Geodia gibberosa Lamarck, 1815

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 93-95

Geodia gibberosa Lamarck, 1815

Figures 58 a–g

Restricted synonymy: Geodia gibberosa Lamarck, 1815: 334 ; Topsent 1931: 3, pl. I fig. 1; Cárdenas et al. 2009: 28, in part (only type specimen redescription and illustrations thereof).

Material examined. RMNH Por. 9795, French Guyana, ‘Luymes’ Guyana Shelf Expedition, station 14, 6.7333°N 52.75°W, depth 76 m, bottom muddy calcareous sand, 26 August 1970 ; RMNH Por. 10508, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station G56, 7.26°N 56.6667°W, depth 67–68 m, Agassiz trawl, 10 May 1966 .

Description. ( Fig. 58 a) Irregular-lobate individuals, one larger, 13 x 7 x 6 cm, the other 3 x 2 x 2 cm. Color light beige (in alcohol), slightly darker inside, with smooth surface. Small oscula grouped in a sieveplate on top of a lobe in the larger individual. Consistency hard.

Several CREOCEAN specimens of this species were larger (up to 40 cm high and wide) and more lobateirregular, with larger sieveplates. On-deck photos show they are greyish white in life.

Skeleton. Cortical region approximately 2 mm in thickness, consisting of a layer of sterrasters and small spheroxyasters carried by the cladomes of subcortical ortho/plagiotriaenes. Small oxeas are scattered among the sterrasters and large oxeas penetrate the cortex, and make up the main mass of the pulpy choanosome, where also the large oxyasters are scattered.

Spicules. ( Figs 58 b–g) Large oxeas, ortho/plagiotriaenes, small oxeas, sterrasters, acanthoxyasters, acanthospheroxyasters.

Large oxeas ( Figs 58 b,b1), fusiform, straight or slightly curved, 636– 1099 –1320 x 12– 28 –39 µm.

Ortho/plagiotriaenes ( Figs 58 c,c1), with straight cladomes tapering to rather abrupt endings, with conical to fusiform cladi set out at a low angle, occasionally truly at right angles, thus varying between plagiotriaene and orthotriaene shapes; rhabdome lengths variable, but not divisible in two distinct categories; rhabdomes 402– 774 –952 x 18 – 32.5 –54 µm, cladomes 117– 211 –276 µm, cladi 68– 114 –156 x 13 – 24.5 –41 µm.

Small cortical oxeas ( Figs 58 d,d1), occasionally inequiended, one end being bluntly rounded the other sharply pointed, 155– 220 –278 x 4 – 6.2 –9 µm.

Sterrasters ( Figs 58 e,e1), round, closely similar in size in both samples, 57– 66.8 –74 µm. The rosettes are smooth and have 6–8 conical rays.

Oxyasters ( Fig. 58 f), rays lightly spined, smooth near the center of the spicule; length of rays variable, but no clear subdivision is apparent; diameters between the two samples slightly different, 15–30 µm in RMNH Por. 9795, 12–18 µm in RMNH Por. 10508, overall 12– 16.2 –30 µm; ray numbers variable between 6 and 11.

Spheroxyasters ( Figs 58 g), with blunt-ending conical rays, with spines concentrated near the ray apices, smooth near the center, shape often irregular; diameters 4– 5.8 –8 µm, ray number 8–12.

Distribution and ecology. Guyana Shelf, Greater Caribbean, Carolinian region and NE Brazil, on reefs, mangroves and sand bottoms, from shallow-waters down to 100 m depth (Guyanan and CREOCEAN specimens 67–77 m), but revision is necessary.

Remarks. This is a common Central West Atlantic species. For a redescription of the type, the synonymy and further discussion see Cárdenas et al. 2009. These authors assigned mangrove specimens from Panama to this species, but later on, Cárdenas et al. 2011 (p. 9) reassigned their identification to Geodia tumulosa ( Bowerbank, 1872) . For that reason, I restricted the references to G. gibberosa above to only the certain citations, pending additional revisions of specimens assigned to it. Anatriaenes were searched for, but not found. The holotype, collected off French Guyana ( Lamarck 1815: 333; Topsent 1931: 3; Cárdenas et al. 2009: 28), apparently also lacked anatriaenes. Other specimens are reported to have a few of these spicules, but it appears to be an unstable element.

The large depth range of the species, from shallow-water ( Rützler et al. 2014) down to 100 m ( Van Soest & Stentoft 1988) is bridged by the present records from 67–77 m depth, but as said above, revision of assignments of specimens to this species are necessary.

Figures

FIGURE 58. Geodia gibberosa Lamarck, 1815, a, habitus of RMNH Por. 9795 (scale bar = 1 cm), b – g, SEM images of spicules, b, large oxea, b 1, details of b, c, ortho / plagiotriaene, c 1, cladome of ortho / plagiotriaene, d, cortical short oxea, d 1, details of d, e, sterraster, e 1, detail of surface of e, f, oxyaster, g, various shapes of spheroxyasters.