Sarcotragus sucinum, Sim & Lee & Kim, 2016

Sim, Chung Ja, Lee, Kyung Jin & Kim, Hyung June, 2016, Ten new species of genus Sarcotragus (Demospongiae: Dictyoceratida: Irciniidae) from Korea, Journal of Species Research 5 (3), pp. 443-458 : 449-450

5. Sarcotragus sucinum n. sp. ( Figs. 5 , 6 )

Type specimen. Holotype (NIBRIV0000325793), Korea:

Jikgudo, Chuja­myeon, Jeju­si , Jeju­do, 5 Nov 2009, Kim HS, by SCUBA , Depth 15 m, deposited in the NIBR .

Description. Thick irregular mass, size up to 10 × 8 × 3 cm. Surface smooth. Conules difficult to distinct except sharp conules on side of sponge. Thick skeletal fibres, irregularly branched out, covered with dense filamentous membrane. Oscules rare, 1 mm in diameter, open on sponge surface. Colour pale gray in life, turn to dark brown upon collection. Texture very soft and compressible. Sponge shape easily changed because soft texture. Choanosome slightly lacunous.

Skeleton: Surface skeletal fibres, thicker than choano­ some’s. Choanosomal skeletal fibres arranged in three dimensions ( Fig. 5F ). All fibres amber colour. Primary fibres, 300­700 μm in diameter, very loose fascicles. Secondary fibres, 50-200 μm in diameter, branched with regular mesh net. Filaments, 5 μm in diameter, terminal knobs, 10­15 μm in diameter.

Etymology. This species name sucinum is named after amber colour of skeletal fibres.

Remark. This new species is similar to Sarcotragus scalaris n. sp. in colour changing, but differs in skeletal structure. Skeletal fibres of S. scalaris n. sp. is arranged like ladder shape in choanosome, but skeletal fibres of this new species have prismatic arrangement with secondary branch in choanosome.

Figures

Fig. 5. Sarcotragus sucinum n. sp.A, entire animal; B, closed surface; C, surface skeletal structure; D, branched secondary fibres with mesh net; E, secondary web between primary fibres; F, choanosome prismatic skeletal structure. Scale bars:A=2 cm, B=10cm, C, F=200μm, D, E=100 μm.

Fig. 6. Sarcotragus sucinum n. sp. A, thick secondary fibres; B, primary fascicles with mesh net; C, choanosome skeletal structure; D, cho­ anosome secondary fibres; E, surface thick skeletal structure; F, thin secondary fibres. Scale bars: A-D, F=100μm, E=1 cm.