Bebryce inermis, Namin & Van Ofwegen, 2010

Namin, Kaveh Samimi & Van Ofwegen, Leen P., 2010, An overview of Bebryce (Cnidaria, Octocorallia, Plexauridae) species with tiny rosettes, with the description of a new species from the Gulf of Oman, Zoosystema 32 (3), pp. 479-493 : 480-490

Bebryce inermis n. sp.

( Figs 1 ; 2A, B ; 3-7 )

TYPE MATERIAL. — Holotype: Oman. 23°31’38.92”N, 58°44’23.32”E, coll. K. Samimi Namin, 1.XII.2007, 1 colony ( MNHN).

Paratypes: Oman. 23°31’48.88”N, 58°43’40.89”E, coll. K. Samimi Namin, XI.2007, 1 colony ( RMNH Coel. 38923). — 23°31’23.73”N, 58°44’50.58”E, coll. K. Samimi Namin, 30.XI.2007, 3 colonies ( RMNH Coel. 38924). — 23°31’48.88”N, 58°43’40.89”E, coll. K. Samimi Namin, 19.V.2009, 4 colonies ( RMNH Coel. 38925). — Daymaniyat islands, 23°50’20.85”N, 57°58’11.19”E, coll.K.SamimiNamin, 5 colonies ( RMNH Coel. 39556). — Bandar Al-Khiran, 23°31’38.92”N, 58°44’23.32”E, 3 colonies ( RMNH Coel. 39557). — Daymaniyat islands, 23°51’42.96”N, 58°07’10.15”E, coll. K. Samimi Namin, 27.V.2009, 4 colonies ( RMNH Coel. 39558). — 23°32’1.80”N, 58°42’54.06”E, coll.K.Samimi Namin, 8.VI.2009, 1 colony ( RMNH Coel. 39559).

ETYMOLOGY. — Latin “inermis”, unarmed, without weapons, defenceless, toothless, without a sting, refers to the calyx margin spindles without split antler-like projection.

DESCRIPTION

The holotype is fan-shaped without anastomoses. The colony is 6.5 cm high and 7 cm wide, the main stem is about 2 mm wide and branching starts at the base of the main stem ( Fig. 2A ). Polyps are situated all around the branches with prominent calyces about 1 mm high. Some parts of the colony, mostly at the base, are covered with an encrusting sponge.

Polyps are retracted and have 3-6 spindles per point. These spindles are up to 0.35 mm long and have spines or a spiny leaf at their distal end ( Fig. 4A ). Th e collaret has 2 or 3 rows of bent spindles, up to 0.40 mm long ( Fig. 4B ). Tentacles have bow-shaped spindles up to 0.07 mm long, and a few small rods, up to 0.05 mm long.

At the margin of the calyces spindles are present, up to 0.12 mm long, with an unilateral projection ( Fig. 4C ).

The surface layer sclerites are rosettes, up to 0.05 mm long, with warty, rounded, or bristle-like projections ( Fig. 4 D-F).

In the subsurface layer a few rosettes occur, up to 0.12 mm long ( Fig. 5A ). Most sclerites are stellate plates, up to 0.18 mm long ( Fig. 5B ). Furthermore, several less developed sclerites are also present ( Fig. 5C ).

Colour

Live colonies were brown-yellowish in colour with yellow polyps ( Fig. 3 ); preserved it is brown, sclerites colourless.

VARIABILITY

Several paratypes have a bushy colony shape ( Fig.2B ). Also the sclerites differ between colonies, in about half of the paratypes the stellate plates with long rays are few in number; also the number of rosettes with bristle-like projections is much smaller in these specimens ( Figs 6 ; 7 ). Very little is known about sclerite characters to use for identification of Bebryce species. At present we consider these observed differences to represent intra-specific variation rather than describing two related species.

HABITAT

Most of the specimens can be seen in dark places such as cracks and caverns on underwater cliffs and walls, often hanging down. We observed all collected specimens to be overgrown by sponges on some parts of the colony.

REMARKS

For comparison with B. studeri we used the material described by Grasshoff (1999): ORSTOM HG

200, New Caledonia, S lagon, Îlot Canard, stn 136, 23 m depth; material stored in the MNHN (under MNHN-Oct.0000-0569). Bebryce studeri differs from B. inermis n. sp. in having different calyx margin spindles, with a split projection ( Fig. 8C ), almost antler-like. Additionally, it lacks poorly developed subsurface sclerites ( Fig. 9 ). For further comparison we also present polyp sclerites and rosettes of B. studeri ( Fig. 8A, B, D, E ).

For comparison with B. stellata we used RMNH material from the type locality Ambon, collected during the 1996 LIPI-NNM Fauna Malesiana Maluku Expedition. Bebryce stellata differs from B. inermis n. sp. and B. studeri in having many ellipsoids in the subsurface layer.

Two colonies of RMNH Coel.39558 have several small colonies of an unknown Astrogorgia Verrill, 1868 species attached to the branches.

Figures

FIG. 1. — Localities of the Bebryce Philippi, 1842 species with tiny rosettes: 1, New Caledonia; 2, Funafuti; 3, Bonin islands, Japan; 4, Ambon, Indonesia; 5, Oman.

FIG. 2. — A, B, Bebryce inermis n. sp.; A, holotype (MNHN); B, paratype (RMNH Coel. 38924); C, D, Bebryce stellata (RMNH Coel. 39560). Scale bars: 10 mm.

FIG. 3. — Live colonies of Bebryce inermis n. sp.: A, a colony with extended polyps,overgrown by sponges on some parts;B, a colony hanging from a rocky underwater cliff. Photos: M. Claereboudt.

FIG. 4. — Bebryce inermis n. sp., holotype (MNHN) and paratype (*, RMNH Coel. 38924): A, point sclerites; B, collaret spindles; C, sclerites of calyx margin; D-F, rosettes of surface layer; E, top views. Scale bars: 0.10 mm.

FIG. 5. — Bebryce inermis n. sp., holotype (MNHN) and paratype (*, RMNH Coel. 38924):A, rosettes of surface layer; B, stellate plates of subsurface layer; C, less developed sclerites of subsurface layer. Scale bar: 0.10 mm.

FIG. 6. — Bebryce inermis n. sp., paratype (RMNH Coel. 39557): A, point sclerites; B, collaret spindles; C, sclerites of calyx margin; D-F, rosettes of surface layer; E, top view. Scale bars: 0.10 mm.

FIG. 7. — Bebryce inermis n. sp., paratype (RMNH Coel. 39557): A, stellate plates of subsurface layer; B, less developed sclerites of subsurface layer. Scale bar: 0.10 mm.

FIG. 8. — Bebryce studeri Whitelegge,1897 (MNHN-Oct.0000-0569):A, point sclerites;B, collaret spindles;C, sclerites of calyx margin; D, E, rosettes of surface layer; E, top views. Scale bars: 0.10 mm.

FIG. 9. — Bebryce studeri Whitelegge, 1897 (MNHN-Oct.0000-0569), stellate plates of subsurface layer. Scale bar: 0.10 mm.