991 1 Gulf of Mexico Science, Vol. 12 [1991], No. 2, Art. 2 94 Opresko, D. M. and S. D. Cairns Figure 1. Antipathes expansa: a, Holotype colony, x 1.0; b, Branch let polyps, x 6.0; c, Branch let spine x 385. https://aquila.usm.edu/goms/vol12/iss2/2 2 DOI: 10.18785/negs.1202.02 Opresko and Cairns: New Species of Black Coral (Cnidaria: Antipatharia) from the Nort New species of Black Coral 95 Figure 2. Stereo view of branchlet segment showing polypar spines on right and abpolypar spines to left, x 105. 8 or 9 polyps per em (Fig 1b). not as crowded as in the center, the mutual distance ranging up to 9 mm. The Description average length of the unbranched bran The holotype is a small colony about chlets is 8.5 mm (n =8) and the maximum 9.5 em high and 13 em wide. The diameter .length is 12 mm. of the stem at the base is 1.7 mm. Larger Spines are relatively tall (polypar branches are 0.9 - 1.3 mm in diameter at spines up to 0.23 mm, abpolypar spines their point of insertion on the stem, spac up to 0.13 mm), conical or very slightly ed 3-5 mm apart (with smaller branch lets compressed, and flared at the base in occurring in between), and extend % to both proximal and distal directions (Figs. % of the height of the corallum. Most of 1c, 2). On the smallest branchlets, and the smaller branchlets are relatively particularly near the tips of the straight, some are slightly curved; the branch lets, spines are smaller (0.06 · 0.12 distal branch angle (angle formed by the mm for branchlet diameters of 0.12 · 0.18 distal or upper side of a branch and the mm) and more triangular than those on adjacent lower order branch from which other parts of the corallum. Both polypar it arises) is generally 60°- 75°, but it can and abpolypar spines have small rounded be as small as 45° and as great as 90°. protuberances scattered over their upper Branchlets are arranged bilaterally, but surface (Fig. 1c); however, abpolypar do not follow a regular alternate or op spines tend to be less tuberculate than posite pattern. They are spaced 0.1 · 2.0 the polypar spines. In general, spines are mm apart on the same or opposite sides slightly inclined distally, but some are of the branches. On the outer edges of almost horizontal, particularly along their the corallum, the terminal branches are distal edge. Published by The Aquila Digital Community, 1991 3 Gulf of Mexico Science, Vol. 12 [1991], No. 2, Art. 2 96 Opresko, D. M. and S. D. Cairns The density of spines on the stem does not say, nor does his illustration in and larger branches does not appear to dicate, whether the abpolypar spines of be appreciably different from that on the A. cancellata are distinctly smaller than branchlets; 3 or 4 very irregular rows of the polypar spines, as in A. expansa; complete spines can be seen from one however, it is quite likely that they are. A. view, and there are 4- 5 spines per mm in cancellata differs from A. expansa in that each row. its corallum lacks major branches, is Polyps are situated primarily on one more densely branched (branchlets most side of the corallum and arranged in a ly 1 mm or less apart), and is extensively single row along the branch lets, although anastomosing. In addition, the polyps are they occasionally occur on the opposite smaller (about 0.55- 0.65 mm in side of the corallum, particularly on larger transverse diameter, based on Brook's il branches and stem. In a well-preserved lustration), with an interpolypar space of state, tentacles are up to 0.5 mm long. 0.3- 0.4 mm or more, resulting in 9- 11 The peristome is about 0.4 mm wide in polyps per em along the branch lets. A. ex transverse diameter and equally wide or pansa also resembles the Indo-Pacific slightly smaller in sagittal diameter. species A. reticulata van Pesch, 1914, a Polyps that occur on the stem are equal flabellate species with long, tuberculate in size to those on the branch lets (0.8 mm spines. In that species, the spines are in transverse diameter). longer (up to 0,.27 mm), narrower (about 0.03 mm near the center), with relatively Remarks fewer knobby protuberances, and not In superficial appearance this new uniform in length on the polyp side of species resembles a small colony of axis. Aphanipathes thyoides (Pourtales, 1880); Considering only the morphology of however, it differs in that its spines are the spines and polyps and not that of the not reduced in size below the center of corallum, it eventually may be shown that the polyps and not more developed A. expansa is related to the western around the outer edges of the polyps, as Atlantic species A. pedata Gray and A. is in the case in A. thyoides. It also dif salix Pourtales. Both of these species fers in spination from the two common have relatively tall, conical, tuberculate flabellate species known from the spines and small distant polyps. In western Atlantic, Antipathes atlantica contrast, in both of the latter species the Gray, 1857 and A. gracilis Gray, 1860, in corallum is densely branched in all direc that the spines of these two species are tions with straight and slightly curved small (mostly 0.04-0.10 mm on the ascending branches and branchlets. smallest branches), triangular, compress ed, and smooth. In A. expansa the spines Etymology are up to 0.23 mm tall on branchlets, The name expansa (from the Latin conical, and tuberculate.

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