Clathria (Clathria) ramus, 2018

Kang, Dong Won & Kim, Hyung June, 2018, Two new species of the Genus Clathria (Demospongiae: Poecilosclerida: Microcionidae) from Jeju Island, Korea, Zootaxa 4504 (3), pp. 390-400 : 391-396

Clathria (Clathria) ramus sp. nov.

(Figs 2–4, Tables 1–2)

Material examined. Holotype. Korea, Jeju-do Island, Seogwipo-si , October 20, 1973, fishing net 100 m depth, coll. B. J. Rho, MABIK IV00164153

Description. Shape (Fig. 2 A): Branching, size up to 85mm wide, 146mm high, 4–11mm thick branch and 6– 8mm thick stalk.

Texture: soft and flexible.

Oscules: 0.4–1.1mm in diameter, scattered on the surface.

FIGURE. 2. Clathria (Clathria) ramus sp. nov.: (A) Image of the holotype specimen, (B) Ectosomal skeleton, (C-F) Choanosomal skeleton, (G) Style, (H) Head of style.

Colour: yellow in life which gradually changes to dark beige in ethanol.

Surface: tough and hispid with spicules.

Skeleton (Fig.2 B–F): Ectosomal skeleton, conspicuously hispid, subectosomal connected forming in plumose bundles of auxiliary styles. Subectosomal skeleton irregularly plumose, exteneding from choanosomal primary fibres. Choanosomal skeleton well-developed primary spongin fibres, thinner connecting secondary fibres, forming a comparatively regularly plumo-reticulate skeleton. Few spicules scattered on primary and secondary fibres. Acanthostyles echinating the primary spongin fibres, cored by multispicular tracts of principal styles, with diameter about 50–100?.

Spicules (Fig.2 G–H, Fig. 3 , Table1–2): Megascleres. Thick styles(Fig. 2 G, H), slightly curved, smooth, with lightly microspined bases. Slender styles( Fig.3 A, B ), straight, long, smooth, with microspined base. Echinating acanthostyles( Fig. 3 C, D ), small, straight, thick, with evenly distributed small spines. Microscleres. Toxas, three categories size, large toxas ( Fig. 3 E–H), wing-shaped, thick, variable in length, the thicker ones with wide angular central curvature, curved arms, slightly reflexed points, and terminal spines. Middle and small toxas ( Fig. 4 A,B ), wing-shaped, thinner ones more sharply curved at centre, sharply pointed. Palmate isochelae( Fig. 4 C,D ), abundant, relatively small, with lateral and front alae approximately same length, lateral alae fused to shaft.

Distribution. So far known only from Jeju-do at depth of 100 m.

Etymology. Named after from the shape of a branch type.

Remarks. Clathria (Clathria) ramus sp. nov. is allocated in the subgenus by having thick styles, thin styles and echinating acanthostyles as megascleres. This new species differs from other Clathria in having palmate isochelae and two categories of toxas (wing-shape). Clathria (Clathria) ramus sp. nov. is compared to other species in Korea in Table. 1.

Species

C. (C.) gimnyeonungensesis

C. (C.) ramus sp. nov. C. (C.) striata Whitelegge, 1907

Kim & Sim, 2008

Character

thick styles 200-(300)-400 × 12-(22.5)-33 250-600 × 18-22 193-(369.5)-546 × 15-(19)-23

slender styles 160-(255)-350 × 3-(4.5)-6 200-450 × 3-6 175-(276.5)-378 × 3.5-(8.5)-8

acanthostyles 100-(125)-150 × 8-(9)-10 80-120 × 4-10 84 -(98)-112 × 6-(8.5)-11

Spicules

isochelae 10-(12.5)-15 Large: 30-40 / Small: 10-15 14 -(17)-20

()

large toxas 110-(255)-400 × 3-(5.5)-8 110-500 × 3-8

middle toxas 70-(80)-90 × 2-(2.5)-3 - 108-(206.5)-305 × 0.8-(1.4)-2

small toxas 30-(40)-50 × 0.5-(0.75)-1 40-90 × 1-2

Growth form branch branch branch

Color in life yellow unknown unknown

The most similar species to C. (C.) ramus sp. nov. is C. (C.) gimnyeonungensesis. However, it differs from the latter by having two categories of palmate isochelae, while C. (C.) ramus sp. nov. has only one category. The thick styles and thin styles of the new species are also smaller than those of C. (C.) gimnyeonungensesis ( Table. 2). We have studied Clathria (Clathria) species in Japan, China and Philippines. However, except for Japan, no paper on Clathria (Clathria) was found in China and the Philippines. Clathria (Clathria) ramus sp. nov. differs from all other Clathria species from Japan based on spicule composition. So, we compared our species to others from the Australian fauna(see Hooper, 1996). Among them, the most similar species to C. (C.) ramus sp. nov. is C. (C.) striata Whitelegge, 1907 . However, it differs from the latter by having only one category of accolade toxas, while C. (C.) raumus sp. nov. has two categories and lacks the accolada toxa. Spicules size are also smaller than those of C. (C.) striata ( Table. 2).

Figures

FIGURE 3. Clathria (Clathria) ramus sp. nov.: (A) Thin style, (B) Head of thin style, (C) Acanthostyle, (D) Head of acanthostyle, (E, G) Large toxa, (F, H) End of large toxa.

FIGURE 4. Clathria (Clathria) ramus sp. nov.: (A) Middle toxa, (B) Toxa; a. middle, b. small, (C) Side view of palmate isochela, (D) Front view of palmate isochela.