Leptogorgia alba (Duchassaing and Michelotti, 1864)

Published, First, 2007, A revision of the genus Leptogorgia Milne Edwards & Haime, 1857 (Coelenterata: Octocorallia: Gorgoniidae) in the eastern Pacific, Zootaxa 1419, pp. 1-90 : 12-19

Leptogorgia alba (Duchassaing and Michelotti, 1864)

( Figs. 4–9)

Lophogorgia alba Duchassaing and Michelotti, 1864: 19; Rossi 1956: 198; Harden 1976: 68; Prahl, et al. 1986: 17; Volpi

& Benvenuti 2003: 58. Gorgonia (Leptogorgia) rigida var. laevis, Verrill, 1866: 327 [Nomen nudum]. Gorgonia (Litigorgia) laevis Verrill, 1868: 415. Litigorgia levis (misspelled) Verrill, 1868b: 398. Lophogorgia laevis Harden 1979: 75. Leptogorgia alba Verrill 1868b: 398–399; Verrill 1869 b: 421; Studer 1894: 68; Bielschowsky 1918: 30; 1929: 107–108;

Kükenthal 1919: 771; 1924: 329; Hickson 1928: 400–405. Leptogorgia alba var. sulcata Bielschowsky, 1929: 108–110; Kükenthal 1919: 771; 1924: 329. Euplexaura lemasti Hickson, 1928: 349–351; Stiasny 1941: 266–267; 1943: 63. Leptogorgia fasciculata Bielschowsky 1918: 29 [Nomen nudum]; 1929: 94 –96; Kükenthal 1919: 912; 1924: 326; Stiasny

1951: 60. Lophogorgia fasciculata Harden 1976: 74.

Material examined. Lectotype: MZUF c163, (figured specimen Duchassaing & Michelotti 1864), dry, Isla Flamenco, Golfo de Panama, Panama, no more data available. Paralectotype: MSNT 164, dry, Panama, no more data available.

Syntypes of L. fasciculata: ZSM 20044789, ZSM 20044790, preserved, no depth given, Panama, Hassler Expedition, A. Kölliker, 1904. Syntypes of L. alba var. sulcata: ZMHC 4496, ZMHC 5615, ZMHC 4580, preserved, Panama, no further data. Syntypes of L. laevis: MCZ 5416, dry, Archipielago Las Perlas, Golfo de Panama, no depth given, F. H. Bradley, 1866; MCZ 7008, dry, Golfo de Nicoya, Costa Rica, no depth given, F. H. Bradley, 1866; YPM 1639, preserved, Archipielago Las Perlas, no depth given, F. H. Bradley, 1866.

Other material examined. COSTA RICA: UCR 1471 (4 specimens), preserved, Punta Burica, 1 m, O. Breedy, 12 February 2002; UCR 1537, preserved, Bolaños Island, Salinas Bay, 3 m, J. Cortés, 1 st February 2006; UCR 1542, preserved, Punta S-E, Caño Island, 18 m, O. Breedy, 14 September 1996; UCR 1543, preserved, Bajo El Diablo, Caño Island, 18 m, O. Breedy, 11 February 2000; UCR 1545 (3 specimens), preserved, Manuel Antonio National Park, Costa Rica, 18 m, O. Breedy, 6 April 2006; UCR 1546 (5 specimens), preserved, Isla Serrucho, Manuel Antonio National Park, 10 m, O. Breedy, 5 April 2006; UCR 1547, preserved, Punta Descartes, Salinas Bay, 6 m, O. Breedy, 9 June 2005; UCR 1553, preserved, Caño Island, 12 m, O. Breedy, 4 September 1996; UCR 1555, preserved, Tombolo oeste, Marino Ballena National Park, Costa Rica, 4 m, O. Breedy, 25 April 2002; UCR 1556, preserved, NE Isla Ballena, Marino Ballena National Park, 7 m, O. Breedy, 27 April 2002; UCR 1560, dry, Peñón Abrazo de la Muerte, Archipielago Murcielago, 25–30 m, O. Breedy & J. Cortes, 12 April 1996; UCR 1561, dry, Punta Matapalito, Peninsula de Osa, 18 m, O. Breedy & A. Fonseca, 15 March 1998; UCR 1661, preserved, Puertas de la Catedral, Archipielago Murcielago, 18 m, O. Breedy, 2 December 2003; UCR 1662, preserved, Nacascolito, Culebra Bay, 7 m, O. Breedy, 23 April 2002. ECUADOR: CDRS 02–25, preserved, Darwin Island, Galapagos Archipelago, 21–30 m, C. Hickman, 18 May 2002; CDRS 597, preserved, Wolf Island, Galapagos Archipelago, 13 m, C. Hickman, 12 November 2003. PANAMA: STRI 465, dry, Bajo Foul, Peninsula de Azuero, 5–20 m, H. Guzman, 9 December 2003; STRI 750, dry, Roca Trollope, Golfo de Panama, 10–20 m, H. Guzman, 6 August 2003; STRI 814, dry, Isla del Rey, Archipielago Las Perlas, 4 m, H. Guzman, 6 April 2004; STRI 850, dry, Isla Pacheca, Archipielago Las Perlas, 3m, H. Guzman, 20 April 2004; UCR 1035, 1036, 1039, 1041, 1502, dry, Islote Frailes, Península de Azuero, 10–30 m, H. Guzman, 9 December 2001; UCR 1047, 1057, dry, Isla Canal Afuera, Golfo de Chiriqui, 3–12 m, H. Guzman, 10 December 2001; UCR 1063, 1065–1066, dry, Isla Santa Cruz, Golfo de Chiriqui, 5–20 m, H. Guzman, 10 December 2001; UCR 1110–1112, dry, Roca Prosper, Golfo de Chiriqui, 10–30 m, H. Guzman, 11 December 2001; UCR 1125, 1126, 1161, dry, Islote Frailes, 5–20 m, H. Guzman, 12 December 2001; UCR 1132, 1134, 1136, 1139, dry, Isla Barca, Golfo de Chiriqui, 5–10 m, H. Guzman, 18 April 2002; UCR 1167, dry, Roca Niagara, Golfo de Chiriqui, 5–20 m, H. Guzman, 13 December 2001; UCR 1191, dry, Isla Jicaron, Golfo de Chiriqui, 5–10 m, H. Guzman, 18 April 2002; UCR 1193, 1195, 1197, 1199, 1201, dry, Isla Saboga, Golfo de Panama, 1–5 m, H. Guzman, 14 December 2001; UCR 1245, 1289, dry, Isla Jicarita, Golfo de Chiriqui, 10–12 m, H. Guzman, 19 April 2002; UCR 1323, dry, Islote Punta Soledad, Golfo de Chiriqui, 10 m, H. Guzman, 20 April 2002; UCR 1327–1328, dry, Isla Passage, Golfo de Chiriqui, 15 m, H. Guzman, 20 April 2002; UCR 1351, dry, Isla Piedra Hacha, Golfo de Chiriqui, 10–25 m, H. Guzman, 22 April 2002; UCR 1382–1383, dry, Bajo La Viuda, Golfo de Chiriqui, 30 m, H. Guzman, 23 April, 2002; UCR 1447, dry, Isla Otoque, Golfo de Panama, 5–10 m, H. Guzman, 9 May 2002; UCR 1460, 1463, Taboguilla Island, Golfo de Panama, 5–10 m, H. Guzman, 9 May 2002; USNM 49362, dry, 7° 55’N, 81° 38’W, 11 March 1948, no further data.

Lectotype Description. The lectotype is a flabellate colony 9.5 cm in height and 11.0 cm in width ( Fig. 4C). Three primary branches sprout from a short stem, 7 mm long, producing secondary branches in an irregular, openly pinnate sequence. The stem is 3 mm in diameter, it is wider at the base and is devoid of sclerites; the holdfast is lacking. Main branches are 1.0– 1.5 mm in diameter, and the pinnae are around 1.0 mm. Unbranched terminal twigs are pointed, mostly 3.0 cm or less in length. Longitudinal grooves that extend along the main branches are very distinct at the base. Polyps are arranged in two rows on each side of the branches, not crowding the branches, fully retractile into the coenenchyme, which is slightly raised around the apertures ( Fig. 4B). Colour of the colony is white. Coenenchymal sclerites are nearly all colourless; a few are pink ( Fig. 4D). They are mostly long spindles, up to 0.18 mm in length, and 0.04–0.06 mm in width, with acute ends, and 4–10 whorls of complex tubercles ( Figs. 4D, 5). The spindles are mostly straight, or have a slightly bent end; some have curved axes. Capstans reach up to 0.06 mm in length, and 0.03 mm in width ( Figs. 4D, 6). Anthocodial sclerites are colourless, flat, long rods up to 0.15 mm in length and 0.03 mm in width, with scalloped margins or with few short, lateral projections ( Figs. 4D, 6).

Other material. Examined colonies reach up to 60 cm in height, and 60 cm in width. The morphology of the colonies is basically flabelliform, irregularly dichotomous or with long, slender pinnate branches, and short, ( Figs. 4A, C, 7A) or long, drooping pinnae ( Fig. 7B). Colonies mostly branch from short stems, up to 2 cm in height, and up to 20 mm in diameter, mostly in one plane, but other branching arrangements can occur. Holdfasts are spreading and thick in large colonies and thin, round or oval in small colonies. Main branches are nearly round in cross-section, or sometimes flattened, reaching up to 1.5–2 mm in diameter. Pinnae are up to 1–1.5 mm in diameter, with round or pointed tips. Unbranched terminal twigs range from 2 to 16 cm long, depending on the dominant short-pinnae or long-pinnae pattern. Retracted polyps may retract completely into the coenenchyme leaving oblong openings, or form small, slightly raised polyp-mounds ( Fig. 4B). They are mostly arranged in two rows on each side of the branches, sparsely distributed on the thin branches, but more close together on the thick branches. Polyps are whitish, or colourless. The anthocodial rods are arranged in points below the polyp tentacles. Colour of the dry colonies is white, but when alive the colony and polyps are light pink. Coenenchymal sclerites are very variable. In small colonies they are often as in the lectotype, where the spindles are the dominant type of sclerite, reaching up to 0.17 mm in length. In large specimens long spindles are scarce to absent, small capstans being the dominant type, e.g. UCR 1057 (40 cm in height, and 55 cm in width). However, we could not establish a relationship between the size of the colony or the branching pattern and the relative abundance of any type of sclerites, since intermediate patterns were observed. For example, UCR 1039 is a large colony (52 mm in height, and 40 cm in width), some acute spindles and blunt spindles are found in the samples along with the capstans which are the dominant type; this colony has the long-pinnae pattern of ramification which is not the case in UCR 1057, which has the normal short-pinnate pattern of the lectotype. In UCR 1057, coenenchymal sclerites are mainly small capstans, up to 0.06 mm in length, and 0.04 mm in width, with a very low occurrence of blunt spindles, and asymmetric spindles, when found they reach up to 0.08 mm in length, and 0.04 mm in width ( Figs. 7C, 8A). In UCR 1039, coenenchymal sclerites are mostly capstans, but larger, 0.07 mm in length, and 0.04 mm in width, and with a higher occurrence of spindles with acute or blunt ends and asymmetric spindles; they reach up to 0.10 mm in length, and 0.04 mm in width ( Figs. 7D, 8B). Anthocodial rods are very consistent in size and shape in the examined specimens, they are long and conspicuous.

Distribution. Isla Flamenco, Panama: type locality (Duchassaing & Michelotti 1864); all along the Pacific coast of Panama, and Costa Rica; San Salvador, Acajutla, Ecuador (Bielschowsky 1929); Malaga Bay, Punta Ardita, Gorgona Island, Colombia (Prahl et al. 1986); Darwin Island, Wolf Island, Galapagos Archipelago; San Carlos Bay, Mazatlan, Baja California, Isabel Island, Mexico ( Table 2, Fig. 9).

Remarks. In 1860 and 1864 Duchassaing and Michelotti published two monographs dealing with species of Coelenterata from the Caribbean region in which they described a number of new species. In their 1864 work, they included two new species from the Pacific of Panama, Lophogorgia panamensis and Lophogorgia alba . The specimen of L. panamensis was analyzed in our study and identified as a species of the genus Eugorgia Verrill, 1868b.

In their description of Leptogorgia alba Duchassaing and Michelotti gave a brief diagnosis, but illustrated accurately only one of their two specimens. Based on the figured specimen, Volpi and Benvenuti (2003) designated the lectotype of this species. It seems that nobody before us, had access to the type material because there has been historical confusion around this species, which is evident from the synonymy list. Verrill (1868b) redescribed L. alba using specimens from Panama and other Central American localities. He was unable to determine whether his specimens, deposited in YPM and MCZ, were the same as L. alba described by Duchassaing and Michelotti (1864). Hickson (1928) described Euplexaura lemasti , which was later reassigned to L. alba by Stiasny (1941). Bielschowsky (1929) described two species L. fasciculata (ZSM 20044789, ZSM 20044790), and L. alba var. sulcata (ZMHC 4496, ZMHC 5615, ZMHC 4580). She separated these species from L. alba without any examination of the types. After studying her specimens, we did not find any reason to retain them as different species. Consequently, we decided to make them synonyms of L. alba .

Leptogorgia alba is one of the most difficult species to define. We observed basically three types of branching, pinnate (as in the lectotype) ( Fig. 4C), the long-pinnate drooping style, as in UCR 1039 ( Fig. 7B), and a more dichotomous pattern, as in ZSM 20044789 and ZSM 20044790 , formerly identified as L. fasciculata ( Fig. 7E). However, we could not determine any relationship between the branching patterns and the types of sclerites. In addition, we observed both patterns in the same colony UCR 1528 ( Fig. 7F), one at the base and the other at the top. The lack of consistent patterns among the many examined specimens shows the plasticity of this species; perhaps in response to several environmental factors such as currents, wave action, depth, or habitat .

Five species of the eastern Pacific Leptogorgia are white and similar to L. alba ( Table 1). Leptogorgia ramulus is separated from the group basically for its type of branching and the prominent polyp mounds. Leptogorgia cofrini , L. fruticosa , and L. peruviana are small, bushy colonies, different from the other two species. Leptogorgia laxa differs from the other species of this group in the lax style of branching, and the slender branches. Sclerite size and composition in L. laxa is similar to L. alba (typical form), but differs by having the highest occurrence of long spindles with acute ends ( Table 1).