Borojevia voigti sp. nov.

Figures 6a–d, 7a–d

Material examined. Holotype, ZMA Por. 13444, Israel, pillar container port, Gulf of Aqaba, depth 5 m, scuba, coll. M. Wunsch, field nr. AQ 65, 5 July 1998.

Description. Cormus (Figs 6a,a 1) a greyish white cushion (Fig. 6a 1, arrow), brighter white in alcohol (Fig. 6a), made up of tightly anastomosed thin tubuli. Oscules small, about 2 mm diameter, flush with the surface. Size of entire specimen is 2.5 x 2 x 1 cm.

Aquiferous system. Asconoid.

Skeleton. (Figs 6b–d) Tubuli walls consist of one–two layers of triactines and tetractines. Apical actines of tetractines protruding into the tubar lumen (Fig. 6d).

Spicules. (Figs 7a–d) Triactines and tetractines, about equal in number. Some trichoxea-like spicules appear present in the spicule slides.

Triactines (Fig. 7a) equiradiate and equiangular, with conical actines measuring 42– 89 –117 x 7 – 8.7 –11 µm.

Tetractines (Figs 7b–d) shaped similarly and of approximate equal size. Apical actines straight, equal in length or longer than the actines of the basal triradiate system, tapering to a thin point (Fig. 7b), occasionally entirely smooth (Fig. 7c left), but usually provided with a few small spines (Figs 7c right). Actines of the basal triradiate system 32– 61 –105 x 4 – 6.8 –10 µm, apical actines 24– 67 –138 x 3 – 5.1 –7 µm.

?Trichoxeas (Fig. 7d), up to 300+ µm, quite thin (less than 0.5 µm in thickness). Not certainly proper as they are not visible in the sections.

Distribution and ecology. Red Sea, Aqaba, under overhangs in reef localities.

Etymology. Named after Dr Oliver Voigt, München, for his excellent contributions to Calcarea systematics.

Remarks. The present specimen resembles to some extent Voigt et al. ’s (2017) description of Borojevia aff. aspina (Klautau et al., 1994) . The trichoxea-like spicules are present in the spicule slide at a low frequency. In the surface section (Fig. 6c) there are some thin long spicules, but they are indistinct and may not be proper to the sponge. Voigt et al. also observed that the trichoxeas are difficult to find in the slides. Voigt et al. did not observe spines on the apical actines of the tetractines, which is a distinct difference. In our new species the spines were very small and occasionally absent in our specimen (Figs 7c left), thus we assume our and Voigt et al. ’s specimens belong to different closely related species. Like Voigt et al. ’s specimen ours has whitish color and it lacks distinct tripods. Since Borojevia aspina is a Brazilian species, the likelihood that a species living on reefs in the Red Sea is conspecific with the Brazilian population is judged to be quite small.

Borojević (1967) described the Mediterranean species Clathrina cerebrum from Eastern South Africa (Natal coast). This combination is now assigned to Borojevia and restricted to the Mediterranean (cf. Klautau et al. 2016). It is cushion-shaped like the new species, but it has tripods, making it unlikely to be the same species.

So far, no other species of Borojevia have been reported from the region, but below we will describe two additional species. Differences with the present species will be given in the Remarks sections of these species.

We were unable to obtain a partial 28SrRNA sequence of this specimen.