Mycale (Mycale) Gray 1867

Subgenus Mycale (Mycale) Gray, 1867

Type species. Hymeniacidon lingua Bowerbank, 1864 (= Mycale (Mycale) lingua).

Remarks. The subgenus is cosmopolitan and rich in species (approximately 50 accepted species to date, cf. Van Soest et al. 2020), but it is likely to be non-monophyletic (Loh et al. 2012). The tangential ectosomal skeleton is a disorganized mass of single intercrossing spicules. Many species have a grooved surface and often have a full complement of spicules, mycalostyles, several sizes of anisochelae and of sigmas and often trichodragmas. Toxas are rare. The smallest anisochelae may frequently have their lower alae reduced to a single stick-like extension of the shaft crowned by a small spur. These features are shared with species of subgenera Mycale (Oxymycale) Hentschel, 1929 and Mycale (Rhaphidotheca) Kent, 1870. With these subgenera Mycale (Mycale) also occasionally shares species with size categories of the mycalostyles. In contrast to Hajdu (1995) we employ here categories of mycalostyles only if there is a clear length difference, because width differences are strongly influenced by growth stage of the spicule. Bluntly rounded pointed ends are also considered subject to variation within the same mycalostyle type.

Among the species occurring in the region, there is a puzzling complex formed by specimens having the identical spicule complement of Mycale (Mycale) grandis (Gray, 1867), but exhibiting two distinct habitus features, (1) red specimens usually occurring somewhat hidden underneath and between corals, often covered partially by sediment, with a smooth surface showing a faint reticulation, and (2) in contrast white specimens, forming thick cushions in exposed position, with the surface distinctly punctate. Preliminary unpublished molecular sequence data (both of 28S and 18S genes) obtained by us from several red individuals and a single white one show small (2–3) differences in the composition of base pair positions. This induced us to consider these M. (M.) grandis forms as potentially specifically different, and we chose to name them provisionally M. (M.) grandis ‘red’ and M. (M.) aff. grandis ‘white’, treated below among the Mycale (Mycale) species in alphabetical order. The justification to treat them separately is debatable, because the type material of early species united under M. (M.) grandis remains incompletely known lacking the decisive information on live color. The red and white ‘morphs’ of this complex resemble the orange and white individuals found in the Caribbean Mycale (Mycale) laevis (Carter, 1882), described and investigated by Loh et al. (2012). No distinct genetic groupings were detected in that species.

Less binary color divisions are found in Mycale (Mycale) crassissima (Dendy, 1905), with color shades varying from orange, via greenish or bluish to whitish. No separate treatment for these are made below.