Mycale (Carmia) rhaphidotoxa Hentschel, 1912

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 : 72-73

Mycale (Carmia) rhaphidotoxa Hentschel, 1912

Figs 47 a–h

Mycale rhaphidotoxa Hentschel, 1912: 340 , pl. XIX fig. 16.

Mycale (Carmia) raphidotoxa ; Carballo & Hajdu 2001: 214.

Material examined. ZMA Por. 08838, Indonesia, Nusa Tenggara, Komodo , north cape, 8.4833°S 119.5683°E, depth 10–17 m, SCUBA, coll. R. W.M. van Soest, Indonesia-Dutch Snellius II Expedition stat. 096, field nr. 096/ IV/33 , 19 September 1984 (dark brown); ZMA Por. 08937, Indonesia, Sulawesi, SE Sulawesi, SW Salayar, reef N of Pulau Bahuluang, 6.45°S 120.43°E, depth 10–15 m, SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 169, field nr. 169/ IV/05 , 30 September 1984 (blackish brown).

Description ( Fig. 47a ). Thin veneer covering coralline algae on dead coral, one specimen also on a keratose sponge ( Fascaplysinopsis reticulata ). Size 2–3 cm in lateral expansion, thickness a few mm. Colors in life reported as dark brown or blackish brown, beige in preservation. Surface in life showing striking venal pattern, but this is retracted in preservation. Consistency soft.

Skeleton ( Fig. 47b ). Delicate and paucispicular. Thin, wispy megasclere tracts (up to 30 µm diameter, 5–7 spicules in cross section) are separately running from the substratum to the surface, where they fan out in brushes of individual spicules. No cross-connecting tracts. Tissue grainy. Microscleres occur throughout the choanosome, but are more common near the surface. Bundles of raphidotoxas are not common, most are scattered individually.A few rosettes of anisochelae I were noted, but likewise most anisochelae are scattered individually.

Spicules ( Figs 47 c–h). Mycalostyles, three categories of anisochelae, one category of sigmas, raphidotoxas.

Mycalostyles ( Fig. 47c, c 1 ), thin, with barely developed elongate heads, 199– 209.6 –224 x 1.5– 2.6 – 3 µm.

Anisochelae I ( Fig. 47d ), well-developed, free part of the shaft 35–40% of spicule length, with slightly outcurving upper median alae, 31– 36.7 – 40 µm

Anisochelae II ( Figs 47e,e 1 ), generally similar to anisochelae I but with upper median alae parallel to shaft, with distinct lip on median lower alae, 17– 21.2 – 29 µm

Anisochelae III ( Fig. 47f ), rather reduced but with median upper and lower alae well-developed, 12– 14.1 – 15 µm.

Sigma I ( Fig. 47g ), robust, narrow-shaped, 76– 92.6 –104 x 3– 4.4 – 5 µm.

Raphidotoxas ( Figs 47h ), thin, curved irregularly but occasionally symmetrically toxiform, 124– 188.0 –241 x 0.5 µm.

Distribution and ecology. Indonesia, reef slope, 10– 17 m.

Remarks. There are two differences between our specimens and Hentschel’s description (which was confirmed in Carballo & Hajdu 2001): the mycalostyles of the type apparently were longer and thicker (304–392 x 5–6 µm) and its chelae were only distinguished in two size categories (39–45 µm and 17–20 µm). The latter difference may be explained by the similarity in shape of the smaller chelae categories, which may have caused Hentschel to consider them a single variable category. The difference in mycalostyle size is here explained as intraspecific variation, but it might indicate interspecific diversity. See also below for further indication of the latter possibility.

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 47. Mycale (Carmia) rhaphidotoxa Hentschel, 1912, ZMA Por. 08838 from Indonesia, a, preserved habitus, thinly encrusting on limestone substratum (scale bar = 1 cm), b, cross section of peripheral skeleton showing spicule brushes and grainy interior, c–h, SEM images of spicules, c, mycalostyle, c1, details of mycalostyle, d, anisochela I, e, anisochela II in back/side view, e1, anisochela II in front view, f, anisochela III (all anisochelae in same magnification), g, sigma, h, raphidotoxas grading into thin toxas.