Stryphnus novaezealandiae Kelly & Sim-Smith, 2012, sp. nov.

Stryphnus novaezealandiae sp. nov.

(Fig. 2 D, 7A–E, 8)

Material examined. Holotype ― NIWA 52581: NIWA Stn TAN0413/109, Rungapapa Knoll, Bay of Plenty, 37.549º S, 176.988º E, 136–142 m, 13 Nov 2004. Paratypes ― NIWA 44381: NIWA Stn W0455, Chatham Rise, 43.465° S, 175.090° E, 130–136 m, 22 Feb 1995; NIWA 52584: Three Kings Islands, 34.146° S, 172.144° E, RV Kaharoa, 17 m, 14 Apr 1999, SCUBA, additional vouchers of this paratype are held in the CRRF reference collection (0 CDN 6576-I) and in the USNM (USNM 1182995); NIWA 52583: North Cape, 34.372° S, 172.015° E, RV Kaharoa, 80 m, 18 Apr 1999, additional vouchers of this paratype are held in the CRRF reference collection (0 CDN 6655-S) and at the USNM (USNM 1182996). Other material. NIWA 44382, NIWA 44390: NIWA Stn W0452, Chatham Rise, 43.450° S, 175.135° E, 120–180 m, 22 Feb 1995; NIWA 44384: NIWA Stn W0447, Chatham Rise, 43.245° S, 175.458° E, 80–85 m, 22 Feb 1995; NIWA 44380: NIWA Stn W0456, Chatham Rise, 43.452° S, 175.116° E, 145–150 m, 22 Feb 1995; NIWA 44385: NIWA Stn W0437, Chatham Rise, 43.241° S, 175.434° E, 78–80 m, 22 Feb 1995; NIWA 52585: NIWA Stn TAN0413/109, Rungapapa Knoll, Bay of Plenty, 37.549º S, 176.988º E, 136–142 m, 13 Nov 2004.

Type locality. Rungapapa Knoll, Bay of Plenty.

Distribution. Three Kings Islands, North Cape, Bay of Plenty, Chatham Rise.

Description. Massive, irregularly lobate, to thickly encrusting sponge, 400 mm x 400 mm x 30 mm thick (Fig. 2 D), often completely invested by the bright orange red encrusting sponge Antho (Acarnia) novizelanica (Ridley & Dendy) (Poecilosclerida: Microcionidae). Surface is macroscopically smooth but harsh to the touch, no oscules are visible. Ectosome is 2–3 mm thick but not visible in life due to the dark pigmentation. Texture firm, barely compressible, the interior is cavernous. Colour in life dark purplish black, in ethanol dark reddish brown.

Skeleton. Ectosome is about 3000 µm deep and clearly differentiated from the underlying choanosome, which is denser and more heavily pigmented. Both the ectosome and the choanosome are cavernous but the ectosome much more so, the ectosome is diaphanous, highly ‘cellular’ or bubbled in appearance. Sanidasters form a thin, moderately densely packed crust at the surface, and are sparsely scattered throughout the choanosome. Plagiotriaenes are abundant in the ectosome, having no particular orientation. Large oxeas are moderately abundant in the choanosome, with a small number protruding into the ectosome, forming thin occasional tracts. Oxeas have no particular arrangement in the choanosome, lying paratangential, oblique, or perpendicular to the surface. Oxyasters are confined to the choanosome where they are sparsely to moderately abundant.

Spicules. Megascleres (Fig. 7 A–C) are oxeas (Fig. 7 A), stout, usually slightly curved, fusiform with sharply pointed ends, 2157 (1779–2442) x 55 (40–73) μm; plagiotriaenes (Fig. 7 B–C) resembling calthrops, highly variable in size with a conical rhabdome 392 (115–391) μm long that is only slightly longer than the clads (238 (115–391) μm). Clads point forward at a 45° angle and are conical in shape. Cladome width 416 (202–672) μm.

Microscleres (Fig. 7 D–E) are oxyasters (Fig. 7 D) with 3–8 very fine recurved acanthose rays, 20 (11–27) μm diameter; sanidasters (Fig. 7 E) with a straight or curved long axis and numerous short, blunt spines that are irregularly spaced along the length of the axis, the entire spicule is sparsely to moderately acanthose, 19 (11–25) μm long.

Substrate, depth range, and ecology. Attached to rocky reefs and rock walls, from 17– 180 m.

Etymology. Named for the relative abundance and broad latitudinal distribution of the species in New Zealand (novaezealandiae = New Zealand in Latin).

Remarks. Stryphnus novaezealandiae sp. nov. is relatively easily differentiated from other New Zealand species of Stryphnus as it has distinctive calthrop-like plagiotriaenes, a very thick ectosome, a small choanosomal oxyaster and a true sanidaster. In terms of morphology, the sponge is easily recognisable with the thick amorphous shape and dark brownish black pigmentation. The only other described species that have plagiotriaenes, are New Zealand species S. spelunca sp. nov. and S. ariena sp. nov., and S. fortis from the Atlantic (although not always present). When present in the latter, they occur in conjunction with dichotriaenes (Boury-Esnault et al. 1994).