Figs 68a–g, 69a–f, 70a–f
Grantilla hastifera Row, 1909: 200, pl. 19 figs 3–4, text fig. 3.
? Grantilla quadriradiata Row, 1909: 198, pl. 19 fig. 2, text fig. 2.
Grantessa hastifera; Dendy 1913: 19, pl. 2 fig. 6; Dendy 1916: 81, pl. 1 fig.2, pl. 2 fig. 7; Borojević 1967: 210, fig. 17.
Material examined. RMNH Por. 9587, Saudi Arabia, Jeddah, near Thuwal, Abu Gishaa, 22.255194°N 39.025639°E, depth 12 m, scuba, coll. N.J. de Voogd, field nr. THU06/JED082, 9 November 2014; RMNH Por. 9644, Saudi Arabia, Jeddah, near Thuwal, Um Alsawi, 22.239306°N 38.985139°E, scuba, coll. N.J. de Voogd, field nr. THU08/JED144, 11 November 2014; RMNH Por. 9645, Saudi Arabia, Jeddah, near Thuwal, Um Alsawi, 22.239306°N 38.985139°E, scuba, coll. N.J. de Voogd, field nr. THU08/JED145, 11 November 2014; RMNH Por. 9659, Saudi Arabia, Jeddah, near Thuwal, Fsar, 22.249417°N 39.002333°E, scuba, coll. N.J. de Voogd, field nr. THU09/JED159, 11 November 2014; ZMA Por. 13421, Israel, Gulf of Aqaba, on pillar of containerport, depth 5 m, scuba, coll. M. Wunsch, field nr AQ70, 5 July 1998; ZMA Por. 13422, Israel, Gulf of Aqaba, Marsa Bareika, depth 20 m, in cave, scuba, coll. M. Wunsch, field nr. RM227, 25 July 1998; ZMA Por. 13429, Israel, Gulf of Aqaba, Shark Observatory, depth 14 m, in cave, scuba, coll. M. Wunsch, field nr. RM241, 26 Juky 1998; ZMA Por. 13443, Israel, Gulf of Aqaba, on pillar of containerport, depth 7 m, scuba, coll. M. Wunsch, field nr. AQ73, 5 July 1998; ZMA Por. 13448, Israel, Gulf of Aqaba, Canyon, cryptic habitat, depth 10 m, scuba, coll. M.Wunsch, field nr. AQ137, 14 July 1998; ZMA Por. 13508, Israel, Gulf of Aqaba, North Pinnacle, depth 8 m, in cave, scuba, coll. M. Wunsch, field nr. AQ56, 4 July 1998; ZMA Por. 13509, Israel, Gulf of Aqaba, North Pinnacle, depth 17 m, in cave, scuba, coll. M. Wunsch, field nr. AQ33, 4 July 1998; ZMA Por. 10524, Seychelles, E of Bird Island, 3.7333°S 55.2333°E, depth 45 m, dredge, coll. R.W.M. van Soest, field nr. NIOP-E stat. 719/08, 20 December 1992; ZMA Por. 11563, Seychelles, Amirantes, St. François Atoll, Île Bijoutier, 7.0833°S 52.7333°E, reef, depth 6–18 m, scuba, coll. R.W.M. van Soest, field nr. NIOP-E stat. 792/16, 5 January 1993.
Description. Cylindrical, hairy sponges (Figs 68a–f, 69a,c), usually hanging down from ceilings or walls of reef caves. Size varies between 1 and 3 cm high, diameter 2–10 mm (protruding diactines included). Colors in situ varying from whitish, pale greenish, to greyish transparent; in preservation (Figs 69b,d) they are light beige. Oscules are slightly constricted, lack a distinct fringe, but have a dense collar of long diactines and trichoxeas (Figs 68f, 69c), which form bundles radiating outwoards from the oscule (Fig. 69e). Consistency soft.
Aquiferous system. Syconoid.
Skeleton. (Figs 68g, 69e–f) Inarticulate, with the choanosomal region supported by the longer paired actines of pseudosagittal triactines and the unpaired actines of subatrial triactines. The cortical skeleton skeleton consists of large regular or slightly sagittal triactines carried by the shorter paired actines of the pseudosagittal triactines. Giant diactines are protruding far outwards from the cortex (Fig. 69e) and penetrate deeply into the choanosomal skeleton contributing to the inarticulate triactine skeleton. The (sub-)atrial skeleton consists of the paired actines of subtrial triactines (Fig. 69f) and smaller sagittal or oxhorn-shaped triactines.
Spicules. (Figs 70a–f) Giant diactines, trichoxeas, cortical triactines, pseudosagittal triactines, subatrial triactines, atrial triactines.
Giant diactines (Figs 70a), sharply pointed or with lance-head ending, 240– 903 – 2040 x 10 – 26.9 –36 µm.
Trichoxeas (Fig. 70b), invariably broken, fragments of all lengths up to 1048 x 3 µm.
Cortical triactines (Fig. 70c), usually more or less equiradiate and equiangular, variable in actine length within and among specimens, 181– 221 –310 x 14 – 16.1 –30 µm.
Pseudosagittal triactines (Fig. 70d), especially variable in thickness of the actines, long paired actine straight, 246– 398 –480 x 14 – 24.2 –40 µm, short paired actine curved 105– 176 –285 x 13 – 20.7 –29 µm, unpaired actine straight or slightly curved, 107– 177 –325 x 14 – 22.4 –32 µm.
Subatrial triactines (Fig. 70e), mostly strongly sagittal, varying from almost T-shaped to widely curved paired actines, with unpaired actine straight, tapering to thin sharp ends or occasionally bluntly rounded; unpaired actines
306– 436 –620 x 17 – 31.1 –46 µm, paired actines 166– 239 –318 x 18 – 27.2 –45 µm.
Atrial triactines (Figs 70f), sagittal, often with curved paired actines; unpaired actines 68– 141 –201 x 7.5– 10.9 –15 µm, paired actines 72– 147 –215 x 9 – 10.7 –15 µm.
Distribution and ecology. Red Sea, Seychelles, Western India, South Africa, in caves and other cryptic habitats, 5–45 m depth; records from the Southwest Atlantic (Lanna & Klautau 2010) probably concern a similar but different species of Sycettusa.
Remarks. As indicated above, we tentatively consider Grantilla quadriradiata Row, 1909 a synonym of S. hastifera based on examination of several slides (sections and spicule mounts) of the holotype incorporated in the collections of the Natural History Museum, London, under reg.nr. BMNH 1912.2.1.8a. There are no tetractines in the slides, so even if they are present in other parts of the type material, they are obviously a minor complement, probably derived from the usual pseudosagittal triactines. The G. quadriradiata spicules were at the larger part of the variation of length and thickness, but fell within it. There are no clear differences with the dozen specimens of S. hastifera present in our collection.
Dendy (1913, 1916) assigned Grantilla Row, 1909 (with species G. quadriradiata and G. hastifera) to Grantessa Von Lendenfeld, 1885, but that genus has been redefined by Borojević et al. 2000, 2002b to have an articulate skeleton. Row’s species and our specimens have clearly inarticulate skeletons and thus answer to Sycettusa Haeckel, 1872 as redefined by Borojević et al. 2002b.
Three sequences available to us, two of our own and one downloaded from the Sponge Barcode Project site, all three from the Red Sea, grouped together in the same clade in the phylogeny of Fig.3.
There are several further species of Sycettusa in our material, which will be described below and their differences with S. hastifera will be discussed in the Remarks of those species below.