Swiftia comauensis, Breedy, Odalisca, Cairns, Stephen D. & Häussermann, Verena, 2015

Breedy, Odalisca, Cairns, Stephen D. & Häussermann, Verena, 2015, A new alcyonacean octocoral (Cnidaria, Anthozoa, Octocorallia) from Chilean fjords, Zootaxa 3919 (2), pp. 327-334 : 329-332

Swiftia comauensis sp. nov.

( Figs. 2–4 )

Swiftia sp. nov. Ofwegen et al. 2009: 199 –200

Material examined. Holotype: UCR 2378, chile1 Nr 22, 0 0 8, Río Tambor, Fjord Comau, Chile, 42°24'14.74" S, 72°25'14.11" W, depth 20 m, coll. V. Häussermann & G. Försterra, 13 March 2004.

Paratypes: USNM 1241828, chile1_a Nr 22, 0 0 8, Río Tambor, Fjord Comau, Chile, 42°24'14.74" S, 72°25'14.11" W, depth 20 m, coll. V. Häussermann & G. Försterra, 13 March 2004; MZUC- UCCC, chile1_b Nr 22, 0 0 8, Río Tambor, Fjord Comau, Chile, 42°24'14.74" S, 72°25'14.11" W, depth 20 m, coll. V. Häussermann & G. Försterra, 13 March 2004; ZSM 20140181, chile#5, VH 86I, close Río Tambor, Chile, depth 20 m, coll. V. Häussermann & G. Försterra, February 2004; UCR 2301, L-7, No 13, Río Tambor, 42°24'14.74" S, 72°25'14.11" W, depth 18–22 m, coll. V. Häussermann & G. Försterra, 9 October 2004.

Diagnosis. Colonies sparsely ramified with long drooping branches subdividing up to three times in lateral branches originating at open angles (60° to 90°). Anastomosis of few branches seldom present. Coenenchyme thin. Coenenchymal sclerites mostly long thin spindles, straight or branched,1.5– 0.35 mm long, and tubercularte spindles, no capstans. Polyp mounds prominent and well spaced without a special type of sclerites. Anthocodial sclerites bar-like rods, and irregular flattened scales. Colour of the sclerites pale orange. Colour of the colonies bright orange with pale yellow polyp mounds.

Description. The holotype is a straggly colony scantily ramified, 13.5 cm tall, arising from an encrusting holdfast that is about 1 cm wide ( Fig. 2 A). The main stem is 2 mm in diameter, extending up to 4.8 cm in length, subdividing in four lateral branches, 1.5–2.8 cm apart: the lateral branches project perpendicular to the main axis, one of them subdivides again in two branches. The branches are flexible, drooping, and reach up to 3 mm in diameter including polyp-mounds, and up to 9 cm long. The main stem is almost devoid of polyps. The colour of the colony is bright orange with pale yellow polyp mounds when alive, and keeps the colour when preserved; polyps are yellowish ( Figs. 2 A–B, 3). The polyps are well spaced, 1–2 mm apart, about 8 polyp mounds/cm (n=5 branches), mostly biserially arranged. The polyp mounds are raised up to 1 mm tall. The anthocodiae are preserved exsert, reaching up to 1 mm tall, and reaching up to 5 mm tall fully expanded in life ( Fig. 3 ).

The coenenchyme is thin. Coenenchymal sclerites consist of long, thin, warty spindles, mostly straight, 1.5– 0.35 mm long and 0.03–0.05 mm wide ( Fig. 4 A); irregularly branched spindles, 0.18–0.20 mm long and 0.01–0.03 mm wide ( Fig. 4 B); spindles with expanded, warty tubercles, 0.09–0.13 mm long and 0.03–0.05 mm wide ( Fig. 4 C); and small immature sclerites, 0.07–0.14 mm long and 0.017–0.03 mm wide. The spindles are concentrated in the polyp mounds. The anthocodial armature is arranged in points, consisting of bar-like rods, straight or slightly bent, 0.15–0.27 mm long, and 0.025–0.036 mm wide ( Fig. 4 D), and irregular flattened scales around the peristome and along the tentacles, 0.06–0.1 mm long, and 0.016–0.028 mm wide ( Fig. 4 E). All sclerites are pale orange.

Variability. The paratypes reach up to 20 cm in height, the main stems extending up to 5 cm, and give off up to four lateral branches. Branches subdivide no more than three times. The branches are separated by about 0.5–4.5 cm, and originate at angles from 60° to 90°. Some colonies consist of a single unbranched stem. Anastomosis occurs in branches of some colonies. The branches and branchlets reach about 3–4 mm in diameter, including polyp-mounds. The polyp mounds are sparsely distributes, 6–8/cm. All other characteristics, including colours and sclerite sizes, are as in the holotype.

Distribution and abundance. This species is known only from the Comau Fjord area, SE Pacific from three sites: mouth of Río Tambor, (42°24'14.74" S, 72°25'14.11" W), Huinay dock (42º22´29"S, 72º 25´41.58"W), and the northern entrance of Quintupeu Fjord (42°9'49.32"S; 72°26'40.32"W), between 15 and at least 30 m depth. At Río Tambor and Quintupeu entrance it was observed in diving depth (15–30 m), while at Huinay dock a similar colony (not collected) was observed in 59 m depth with the ROV in October 2007. Type locality: Río Tambor, Comau Fjord.

The new species appears to be rare. In 2003 when we discovered the species, we observed approximately 30 to 40 colonies close together, approximately 50–60 cm tall at Río Tambor, and a couple of colonies at the entrance to Quintupeu Fjord. In late 2013, there were only about 10 colonies up to 20 cm tall sparsely distributed at Río Tambor, whereas, we did not see any colonies at the entrance of Quintupeu Fjord.

Habitat and Biology: The specimens are patchily distributed in clusters on hard, moderately steep to nearly vertical substrates between 15 and at least 59 m depth. At Huinay dock the predominant substrate is soft bottom, with a scattering of stones and rocks to which the observed colonies were anchored with encrusting holdfasts ( Fig. 3 ).

We have regularly observed amphipods of the species Caprella equilibra Say, 1818 clinging to the stem of the gorgonian.

Etymology. The species is named after the Comau Fjord, the type locality.

Figures

FIGURE 2. Swiftia comauensis sp. nov., holotype UCR 2378; A, Complete colony; B, Branch detail, after preservation in ethanol.

FIGURE 3. Swiftia comauensis sp. nov., live colonies in situ, Río Tambor (type locality), 20 m.

FIGURE 4. Swiftia comauensis sp. nov., holotype UCR 2378; A – C, spindles, scale 0.1 mm; D, point bar-like rods, scale 0.1 mm; E, tentacular scales, scale 0.03 mm.