Mycale (Zygomycale) pectinicola 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 : 184-187

Mycale (Zygomycale) pectinicola Hentschel, 1911

Figs 120 a–b, 121a–l

Mycale pectinicola Hentschel, 1911: 299 , fig. 8.

Mycale (Zygomycale) pectinicola ; Calcinai et al. 2013: 47, fig. 31, table 14.

Material examined. ZMB 4404 , syntype (2 specimens, Figs 120 a–b), West Australia, Shark Bay, 3.5–16 m depth, coll . R. Hartmeyer & W. Michaelsen, 1905, stats. 9, 14 and 15, 30 September 1905 .

ZMA Por. 07634, Indonesia, Sumatera, Biliton (Belitung), approx. 2.83°S 107.92°E, depth 20–40 m, bottom muddy sand, on Mimachlamys shell (ex ZMA Moll. 143 701), coll. H.H. Dijkstra, from local fishermen, 1986 .

Description. The syntype ( Figs 120 a–b) is massively encrusting the upper ( Fig. 120a ) and lower valves ( Figs 120b ) of shells identified as Mimachlamys spinicostata Dijkstra & Beu, 2018 (Henk Dijkstra in litteris). The greatest thickness of the sponge is up to 6 cm. The thicker parts have a papillate surface. Color (in alcohol) mixture of reddish, greyish and yellowish tinges. The ZMA specimen ( Fig. 121a ) from Indonesia has been cut off from the shell of Mimachlamys sanguinea ( Linnaeus, 1758) . It largely lost its shape and is fragmentary. No ‘skin’ is left, because it was kept in a dry condition before having been put in alocohol. Color on deck ‘polychromatic reddish’.

Skeleton. Choanosomal skeleton ( Fig. 121b ) of spongin-enforced megasclere tracts of 10–15 spicules thick (type), 80–200 µm in diameter (ZMA specimen), fanning out below the surface into thinner tracts with little spongin (type). Ectosomal skeleton of the type is aegogropila-like with triangular-polyangular meshes formed by megasclere tracts with thickness of 5–10 spicules. Inbetween the tracts occur rosettes of anisochelae I (type).

Spicules. Mycalostyles ( Figs 121 c–l), three categories of anisochelae, isochelae, two categories of sigmas, toxas, raphides arranged in trichodragmas, micracanthoxeas.

Mycalostyles ( Fig. 121c,c 1 ), robust with faintly developed heads, 286– 303.2 –318 x 5– 8.6 – 11 µm (ZMA specimen), 200–286 x 4–8 µm (type).

Anisochelae I ( Fig. 121d ), slim, with outward-curved upper median alae and comparatively feebly developed lower alae, free part of the shaft 50% of spicule length, 42– 46.3 – 50 µm ( ZMA specimen), 40–45 µm (type) .

Anisochelae II ( Fig. 121e ), compact, with robustly developed upper and lower alae, with free part of the shaft 15–20% of spicule length, not recognized separately in the type by Hentschel and by Calcinai et al. (obviously included in the size of the anisochelae III), rare in the ZMA specimen, 20–24 µm (n = 5).

Anisochelae III ( Fig. 121f ), with well developed upper alae, but reduced lower alae, 16– 17.1 – 19 µm (ZMA specimen), 15–28 µm (unrecognized anisochelae II included) (type).

Isochelae ( Fig. 121g ), well developed, 10– 10.8 – 12 µm (ZMA specimen), 9–10 µm (type).

Sigma I ( Fig. 121h ), robust, relatively narrow, 76– 81.3 –84 x 4– 4.7 – 6 µm ( ZMA specimen), 80–85 µm (type) .

Sigma II ( Fig. 121i ), smaller and thinner 17– 21.2 – 24 µm x 1 µm (ZMA specimen), but not specified in the type description (Calcinai et al. measured them to be 15–35 µm).

Toxas ( Fig. 121j ), shallow-curved with slightly upturned apices, 57– 70.6 – 98 µm (ZMA specimen), approximately 40 µm (‘4x the length of the isochelae’) described for the type (15–60 µm according to redescription in Calcinai et al.).

Raphides ( Fig. 121k ), fusiform, in trichodragmas, rare, 30– 32.2 –36 x 7–8.0– 10 µm (ZMA specimen); presumably these are mentioned in Hentschel’s description as ‘microxe, spindelf̂rmig, selten’ (measured by Calcinai et al. as 15–20 µm),.

Micracanthoxeas ( Fig. 121l ), fusiform, strongly spined, 3–4 µm (ZMA specimen); presumably not mentioned in the type description, but present nevertheless (Calcinai et al. discovered and measured them to be about 4 µm long, sparingly spined),.

Distribution. Western Indonesia; also Shark Bay, West Australia, 3.5–16 m depth.

Remarks. Calcinai et al. (2013: 47, fig. 31, table 14) studied the type material and published SEM images and measurements of the spicules. We complement this here by providing a photo of the habitus. For further details see Calcinai et al. Our Indonesian specimen conforms closely to the type material, although the original description of the type and its redescription in Calcinai et al. lack details about anisochelae II and III. We also provide the identity of the shells on which the type was encrusted, thanks to Pectinidae expert Henk Dijkstra.Apparently, the sponge has a preference for shells of the genus Mimachlamys Iredale, 1929 .

The spicule complement of M. (Z.) pectinicola is largely similar to that of M. (Z.) parishii (cf. above) and virtually indistinguishable from M. (Z.) ramulosa Carballo & Cruz-Barraza, 2010 . These species both have ramose habitus, which appears to be a clear difference from the present species.

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 120. Mycale (Zygomycale) pectinicola Hentschel, 1911, syntype ZMB 4404, from Shark Bay, W Australia, specimens encrusting both upper (a) and lower (b) valves of Mimachlamys shells (photos N.J. de Voogd).

FIGURE 121. Mycale (Zygomycale) pectinicola Hentschel, 1911, ZMA Por. 07634, from Bilitung, Indonesia, a, preserved habitus (scale bar = 1 cm), b, light microscopic image of cross section of peripheral choanosomal skeleton, c–l, SEM images of the spciules, c, mycalostyle, c1, details of mycalostyle, d, anisochela I, e, anisochela II, f, anisochela III, g, isochela, h, sigma I, i, sigma II, j, toxas, k, raphide/microx, l, micracanthoxeas.