Grantessa woerheidei, Van & De, 2018

Van, Rob W. M. & De, Nicole J., 2018, Calcareous sponges of the Western Indian Ocean and Red Sea, Zootaxa 4426 (1), pp. 1-160 : 109-112

Grantessa woerheidei sp.nov.

Figs 66a–f , 67a–g

Material examined. Holotype, RMNH Por. 9586, 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/JED081, 9 November 2014.

Description. Extremely ‘hairy’ sycon-like ovoid sponge ( Figs 66a–b ), whitish in situ, light beige in preservation. Size 2 cm high, 0.5 cm in diameter (1 cm if protruding diactines are included). Consistency compressible but firm.

Aquiferous system. Syconoid.

Skeleton. ( Figs 66c–f ) Articulate, with radiating structure following the syconoid aquiferous system. The wall of the sponge is pierced almost for its entire thickness by long giant diactines, and these protrude beyond the surface for a considerable distance. From the periphery to the atrial cavity there is first a thin cortical layer of small triactines, overlying a layer of pseudosagittal triactines, with the unpaired and short paired actine tangential to the surface and the long paired actine directed inwards. Next, the choanosomal skeleton ( Figs 66c–d ) consists of aligned tracts of sagittal tubar triactines with the unpaired actines directed outwards and the paired actines similarly aligned parallel to the cortical and atrial surfaces. Below this, the subatrial skeleton is formed by triactines similar to the tubar triactines but with unpaired actines elongated, also directed outwards. Finally, the atrial skeleton is formed by the basal triadiate system of tetractines, with their apical actines protruding far into the atrial cavity ( Fig. 66d ). Although there is not a separate fringe, the oscular opening is surrounded by protruding diactines ( Fig. 66e ) even longer than those of the main body, and these also form bundles, which give the opening a star-like appearance. The oscular rim is strengthened by rows of triactines ( Fig. 66f )

Spicules. ( Figs 67a–g ) Diactines, triactines, pseudosagittal triactines, tetractines.

Giant diactines ( Figs 67a,a 1 ), long, straight, varying in thickness from trichoxea-like thin diactines to thickly fusiform longer and shorter spicules, with endings varying from thinly sharply tapering to lance-shaped, those protruding from the main body 700– 2791 –4900 x 4 – 25.8 –33 µm, the oscular diactines are at least 6–7 mm x 3–20 µm.

Triactines of the oscular rim ( Fig. 67b ), sagittal, rather strongly recurved, only a few could be measured, actines 70–130 x 7–10 µm.

Triactines of the cortical skeleton ( Figs 67c ), slightly sagittal, actines 62– 111 –145 x 5 – 7.6 –9 µm.

Pseudosagittal triactines ( Figs 73d ), of variable shape but always clearly distinct from other triactines by having all actines of different length and usually partially curved, unpaired actines 86– 112 –132 x 5 – 6.2 –7.5 µ, long paired actines 92– 189 –244 x 5 – 6.0 –7.5 µm, short paired actines 36– 48 – 65 x 5 – 5.7 –7 µm.

Tubar triactines ( Figs 67e ), sagittal, equiangular, unpaired actines 110– 124 –146 x 5 – 7.6 –11 µm, paired actines 84– 125 –193 x 5 – 7.1 –10 µm.

Subatrial triactines ( Fig. 67f ), sagittal, equiangular, with unpaired actine longer than paired actines, measuring 195– 223 –285 x 5 –7.7–11 µm, paired actines 63–110–132 x 4 – 6.4 –10 µm.

Atrial tetractines ( Figs 67g ), with slightly curved actines, often with apical actines longest; unpaired actines 102– 134 –186 x 4 –5.6–8 µm, paired actines 99– 144 –180 x 4 –5.3–7 µm, apical actines 46– 155 –345 x 3 – 5.3 –10 µm.

Distribution and ecology. Saudi Arabia, Red Sea, from shallow-water reef overhangs.

Etymology. Named after Professor Gert Wörheide, München, to acknowledge his important contributions to Calcarea systematics.

Remarks. On paper this species appears close to Southeast Australian Grantessa hirsuta ( Carter, 1886) (originally as Hypograntia ), as redescribed by Dendy (1893a) and Burton (1963: 461). Unfortunately there are no images of this species published so far. From the description it is clear that it is a small cylindrical sponge (about 2 cm high) with hispid surface and apical fringe. However, the details provided by the latter two authors show several distinct differences with our new species: (1) the diactines protruding from the surface are given as 500– 1000 x 14 µm, against up to 7000 x 35 µm in our specimen, (2) the apical actines of the atrial tetractines are given as up to 100 x 6, against up to 345 x 10 µm in our specimen, (3) the articulated skeleton is described as being irregular, whereas our specimen has a very regular tubar skeleton. The lack of differentiation in the various kinds of tri- and tetractines provided in these descriptions makes it hard to be certain of the value of these differences. At least, the length of the diactines and the atrial apical actines provide quite a different aspect in the skeletal structure. The geographic distance and temperature discrepancy between temperate SE Australian waters and the tropical Red Sea adds a further argument for specific distinctness.

There is a possibility that our new species was previously recorded from the Gulf of Aden by Burton (1959) under the name Grantessa sycilloides ( Schuffner, 1877) . We reexamined Burton’s specimen (Murray Expedition station 24, nr 538) in 2004 and from our notes found this to be close in spiculation: giant diactines protruding from the surface, cortical skeleton of small triactines, an articulate main skeleton of pseudosagittal and sagittal triactines, and atrial skeleton of tetractines. In alcohol the specimen was brownish, shaggy. It is certainly unlike Sycortis sycilloides Schuffner, 1877 , as this is largely smooth and does not have atrial tetractines. Schuffner’s species could be a junior synonym of Sycettusa stauridia (see below), but this remains undecided.

The genus Grantessa is large. In our recent paper on Indonesian Calcarea, in which we described two new species, we discussed most of the species occurring in the Indo-West Pacific. We refer to this paper (pp. 82–86) for the more distantly distributed species. The two Indonesian species ( G. borojevici Van Soest & De Voogd, 2015 and G. tenhoveni Van Soest & De Voogd, 2015 ) are clearly distinct from G. woerheidei sp.nov. in having a smooth surface (with only small diactines in the cortical region) and both comprise coalescent groups of individuals. Additionally, they differ in details of their spiculation. The small diactines mentioned for the Indonesian species also occur in the widespread, smooth-surfaced G. intusarticulata ( Carter, 1886) (originally as Hypograntia ) and the South African G. rarispinosa Borojević, 1967 . The latter two species lack tetractines. G. ramosa ( Haeckel, 1872) (originally as Sycandra ) as described by Borojević (1967, p. 204) from South Africa forms a group of coalescent individuals and has sagittal triactines with long swollen unpaired actines and tetractines likewise with swollen apical actines. No other Grantessa species are known from the region.

We obtained a partial 28S sequence of this specimen. In our Calcarea phylogeny of Fig. 3 , which included a Grantessa cf. intusarticulata sequence downloaded from the Sponge Barcode Project, Grantessa woerheidei sp.nov. ended up in a mixed larger clade quite close to Indonesian Uteopsis argentea ( Poléjaeff, 1883) , away from Grantessa cf. intusarticulata . In a trimmed alignment of three identical Uteopsis argentea sequences and one Grantessa woerheidei sequence of 428 sites, only 5 sites were found to be different, indicating that the two are inexplicably close. Voigt et al. (2012) already found that the family monophyly of Heteropiidae could not be retrieved resulting in two Heteropiidae groups separated by some Jenkinidae . Clearly, more taxa are needed to sort out the relationships of Grantessa .

Figures

FIGURE 1. Marine Ecoregions in the Western Indian Ocean with localities (numbered blue squares) from where the studied calcareous sponges were obtained. 1, Israelian Red Sea, Gulf of Aqaba, 2, Saudi Arabian Red Sea, off Jeddah, 3, Eritrean Red Sea, Dahlak Archipelago, 4, Oman, Gulf of Arabia, 5, Maldives, 6, India, Lakshadweep, 7, Seychelles, Mahé region, 8, Seychelles, Amirantes, 9, Mayotte, 10, Mozambique Channel, 11, Mauritius, 12, Rodrigues, 13, South Africa, Kwazulu Natal, 14. South Africa, Port Elizabeth, 15. Nosy Be, Madagascar.

FIGURE 3. Maximum-likelihood tree based on analysis of sequences of the partial 28S gene (C2–D2 region, comprising 461 sites) of Western Indian Ocean Calcaronea newly generated by the Naturalis Biodiversity Center and sequences additionally obtained from GenBank, the Sponge Barcode Project and from Oliver Voigt (München) from the Red Sea, Indonesia, Australia, and a few sequences from other parts of the world, to demonstrate the affiliation of the compared species. Numbers at the root of clades are bootstrap values of 1000 replicates.

FIGURE 66. Grantessa woerheidei sp.nov., holotype RMNH Por. 9586 from Saudi Arabia, Red Sea, a–b, habitus in situ from above and from the side (photos N.J. de Voogd), c–f, light microscopic images of skeleton, c, cross section, d, detail of c, showing choanosomal and atrial region, e, view of oscular region, f, detail of oscular rim.

FIGURE 67. Grantessa woerheidei sp.nov., holotype RMNH Por. 9586 from Saudi Arabia, Red Sea, SEM images of the spicules, a, giant diactine with pointed apices, a1, smaller diactine with lance head, b, triactine of the oscular rim, c, triactines of the cortical skeleton, d, pseudosagittal triactines of the subcortical region, e, tubar triactines, f, subatrial triactines, g, atrial tetractines.

FIGURE 73. Sycettusa simplex (Jenkin, 1908), a–c, habitus of RMNH Por. 10154 from the Maldives, a, habitus in situ (photo N.J. de Voogd), b, on deck (photo N.J. de Voogd), c, preserved (scale bar = 1 cm), d, light microscopic image of cross section, e, detail of the same.