Mycale (Mycale) ernsthentscheli Van Soest & Hooper, 2020 comb.nov.

Mycale macilenta var. australis Hentschel. 1911: 296, fig. 6a–d.

Mycale hentscheli Hooper in Hooper & Wiedenmayer, 1994: 288.

Mycale (Carmia) hentscheli; Calcinai et al. 2013: 42, figs 26G–N.

Mycale (Carmia) ernsthentscheli Van Soest & Hooper, 2020: 33 .

Summary description. Encrusting, two specimens, but no further details on the habitus. Ectosomal skeleton a dense tangential layer of megascleres carried by choanosomal megsclere tracts that fan out beneath the surface. Rosettes of anisochelae I present. Spicules mycalostyles 232–306 x 3–4 µm, anisochelae I 32–41 µm, anisochelae II 12–20 µm, sigmas I 67–105 µm, sigmas II 17–30 µm (reported subsequently by Calcinai et al. 2013), toxas I 80–230 µm, toxas II present but no size given (toxas respectively 190–270 µm (I) and 47–115 µm (II) reported subsequently by Calcinai et al. 2013), micracanthoxeas 4 µm (subsequently reported by Calcinai et al. 2013).

Distribution. Shark Bay, Western Australia, 7–12 m depth, on coral reefs.

Comments. Calcinai et al. 2013 re-examined the type ZMB 4402 and found that Hentschel’s description of the spicules omitted to report small sigmas and micracanthoxeas. Remarkably, Calcinai et al. assigned the species to subgenus Carmia, but discussed it in their remarks on Mycale (Aegogropila) furcata . They gave no reason for the assignment to Carmia, but presumably this was caused by the fact that Mycale macilenta, of which this species originally was assigned to as a variety, is the type species of Carmia . The description by Hentschel of a dense tangential layer of megascleres in his specimens leaves little doubt that this species is not a member of Carmia .

A possible senior synonym is Mycale multisclera Pulitzer-Finali, 1993 (cf. below), but this remains uncertain as the description of that species is inadequate.

Hooper in Hooper & Wiedenmayer (1994: 288) proposed a new name Mycale hentscheli for Mycale macilenta australis Hentschel, 1911 from Shark Bay, Western Australia, because the subspecific name australis was already in use for Mycale (Grapelia) australis (Gray, 1866) . However, when Carmia hentscheli Bergquist & Fromont, 1988 was transferred to Mycale the name became a senior secondary homonym of Hooper’s name. ICZN Art. 57.3 required a new name to remove the homonymy, which was proposed recently as M. (C.) ernsthentscheli Van Soest & Hooper, 2020 . We now believe this needs to be transferred to subgenus Mycale .