Chrysogorgia upsilonia, Cordeiro, Ralf T. S., Castro, Clovis B. & Pérez, Carlos D., 2015

Cordeiro, Ralf T. S., Castro, Clovis B. & Pérez, Carlos D., 2015, Deep-water octocorals (Cnidaria: Octocorallia) from Brazil: Family Chrysogorgiidae Verrill, 1883, Zootaxa 4058 (1), pp. 81-100 : 90-93

Chrysogorgia upsilonia sp. nov.

( FigS. 2 A,D, 6, 7)

Holotype: MNRJ 6016, 22°42'26"S, 40°07'63"W, Rio de Janeiro, 1300 m (1 colony with broken base).

Paratype: MNRJ 8567, same collection data of the holotype (1 colony with broken base).

Diagnosis: Chrysogorgia with uniplanar wiry colonies, slightly flexible at terminal branches, sparse and straight branches and strongly dichotomous branching pattern. Polyps cylindrical, sparsely distributed only on convex face of the colony, perpendicularly or slightly inclined upwards. Body wall of zooids filled with tuberculated spindles, longitudinally arranged. Coenenchymal scales with serrated margins, sometimes with a median waist and with small and low tubercles. Tentacular scales irregular with serrated margins.

Description: Colony uniplanar, slightly convex, 14 cm maximum height, with sparse straight branches curved on the polypar face. Branching pattern strongly dichotomous ( Fig. 2 A,D). Axis with smooth texture, base broken (lost). Uniform diameter in main stem (1.9 mm). Diameter of secondary branches decreases every bifurcation; thickness of last branches typically 0.1 mm. Branches up to tenth order, most commonly fifth to eighth. First bifurcations with angles 65°–70°; last bifurcations angles 30°–45°. Main stem 16.8 mm long. Branches 4–30 mm long, regardless of order. Polyps cylindrical polyps, to 4.0 mm long, 1.3 mm diameter ( Fig. 6 A), sparsely distributed only on convex face, perpendicularly or slightly inclined upwards. Body wall of zooids filled with tuberculate spindles, longitudinally arranged, 0.25–0.67 mm long ( Fig. 6 A,B, 7A). Coenenchymal scales with serrate margins, sometimes waisted and with small, low tubercles, 0.08–0.33 mm long and 0.03–0.08 mm wide ( Fig. 6 C, 7B). Tentacular scales irregular, with serrate margins, 0.06–0.16 mm long and 0.02–0.04 mm wide ( Fig. 6 D, 7C).

Variability of paratype: A striking feature of the paratype is the extremely short (3 mm) second-order branch. Another difference is the number of remaining polyps in each colony, which is due to damage caused by collection method. There is little variation between the sclerites of the holotype and those of paratype.

Remarks: Although incomplete (lacking holdfast) ( Fig. 2 A,D), it seems to us that the specimens had its main stems broken near the basis, as typically occurs in chrysogorgiids attached to hard substrates that were collected by trawling ( Fig. 1 C,E,F,G). Therefore, here we describe the species with a dichotomous branching pattern; nevertheless this interpretation would change if new specimens show a different pattern.

According to the species groupings within the genus Chrysogorgia proposed by Wright & Studer (1889) and Versluys (1902)—see Cairns (2001: 755) — Chrysogorgia upsilonia could not fit within the group B (squamosae aberrantes), because species of this group possess rods and /or spindles in tentacles but not in the body wall; neither in group C (squamosae typicae), since it includes species that do not have rods or spindles, just scales. The group A (spiculosae) comprises species with rods and/or spindles in body wall and tentacles, which also does not fit C. upsilonia , which has spindles in the body wall and scales in tentacles. However, group A (spiculosae) contains the only one known species with a dichotomous branching pattern: C. pellucida Kükenthal, 1908 , with distribution restricted to Japan. This has polyps up to 2.5 mm long, in contrast with the polyps to 4.0 mm in C. upsilonia sp. nov. A second difference is the shape and size of the polyp spindles, which are flat and up to 0.12 mm long in C. pellucida while being tuberculate and up to 0.67 mm in new species. Ultimately, the creation of a Group D (spiculosae aberrantes) seems to be the most reasonable way to group this unique species and prevent possible new conflicts in the systematics of Chrysogorgia .

Etymology: From the Greek ύψιλον (ýpsilon, “upsilon”), letter of the Greek alphabet (corresponding to the Latin letter “ Y ”). In relation to the manner in which the main stem bifurcates in this species. Gender female. Distribution: Known only from type locality, Off Rio de Janeiro, 1300 m.

Figures

FIGURE 1. Map of collection stations of Chrysogorgiidae in Brazil.

FIGURE 2. Deep-water Chrysogorgiidae from Brazil. A: holotype of Chrysogorgia upsilonia sp. nov. (MNRJ 6016); B: holotype of Chrysogorgia tuberculata sp. nov. (MNRJ 8565); C: Chrysogorgia multiflora Deichmann, 1936 (MOUFPE-CNI 147); D: Paratype of Chrysogorgia upsilonia (MNRJ 6016); E: juvenile colony of Chrysogorgia fewkesi Verrill, 1883 (MNRJ 6703); F: adult colony of C. fewkesi (MOUFPE-CNI 148); G: Chrysogorgia elegans (MNRJ 6785); H: holotype of Radicipes kopelatos sp. nov. (MNRJ 8566). Scale bars: 10 mm.

FIGURE 6. Sclerites of Chrysogorgia upsilonia sp. nov. (MNRJ 6016). A: polyp view; B: spindles from body wall; C: coenenchymal scales; D: tentacular scales. Scale bars: A: 1.0 mm; B: 0.05 mm; C – D: 0.1 mm.