Burtonulla sibogae Borojevic & Boury-Esnault, 1986

Van Soest, Rob W. M. & De Voogd, Nicole J., 2015, Calcareous sponges of Indonesia, Zootaxa 3951 (1), pp. 1-105 : 31-33

Burtonulla sibogae Borojevic & Boury-Esnault, 1986

Figures 22a–c , 23a–f

Dendya prolifera ; Burton, 1930: 2, figs 1–2; Colin & Arneson, 1995: 61, photo 234 (not: Dendy, 1913: 6)

Burtonulla sibogae Borojevic & Boury-Esnault, 1986: 447 , text–fig. 2, pl. 2 figs A–D.

Material examined. Holotype ZMA Por. 00146 ( Fig. 22b ), Indonesia, Lesser Sunda Islands, E coast of Roti Island, Papela Bay, 10.63°S 123.42°E, depth 22 m, trawl, Siboga Expedition stat. 301, 30 January 1900.

Paratype ZMA Por. 00145, Indonesia, Irian Jaya, 1.71°S 130.79°E, depth 32 m, dredge, coll. Siboga Expedition stat. 164, 20 August 1899 .

Additional specimens. RMNH Por. 1653, Palao Islands, channel between Koror and Babeldaob, SW side near Itelblong Island , 7.34°N 134.517°E, depth 12 m , SCUBA, coll. N.J. de Voogd, # KOR04 /130505/029, 13 May 2005 ; RMNH Por. 1821, Indonesia, Kalimantan, Berau region , Maratua, depth not recorded, barrier reef, coll. L. De Senerpont Domis, #BER28/171003/206 ; RMNH Por. 1824, Indonesia, Bali, Tulamben area , Temple Bay E, 8.27°S 115.6°E, depth 20 m , SCUBA, coll. N.J. de Voogd, #BAL24/140401/192, 14 April 2001 ; RMNH 1922 , Indonesia, Nusa Tenggara, Bali, N side of Nusa Pendida, off Desa Byuk, 8.6736°S 115.5436°E, depth 15–20 m, deep reef slope with patches of sand , SCUBA, coll. N.J. de Voogd, #BAL34/NV/210401/263, 21 April 2001 ; RMNH Por. 1924, Indonesia, North Sulawesi, Manddin, between Bunaken and Manado Tua , depth 18 m , SCUBA, coll. N.J. de Voogd, # MD04 /190502/117, 19 May 2002 ; RMNH 2158 , Indonesia, Sulawesi, Spermonde Archipelago, Kundingareng Keke, 5.642°S 119.74°E, depth 10–15 m , SCUBA, coll. N.J. de Voogd, # UP /KK/ 180500/054, 18 May 2000 ; RMNH 9195 , Indonesia, Halmahera, Tidore Dea Tahua, 0.7528°N 127.392°E, depth 10–15 m , SCUBA, coll. N.J. de Voogd, #TER07/281009/, Ternate-Halmahera Expedition 2009, 28 October 2009 ; RMNH Por. 9344 Indonesia, Papua, Raja Ampat, Pulu Wai East, reef, 0.6999°S 130.6666, depth 10–20 m , SCUBA, coll. L.E. Becking, #RAJ61/ LE222 /245, Naturalis-LIPI 2007 Expedition , 11 December 2007 ; RMNH Por. 9345, Indonesia, Papua, Raja Ampat, Pulu Wai East, reef, 0.6999°S 130.6666, depth 10–20 m , SCUBA, coll. L.E. Becking, #RAJ61/ LE233 , Naturalis-LIPI 2007 Expedition , 11 December 2007 .

Description ( Figs 22a–c ) Very characteristic yellow or pale light brown masses of small rounded globules hiding for the most part a central tube, which usually protrudes slightly at the top. Basically, the cormus consist of a single tube, ending in a small oscule with slightly raised rims, with side outgrowths (diverticulae or side-canals) taking the form of clusters of globules reminding of the alveolae of human longs. We propose ‘alveolae’ as the term for these globules. Inbetween the clusters of these alveolae the walls of the tube and its diverticulae are here and there visible as a smooth membrane. Size of individuals may be up to 8 x 5 x 5 cm. Consistency soft.

Histology. Choanocytes are confined to the inner surfaces of the alveolar outgrowths, absent from the walls of the tube (see extensive description of Borojevic & Boury-Enault, 1986).

Skeleton. ( Figs 23a–b ) The alveolae possess a skeleton consisting of a single layer of small equiangular and equiactinal triactines and tetractines. The atrial wall possesses a single layer of larg e equiangular and sagittal triactines and tetractines, the latter dominating.

Spicules. ( Figs 23c–f ) Large and small triactines and tetractines.

Large triactines ( Fig. 23c ), thin, cylindrical, slightly inequiactinal, but not truly sagittal, actines 186– 226.4 – 306 x 7– 7.8 –9 µm

Large tetractines ( Figs. 23e ), thin, cylindrical, similarly equiactinal, except for apical actines, actines of the basal triradiate system 192– 270. 3–390 x 6– 7.4 –10 µm, apical actines 84–330 µm x 4–6 µm.

Small triactines ( Figs. 23d ), usually slightly inequiactinal, 30– 82.6 –138 x 3.5– 5.4 –6.5 µm.

Small tetractines ( Figs 23f ), actines of the basal triradiate system 81– 103.2 –148 x 4–5.6–7 µm, apical actines 27– 51.9 –84 x 3– 3.7 –5 µm.

Ecology. Deeper parts of the reef.

Distribution. Indonesia, Palau.

Remarks. Burton (1930) in his work on the Calcarea of the Siboga Expedition assigned this species to Dendya prolifera Dendy, 1913 (now Levinella prolifera ), but this is clearly a different species with less prominent alveolar diverticulae, and the choanocytes distributed all over the inner atrial surface. The present species was described by Borojevic & Boury-Esnault (1986) on the basis of the misidentified Siboga specimens. It appears to be rather common in Indonesia and surrounding regions, as it is pictured in several underwater guides.

Figures

FIGURE 22. Burtonulla sibogae Borojevic & Boury-Esnault (1986), a, in situ image of RMNH Por. 1653 from the Palau Islands (photo N.J. de Voogd), b, preserved holotype ZMA Por. 00146 (scale bar = 1 cm), c, in situ image of RMNH 1821 from Maratua Island (photo B.W. Hoeksema).

FIGURE 23. Burtonulla sibogae Borojevic& Boury-Esnault (1986), a, holotype ZMA Por. 00146, overview of skeleton (scale bar= 500 µm), b, detail of skeleton of diverticula and tube wall (scale bar = 200 µm), c–f, SEM images of spicules, c, large triactine of the tube wall, d, small triactines of the diverticula, e, large tetractine of the tube wall, f, small tetractines of the diverticula.