Mycale (Arenochalina) Von Lendenfeld, 1887

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 : 33

Subgenus Mycale (Arenochalina) Von Lendenfeld, 1887

Arenochalina Von Lendenfeld, 1887: 821 .

Mycale (Arenochalina) ; Van Soest & Hajdu 2002: 676 (with further synonyms).

Type species. Arenochalina mirabilis Von Lendenfeld, 1887: 821 , pl. 26 fig. 70, pl. 27 fig. 28.

Remarks. The subgenus is recognized by its universal skeletal features (rectangular reticulation of thick spongin fibres cored by thin, often almost vestigial, mycalostyles, and in several species foreign materials such as sand grains, spicule debris, and algal strands) and the production—at least in most species—of copious slime when exposed to air. The ectosomal region usually has an organic thick ‘skin’, in preserved material flaky, and there is usually no elaborate ectosomal skeleton. However, single megascleres and microscleres may be present strewn tangentially in the surface membrane.

Present treatment of this subgenus follows the Systema Porifera, chapter on Mycalidae by Van Soest & Hajdu (2002). This relies heavily on Wiedenmayer’s (1989) descriptions of materials from Australia, where the subgenus appears to be particularly common, and his suggestions for synonymies. We also adopted Hajdu & R̹tzler’s (1998) description of the Western Atlantic material as applying to our specimens. Following this, species of the subgenus are apparently notoriously variable in growth forms and presence of microscleres. Specimens, all co-occurring in the same sympatric localities, may have tubular, massive, stipitate or irregularly ramose form, coarse or more smooth surface, and may lack anisochelae, sigmas, or both. This variability makes it especially difficult to distinguish discrete species over a larger region such as we consider here. A review of the literature identifies a large number of species names in the region considered here apparently belonging to the subgenus: M. (Ar.) mirabilis ( Von Lendenfeld, 1887) , M. (Ar.) spongiosa ( Dendy, 1896) , M. (Ar.) imperfecta Baer, 1906 , M. (Ar.) euplectellioides ( Row, 1911) , M.(Ar.) fistulata Hentschel, 1911 (including var. macrochela ), M.(Ar.) regularis Wilson, 1925 , and M.(Ar.) tylostrongyla Pulitzer-Finali, 1982a . Additional likely Arenochalina species from the region are M. tenuispiculata Dendy, 1905 , and M. monanchorata Burton & Rao, 1932 .

Van Soest (1984: 30), followed by Erpenbeck et al. (2016, supporting information), referred Gelliodes setosa Keller, 1889 to Mycale (Arenochalina) , but we disagree. We examined Keller’s type, ZMB 270, and found this to be conforming to Gelliodes , and not to Mycale (Arenochalina) . The records of Van Soest and Erpenbeck et al. are here assigned to Mycale (Arenochalina) imperfecta Baer, 1906 (cf. below).