Alcyonium haddoni Wright & Studer 1889
Creators: name: Ofwegen, Van
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Alcyoniidae
Alcyonium
Alcyonium haddoni

description: Alcyonium haddoni Wright & Studer, 1889
(Figs. 1 d–f, 2b–c, 3b–c, 6–7, 11)
Alcyonium haddoni Wright & Studer, 1889: 240, pl. 42 fig. 6.? Alcyonium haddoni Verseveldt, 1967: 5, figs 2, 6C–D.
Not Alcyonium haddoni Pérez & Zamponi, 2004: 4, fig. 2B.
Material: RMNH Coel. 34937, two colonies and two microscope slides, Chile, Piedra Lile, Isla Laitec, 43°10'58.6" S, 73°38'27.2" W, depth 13–20 m, coll. VH & GF, 4 March 2005; RMNH Coel. 34938, one colony and three microscope slides, Chile, Cailín Island, 43°09'02.1" S, 73°35'30.9" W, depth 10 m, coll. VH & GF, 31 January 2001; MZUC-UCCC 32678, one colony, Chile, Canal Ofhidro, 48°09'52.1" S, 74°23'48.4" W, steep wall, low diversity, few overhangs, depth 15 m, coll. VH, 16 March 2006; ZSM 20061188, one colony, Chile, Canal Pasaje, 50°27'49.2" S, 75°07'41.6" W, depth 20 m, slowly descending wall, many terraces, medium diversity, thick mussel beds, coll. VH & GF, 9 March 2006; ZSM 20061189, four colonies, Chile, Canal Pitt Chico, 50°50'07.1" S, 74°08'20.9" W, very mixed, steep walls, strong current, lots of Alcyonium, hydrocorals and crabs, depth 6 m, coll. PW & LA; MZUC-UCCC 32679, one colony, Chile, Seno Waldemar, 48°23'48.5" S, 74°43'48.8" W, slope/wall, some terraces, patches of high diversity, depth 25 m, coll. GF, 15.iii.2006; ZSM 20061190, three colonies, Chile, Canal Adalberto, 48°36'28.7" S, 74°53'55.7" W, sloping wall, some overhangs, high diversity of sponges, lots of Alcyonium, depth 30 m, coll. GF, 12 March 2006; ZSM 20061191, four colonies, Chile, Canal Pitt Chico, 50°50'07.1" S, 74°08'20.9" W, very mixed, steep walls, strong current, lots of hydrocorals and crabs, coll. VH & GF, depth 22 m; 7 March 2006; RMNH Coel. 34939, one colony, Chile, Paso del Abismo, 49°34'38.7" S, 74°26'49.3" W, steep/overhanging wall, high diversity, depth 22 m, coll. VH & GF, 10 March 2006; RMNH Coel. 34940, one colony and one microscope slide, Chile, Angostura Inglesias, 48°59'17.6" S, 74°25'08.2" W, depth 26 m, coll. VH & GF, 11 March 2006; MZUC-UCCC 32680, one colony, Chile, Canal Adalberto, 48°36'28.7" S, 74°53'55.7" W, depth 20–30 m, on gorgonian, sloping wall, some overhangs, high diversity of sponges, lots of Alcyonium, coll. PW & LA, 12 March 2006; RMNH Coel. 34941, five colonies on a gorgonian branch, Chile, Canal Adalberto, 48°36'28.7" S, 74°53'55.7" W, sloping wall, some overhangs, high diversity of sponges, lots of Alcyonium, depth 30 m, coll. VH, 12 March 2006; MZUC-UCCC 32681, one colony, on dead gorgonian, Chile, Seno Waldemar, 48°23'48.5" S, 74°43'48.8" W, slope/wall, some terraces, patches of high diversity, depth 25 m, coll. GF, 15 March 2006; ZSM 20061192, two colonies, Chile, Grupo Dacres, 51°36'20.8" S, 73°55'33.8" W, large steps with slight overhangs, high biodiversity, strong current convection, depth 11 m, coll. VH & GF, 7 March 2006; ZSM 20061193, one colony, Chile, Canal Castillo, 48°44'11.4" S, 75°24'53.1" W, terraced wall, with high diversity, lots of Alcyonium and sponges, depth 23 m, coll. VH, 12 March 2006. MZUC-UCCC 8156, three colonies, Isla Inocentes, 50°33' S, 74°53' W, coll. H. Moyano, 9 October 1972.
Description of RMNH Coel. 34937. Colony consisting of a single, flattened, rounded lobe, 3.5 cm high, 3 cm wide, and 1.5 cm thick (Fig. 1 e).
Polyps distributed over the whole surface of the colony, almost reaching the base. Calyces are dome shaped and all polyps are retracted.
Anthocodiae have a collaret composed of 5–6 rows of spindles (Fig. 3 c); these spindles are up to 0.40 mm long, with simple tubercles (Fig. 6 a). Points have spindles similar to those of the collaret, with clubs present distally, up to 0.25 mm long (Fig. 6 b). In the tentacles spiny rods are found, up to 0.20 mm long (Fig. 6 c).
The surface layer of the top of the colony has clubs, up to 0.20 mm long, with spiny heads (Fig. 6 d); the interior has spindles with rather complex tubercles, up to 0.30 mm long (Fig. 6 e).
The surface layer and interior of the base of the colony have sclerites similar to those of the top of the colony (Fig. 6 f–g), but they are slightly shorter.
Colour. The orange colour of the live colony is still preserved; tentacle rods are colourless, other sclerites yellow.
Habitat, distribution and abundance. This species is the most abundant of all Alcyonium species so far recorded in Chile. Specimens inhabit rocky and biogenic substrata (dead gorgonians, chitons) starting in 6 m depth in channels of the North and Central Patagonian Zone from 43°09'02.1" S, 73°35'30.9" W to 51°36'20.8" S, 73°55'33.8" W. The typical colonies are round to slightly elongated with a distinct domeshaped extremity and consist of a single lobe. On rare occasion, however, colonies are longer and/or slightly to strongly lobed with each lobe having a dome-shaped extremity (see variability). In several colonies, conspicuous pink eggs/larvae were visible through the transparent body wall of some polyps. On one colony (Fig. 3 c) the amphipod Metepimeria acanthurus was observed.
Variability. RMNH Coel. 34938 is similar to RMNH Coel. 34937, but larger, with cream to orange color, and with many polyps expanded (Fig. 1 f). Therefore, this specimen was used to make the drawing of the polyp armature (Fig. 3 c). In this specimen the polyps are up to 1.20 mm wide and 1 mm high.
All recently collected material examined except two seem to consist of a single lobe. One of the colonies of ZSM 20061191 has some irregular outgrowths, probably re-growth after damage instead of real lobes. RMNH Coel. 34940 seems to be a digitate colony (Fig. 2 c), but could be the result of several digitiform colonies grown together to form one large digitate colony. It surely is an exceptional growth form for this species and therefore SEM images of its sclerites (Fig. 7 a–d) and a lateral view of its polyp armature (Fig. 3 b) are presented. Specimen RMNH Coel. 34940 has somewhat larger anthocodial sclerites, up to 0.50 mm long, and the distal ones are less club-like. Furthermore its internal spindles are less tuberculate. We consider these differences intraspecific variation and despite its aberrant growth form to belong to A. haddoni.
The ZSM 20061190 colonies have a white base and polyps, with all anthocodial and base sclerites colourless.
Remarks. Alcyonium haddoni was described by Wright & Studer (1889), found 315 m deep in the Messier Channel, Chile. In their publication the description of the colony shape was rather misleading (see remarks of A. roseum). Therefore, here two syntypes of A. haddoni (BMNH 89.5.27.125) are shown in Fig. 1 d. Also the sclerites of this species were depicted rather schematic (pl. 42 fig. 6).
Verseveldt (1967) re-examined the syntype material of A. haddoni in order to identify material collected east from Rio de la Plata, Argentine. He noted some significant sclerite differences between his material and the syntypes but nevertheless decided the Rio de la Plata material belonged to A. haddoni. Two microscope slides of the top of the colony of a syntype, made by Verseveldt, are stored in the RMNH, and were re-examined by us. They showed much wider clubs in the top of the colony (up to 0.10 mm wide heads) than those in the recently collected material. Only after examining the MZUC-UCCC 8156 material did it become obvious that this difference probably represents intraspecific variation as MZUC-UCCC 8156 shows clubs (Fig. 7 e) intermediate between the syntype and the recently collected material.
We have our doubts about the identification of Verseveldt (1967), the colonies he depicted are digitate and the clubs are even less developed than in our material.
It is very unlikely Pérez & Zamponi (2004) had A. haddoni as their colony was clearly lobate.
Alcyonium paucilobulatum Casas et al., 1997, from the Scotia Arc, can have a similar looking colony shape. However, this species has mostly capstans and spherical sclerites in the surface layer of the coenenchyme. A. patagonicum (May, 1899), from the Patagonian shelf, also resembles the present species, but has a more finger-shaped colony form, and has wider interior spindles with coarser warts (see Verseveldt & Ofwegen, 1992). Moreover, colonies of these two species are white to cream while A. haddoni has orange colonies.
description: Published as part of Ofwegen, Van, 2007, The genus Alcyonium (Octocorallia: Alcyonacea: Alcyoniidae) in Chile, pp. 1-19 in Zootaxa 1607 on pages 9-12, DOI: 10.5281/zenodo.178819