Penares astronavis sp. nov.

(Fig. 34–36, Table 11)

Material examined. Holotype— NIWA 82272, NIWA Stn TAN1206/34, Kermadec Ridge, 36.447° S, 177.839° E, 850–980 m, 18 Apr 2012 .

Type locality. Southern Kermadec Ridge, New Zealand .

Distribution. Only known from type locality, the Southern Kermadec Ridge, New Zealand; 980 m (Figure 36).

Description. Morphology is a thinly encrusting, nodular sponge, growing over dead coral branches (Figure 34A); 25 mm × 10 mm × 2 mm thick. Texture is firm but compressible. Surface is slightly scratchy to the touch. No pores or oscules are visible. Colour in ethanol is greyish brown throughout.

Skeleton. Cortical skeleton comprises a densely packed layer of microrhabds, 100–150 µm thick. Microrhabds have no particular orientation in the cortex (Figure 34C). Choanosomal skeleton is densely packed with oxyasters (Figure 34C). Very short triaenes are common and positioned just below the cortex (Figure 34B). Oxeas occur infrequently in the choanosome, having no particular orientation.

Spicules (Figure 35; Table 11). Megascleres —oxeas (Figure 35A) are short, very slender and almost straight; 1269 (768–1692) × 21 (13–27) µm (n = 20). Dichotriaenes (Figure 35B & C) have a short rhabdome; 180 (117–255) µm long × 593 (407–946) µm wide (n = 20). Deuteroclads are conical, widely separated and longer than proto- clads.

Microscleres —oxyasters (Figure 35D), highly modified into asymmetrical shapes. Rays are smooth, strongly conical, of varying length, and have a mixture of sharply pointed and bluntly rounded tips; 54 (39–85) µm in diam- eter (n = 20). Microrhabds (Figure 35E) vary from short, very stout, straight rods with pointed or bluntly rounded tips to perfectly spherical balls. Occasionally, fused or cross-shaped microrhabds occur; 40 (16–82) × 13 (6–20) µm (n = 20).

Etymology. Named for the unusual shape of the oxyasters, which resemble a spaceship (astro, of the stars; navis, ship; Latin).

Remarks. The unusual oxyasters of P. astronavis sp. nov. differentiate it from all other Penares species. The species also possesses smooth spherules, but these appear to be a reduced form of microrhabd rather than a separate spicule category in this species. Penares astronavis sp. nov. also has particularly short and wide dichotriaenes (180 (117–255) µm long × 593 (407–946) µm wide). The only other New Zealand Penares that has similar length dicho- triaenes is P. kermadecensis sp. nov. (197 (122–300) µm long × 854 (644–1085) µm wide, but it has a much wider cladome than P. astronavis sp. nov.