Mycale (Mycale) grandoides, 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 : 135-137

Mycale (Mycale) grandoides sp.nov.

Figs 87 a–d, 88a–g

Material examined. Holotype ZMA Por. 02904, Indonesia, Nusa Tenggara, Sapeh Strait , 8.3916°S 119.0733°E, bottom corals and shells, depth 69 m, dredge, coll. Siboga Expedition stat. 049a, field nr. SE1345.4, 14 April 1899.

Paratype ZMA Por. 01613, Indonesia, Nusa Tenggara, between Komodo and Sumbawa, 8.5°S 119.125°E, bottom dead corals and sand, depth 73 m, dredge, coll. Siboga Expedition stat. 310, field nr. SE54 CXIII–I, 12 February 1900 .

Description ( Fig. 87 a–b). The holotype ( Fig. 87a ) has a detached cylindrical shape with both ends rounded, size 3 cm high, 1 cm in diameter. The paratype ( Fig. 87b ) has a similar cylindrical shape, so this is likely an important feature of the species, Surface is smooth (holotype) or slightly roughened (paratype) and lacks visible openings. The color in alcohol is dirty white to pale orange. Consistency compressible, but crumbly and easily damaged.

Skeleton ( Figs 87 c–d). Plumose, with long undivided spicule tracts ( Fig. 87c ), 80–130 µm in diameter, separated at distances of 400–600 µm. In the deeper parts of the choanosome many loose megascleres are strewn without arrangement. Anisochelae I occur in clusters ( Fig. 88a ) that may be characterized as indistinct rosettes and and anisochelae II occur in vaguely circular arrangement ( Fig. 88b ), associated with the skeletal tracts, but neither form clear rosettes. At the surface ( Fig. 87d ), there is a dense mass of intercrossing tangentially arranged megascleres, carried by the extended endings of the choanosomal tracts.

Spicules ( Figs 88 c–i). Mycalostyles, three categories of anisochelae, two categories of sigmas, trichodragmas.

Mycalostyles ( Figs 88c,c 1 ), slightly rounded or straight, with narrow bluntly rounded heads, without visible constricted ‘neck’, with sharply pointed end, 405– 485.7 –576 x 11– 14.1 – 19 µm.

Anisochelae I ( Fig. 88d ), of ‘normal’ shape, with free part of the shaft approximately 35% of spicule length, with prominent oval upper alae, lower median alae broad with straight upper rim, lower latera alae rounded, 57– 77.8 – 90 µm.

Anisochelae II ( Fig. 88e ), very common in both specimens, shape compact, globular in outline, with free part of the shaft 15% or less of the length of the spicule, with upper alae extended outwards but with rims curved inwards agains, shape of alae oval with rounded rims, with lower alae also well-developed, both median and lateral alae rounded, 25– 30.6 – 37 µm.

Anisochelae III ( Fig. 88f ), upper alae dominating, forming a sheath around the upper part of the shaft, lower part lacking alae and provided with a distinct spur, 16– 18.8 – 22 µm.

Sigma I ( Fig. 88g ), about 1–1.5 µm in thickness, asymmetrical, 39– 48.1 – 60 µm.

Sigma II ( Fig. 88h ), thin, tending to be symmetrical, 13– 19.3 – 24 µm.

Trichodragmas ( Fig. 88i ), straight, compact, variable in length, 15– 28.5 –39 x 5– 6.4 – 9 µm.

Distribution and ecology. Both specimens were obtained from nearby localities in Sape (or Sapeh) Strait between the islands of Komodo and Sumbawa, Indonesia, at greater depths (69–73 m).

Etymology. Grandoides is a composite word consisting of grandis, a Latin adjective meaning great or large, and -oides, a suffix from Ancient Greek meaning ‘resembling’; the composite name is chosen because of the similarity of the present species to Mycale (Mycale) grandis .

Remarks. The new species resembles M. (M.) grandis in the overall spicule complement, with all spicule types of that species present in approximately the same size range, except for anisochelae I. The latter lacks the size and characteristic shape, being much more compact, with oval upper alae and shorter free part of the shaft. Anisochelae II are even more compact than those of M. (M.) grandis , and its upper alae curve outwards giving the shape a characteristic globular outline. The mycalostyles appear oxea-like in having a narrow bluntly rounded head lacking any swelling or subterminal neck. The shape of the specimens is fingerlike unlike most M. (M.) grandis specimens. Because of the paucity of material for the new species and lack of in situ images, it is possible that some of the mentioned differences may turn out to have limited value for distinction of M. (M.) grandis and M. (M.) grandoides sp.nov. if more and better known material will be found.

The nearest to this species in morphology is probably Mycale (Mycale) sundaminorensis sp.nov. The two are compared below.

There is also considerable similarity with M. (M.) crassissima , which has the same spicule complement, but the shape of the anisochelae II is clearly different.

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 87. Mycale (Mycale) grandoides sp.nov., a, preserved habitus of holotype ZMA Por. 02904, from Sapeh Strait, Indonesia (scale bar = 1 cm), b, preserved habitus of paratype ZMA Por. 01613, from the same region, c–d, light microscopic images of the skeleton of the holotype, c, cross section of peripheral skeleton, d, tangential ectosomal crust.

FIGURE 88. Mycale (Mycale) grandoides sp.nov., holotype ZMA Por. 02904, from Sapeh Strait, Indonesia, a–b, light microscopic images of anisochelae clusters, a, rosette-like cluster of anisochelae I, b, clusters of anisochelae II, c–i, SEM images of the spicules, c, mycalostyle, c1, details of mycalostyle, d, anisochela I, e, compact globular anisochela II, f, spurred anisochela III (please note anisochelae not at same scale), g, sigma I, h, sigma II, i, trichodragma.