Mycale (Zygomycale) isochela 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 : 190-191

Mycale (Zygomycale) isochela Hentschel, 1911

Mycale isochela Hentschel, 1911: 297 , fig. 7.

Summary description. Encrusting algae, foraminifera and mollusk shells, size up to 11 cm in lateral expansion. Color (in alcohol) mixed purple and yellow. Consistency soft. Ectosomal skeleton aegogropila-like, with triangular meshes formed by tracts containing 1–5 megascleres in cross section. Hentschel did not mention the presence of rosettes of anisochelae. Choanosomal skeleton with branching tracts with thickness of 6 spicules, spongin not apparent. Below the surface the tracts fan out carrying the ectosomal skeleton. Spicules: mycalostyles 216–255 x 4–5 µm, anisochelae I 17–20 µm, isochelae 10–20, sigmas I 17–22 µm, toxas 45–50 µm, trichodragmas 20 µm.

Distribution. Shark Bay and Freemantle region, West Australia, depth 7– 11 m.

Comment. The species stands out among Mycale (Zygomycale) of the region by having only a single category of small anisochelae.

Key to the Mycale (Zygomycale) species from the region

1 A single category of small anisochelae............................................. Mycale (Zygomycale) isochela

- Two or more categories of anisochelae.................................................................... 2

2 A single category of small sigmas (<30 µm); toxodragmas frequently ‘double’ (diamond-like)............................................................................................... Mycale (Zygomycale) sibogae sp.nov.

- Two distinct categories of sigmas, the larger one 80 µm or more................................................ 3

3 Two categories of anisochelae, micracanthoxeas present, no trichodragmas.............. Mycale (Zygomycale) pectinicola

- Three categories of anisochelae, no micracanthoxeas, trichodragmas present............... Mycale (Zygomycale) parishii

Global diversity and distribution of the subgenus Mycale (Zygomycale)

We queried the World Porifera Database (Van Soest et al. 2020) and added the above results from our Indo-West Pacific Mycale (Zygomycale) study to arrive at the current tentative estimate of known accepted species, which numbers 7. Their distribution over the world oceans summarized as the numbers of species found in Marine Ecoregions of the World (cf. Spalding et al. 2007) is presented in Fig. 124 . The subgenus is typically circumtropical, with no species known from colder water.

Subgenus uncertain

Figures

FIGURE 124. Global diversity and distribution of the subgenus Mycale (Zygomycale) based on data derived from the World Porifera Database 2020 combined with the new data from the present study. The map presents the number of species found in each of the Marine Ecoregions of the World (Spalding et al. 2007).