Stephanogorgia rattoi, Castro & Medeiros & Loiola, 2010

Castro, C. B., Medeiros, M. S. & Loiola, L. L., 2010, Octocorallia (Cnidaria: Anthozoa) from Brazilian reefs, Journal of Natural History 44 (13 - 14), pp. 763-827 : 819-821

Stephanogorgia rattoi sp. nov.

( Figures 1 , 24A,A′ )

Diagnosis

Stephanogorgia without sclerites; terminal branches up to 53 mm long (average 6– 27 mm long); branches originated all over colony; branches of lower region of colony do not reach colony apex; contracted polyps up to 0.8 mm high and 0.9 mm wide.

Description

Holotype complete colony 87 mm in height, 89 mm in width, with main axis 2 mm in diameter near basis; paratypes 30–160 mm in height, 5–124 mm in width, with main stem 0.6–4.8 mm in diameter at base. Planar colonies (although a few specimens almost bushy), with monopodial pinnate branching, no anastomosis ( Figure 24A ). Axes approximately circular in transverse section, strongly calcified on lower parts of colony and with flexible terminal twigs. Axis yellowish to metallic copper-coloured. First ramification 2–15 mm from colony bases. Trunk diameter just below first ramification 0.6–3.1 mm. Branching may proceed at least up to fifth order. Branches alternate on both sides of main axis, internodes from 0.9 to 15 mm long, measured between successive branchlets, average interval being from 3.1 ± 0.9 to 5.8 ± 3.1 mm. Main axis often bends slightly away from lateral branches forming zigzag course ( Figure 24A ). Median branches diameter 0.2–1.7 mm, with average in different colonies varying from 0.38 ± 0.10 to 1.05 ± 0.38 mm. Terminal branches maximum length from 12 to 53 mm on different colonies, but on average undivided branchlets from 8.4 ± 2.0 to 27.3 ± 13.3 mm long; terminal branches diameter 0.1–0.6 mm, with average in different colonies varying from 0.1 ± 0.02 to 0.43 ± 0.12 mm. Polyps placed biserially along branches, alternating or opposite ( Figure 24A′ ). Depending upon state of contraction, polyps from nearly cylindrical, trumpet-shaped, conical, to almost globose, rising from branches obliquely towards distal end of branches. Polyps up to 0.8 mm high and 0.9 mm wide; average 0.2 ± 0.06 to 0.46 ± 0.11 mm high and 0.40 ± 0.06 to 0.69 ± 0.08 mm wide. Polyps close-set on distal branches (up to 0.9 mm apart, average from 0.16 ± 0.05 to 0.54 ± 0.27 mm apart), becoming sparser on median (up to 1.6 mm apart, average from 0.2 ± 0.17 to 1 ± 0.4 mm apart), and basal (up to 2.1 mm apart, average from 0.16 ± 0.08 to 0.9 ± 0.6 mm apart) parts of colonies. Density of polyps on terminal branches from 14 to 39 per centimetre (average from 20.9 ± 4.39 to 32.4 ± 3.65 polyps per centimetre). Polyps pale yellow or white, column translucent; polyps and coenenchyme in specimens from Califórnia Reef bright orange. No sclerites.

Material

Holotype. Brazil: Bahia, Pedra Grande , Parcel das Paredes, 17°44′44.1′′ S, 038°55′08.7′′ W, c. 16 m, collected by B. Segal and C. B. Castro, 19 February 2000 ( MNRJ 06071 ) ( Figure 1 ).

Paratypes. Brazil: Bahia, Off Itacolomis Reefs, 16°56′29′′ S, 039°00′24′′ W, 14–22 m ( MNRJ 03684 ) ; “ Salteado de Timbebas ”, 17°25′34.3′′ S, 038°58′16.6′′ W, 23 m ( MNRJ 04323 ) ; south of Parcel de Timbebas , 17°30′22.4′′ S, 039°00′47.5′′ W, 3.5– 13 m ( MNRJ 04324 ) ; Parcel de Timbebas , 17°30.057′ S, 039°00.776′ W ( MNRJ 02844 , 02845 ) ; Pedra Grande , Parcel das Paredes, 17°44′44.1′′ S, 038°55′08.7′′ W, c. 16 m ( MNRJ 04319 – 14 paratypes) ; Lixa Reef , Parcel das Paredes, 17°46.54′ S, 039°01.58′ W, 12 m ( MNRJ 02954 ) ; Lixa Reef , Vigilante, Parcel das Paredes ( MNRJ 03064 ) ; Parcel das Paredes , 17°52′37.83′′ S, 038°58′34.15′′ W ( MNRJ 03169 ) ; Popa Verde Reef , Abrolhos Bank, 18–20 m ( MNRJ 02967 ) ; Califórnia Reef , 18°06′07.8′′ S, 038°35′26.0′′ W, 15–32 m ( MNRJ 04071 – seven specimens; 04318 – 24 specimens) ; Califórnia Reef , 18°07′ S, 038°34′ W, 20–30 m ( MNRJ 04146 – 16 specimens; MNRJ 06000 ) ; south-east of Califórnia Reef , 18°34′00′′ to 18°39′48′′ S, 038°04′00′′ to 037°52′13′′ W, 65 m ( MNRJ 04823 , MNRJ 05994 ) ; Espírito Santo, off Doce River , 19°42.626′ to 19°43.857′ S, 039°26.321′ to 039°26.372′ W, 100–417 m ( MNRJ 04221 ) ( Figure 1 ).

Etymology

In honour of Cláudio Continentino Ratto, for his help in several field and laboratory stages of the current study and for his keen eye that made him the first to recognize the octocoral nature of these chrysogorgiids while collecting underwater.

Remarks

Three species were assigned to Stephanogorgia by Bayer and Muzik (1976), namely: S. wainwrighti Bayer and Muzik, 1976 , from a depth of 10 m at Fiji Islands, S. diomedea Bayer and Muzik, 1976 , from a depth of 37 m at the Philippines, and S. faulkneri (Bayer, 1974) , from a depth of 14 m at Palau Islands. The new species, collected at depths of 12–239 m at the Abrolhos Bank, Brazil, can be readily distinguished from these by the absence of sclerites in the new species. This is the first record of this genus in the Atlantic Ocean.

Figures

Figure 1. Map of distribution of reef octocorals in different regions off the Brazilian coastline. The Espírito Santo State area (*) includes the Vitória- Trindade seamount chain. “BA Sector” refer to a division of reef areas in Bahia State by Leão (1996).

Figure 24. Stephanogorgia rattoi sp. nov. (MNRJ 04319 – type series): (A) colonies, (A′) branches. Trichogorgia brasiliensis sp. nov. (MNRJ 03191 – holotype): (B) colony, (B′) branches. Scale bars: A, B, 2 cm; A′, B′, 2 mm.