Trichogorgia brasiliensis, 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 : 821-823

Trichogorgia brasiliensis sp. nov.

( Figures 1 , 24B,B′ , 25)

Diagnosis

Trichogorgia with polyps alternating or opposite on lateral sides of branches; polyps small (less than 2 mm high); sclerites on polyps and coenenchyme; polyp sclerites more densely distributed on polyp’s abaxial side; coenenchymal sclerites sparse (margins of adjacent sclerites usually do not overlap).

Description

Lower parts of axes strongly calcified. Holotype complete colony 200 mm in height, c. 130 mm in width, with main axis 1.4 mm in diameter near basis; paratype (MNRJ 04312) 180 mm in height, 45 mm in width, with main stem 1.2 mm in diameter near basis. Planar colonies, with lateral to almost dichotomical branching, no anastomosis ( Figure 24B ). Axes approximately circular in transverse section, strongly calcified on lower parts of colony and with extremely flexible terminal twigs. Axis creamy whitish, with metallic hues. Ramifications exclusively on lower part of colonies. Branch internodes from 6 to 8 mm long, measured between successive branchlets, average interval 7.0 ± 1.5 mm. Median branches diameter 0.3–0.5 mm, with average of 0.35 ± 0.08 mm. Terminal branches maximum length from 22 (small colony) to 150 mm in different colonies; on average undivided branchlets 122.2 ± 20.1 mm long; terminal branches diameter 0.1–0.2 mm, with average in different colonies varying from 0.12 ± 0.02 to 0.13 ± 0.02 mm. Polyps placed biserially along branches along all branches, alternating or opposite ( Figure 24B′ ); rarely polyps inclined 45° away from polyp rows. Depending upon state of contraction, polyps from nearly cylindrical to almost globose, rising from branches obliquely towards distal end of branches. Polyps up to 0.54 mm high and 0.56 mm wide; average 0.31 ± 0.01 to 0.41 ± 0.12 mm high. Polyps close-set on distal branches (up to 0.8 mm apart, average 0.6 ± 0.01 mm apart), becoming sparser on lower (up to 1.3 mm apart, average 0.70 ± 0.36 mm apart) parts of colonies. Density of polyps on terminal branches from 12 to 21 per centimetre (average 16.5 ± 3.16 polyps per centimetre); denser on median branches (15 to 34, average 27.0 ± 5.3 polyps per centimetre); sparser on main branches (four to eight, average 6.3 ± 2.1 polyps per centimetre). Sclerites as twisted scales on polyps and coenenchyme ( Figure 25 ), 0.03–0.25 mm long (average 0.10 ± 0.05 mm long); polyp sclerites more densely distributed on polyp’s abaxial side; coenenchymal sclerites sparse (margins of adjacent sclerites usually do not overlap).

Material

Holotype. Brazil: Bahia, Lixa Reef , Parcel das Paredes, 12 m, collected by C.C. Ratto, 8 June 1996 ( MNRJ 03191 ) ( Figure 1 ).

Paratypes. Brazil: Amapá, off Maracá Island , 03°00.0′ N, 048°20.0′ W, 117 m ( MNRJ 06072 ) ; Bahia, Califórnia Reef, Parcel dos Abrolhos, 18°06′07.8′′ S, 038°35′26.0′′ W, 15–32 m ( MNRJ 04312 ) ( Figure 1 ) .

Etymology

The epithet refers to the place of origin of the type material (“ Brasil ” in Portuguese).

Remarks

There are five previously described species of Trichogorgia currently assigned to this genus, namely: T. flexilis Hickson, 1904 (type species), from a depth of about 100 m from South Africa; T. constricta (Hiles, 1899) , from Indonesia; T. capensis ( Hickson, 1904) , from depths of 46–73 m in South Africa; T. viola Deichmann, 1936 , from a depth of about 80 m from western Tortugas; and T. lyra Bayer and Muzik, 1976 , from depths of 23–183 m off Yucatan (to the east), Atlantic Central America and Atlantic Colombia. Trichogorgia flexilis can be distinguished from the new species by its polyps being “very numerous, crowded on all sides of terminal branches and closely set on the sub terminal branches” and its calyces and coenenchyme “protected by a great number of calcareous overlapping scale-like spicules, arranged in a single layer” ( Hickson 1904: 223). Trichogorgia capensis and T. lyra can be readily distinguished from the new species because they do not have sclerites. Trichogorgia constricta has polyps much larger [6.5 mm high ( Kükenthal 1924)] than all other species. Trichogorgia viola is a species of uncertain identity. It was described from small fragments with almost no polyps [“most of which [polyps] have been torn off” ( Deichmann 1936)]. Deichmann (1936) also stated that “the poor condition of the specimens makes it impossible to decide whether they belong to Hickson’s T. flexilis ... or not”.

Final comments

A few other species recorded from reef areas in the Caribbean ( Bayer 1961) have been collected off Brazil, although not specifically in reef areas. They may be added to the list of octocorals from Brazilian reef or their vicinities in the future. These species include:

• Diodogorgia nodulifera (Hargitt; in Hargitt and Rogers 1901), collected off Pará (00°16′ N, 044°28′ W, off the Amazon River ( USNM 55461 [91m]).

• Iciligorgia schrammi Duchassaing, 1870 , collected off Pará [ Bayer, 1959; 02°35′ N, 048°14′ W, USNM 50846 – “ Oregon ” Sta. 2063; 00°16′ N, 044°28′ W, USNM 55257 – “ Oregon ” Sta. 4223 (91 m); 00°17′ N, 044°27′ W, MNRJ 01255 (former USNM 55258 ) – “ Oregon ” Sta. 4224 (110 m); 00°18′ N, 044°17′ W, USNM 55259 – “ Oregon ” Sta. 4226 (273 m)] .

• Leptogorgia miniata ( Milne-Edwards and Haime, 1857) , collected off Pará [00°17′ N, 044°27′ W, off Carutapera, Marajó Bay, USNM 56277 (110 m); 00°27′ S, 047°09′ W, off Carutapera, Marajó Bay , USNM 56276 / MNRJ 01828 (22 m)] and Maranhão [01°50′ S, 043°06′ W, off São Luís Island , USNM 56278 / MNRJ 01827 (67 m)] .

• Pacifigorgia elegans ( Milne-Edwards and Haime, 1857) , collected off Maranhão (Banco do Álvaro, MNRJ 03962).

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.

Figure 25. Sclerites of Trichogorgia brasiliensis sp. nov. (MNRJ 03191): (A) frontal view; (B) side view.