Adelogorgia adusta, Breedy, 2018

Breedy, Odalisca, 2018, Revision of the genus Adelogorgia Bayer, 1958 (Cnidaria: Anthozoa: Octocorallia) with the description of three new species, Zootaxa 4369 (3), pp. 327-348 : 344-347

Adelogorgia adusta sp. nov.

( Figs. 12–13 , 7C )

Material examined.

Holotype: STRI-HH 1220 , ethanol preserved, Hannibal Bank , Panamá, 73 m deep, Dive 293, submersible Nadir, M / V Alucia, 9 April 2015.

Paratypes: STRI-HH 1289 (3 fragments), ethanol preserved, Hannibal Bank, 91 m deep, Dive 297, submersible Nadir, M/V Alucia, 13 April 2015. STRI-HH 1307 (complete colony), ethanol preserved, Hannibal Bank, 94 m deep, Dive 297, submersible Nadir, M/V Alucia, 13 April 2015.

GenBank accession number MF579540 .

Diagnosis. Colonies bushy, branching lateral, without anastomoses. Branches of nearly uniform thickness 3-4 mm in diameter with wide tips up to 4.5 mm in diameter. Branching up to 10 times. End branches up to 3.5 cm long. Polyps distributed all around the branches. Polyp mounds closely placed, and slightly raised. Anthocodiae with 8 slightly curved spinous rods in points up to 0.23 mm long. Coenenchyme with tuberculate spindles, up to 0.20 mm long, double discs with serrate edges up to 0.09 mm long and 0.10 mm wide; and leaf clubs up to 0.18 mm long. Outermost coenenchyme with predominance of double discs. Axial sheath containing radiates up to 0.12 mm long and 0.10 mm wide. Colony bright red. Sclerites red, orange, whitish to transparent, and bicoloured.

Description. The holotype is a bushy, 11 cm long and 12 cm wide colony, branching is mostly lateral and in several planes, up to four ( Fig. 12A ). The stem, 3 mm in diameter, rises a few millimetres from a 1.5 cm diameter holdfast. It subdivides producing several secondary branches of uniform thickness, about 3 mm diameter, with wider tips, 3–4.8 mm diameter. Some branchlets are thinner about 2–2.5 mm in diameter. The branches mostly bifurcate 0.5–1.0 cm apart, at angles of 45–90°. The colony branches up to 10 times. Unbranched terminal ends are 1.5–3.5 cm long ( Fig. 12 A-B). The axes are composed of longitudinal gorgonin layers with a loculated central cord filled with organic fibres without mineralization ( Fig. 7C ). The polyps are distributed evenly all around the branches, closely placed about 1 mm apart. The polyps are fully retractile into slightly raised polyp mounds, with circular polyp apertures ( Fig. 12B ). The polyp mounds do not have a special type of sclerites but they mostly contain leaf clubs and spindles. The anthocodiae are composed of eight points consisting of about 8 almost straight and slightly bent spiny rods, without a collaret. The anthocodial rods are 0.10-0.23 mm long and 0.02–0.03 mm wide ( Fig. 13A ). The coenenchyme is moderately thick. The superficial layer with a dominance of red and orange double discs, and wide globose spindles, white, orange, red and bicoloured ( Fig. 13C ). Beneath this layer are the warty spindles, radiates, and immature forms ( Fig. 13 D-E) The leaf clubs are 0.11–0.18 mm long and 0.045–0.06 mm wide with warty handles and elongated or foliate heads ( Fig. 13B ). The spindles are 0.15–0.20 mm long and 0.06–0.08 mm wide ( Fig. 13C ); smaller immature forms are 0.11–0.12 mm long and 0.04–0.07 mm wide ( Fig. 13D ); and globose radiates are 0.08–0.12 mm long and 0.06–0.10 mm wide ( Fig. 13E ). The double discs are 0.06– 0.09 mm long and 0.07–0.10 mm wide ( Fig. 13F ). Coenenchymal sclerites are red, orange, whitish to transparent and bicoloured with the inner part red and the periphery transparent ( Fig. 12C ). The colour of the colony is bright red when recently collected ( Fig. 12A on deck photograph), it gets darker after ethanol preservation or dry to a brownish orange, looks like burnt ( Fig. 12B ).

Variability. The paratype STRI-HH 1307 is a 10 by 10 cm colony, more openly branched than the holotype, and mostly branching in two planes. It has a small black coral attached at the base. Cirripedia tumours were found in some branches of the holotype and the paratype STRI-HH 1307.

The other paratypes are two 2 cm fragments. The paratypes’ characteristics are according with those of the holotype.

Habitat and Distribution. The species was found in the Hannibal Bank, on rocky substrates impacted by currents. Adelogorgia adusta is only known from the type locality Hannibal Bank, from 73 to 94 m deep. Etymology. Named adusta, Latin adjective meaning burnt, scorched, charred, in allusion to the burnt appearance that the colony takes after fixation. The word adustus, in Castellan language, adusto, was evoked in verse 62 of The Fable of Polifemo and Galatea (Spanish poet Luis de Góngora) referring to the son of the Pirineo (giant mount) who supposedly was put in flames.

Remarks. The colony colour and the shape of A. adusta are clearly different from the other four species. The closest species could be A. phyllosclera which is similar in the lateral branching style, thickness of branches and end-branches length, especially in the paratype STRI-HH 1307. But the sclerites composition and size of anthocodial sclerites definitely separate these species. Differences between the species are shown in Tables 1 and 2.

Figures

FIGURE 12. Adelogorgia adusta sp. nov., STRI-HH 1220 (holotype). (A) colony; (B) detail of the branches; (C) sclerites. B, photograph by Sean Mattson.

FIGURE 13. Adelogorgia adusta sp. nov., STRI-HH 1220 (holotype) SEM micrographs. (A) anthocodial rods; (B) leaf clubs; (C) spindles; (D) spindles from inner coenenchyme; (E) globose radiates; (F) double discs.

FIGURE7. Structure of non-mineralised axes:Longitudinal sectionof axial core showing chamberswith fibres (left); detail of fibres (right).(A) Adelogorgia osculabunda; (B) Adelogorgia hannibalis; (C) Adelogorgia adusta.