Pozziella clavisepta Topsent, 1896

Díaz-Agras, Guillermo, 2008, Revision of the genus Pozziella (Porifera: Poecilosclerida) with description of three new species from the eastern Pacific *, Zootaxa 1866, pp. 69-94 : 70-73

publication ID	https://doi.org/ 10.5281/zenodo.183749
DOI	https://doi.org/10.5281/zenodo.5670638
persistent identifier	https://treatment.plazi.org/id/5614A96E-2477-FFDD-06E1-F893FCA1D68E
treatment provided by	Plazi
scientific name	Pozziella clavisepta Topsent, 1896
status

Treatment

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 19 View FIGURE 19. A )

Examined Material: Pozziella clavisepta (Syntype) MNHN no. 12 P. A 1895 (one preparation of clean spicules).

Description

Habitus: Incrusting sponge, thin, forming more or less extensive patches. Tissue easily separable from substrate, soft. White or greyish ectosome. No visible orifices when viewed without magnification. Choanosome brownishgrey, cavernous and fibrous ( Topsent, 1896).

Spicules

Megascleres: Smooth styles, fusiform, shaft straight or slightly curved ( Fig. 1 View FIGURE 1 A, B; 2 A–D), in two different size classes. Large styles (style I, Fig. 1 View FIGURE 1 A) 460–550 µm in length (Mean (M.) ± Standard deviation (S.D.), 502.8 ± 24.41 µm) and 12.5–15 µm in width (M. ± S. D., 14.4 ± 1.09 µm) at midshaft, latter dimension decreasing towards rounded end to 5–7.5 µm (M. ± S. D., 6.2 ± 1.27 µm) ( Fig. 2 View FIGURE 2 A–C) (form index: 0.028). Smaller styles (style II, Fig. 1 View FIGURE 1 B) 280–360 µm in length (M. ± S. D., 316.4 ± 17.77 µm) and 10–12.5 µm in width at midshaft (M. ± S. D., 11.5 ± 1.25 µm), latter dimension gradually decreasing to 2.5–5 µm at rounded end (M. ± S. D., 4.9 ± 0.50 µm) ( Fig. 2 View FIGURE 2 D) (form index: 0.036).

Exotyles straight or slightly curved, 210–250 µm in length (M. ± S. D., 228 ± 10 µm) and 9–12 µm in width (M. ± S. D., 10.36 ± 0.86 µm), smooth shafts with uniform diameter ( Fig. 1 View FIGURE 1 C; 2 E–G). Spherical tyle with width of 15–20 µm (M. ± S. D., 17.41 ± 1.49 µm), covered with small warts ( Fig. 2 View FIGURE 2 E, F) (form index 0.045).

Microscleres: Large cyrtancistras of uniform size ( Fig. 1 View FIGURE 1 D; 2 H), 310–400 µm in height (M. ± S. D., 355.2 ± 26.94 µm) and 7.5–12.5 µm in width (M. ± S. D., 10.6 ± 1.49 µm). Singular, distinctive, terminal hooks ( Fig. 2 View FIGURE 2 I) with smooth body (index form: 0.37). Numerous sigmas with variable curvature and in two size classes ( Fig. 1 View FIGURE 1 E, F; 2 J, K). Larger sigmas (type I) horizontally stretched Cshape, actines tending to be parallel, 190–320 µm in height (M. ± S. D., 232 ± 29 µm) and 1 µm in width (M. ± S. D., 1.0 ± 0.0 µm) (index form: 0.94). Smaller sigmas (type II) vertically stretched Cshape, 23–33 µm in height (M. ± S. D., 29.4 ± 2.61 µm﹚ and 1 µm in width (M. ± S. D., 1.0 ± 0.0 µm) (index form: 0.43).

Skeleton

Skeletal arrangement: Styles arranged in long plurispicular fibres in choanosome, interweaved in no particular order in the ectosome. Exotyles inserted vertically in ectosome with tyle pointing outwards and making up the characteristic armour of the genus. Cyrtancistras hooked in fascicles along the choanosomic fibres of styles ( Topsent, 1896).

Distribution: Only known from type locality. Azores archipelago, between San Miguel and Terceira. Between 550 and 1165 m depth ( Topsent, 1896) ( Fig. 19 View FIGURE 19. A ).

Remarks. P. c l a v i s e p t a Topsent, 1896 is the type species of Pozziella and is clearly distinguishable from the other species by the presence of two different kinds of sigmas.

The existence of two types of styles is not mentioned in the original description of P. c l a v i s e p t a Topsent, 1896. Topsent (1904) does, however, mention it superficially. Our examination of the syntype confirmed the presence of two types of styles of different length ( Fig. 3 View FIGURE 3 ).