Axinyssa djiferi, Boury-Esnault & Marschal & Probst & Barnathan, 2002

Boury-Esnault, Nicole, Marschal, Christian, Probst, Jean-Michel Korn- & Barnathan, Gilles, 2002, A new species of Axinyssa Lendenfeld, 1897 (Porifera, Demospongiae, Halichondrida) from the Senegalese coast, Zootaxa 117, pp. 1-8 : 4-5

Axinyssa djiferi sp. nov.

Material examined: 24.4.83 DAK­52 , at low tide in the mangrove swamp of Saloum which is designated as the type specimen and deposited in the MNHN under the number: MNHN . Several specimens from the same locality in the authors’ collection.

Morphology ( Fig. 1 ): The holotype forms a sleeve around the roots of the mangroves close to the bottom. The dimensions are about 10 cm in length and 1­3 cm in thickness. The live specimens have a black surface, and the choanosome is yellow greenish. The surface is raised by conules which are hispid. The surface between the conules is smooth. The consistency is soft. The oscules (3­4 mm in diameter) are clearly visible at the top of fistules of about 1.5­ 2 cm height and 1 cm diameter at the base ( Fig. 2 ). The others specimens are very similar to the type­specimen. The type specimen, collected in April, is in reproduction and shows a wide range of oocytes and embryos from 15 to 20 µm in diameter especially abundant at the base ( Figs. 3­4 ). The sponge is thus viviparous.

Skeleton ( Figs. 3 , 5 ): Choanosomal skeleton ( Fig. 3 ) composed of ascending tracts of about 50 to 100 µm in diameter which rise the surface. The spicule tracts end in brushes at the surface conules. Single spicules are present between the tracts. In the ectosome, the smallest oxeas constitute the brushes and form a tangential skeleton between the brushes ( Fig. 5 ).

Spicules ( Figs. 6, 7 ): Oxeas of the choanosomal tracts are slightly curved, with two regular acerate extremities, and with a clearly visible axial canal ( Fig. 6 ); some of these oxeas are styloid ( Fig. 7 ): 281­567/10.6­26.5 µm (mean 418±74/13.6±4.5 µm). Oxeas of the ectosome are straight and acerate ( Fig. 6 ): 101­233/5.3­10.6 µm (mean 147±31/6±1.8 µm).

Figures

FIGURES 1 ­ 3. Type­specimen of Axinyssa djiferi spec. nov.. 1, A upper surface, arrow papilla. Scale bar: 10 mm. B transversal section. Scale bar: 13 mm. 2, Longitudinal section through a papilla showing the skeleton. T: choanosomal tracts; E: ectosomal skeleton. Scale bar: 5 mm. 3, Choanosomal skeleton. T: tracts; E: embryos. Scale bar: 30 µm.

FIGURES 4 ­ 5. Axinyssa djiferi spec. nov. 4, Details of embryos. Scale bar: 3 µm; 5, Details of ectosomal and choanosomal skeleton. C: conules. E: tangential oxeas. B: brushes. T: choanosomal tracts. F: free spicules. Scale bar: 370 µm

FIGURES 6 ­ 7. Axinyssa djiferi spec. nov. 6, Spicules, large (L) and small (s) oxeas. Scale bar: 55 µm; 7. Detail of a styloid spicule. Scale bar: 40 µm.