Mycale (Carmia) tydemani, Van & Aryasari & De, 2021

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 : 79-81

Mycale (Carmia) tydemani sp.nov.

Figs 52 a–k

Material examined. Holotype ZMA Por. 02886, Indonesia, Nusa Tenggara, W coast of Lombok, Ampenan , 8.7478°S 116.0579°E, depth 23.4 m, coll. G.F. Tydeman, field nr. SE3015, May 1909.

Not type material. ZMA Por. 10405, Seychelles, Mahé, Pointe au Sel, 4.7333°S 55.5333°E, reef flat, depth 1–2 m, snorkeling, coll. R. W.M. van Soest, Netherlands Indian Ocean Expedition stat. 603, 7 December 1992 (live color yellowish red) .

Description ( Fig. 52a ). Thin encrustations on corals and hydroids, size 3 x 2 x 0.5 cm. Color in life yellowish red ( Seychelles specimen), in preservation similarly reddish beige. Surface smooth, no visible openings. Consistency soft.

Skeleton ( Figs 52b,b 1 ). Choanosomal spicule tracts of 25–80 µm in diameter (4–10 spicules in cross section) run from the substratum to the surface where they fan out into individual spicules. Tracts are not connected, and lie at distances of 200–300 µm. Anisochelae arranged in clusters of about 50–70 µm in size. In the holotype there are no clear rosettes, but in the Seychelles specimen these are common.

Spicules ( Figs 52 c–j). Mycalostyles, three categories of anisochelae, two categories of sigmas, toxas, raphidotoxas, trichodragmata.

Mycalostyles ( Fig. 52c,c 1 ), slim, with prominent elongated heads and pointed opposite ends, 182– 237.9 –276 x 2– 3.4 – 5 µm (ZMA Por. 10405: 246– 260.3 –291 x 3– 3.2 – 4 µm).

Anisochelae I ( Fig. 52d ), well developed, with upper median alae extended outward, free part of the shaft approximately 25–30% of spicule length, lower alae robust, 30– 32.1 – 34 µm (ZMA Por. 10405: 27– 29.9 – 32 µm).

Anisochelae II ( Fig. 52e ), rare, well developed, narrow-shaped, with free part of the shaft only 10–15% of spicule length, 18– 19.6 – 21 µm (ZMA Por. 10405: 17– 18.8 – 22 µm).

Anisochelae III ( Fig. 52f ), with well-developed upper alae, with less developed lower alae, lower median alae with an upward projection, 9– 10.8 – 13 µm (ZMA Por. 10405: 9– 11.0 –13).

Sigmas I ( Fig. 52g ), common, robust, thickness 2.5–3.5 µm, narrow, asymmetrical, 54– 58.6 – 64 µm (ZMA Por. 10405: 65– 73.6 – 81 µm).

Sigmas II ( Fig. 52h ), rare, thin, symmetrical, 11–24 µm (ZMA Por. 10405: 11–16 µm).

Toxas ( Fig. 52i ), rare, thin, deeply curved with upturned endings, 32– 67.4 – 105 µm (ZMA Por. 10405: 68– 90.6 – 120 µm).

Raphidotoxas ( Figs 52j,j 1 ), common, curved, with elongated upturned endings, 310– 335.5 –360 x 0.5 µm (ZMA Por. 10405: 242– 308.2 – 366 µm).

Trichodragmas ( Fig. 52k ), short, fusiform, many loose individual raphides of 0.5–1 µm thick, dragmas are 15– 21.3 –32 x 7–9 µm (ZMA Por. 10405: 15– 21.8 –31 x 5–12 µm).

Distribution and ecology. Indonesia, Seychelles, shallow water down to 23 m.

Etymology. The name is proposed to honour Vice-Admiral Gustaaf Frederik Tydeman, commander of H.M.S. ‘Siboga’, who collected the holotype during a fieldtrip while serving as naval commander in Nederlands Oost Indië.

Remarks. The present specimens differ from other raphidotoxa-possessing species ( M. (C.) rhaphidiophora , M. (C.) rhaphidotoxa and M. (C.) tenuichela sp.nov. described above by possession of the combined presence of robust sigma I, small genuine toxas with upturned wings, and short trichodragmas. From the first two mentioned species, the new species differs also in lacking the grainy/sandy interior.

We are not entirely confident that the two specimens from widely different localities belong to the same species. The holotype has no clear rosettes of anisochelae I, whereas ZMA Por. 10405 has them clear and abundant. Sigmas I differ significantly in size (54–64 in the holotype against 65–81 for ZMA Por. 10405). Also, the toxas of the latter are not curved entirely symmetrically and may have to be considered small raphidotoxa rather than proper toxas. For that reason we refrain from assigning paratype status to ZMA Por. 10405. We provide here the separate measurements of the two individuals, to facilitate future distinction between the two. However, we remain confident the two are members of the same species as the other spicule types conform closely between the two .

Mycale (Carmia) confundata ( De Laubenfels, 1954) from the Mid Pacific is also a species likely possessing raphidotoxas as well as proper toxas, but it apparently has only a single category of small (20 µm) anisochelae and no short trichodragmas.

Mycale (Carmia) levii Samaai & Gibbons, 2005 from the Atlantic coast of South Africa, recently renamed as Mycale (Carmia) samaaii Van Soest & Hooper, 2020 (because it was preoccupied by Mycale (Paresperella) levii Uriz, 1987 ), has the general spicule complement of the present new species, but the spicular dimensions differ significantly: mycalostyles of M. (C.) samaaii are up to 12 µm in thickness, all three anisochelae sizes are larger and not overlapping. The South African species lacks sigma II and has next to raphides (thought to be equivalent to our raphidotoxas) also thin long oxeas of 400–600 µm, which were mentioned as the defining character of the South African species. These differences and the geographic separation are sufficient to consider them separate but closely related species. Samaai & Gibbons compare their species with Lévi’s South African record of Carmia macilenta , which on paper appears exactly like their species, except for the long raphidotoxa-like oxeas. We suggest that Carmia macilenta sensu Lévi (1963) (not: Bowerbank 1866) could belong also to Mycale (Carmia) samaaii .

Additional Mycale (Carmia) species from the region

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 52. Mycale (Carmia) tydemani sp.nov., holotype ZMA Por. 02886, from Indonesia, a, preserved habitus encrusting hydroids (scale bar = 1cm), b, light microscopic image of peripheral skeleton, b1, ditto of cross section of entire sponge, c–k, SEM images of spicules, c, mycalostyle, c1, details of mycalostyle, d, anisochela I, e, anisochela II, f, anisochela III, g, sigma I, h, sigma II, i, toxa, j, raphidotoxa, j1, details of raphidotoxa, k, trichodragma.