Mycale (Carmia) raphidiophora Hentschel, 1911

Van, Rob W. M., Aryasari, Ratih & De, Nicole J., 2021, Mycale species of the tropical Indo-West Pacific (Porifera, Demospongiae, Poecilosclerida), Zootaxa 4912 (1), pp. 1-212 : 70

Mycale (Carmia) raphidiophora Hentschel, 1911

Figs 46 a–i

Mycale raphidiophora Hentschel, 1911: 291 .

Mycale (Carmia) raphidiophora ; Shaw 1927: 424 (no description).

Material examined. ZMA Por. 11176, Seychelles, Mahé, of SE coast, 4.7667°S 55.55°E, depth 45–50 m, rectangular dredge, coll . R. W.M. van Soest, Netherlands Indian Ocean Expedition stat. 742, field nr. IOP-E 742/04, 24 December 1992 (red) ; ZMA Por. 12704, Seychelles, Mahé, off SE coast, 4.7667°S 55.55°E, depth 45–50 m, rectangular dredge, coll . R. W.M. van Soest, Netherlands Indian Ocean Expedition stat. 742, field nr. IOP-E 742/03, 24 December 1992 (red) .

Description ( Fig. 46a ). Encrusting shells, up 6 x 4 cm in lateral expansion, several mm thick. Red colored in life, in preservation grayish beige. Surface irregular, slightly punctate, no visible openings. Consistency soft, easily damaged.

Skeleton ( Fig. 46b,b 1 ). The interior of the sponge is filled with refractile grains. The skeleton consists of thick spicule tracts of 55–110 µm diameter (consisting of 8–12 megascleres in cross section) coursing from the substratum to the surface, where they fan out into brushes of individual spicules. The surface membrane is charged with microscleres and these also are scattered in the tissue between the refractile grains. Rosettes of anisochelae I, 80–125 µm in diameter, are rare but do occur in both specimens.

Spicules ( Figs 46 c–i). Mycalostyles, three categories of anisochelae, two categories of sigmas, raphidotoxas.

Mycalostyles ( Figs 46c,c 1 ), short, fusiform, and comparatively robust, with prominent head and subterminal neck, 254– 277.6 –298 x 4– 6.4 – 8 µm.

Anisochelae ( Fig. 46d ) I, robust with well developed upper and lower alae, free part of the shaft 30–35% of spicule length, 44– 47.8 – 52 µm.

Anisochelae II ( Fig. 46e ), narrow-shaped, well-developed upper and lower alae, free part of shaft about 35% of spicule length, 19– 21.9 – 25 µm.

Anisochelae III ( Fig. 46f ), reduced, with poorly developed upper and lower lateral alae, 10– 14.2 – 18 µm.

Sigmas I ( Fig. 46g ), robust, narrow-shaped, asymmetrical, 71– 85.1 –105 x 4.5– 6.1 – 7 µm.

Sigmas II ( Fig. 46h ), thin (1 µm or less in thickness), almost symmetrical, 17– 18.3 – 21 µm, quite rare in ZMA Por. 11176.

Raphidotoxas ( Figs 46i,i 1 ), usually arranged in loose bundles, curved shape, about 1 µm thick in the middle, 250– 338.5 – 462 µm.

Distribution and ecology. Seychelles, West Australia, possibly Tasmania, on shells, collected at greater depth (down to 50 m).

Remarks. The description of Hentschel of the holotype from West Australia differs in several aspects, anisochelae I are only up to 28 µm (against up to 50 µm in our specimens), and within the smaller anisochelae no distinction was made into anisochelae II and III, sized only 12–15 µm (against 10–24 µm in our specimens). Furthermore, no sigma II were mentioned by Hentschel, but these are easily overlooked in many specimens of Mycale , and are rare in our specimens. The occurrence on shells, the shape of the mycalostyles, the presence of raphidotoxas and robust sigma I are similarities between the holotype and our specimens. We prefer to emphasize these similarities.

There is considerable resemblance to Mycale (Carmia) rhaphidotoxa Hentschel, 1912 , which will be treated below. The difference between the two species as defined here is the more delicate skeletal tracts and the apparent absence of sigmas II in M. (C.) rhaphidotoxa .

There are several other species in the region possessing raphidotoxas, see below, M. (C.) raphidotoxa Hentschel, 1912 , M. (C.) tenuichela sp.nov., and M. (C.) tydemani sp.nov. The present material stands out by having relatively robust skeleton and spicules, and detailed small differences (cf. key below).

Figures

FIGURE 1. A. Numbers of available specimens for the present study from the collections of the Naturalis Biodiversity Center distributed over Indo-West Pacific Marine Ecoregions (MEOWS, cf. Spalding et al. 2007). B. Ditto for type specimens and additional specimens from other institutions consulted for this study.

FIGURE 46. Mycale (Carmia) raphidiophora Hentschel, 1911, ZMA Por. 11176, from the Seychelles, a, preserved habitus encrusting a bivalve shell (scale bar = 1 cm), b, light microscopic image of peripheral skeleton, b1, ditto of choanosomal skeleton, c–i, SEM images of spicules, c, mycalostyle, c1, details of mycalostyle, d, anisochela I, e, anisochela II, f, anisochela III (all anisochelae in same magnification), g, sigmas I, h, sigma II, i, raphidotoxa, i1, details of ends and middle part of raphidotoxa.