Diplopodospongia rara, Sim-Smith, Carina & Kelly, Michelle, 2011

Sim-Smith, Carina & Kelly, Michelle, 2011, Two new genera in the family Podospongiidae (Demospongiae: Poecilosclerida) with eight new Western Pacific species, Zootaxa 2976, pp. 32-54 : 47

Diplopodospongia rara gen. nov. sp. nov.

( Fig. 1 G, 5A–D)

Material examined. Holotype ― NIWA 52693, Campbell Plateau, south of New Zealand, NZOI Stn B175, 50.442° S, 166.625° E, 165 m, 8 Oct 1959.

Type location. Campbell Plateau, S of New Zealand.

Distribution. Known only from type location.

Description. The specimen is a small fragment (10 mm wide x 10 mm long) of a thinly encrusting sponge, 6 mm high. Surface is easily separable from underlying choanosome, with small oscules, <1 mm diameter on the apical surface ( Fig. 1 G). Texture is slightly compressible, interior crumbly, surface granular to the touch. Colour in ethanol is white, interior is light beige.

Skeleton. Ectosome, a dense layer of diplospinorhabds. Choanosomal skeleton composed of thick tracts of megascleres that emerge vertically from a basal layer of spongin, which swirl and divide towards the surface. Microscleres are moderately densely scattered between the tracts.

Megascleres ( Fig. 5 A, Table 3)― Anisoxeas, irregularly thickened but slender, curved or sinuous, one end thicker than the other, frequently centrotylote; 332 (294–362) x 6 (4–8) µm.

Microscleres ( Fig. 5 B–D, Table 3)― Diplospinorhabds, squat, with symmetrical ends that are separated by a short shaft. The basal spine and whorl, and apical spine and whorl, are identical in ornamentation. The apex and base consist of three smooth spines that point obliquely away from the end of the microscleres. The basal and apical whorls consist of four smooth, bifurcate spines, separated by a smooth thick shaft; 28 (24–33) µm long x 25 (21–30) µm wide. Protospinorhabds are linear, and shaped like a bow-tie ( Fig. 5 C–D).

Substrate, depth range, and ecology. Encrusting in a small patch on the surface of a boulder at 165 m.

Etymology. Named for the rarity of this species. No further specimens have been collected since the holotype was found in 1959 ( rara =Latin for rare).

Remarks. Diplopodospongia rara gen. nov. sp. nov. was first bought to the authors’ notice by Dame Professor Patricia Bergquist some years ago. Bergquist first illustrated the unique diplospinorhabds in Bergquist (1978 pl. 7, fig. b), in which she assigned them to Sigmosceptrella , with no additional comment. Since that time, several more Podospongiidae species have come to hand and a clearer picture of the whole group has emerged. The key difference between encrusting species of Sigmosceptrella , Neopodospongia gen. nov., and Diplopodospongia gen. nov., is the presence of sigmoidal protospinorhabds in the former two genera and a linear bow-tie shaped protodiplospinorhabd in the latter. Neopodospongia gen. nov. species also have aciculospinorhabds that clearly differentiate them from species of Diplopodospongia gen. nov..

Figures

FIGURE 1. New genera and species of Podospongiidae from New Zealand, Australian, and Indonesian waters: A. Podospongia virga, holotype NIWA 52692, Cape Reinga, New Zealand; B. Podospongia colini, holotype USNM 1154618, Sulawesi, Indonesia; C. Neopodospongia pagei, holotype NIWA 52580, Three Kings Islands, New Zealand; D. Neopodospongia exilis, holotype NIWA 52579, Cavalli seamounts, New Zealand; E. Neopodospongia bergquistae, holotype NIWA 62016, Poor Knights Islands, New Zealand; F. Diplopodospongia teliformis, holotype NIWA 35005, Hikurangi Channel, New Zealand; G. Diplopodospongia rara, holotype NIWA 52693, Campbell Plateau, New Zealand; H. Diplopodospongia macquariensis, holotype QM G 331915, Seamount 8, Macquarie Ridge, Australia. Scale = 10 mm for all images.

FIGURE 5. Megascleres and microscleres of Diplopodospongia gen. nov. spp. nov.: Diplopodospongia rara, holotype NIWA 52693, A. anisoxea, scale = 100 µm; B. diplospinorhabd; C, D. protodiplospinorhabds, scale B – D = 20 µm. Diplopodospongia teliformis, holotype NIWA 35005, E. anisoxea, scale = 100 µm; F. G. diplospinorhabd I; H. protodiplospinorhabd; I – K. diplospinorhabd II, scale F – K = 20 µm. Diplopodospongia macquariensis, holotype QM G 331915, L. anisoxea, scale = 100 µm; M. diplospinorhabd, scale = 20 µm.