Mycale (Carmia) monomicrosclera Van & Aryasari & De 2021, sp.nov.
Creators: name: Van, Rob W. M.
name: Aryasari, Ratih
name: De, Nicole J.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Poecilosclerida
Mycalidae
Mycale
Mycale monomicrosclera

description: Mycale (Carmia) monomicrosclera sp.nov.
Figs 39 a–e, 40a–d
Not: Mycale monanchorata Burton & Rao, 1932: 329, text-fig. 6; Rao, 1941: 446,
Material examined. Holotype RMNH Por.7288.a, Taiwan, Penghu Islands, Gupoyu, 23.7127°N 119.5524°E, depth 12 m, coll. Y. Huang, 19 August 2010 (orange).
Non-type specimens, ZMA Por. 08405, Indonesia, Nusa Tenggara, E of Komodo, Selat Linta, 8.5833°S 119.57°E, reef, depth 4–11 m, SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 079, field nr. 079/ III/31, 18 September 1984 (orange; slide only); ZMA Por. 16354, New Caledonia, near Nouméa, 22.3333°S 166.4333°E, depth 20 m, coll. B. Richer, ORSTOM (donated by H. Dijkstra), 22 May 1984 (dried).
Description (Figs 39a, 40a). The Taiwanese holotype is a thin orange crust, beige in alcohol, with slippery smooth surface. Consistency soft, rather slimy. It was encrusting a bivalve but is now broken into two equal-sized fragments of 2 x 2 cm (Figs 38a). Surface irregularly microlobate, smooth, no visible openings in preseverved condition. The dried New Caledonia specimen is thickly encrusting on a bivalve shell (Fig. 40a). Color orange in life, pale orange in dry condition. The Indonesian specimen was reported to be also orange, but only a thick section of the skeleton remains (Fig. 39e)
Skeleton. Typically Carmia -like, with a dense choanosomal skeleton of thin spicule tracts, 30–50 µm in thickness, lying parallel at a distance of 100–150 µm, running through the sponge body and thinning out at the surface (Figs 39b,e, 40b). No tangential ectosomal skeleton. No rosettes were observed. Tissue charged with some sand grains and small foreign particles.
Spicule s (Figs 39 c–d, 40c–d). Mycalostyles and anisochelae (no sigmas).
Mycalostyles (Figs 39c,c 1), thin, slightly or strongly curved, occasionally sinuous, occasionally straight. The latter condition is found in the holotype and the Indonesian specimen, 171– 215.8 –352 x 2.5– 3.9 – 5 µm; the New Caledonian specimen has the mycalostyles somewhat shorter and distinctly more curved than both others (Figs 40c,c 1), 170– 230.8 –267 x 2.5– 3.4 – 4.5 µm.
Anisochelae (Fig. 33d, 34d), variable in length but in a single size category, narrow, upper median alae occasionally with a slightly outwardly turned lower rim, lower median alae with a prominent upwardly projecting lobe, free part of the shaft approximately 35% of spicule length, 11– 18.4 – 24 µm.
Distribution and ecology. Taiwan, Indonesia, New Caledonia, on coral reefs, 4–20 m depth.
Etymology. The name is a noun consisting of the Greek word mono = one and the sponge term microsclera = microsclere, referring to the possession of only a single microsclere type in this species.
Remarks. If only spicule complement is taken into account, the present specimens would conform to Mycale monanchorata Burton & Rao, 1932, as this is the only known species so far from the region with a single size of anisochelae as exclusive microsclere category. However, above we proposed that this is likely a junior synonym of Mycale (Arenochalina) imperfecta Baer, 1906. In Mycale (Arenochalina) species often one or both of the microsclere categories are rare or absent, especially in preserved material because of the extreme production of mucus which drains from the skeleton when lifted out of the water, in the process taking microscleres along. Our suggestion is based on observations by Burton & Rao of thick mycalostyle-filled skeletal tracts in M. monanchorata, clearly thicker tracts and anastomosed to form rectangular meshes, whereas our present species has clearly thinner and unconnected tracts. Rao (1941) measured the spicule tracts of M. monanchorata as 60–200 µm. Burton & Rao described the megascleres as having a conspicuous axial canal and compared their specimen to Mycale (Arenochalina) mirabilis. The anisochelae of our specimens are smaller (up to 24 µm vs up to 36 µm in Burton & Rao’s specimen) and did not occur in rosettes like Burton & Rao’s specimen. M. monanchorata is clearly Mycale (Arenochalina) -like in skeletal and spicular properties, similar to M. (A.) imperfecta. Our specimens are not similar to that species and are obvious members of subgenus Carmia, not Arenochalina.
Three similar specimens distributed over a wide area (New Caledonia, Indonesia, Taiwan) confirm the distinctness of the present new species. Because the specimens occur in widely distant localities, and one of the specimens have distinct curved mycalostyles, we refrain from giving type status to the New Caledonian and Indonesian specimens.
The curved-sinuous mycalostyles of the New Caledonian specimen remind somewhat of Japanese M. (C.) tenuisinuositylostyli Hoshino, 1981, but that species has a full complement of microscleres, incuding two size categories of anisochelae, sigmas I and toxas.
In several aspects (life color, skeleton) the new species is similar to Mycale (Carmia) phyllophila Hentschel, 1911 (cf. below). But all specimens we assigned to this species have abundant sigmas, lacking entirely in the present species.
description: Published as part of Van, Rob W. M., Aryasari, Ratih & De, Nicole J., 2021, Mycale species of the tropical Indo-West Pacific (Porifera, Demospongiae, Poecilosclerida), pp. 1-212 in Zootaxa 4912 (1) on pages 61-64, DOI: 10.11646/zootaxa.4912.1.1, http://zenodo.org/record/4450930