Pacifigorgia rubinoffi, Breedy, Odalisca & Guzmán, Héctor M., 2003

Breedy, Odalisca & Guzmán, Héctor M., 2003, A new species of Pacifigorgia (Coelenterata: Octocorallia: Gorgoniidae) from Panamá, Zootaxa 128, pp. 1-10 : 3-7

Pacifigorgia rubinoffi new species

Figures 2­4

Material examined. Southwest Brincanco Island, Gulf of Chiriquí, Panamá, 1­4 m, 26 April 2002, dry, UCR 1024 ( STRI 339), holotype. Northwest Canal de Afuera Islands, Gulf of Chiriquí, Panamá, 1­4 m, 10 December 2001, coll. H.M. Guzmán, MCZ 50655 ( STRI 16), preserved in ethanol, UCR 1027 ( STRI 16A), dry, paratype. Frijol South Islet, Gulf of Chiriquí, Panamá, 1­4 m, 25 April 2002, coll. H.M. Guzmán, UCR 1024 ( STRI 324), 1025 ( STRI 325), dry paratypes. Frijol South Islet, Gulf of Chiriquí, Panamá, 1­4 m, 24 August 2002, coll. H.M. Guzmán & O. Breedy, UCR 1028 ( STRI 391), dry, paratype. Curly Islet, Gulf of Chiriquí, Panamá, 1­4 m, 25 August 2002, coll. H.M. Guzmán & O. Breedy, UCR 1029 (2) ( STRI 398), preserved in ethanol, paratype. Southwest Brincanco Island, Gulf of Chiriquí, Panamá, 1­5 m, 24 August 2002, coll. H.M. Guzmán & O. Breedy, MCZ 50656 ( STRI 395), dry paratype.

Other material. Curly Islet, Contreras Archipelago, Gulf of Chiriquí, Panamá, 1­4 m, 25 August, 2002, coll. H.M. Guzmán & O. Breedy, ten colonies preserved in ethanol, to be used in other studies.

Holotype. Colony measures 21 cm in height, and 26 cm, consists of a main fan and 3 small secondary fans. Colony arises from an oval, strong holdfast (15 mm in diameter). It has three thick branches (about 5 mm in diameter at the base) that reach up to the middle of the colony; the secondary fans sprout from them and radiate perpendicular to the main fan. No distinct midribs are present. Meshwork is regular, and closed, of mostly round meshes (up to 9 by 5mm in diameter). Color of the colony is a bright deep orange ( Fig. 2 A). Calyces are round, slightly raised with slit­like apertures. Calyces are arranged not very close, distributed mostly in two rows on all sides of the branches, but in three or more rows on the thick branches ( Figs. 2 C, D, 3). Polyps are white, fully retractile into the coenenchyme ( Fig. 2 D). Anthocodiae are weakly armed with collaret­like masses of slender orange and yellow rods at the base of the tentacles. The most common coenenchymal sclerites are capstans ( Fig 4 B) measuring 0.04­0.08 mm by 0.02­0.06 mm. They have a distinct waist and clusters of closely group tubercles at either end. Some show a tendency to have two whorls of tubercles ( Fig 4 Ba) and are intermediate to the coenenchymal spindles. The spindles ( Fig 4 A) vary from 0.09­0.1 mm in length and 0.05­0.06 mm in width. They generally have from two to four whorls of tubercles and the sclerite's tips can be blunt or acute. The longer spindles tend to be narrow, with acute tips that can be slightly curved. On some spindles the tubercles are irregularly arranged, such as Fig 4 Aa,b. Amongst the coenenchymal sclerites are some crosses, up to 0.1 mm in diameter ( Fig. 4 C), and some conspicuous barrel­ or oval­shaped sclerites up to 0.07 mm long ( Fig. 4 D). A number of immature sclerite forms ( Fig 4 F) are also present. Sclerites are all usually deep orange or dark yellow. Anthocodial sclerites are light orange, somewhat flattened rods up to 0.07 mm by 0.03 mm with mostly smooth or lobed margins ( Fig. 4 E). Spindly capstans, in small numbers, were also in the preparations of sclerites, as in most of the species of this genus.

Description. Colonies are wider than high, up to 25 cm in height, and 35 cm in width, composed of several reticulate fans. Fans arise from strong, laminar holdfasts covered with coenenchyme bearing scarce, distant polyps, and spread over solid substrate. New branches and secondary fans originate directly from the holdfast, growing perpendicularly and forming complex multiplanar arrangements that also can be observed in small colonies. Several thick branches, up to 5 mm in diameter, can be traced from the base of the colonies and extend for some distance, but no distinct midribs totally cross the fans. Thinner branches, 1­2 mm in diameter, form a regular network of close meshes (around 11 meshes/cm²), mostly round or squarish, without angular corners, and up to 9 by 5 mm in size. End­branchlets are up to 7 mm in length, and there are few, short free­twigs that project into the lager meshes. Axes of the thick branches look dark purple, due to the color of the axial sheath sclerites (P. Alderslade, pers. comm.) and they are of a straw color in the thinner branches. Calyces and polyps are as described for the holotype. Color of the colonies, varies from a colorful deep orange ( Fig. 2 A, B, C), to a dark yellow (paratype UCR 1026). In some preserved specimens (dry or ethanol), the sclerites around the apertures of the calyces are lighter than the others and form pale yellow rings (e.g. paratypes UCR 1028, MCZ 50655 (STRI 16)). Sclerites are as described for the holotype, with some variation in color, from deep orange to dark yellow. Some variation exists also in the abundance of types of sclerites, for example in the paratype MCZ 50655 (STRI 16), spindles with acute ends are more abundant in the microscopic preparations of sclerites, than they are in the holotype.

Etymology. We dedicate this species to Dr. Ira Rubinoff, who has been the Director of the Smithsonian Tropical Research Institute (STRI) since 1973; his vision and combination of political skill and scientific knowledge has made STRI one of the world's best center for basic research in the tropics.

Remarks. The new species differs from other taxa in Pacifigorgia by having the following combination of characters. First, the colony is composed of multiple fans, a closed meshwork, a lack of distinct midribs, and a conspicuous orange color of both colony and sclerites. Second, it has a low occurrence of spindles with acute ends; in some colonies, however, an increase of this type is evident in the sclerite­preparations; the occurrence of spindles with bent ends, instead of the more common type with straight ends. The presence of large, conspicuous, asymmetric rods; and the occurrence of barrels are also distinctive features. Finally, the anthocodial rods have mostly smooth borders and reach no more than 0.07 mm in length.

Habitat. Populations of this species were found in shallow water from 1.5 to 5 m at eight sites only in the Gulf of Chiriquí; they grow on rocky substrates in zones of strong swell and currents. Populations are patchily distributed, but can constitute the dominant species in a small (<550 m 2) area. Population abundance (number of colonies) was recorded at each site (see Fig. 1 ); 6 individuals in Canal de Afuera Islands, 38 in Frijol South Islet (near Coiba Island), 2 in Curly and Secas West Islets (Secas Archipelago), 3 in Ladrones Islands, 5 in Montuosa Island, 3 in Jicarita Island, and the largest population of ca. 323 colonies in Brincanco Island (Contreras Archipelago) composed of a large number of recruits. The species often co­occur with individuals of another new species of Pacifigorgia (pers. obs.), Leptogorgia alba Duchassaing & Michelotti , and another small undetermined species of Leptogorgia .

Distribution. Gulf of Chiriquí, Panamá.

Figures

FIGURE 1. Map of Panamá with a detail of the Gulf of Chiriquí, showing the sites where Pacifigorgia rubinoffi n. sp. was found.