Leucetta sulcata, 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 : 85

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https://doi.org/ 10.11646/zootaxa.4426.1.1

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scientific name

Leucetta sulcata

sp. nov.

Leucetta sulcata sp.nov.

Figs 49a–d View FIGURE 49 , 50a–d View FIGURE 50

Material examined. Holotype, RMNH Por. 11639, Mauritius, Rodrigues, Mourouk Ebony, Castel Rock , 19.76203°S 63.46273°E, depth 10 m, scuba, coll. N.J. de Voogd, field nr. ROG042, 17 October 2016. GoogleMaps

Paratypes, RMNH Por. 11643, Mauritius, Rodrigues, Mourouk Ebony, Castel Rock , 19.76203°S 63.46273°E, depth 10 m, scuba, coll. N.J. de Voogd, field nr. ROG046, 17 October 2016 GoogleMaps ; RMNH Por. 11645, Mauritius, Rodrigues, Mourouk Ebony, Castel Rock , 19.76203°S 63.46273°E, depth 10 m, scuba, coll. N.J. de Voogd, field nr. ROG048, 17 October 2016 GoogleMaps .

? Additionally : ZMA Por. 1 6368, Madagascar, Nosy Bé, Ambariobé, N of Kosy Komba, depth 6–8 m, scuba, coll. J.H. Stock, 28 December 1963.

Description. The in situ shape is a massive lumpy sponge ( Fig. 49a View FIGURE 49 ) with irregular grooves and deep holes. Live color pale greyish white with pink rims in the peripheral parts. Surface irregular, in places somewhat conulose. Oscules inconspicuous, almost flush with the surface. Color of specimens on deck ( Fig. 49b–c View FIGURE 49 ) and preserved ( Fig. 49d View FIGURE 49 ) remains the same. Size of preserved specimens up to 13 x 8 x 8 cm, oscules 5 mm in diameter. Grooves and ridges up to 1 cm wide. Consistency coarse, harsh and hard.

Aquiferous system. Leuconoid.

Skeleton. A dense mass of giant triactines and small triactines. The oscules lead to into round atrial cavities lined with tetractines and triactines.

Spicules. ( Figs 50a–d View FIGURE 50 ) Giant triactines, small triactines, tetractines.

Giant triactines ( Figs 50a View FIGURE 50 ) equiradiate, equiangular, 408– 984 –1380 x 43 – 107.2 –204 µm.

Small triactines ( Figs 50b View FIGURE 50 ) equiradiate, equiangular, 124– 186 –241 x 10 – 16.8 –22 µm; small sagittal triactines with wavy paired actines (not shown), 83– 106 –133 x 7 – 10.2 –14 µm.

Tetractines ( Figs 50c–d View FIGURE 50 ) with basal triradiate system similar to triactines, 102– 163 –204 x 9 – 12.6 –16 µm, apical actines thin, curved ( Fig. 50d View FIGURE 50 ), 29– 58 – 96 x 3 – 5.2 –8 µm.

Distribution and ecology. Rodrigues, possibly Madagascar, on reefs in shallow depth.

Etymology. Sulcatus (L.) meaning grooved, referring to the habitus.

Remarks. The spicule sizes and shapes are similar to those of Leucetta microraphis , to which the present species is most closely related. Two small irregular fragments of a white sponge, ZMA Por. 16368, collected near Nosy Bé, Madagascar, could belong to the present species based on its skeleton and spicules, but the small material without a definite shape precludes a definite conclusion.

We obtained sequences of the holotype and two of the paratypes and in our phylogenetic analysis ( Fig. 2C View FIGURE 2 ) they grouped together (at 85% bootstrap value) in a larger clade containing sequences of L. microraphis from Mayotte, Madagascar, Australia and the Red Sea. Aligned and trimmed sequences of this larger L. microraphis - group (length 396 sites), showing 19 non-conserved sites, resulted in observed differences of 2–8 sites between L. sulcata sp.nov. and various sequences of L. microraphis s.l. The four sequences of L. sulcata sp.nov. shared two unique non-conserved sites. The three sequences of L. microraphis with pinkish red-brown-green color, described above from Mayotte and Madagascar, shared three unique non-conserved sites. These were not shared by the one Indonesian sequence of a specimen with similar morphology as the Mayotte and Madagascar specimens.

Remarkably, Oliver Voigt’s Red Sea sequences did not have any uniquely shared sites, individual sequences sharing non-conserved sites variously with L. sulcata sp.nov. or Western Indian Ocean L. microraphis , and the Australian and Indonesian sequences. Clearly, the morphological discrepancies and inconsistencies in L. microraphis s.l. are not easily solved by molecular sequence data. L. microraphis s.l. are likely a complex of sister species. The morphological differences of the present new species (white color, grooved and holed habitus) with L. microraphis s.s. (pinkish red-brown-green tubular masses) preclude conspecificity. The pink-white Red Sea specimens and L. pyriformis specimens described above are additional members of the group, differing in shape, color and e.g. in the long straight vs. curved condition of the apical actines of the tetractines. More study is necessary to differentiate the species.

Leocorny et al. (2016) recently studied the Leucetta species from (sub-)tropical Australian waters: Leucetta prolifera ( Carter, 1878) (originally as Teichonella ), L. insignis Row & Hozawa, 1931 , L. infrequens Row & Hôzawa, 1931 , L. expansa Row & Hôzawa, 1931 , L. villosa Wörheide & Hooper, 1999 , L. foliata Leocorny et al., 2016 and L. purpurea Leocorny et al., 2016 . Of these species, two are slightly similar to the new species in having a folded habitus, L. prolifera and L. foliata , but the former has the folds broadly bladed with rows of oscules on the upper surface of the folds, whereas the latter has the folds sharply and thinly bladed. Both do not really resembly the irregularly grooved-holed specimens of the new species. Both species have next to the usual complement of giant triactines, small triactines and small tetractines also large tetractines of the same size or larger as the giant triactines. The remaining species have a more compact or globular habitus, also unlike our new species: L. insignis is shaped like L. chagosensis but has tripod-like giant triactines, L. infrequens is a small erect clump, which apparently lacks small tetractines, L. expansa is also a small, but squat clump, possessing ectosomal microdiactines in addition to the usual spicule complement, L. villosa is provided with villous hair-like outgrowths on the surface, and finally L. purpurea is a small globular purple-colored sponge with giant tripods, sharing this feature with L. insignis .


National Museum of Natural History, Naturalis


Universiteit van Amsterdam, Zoologisch Museum













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