Mycale (Oxymycale) klausjanusorum Van Soest, 2018

Figs 106 a–j

Mycale (Oxymycale) klausjanusorum Van Soest, 2018: 50, figs 1–3.

Material examined. Holotype ZMA Por. 09452, Indonesia, Flores Sea, SW Salayar, E of Bahuluang, 6.485°S 120.45°E, depth 295–300 m, rectangular dredge, coll. J. van der Land, Indonesian-Dutch Snellius II Expedition, stat. 217, 12 October 1984.

Paratypes (detached fragments) ZMA Por. 09459, same data as holotype .

Summary description. The species has been recently erected in a separate paper (Van Soest 2018), but for completeness sake its properties are here summarized, including a summary illustration. For more extensive illustrations see Van Soest 2018. Shape (Fig. 106a) semiglobular, white (preserved), markedly hispid encrustations of up to 2 x 1 x 1 cm on calcareous rubble. Consistency firm. Choanosomal skeleton (Fig. 106b) strongly plumose, with thick tracts (500–600 µm diameter) fanning out close to the surface into thinner tracts carrying the tangential ectosomal skeleton. This tangential surface skeleton is penetrated by strongly developed bouquets of long megascleres crowning the subectosomal tracts. Spicules include longer substylostyle megascleres (Figs 106c,c 1), 992– 1175 x 19–22 µm, making up the surface bouquets, but also occurring in the choanosomal tracts, shorter oxeote megascleres (Figs 106d,d 1), 522–732 x 14–20 µm, concentrated in the tangential ectosomal skeleton, but also occurring in the choanosomal tracts, microscleres consisting of three categories of anisochelae, I (Fig. 106e) 152–189 µm, II (Fig. 106f) 33–57 µm, III (Fig. 106g) spurred, 21–29 µm, the largest occurring in subectosomal rosettes, two categories of sigmas, I (Fig. 106h) 33–54 µm, II (Fig. 106i) 16–27 µm) and trichodragmata (Fig. 106j) 24–107 µm.

Distribution and ecology. Indonesia (Flores Sea), 300 m depth. For differences with the northern Pacific Mycale (Oxymycale) koreana (Sim, 1982) and M. (O.) rhoi (Sim & Lee, 1998), and with Western South African M. (O.) stephensae Samaai & Gibbons, 2005, see Van Soest (2018).

Additional species of Mycale (Oxymycale) reported from the region

There are no definite additional Mycale (Oxymycale) species present, as neither Oxymycale stecarmia De Laubenfels, 1954: 93, nor Oxymycale strongylophora De Laubenfels, 1954: 94 were found to be members of the subgenus after re-examination of fragments of the types.

Oxymycale stecarmia (type USNM 22890) from SW Ponapé (approx. 6.94°N 158.28°E) is a semi-encrusting sponge specimen of 2 x 4 x 1 cm, of which the skeleton is a haplosclerid reticulation of mucronate oxeas 150–185 x 4 µm in size. The skeleton is largely unispicular, but there are primary tracts of up to 3 spicules in diameter, with little binding spongin, without microscleres. Overall it is Haliclona -like, but on the surface there are small clumps of Mycale spicules, including ‘normal’ anisochelae of 47–51 µm, two size classes of cleistochelae 16–23 µm and 12– 15 µm, sigmas of 22–30 µm, and a few toxodragmas of 50–52 µm. We conclude that this ‘species’ is predominantly a Haliclona spec. with just some contamination from a nearby growing Mycale (Naviculina) aff. cleistochela .

Oxymycale strongylophora (type USNM 22937, cf. also Fig. 78f above) from Ailing-lap-lap Atoll (7.3817°N 168.7667 E) is in all described aspects a typical Mycale (Mycale) grandis ‘red’: a red-orange massive sponge, with a dense layer of ectosomal mycalostyles and thick choanosomal megasclere tracts, mycalostyles with both blunt and more sharply pointed endings, 468–576 x 11–17 µm, typical grandis anisochelae I 121–141 µm (see above Fig. 81d), a few anisochelae Ib 71–89 µm, anisochelae II 25–29 µm, spurred anisochelae III 15–19 µm, sigmas I 45–59 µm (NOT: 120 µm, we did not find such sigmas in our fragment), sigmas II 17–19 µm, and abundant fusiform trichodragmas 25–52 x 7–9 µm. There is little doubt that this is a typical specimen of the wide-spread Mycale (Mycale) grandis ‘red’.

Global diversity and distribution of the subgenus Mycale (Oxymycale)

We queried the World Porifera Database (Van Soest et al. 2020) and added the above results from our Indo-West Pacific Mycale (Oxymycale) study to arrive at the current tentative estimate of known accepted species, which numbers 10. 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. 107. One species, M. (O.) renieroides (Schmidt, 1870), is dubious (cf. question mark in Fig. 107). The subgenus is circumglobal, but its distribution is erratic, due no doubt to its likely non-monophyly (cf. Van Soest 2018).