Niphates arenata, Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014

Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014, Diversity of sponges (Porifera) from cryptic habitats on the Belize barrier reef near Carrie Bow Cay, Zootaxa 3805 (1), pp. 1-129 : 85-86

Niphates arenata new species

( Figures 4 d, 39)

Material. Holotype: USNM 1229119, Carrie Bow Cay forereef, bottom of small cave, 25 m; M. C. Diaz col. 8 Sep 2009.

Paratype: USNM 1229120, same data as holotype.

Diagnosis. Encrusting to cushion-shaped Niphates , pinkish orange in color, with sediment incorporated in netlike pattern in the ectosome and abundant throughout the choanosome. Spicules are strongyles, accompanied by rare, small toxas.

External morphology. The holotype is an elongate cushion, up to 17 mm thick, covering about 25 cm 2. Oscula evenly dispersed over the surface, slightly elevated, 2–4 mm diameter, and each surrounded by a low, membranous collar. Surface bristly conulose from protruding primary fibers, whitish from fine sand embedded in a net-like pattern. Consistency firm but elastic. Color in life orange, with a pink hue due to the ectosomal sand, light cream in preservation alcohol.

Skeleton structure. The ectosome shows a tangential network of spicules and multispicular fibers and is charged with fine sand and foreign spicules; brushes of perpendicular primary fibers disrupt the pattern. Circular areas of ostial groups are surrounded and crossed by spicule fibers. In the choanosome, spicules are arranged in an isotropic network, interrupted by multispicular tracts, 30–130 Μm thick, that lead toward and penetrate the ectosome. There are also loose spicules without orientation and sand grains occur throughout the choanosome but are particularly numerous along the fibers tracts.

Spicules. Straight to somewhat curved and a few double-bent strongyles and rare, delicate toxas, some straight and resembling raphids. Strongyles: 205–280 x 5–8 (235 x 7) Μm; a few shorter and thinner strongyles and oxeas appear to be developmental stages. Hairlike toxas: 36– 76 x <1 Μm (some appear rugose on the concave side, possibly an artifact).

Ecology. Found on the bottom of a forereef cave in 25 m.

Distribution. So far only found on the Belize barrier reef off Carrie Bow Cay.

Etymology. The species name, arenata , is Latin for “with sand,” referring to the abundance of sedimentderived sand embedded in the surface net and throughout the body.

Comments. Color and a spiculation of strongyles make this species resemble Niphates lutea Lehnert & van Soest, 1999, from the deep forereef of Jamaica. The principal characteristics that distinguish N. arenata are the large quantity of incorporated fine sand, particularly the net-like pattern at the surface, and the presence of toxas as microscleres. Some species of Niphates are known to have sigmas as microscleres, but toxas like in our material are easily overlooked for their thinness (0.5–0.8 Μm). In fact, Zea & van Soest (1986) report the occurrence of minute toxas in some specimens of their new species Niphates caycedoi (Zea & van Soest, 1986; first described as Xestospongia ), an encrusting to branching species distinguished by vivid blue to violet color. Because many foreign spicules were seen in our preparations (including oxeas, sigmas, anisocheles, long raphids), we sampled tissue from various parts of all available specimen fragments; only the toxas were consistently present.

Figures

FIGURE 4. In-situ photographs of new sponge species reported in this contribution (measurements in parentheses are picture widths): a, Wigginsia curlewensis (8 cm); b, Phorbas aurantiacus (10 cm); c, Myrmekioderma laminatum (12 cm); d, Niphates arenata (10 cm); e, Siphonodictyon occultum (10 cm); f, Xestospongia purpurea (8 cm); g, Aplysina sciophila (20 cm).