Leptogorgia pseudogracilis, 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 : 804-807

Leptogorgia pseudogracilis sp. nov.

( Figures 1 , 16C,C′ , 19)

Pterogorgia gracilis Verrill 1868a: 359 , pl. IV, figs. 2, 2a, 3 [specimen c, but not specimens a, b and d = Olindagorgia Bayer 1981c ]

? Lophogorgia barbadensis: Tixier-Durivault 1970: 158 . [Non- L. barbadensis: Bayer 1961: 199–201 , text-fig. 59j–l].

Diagnosis

Colonies pink or dull yellow, flattened, sparsely branching up to the third level. Coenenchymal mounds low or absent, laterally flattened, slightly conical or round. Coenenchymal sclerites colourless or light pink Anthocodial armature poorly developed, with flattened rods sparsely distributed on polyp walls.

Description

Colonies up to 252 mm high (holotype 143 mm high), 171 mm wide, flattened, sparsely branching up to the third level, diverging from both sides of main stem and branches ( Figure 16C ). Trunks up to 54 mm long (holotype 23 mm long), 2.2 mm thick near basis. Main branches slightly curved, up to 151 mm long (holotype 116 mm long), 2.2 mm thick with polyp mounds, and 1.9 mm thick without polyp mounds; more slender towards distal end (1.1 mm thick with polyp mounds and 0.8 mm without polyp mounds). Secondary branches almost straight, up to 79 mm long, 1.0 mm thick at basis; up to 1.8 mm thick with polyp mounds and 1.0 mm thick without polyp mounds near basis; up to 0.9 mm thick with polyp mounds and 0.8 mm thick without polyp mounds near end. Terminal twigs almost straight, up to 37 mm long, 0.6 mm thick at basis; up to 1.1 mm thick with polyp mounds and 0.6 mm thick without polyp mounds near basis; up to 0.8 mm thick with polyp mounds and 0.6 mm thick without polyp mounds near end. Polyps mainly in two lateral rows, very rarely on other sides of trunk and branches; almost always alternate, opposite in some few areas. Branches with thickened ends (up to 1.8 mm) because of the presence of two opposite polyp mounds ( Figure 16C′ ). Polyp mounds low (up to 0.5 mm high by 2.4 mm wide) or absent, laterally flattened, slightly conical or round; distance between polyp mounds from 4.5 mm (near the basis of main branches) to almost contiguous; four to eight polyp mounds per centimetre. Trunk, near basis of colony, without polyp mounds. Coenenchyme of distal branches mostly with acute spindles with densely set tubercles (up to 0.17 mm long, Figure 19A ); basal branches mostly with smaller blunt spindles and capstans ( Figure 19B ). Axial sheath with similar sclerites, but with smaller and sparser tubercles: acute spindles in distal branches ( Figure 19C ), blunt spindles and capstans in basal branches ( Figure 19D ). Polyps with flattened rods, with crenate margins (up to 0.12 mm long, Figure 19E ), sparsely distributed on polyp walls. Colony colour (fixed in alcohol) pink or dull yellow; coenenchymal sclerites colourless or light pink; anthocodial rods colourless. Axis brownish, slightly fibrous.

Material

Holotype. Brazil: Rio de Janeiro, off north of São Tomé Cape (21°38′57′′ S, 040°10′47′′ W) ( MNRJ 05083 , 100–180 m) ( Figure 1 ).

Paratypes. Brazil: Bahia, one specimen, Abrolhos Reefs ( YPM 1516 specimen c – former syntype of Pterogorgia gracilis Verrill, 1868a ) ; Espírito Santo, four specimens, off mouth of Doce River (19°45′00′′ S, 039°31′38′′ W) ( MNRJ 04910 , 66–68 m) ( Figure 1 ) .

Etymology

From the Greek pseudos (false) and the Latin gracilis (slender). The name refers to the fact that a specimen of this species was formerly included among the syntypes of Pterogorgia gracilis Verrill, 1868 .

Remarks

Other species of Leptogorgia recorded from Brazilian waters differ from the present specimens mainly in the following points.

• L. violacea has thicker branches that strongly curve upwards and run nearly parallel to each other.

• L. punicea has profusely branched colonies, with thicker branches and conspicuous, close-set polyp mounds.

• L. miniata has colonies somewhat similar to L. pseudogracilis , but its anthocodial rods are longer (0.14–0.19 mm) than its coenenchymal spindles. These anthocodial rods are arranged in multiple rows on the points of the crown.

The description by Tixier-Durivault (1970) of specimens from the Abrolhos area as Leptogorgia barbadensis agrees with the characteristics of the specimens herein described. However, L. barbadensis , from the Caribbean, has very peculiar sclerites, with very long and slender anthocodial rods and inner coenenchymal spindles ( Bayer 1961: fig. 59j–l).

Other species of Leptgorgia with symmetrically developed tuberculation have been described from the western Atlantic Ocean. Leptogorgia cardinalis ( Bayer 1961) , described from Florida and Cuba, has dark orange-red colonies, with colourless or amber-yellow sclerites, and anthocodial rods as long as the acute spindles ( Bayer 1961). Leptogorgia hebes ( Verrill, 1869) , from North Carolina to Texas [the specimens of Bayer (1961) from Brazil herein considered as L. punicea ], has profusely branched colonies, polyps in alternating double rows on terminal twigs and sclerites as blunt, ovate capstans ( Bayer 1961).

The description by Carpine and Grasshoff (1975) of coenenchymal sclerites of Leptogorgia sarmentosa (Esper, 1791) , from the Mediterranean Sea, agrees with the characteristics of our specimens – mainly acute spindles in apical and blunt spindles and capstans in basal branches. The pink colour of the coenenchyme has been recorded (as a rare condition) in Mediterranean specimens [ Weinberg (1976), as L. ceratophyta (Linnaeus, 1758) ]. Grasshoff (1992) showed that L. sarmentosa is a highly variable species, occurring in the Atlantic from the Gulf of Biscay to Morocco. He presented detailed illustrations of several colony–sclerite combinations of L. sarmentosa , which clearly differ from those of Brazilian specimens. It is unlikely that our specimens belong to L. sarmentosa . Grasshoff (1992) also stated that no amphi-Atlantic species of gorgonian has been recorded so far. Indeed, none of the 28 European and West African species of Leptogorgia reviewed by Grasshoff (1992) resembles L. pseudogracilis .

The specimens studied here do not possess spindles or capstans with partially fused tubercles, as described in L. setacea ( Pallas, 1766) and other species of Leptogorgia sensu Bayer, 1961 .

A specimen from lot MNRJ differed in comparison to other colonies from this lot and to the specimen in lot MNRJ 05083. This specimen was more slender (252 mm high and 80 mm wide) and less ramified (only to the second level). It also had very low or almost absent polyp mounds (up to 0.4 mm high), which gives a much less flattened aspect to the branches. These variations were not considered strong enough to separate these specimens into a different species or to classify them in any other species of Leptogorgia .

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 16. Leptogorgia punicea (Milne-Edwards and Haime, 1857) (MNRJ 01839): (A) colony, (A′) branches. Leptogorgia violacea (Pallas, 1766) (MNRJ 00368): (B) colony, (B′) branches. Leptogorgia pseudogracilis sp. nov. (MNRJ 05083): (C) colony, (C′) branches. Scale bars: A–C, 2 cm; A′–C′, 5 mm.

Figure 19. Sclerites of Leptogorgia pseudogracilis sp. nov. (MNRJ 05083): (A) coenenchyme of distal branches; (B) coenenchyme of basal branches; (C) axial sheath from distal branches; (D) axial sheath from basal branches; (E) anthocodia.