Pacifigorgia stenobrochis ( Valenciennes, 1846 )

Breedy, Odalisca & Guzman, Hector M., 2003, Octocorals from Costa Rica: The genus Pacifigorgia (Coelenterata: Octocorallia: Gorgoniidae), Zootaxa 281 (1), pp. 1-60 : 50-52

Pacifigorgia stenobrochis ( Valenciennes, 1846)

( Plate 13 , Fig. 12 )

Synonymy. See Breedy & Guzman 2002: 833.

Material examined.

Holotype: MNHN OCT.S.2000.03, (?) New Zealand, M. A. du Petit­Thouars, Voyage Autour du Monde, La Venus, 1839.

Other material: UCR 477, Dominical, 13 m, J. Cortés, 23 February 1984; UCR 498, Caño Island, 22 m, H. Guzman, 11 February 1984; UCR 771, Montezuma, Costa Rica, 10 m, L. Mena, 25 April 1993; UCR 831, Los Pedrones, Cabo Blanco, Costa Rica, 7 m, L. Mena, 18 April, 1994; UCR 905, Archipelago Murciélago, J. Jiménez, October 1997; UCR 962, 1005(2) Punta Matapalito, Osa Peninsula, 18 m, O. Breedy and A. Fonseca, 15 March 1998; UCR 963, Caño Island, 18 m, O. Breedy, 26 April 1997; UCR 1004 Caño Island, 20 m, O. Breedy and A. Fonseca, 13 November 1997; UCR 1020, Bajo Viuda, Ballena Marine National Park, 20 m, O. Breedy, 26 April 2002.

Diagnosis. Colonies large, up to 200 mm in height and 580 mm in width, and stiff ( Plate 13A ). Colour of the colonies varies from deep pink, reddish­purple, dark yellow, to brown, sometimes intermingled with orange. Fans open reticulate, with a single fan or subdivided into 2–5 lateral fans. Stem very short or absent; holdfast wide and strong. Branches mostly compressed, around 2–5 mm thick, and nearly round in cross­section at the tips. No distinct midribs present. Network of long, oblong, or rectangular meshes around 10–35 mm by 1–4 mm in size (2 meshes/cm²). End­branchlets up to 30 mm long. Calyces low, oval, distributed on both sides of the branches, not very crowded, leaving the branches with a smooth texture. Polyps orange, reaching about 1.5 mm in diameter when fully expanded, possessing collaret­like masses of pale yellow sclerites arranged vertically, and projecting slightly into the base of each tentacle. Coenenchymal sclerites pink, grey, and yellowish: a few long spindles (up to 0.12 by 0.04 mm) with warty, acute ends, and four whorls of tubercles ( Fig. 12A ), blunt spindles (up to 0.1 by 0.05 mm) with four whorls of tubercles ( Fig. 12B ) some with one elongated end; capstans very abundant (up to 0.10 by 0.05 mm) with different arrangements of tubercles, and most of them with elongated warty ends ( Fig. 12C ); six­radiates (up to 0.06 by 0.04 mm) ( Fig. 12D ), and immature sclerites (up to 0.05 by 0.04 mm) with low tubercles ( Fig. 12E ). Anthocodial sclerites yellow rods (up to 0.09 by 0.02 mm) with scalloped or short lobed edges, weakly serrated at both ends ( Fig. 12F ).

Remarks. Although the morphology of this species is very constant, the dominance of different sclerite­forms and also the colour of both colonies and sclerites vary among different specimens. This variation was pointed out by Hickson (1928) in colonies collected from the same place at the same time. In different sites in Costa Rica, we have observed both yellow and reddish­purple varieties together and some colonies have both yellow and reddish­purple sections. UCR 771 presents a dominance of spindles with sharp ends. In UCR 498, we found six­radiates (around 0.05 by 0.03 mm) with warty blunt ends ( Fig. 12D ) which were not reported for the holotype.

Habitat. Found between 15–30 m deep on rocky bottoms or vertical walls. Very few colonies of this species are found scattered in environments dominated by other species like P. irene . Specimens from Pearl Islands and Zorritos ( Perú) were collected in shallower waters, between 12 and 16 m deep ( Verrill 1868c). Recent field observation showed that they also live at a depth of 8 m (Cortés, pers. comm. 2000).

Distribution in Costa Rica. Murciélago Archipelago; Cabo Blanco; Gulf of Nicoya; Sámara Bay; Caño Island; Ballena Marine National Park; and Punta Matapalo, Osa Peninsula.

Published records. From Verrill (1868c): Acapulco, México; San Salvador, El Salvador ; Corinto, Punta Arenas, Nicaragua; Pearl Islands , Panamá ; Zorritos, Perú. Type locality, New Zealand , is probably erroneous.

Figures

FIGURE 12. Pacifigorgia stenobrochis Valenciennes (UCR 831), SEM­micrographs of the sclerites: A–B, spindles; C, capstans; D, six­radiates, E, immature sclerites; F, anthocodial rods.

PLATE 13. Pacifigorgia stenobrochis Valenciennes (UCR 831) (dry specimen); A, entire colony; B, detail of the branches; C, photomicrograph of the sclerites.