Rubrafasciculus fijiensis Ekins, Erpenbeck & Hooper, 2023

Ekins, Merrick, Erpenbeck, Dirk, Debitus, Cécile, Petek, Sylvain, Mai, Tepoerau, Wörheide, Gert & Hooper, John N. A., 2023, Revision of the genus Fascaplysinopsis, the type species Fascaplysinopsis reticulata (Hentschel, 1912) (Porifera, Dictyoceratida, Thorectidae) and descriptions of two new genera and seven new species, Zootaxa 5346 (3), pp. 201-241 : 232

Rubrafasciculus fijiensis Ekins, Erpenbeck & Hooper sp. nov.

Figures 13 , 17

urn:lsid:zoobank.org:act:864716BE-93A6-4514-9B25-6F193E7BC40B

Material examined.

Holotype QM G312740, Shark Reef , Viti Levu , Fiji, - 18.30027778 S, 178.0169444 E, 29.5 m, outer reef drop-off, outside point, sheer coral slope, SCUBA, NCIOCDN4234M, Coll. J.N.A. Hooper, 25/X/1996.

Etymology. named after the location where it was first discovered.

Distribution. This species is currently known only from the Fiji Islands ( Fig. 13 ).

Description:

Growth form:A long massive sponge creeping over the surface ( Fig.17A ).The original sponge was approximately 15 cm long, by 5 cm wide, by 5 cm deep. The remaining fixed holotype is only a 5 cm wide hemisphere ( Fig. 17 B ).

Colour: The sponge is a dark brown to grey coloured massive sponge underwater. Spiderweb-like traces formed by sand can be observed where it is incorporated into the conules ( Fig. 17 C ). In 70% ethanol, the exterior colour is a green to grey, influenced by the epibionts. The interior colour is a creamy brown, with bright red fibres ( Fig. 17 B )

Oscules: The sponge has few conules, scattered over the surface. The oscula opening is approximately 3 mm in size.

Texture: The sponge is compressible, firm and tough.

Surface: The sponge has a conulose surface, the blunt conules are 3–4 mm in height and separated by 3–5 mm ( Fig. 17 B ). The exterior surface is often overgrown by epibionts such as algae.

Ectosomal skeleton:It has an armoured surface consisting of sand incorporated into the ectosome of approximately 700–1000 μm ( Figs. 17 B, C, G ).

Choanosomal skeleton: The choanosome is composed of thick collagenous material. The skeleton in this hemispherical part of the sponge is a fairly regular radial pattern of large (300–700 μm in diameter) laminated cored primary fibres ( Fig. 17 C–F ), these primary fibres are loosely fasciculated and connected in loose ladder like formation of uncored laminated secondary fibres (100–250 μm in diameter) ( Figs. 17 E, H ).

Ecology. This species lives on hard dead coral substrates of the reef, at 30 m in depth. It is overgrown with encrusting algae, sponges, ascidians and hydroids.

DNA Barcodes.

28S: Holotype QM G312740 (OX458938)

ITS: Holotype QM G312740 (OX458948)

Remarks. This species differs by the difference in fasciculation, the lack of geometric patterning in the surface, the encrusting habit, and the lack of obvious fistules as well as lacking the red colouration.

Figures

FIGURE 13. Distribution of Rubrafasciculus cerasus sp. nov. and Rubrafasciculus fijiensis sp. nov. Base map modified from freevectormaps.com.

FIGURE 17. Rubrafasciculus fijiensis sp. nov. A. Holotype QM G312740 underwater. B. Holotype QM G312740 fixed. C. Cross section through the ectosome and choanosome, whilst undergoing bleach digestion. Note the sand armouring. D. Branching large cored primary fibres that emerge through the ectosome. E. Large sand cored primary fibres fasciculated with uncored secondary fibres. F. Microscope section showing a cored laminated primary fibre. G. Microscope section showing the heavy armouring and clear secondary fibres. H. Microscope section showing the clear secondary fibres connecting the heavily cored primary fibres.