Podospongia virga Sim-Smith & Kelly, 2011, sp. nov.

Podospongia virga sp. nov.

(Fig. 1 A, 2A, 3A–D)

Podospongia n. sp. Kelly et al. (2009: 44).

Material examined. Holotype ― NIWA 52692, NZOI Stn E271, 18 nautical miles west of Cape Reinga, 34.500° S, 172.333° E, 134 m, 7 Apr 1965.

Type location. W of Cape Reinga, northern New Zealand.

Distribution. Known only from type location.

Description. Stipitate sponge, 70 mm high, with an elliptical body region 15 mm long x 10 mm wide, above a stalk 3 mm diameter, attached to the substrate by a solid expanded base (Fig. 1 A). Contracted ostia are visible on the surface of the globular head, and a single oscule is present on the apex of the body; there is no evidence of differentiated aquiferous faces. Surface is smooth, slightly granular to the touch. Texture is compressible, with a tough stalk. Colour in life and in ethanol, cream throughout.

Skeleton. Ectosome, a very dense palisade of aciculospinorhabds with the apical tuft projecting from the external surface of the sponge. Short thick anisostrongyle megascleres are packed in broad primary tracts that radiate from the base of the elliptical body towards the ectosome, the primary tracts emerging from the spongin encased tracts in the stalk. Long thin anisoxeas form secondary tracts that emerge from the primary tracts to form an umbelliform arrangement, expanding to form brushes at the surface. Aciculospinorhabds are sparsely scattered through the choanosome (Fig. 2 A).

Megascleres (Fig. 3 A–B, Table 1)― Anisostrongyles (Fig. 3 A), thick, often irregularly curved with hastate ends, forming the stalk and primary fibre tracts; 606 (506–689) x 17 (13–22) μm. Anisoxeas (Fig. 3 B), longer, thinner, with one end faintly expanded, almost subtylostylote, often irregularly curved and thickened, forming secondary tracts that emerge from the primary tracts towards the surface; 867 (731–969) x 12 (10–15) μm.

Microscleres (Fig. 3 C–D, I, Table 1)― Aciculospinorhabds are short, stout, asymmetrical. Basal whorl composed of clusters of bifurcate spines extending horizontally, a small tuft of spines emerges vertically from the base of the spicule. Apical whorl is also a cluster of bifurcate spines, more densely clustered than the basal whorl. The apex is a tuft of spines or several long individual spines; 31 (28–35) μm long x 22 (17–27) μm wide. Protospinorhabds are sigmoid.

Substrate, depth range, and ecology. Attached to hard substrate at 134 m.

Etymology. Named for the wand-like morphology of the sponge (virga = Latin for wand or rod).

Remarks. The first record of Podospongia in New Zealand waters was given in Kelly et al. (2009). This new species, P. virga sp. nov., differs from New Caledonian P. similis, by the possession of a simple aquiferous system where surface ostia lead to an apical oscule; P. similis has a differentiated aquiferous system with clearly separate inhalant and exhalant faces on the body. The megascleres of P. similis are given as oxeas and strongyloxeas (Lévi 1993) whereas those of P. virga sp. nov. are anisoxeas and anisostrongyles. The anisoxeas of P. virga are shorter than the oxeas of P. similis (731–969 µm vs 900–1150 µm).

Podospongia virga sp. nov. has remarkably similar aciculospinorhabds to P. similis from New Caledonia; in both species the apex is a tuft of short bifurcate or trifurcate spines that may or may not project beyond the general apex. However, P. virga sp. nov. has shorter aciculospinorhabds than P. similis (28–35 µm vs 40–50 µm). The aciculospinorhabds of P. virga and P. similis differ markedly from the aciculospinorhabds of P. india and P. loveni, which have elongate individual spines that project well beyond the apical whorl and basal whorl in some cases. Finally, P. similis was collected between 335 and 600 m while P. virga sp. nov. was collected from comparatively shallow waters (134 m) west of Cape Reinga.