Niphates laminaris Calcinai, Bastari, Bertolino & Pansini

Calcinai, Barbara, Bastari, Azzurra, Bavestrello, Giorgio, Bertolino, Marco, Horcajadas, Santiago Bueno, Pansini, Maurizio, Makapedua, Daisy M. & Cerrano, Carlo, 2017, Demosponge diversity from North Sulawesi, with the description of six new species, ZooKeys 680, pp. 105-150 : 115-116

Niphates laminaris Calcinai, Bastari, Bertolino & Pansini sp. n. Figure 8

Material examined.

Holotype: MSNG 60139, PH-47, 17/01/2005, Tiwoho (Bunaken Island), 20 m depth.

Diagnosis.

Lamellate, azure-violet sponge, with differentiated inhalant and oscular faces. Skeleton is a regular reticulum of primary and secondary fibres, with superficial brushes hispidating the surface; megascleres are straight and sinuous oxeas. Microscleres are sigmas.

Description.

The sponge is a thin, irregular, folded lamina, attached to the substrate in few points (Fig. 8A); its rim is more or less rounded, not regular (Fig. 8B). The holotype consists in alcohol-preserved fragments, collected from a bigger specimen (Fig. 8A, B). The largest observed specimen is approximately 8 × 4 cm long and 2 mm thick. The colour in life is azure-violet in the part exposed to light and beige on the shadowed side (Fig. 8B). The sponge becomes white-bluish when dried. Consistence soft, slightly elastic. The aspect of the two sides of the laminar sponge is different: roundish vents, 700-1,300 µm in diameter, most probably acting as oscula, are concentrated on the excurrent side (Fig. 8C); on the opposite side, a thin dermal membrane, pierced by numerous pores, covers several smaller apertures, not visible to the naked eye (Fig. 8D). In the dried state, spicule brushes and small ridges (made by tracts of tangential oxeas connecting the brushes) create a microconulose surface, visible also to the naked eye, in both sides of the sponge.

Skeleton. The ectosomal skeleton is a reticulation of multispicular tracts (30-60 µm thick) forming polygonal (mostly quadrangular) meshes 340-900 µm in diameter, with brushes of spicules at the nodes (Fig. 8D). The choanosomal skeleton is a not very regular reticulation, with elongated, almost rectangular meshes 400-800 µm across and empty spaces. The spicule tracts may be divided into ascending primary tracts, 55-100 µm thick, and secondary tracts, 25-35 µm thick, with a more or less transverse arrangement. The extremities of the ascending tracts protrude through the surface, forming brushes (Fig. 8D). Very numerous pigmented (green) cells and abundant spicules, both megascleres and microscleres, are dispersed in the ectosome and choanosome.

Spicules. Oxeas slightly curved or sinuous, rarely straight, with acerate tips (Fig. 8E). They measure 150.8 - (163.37 ± 7.0) - 176.8 × 2.5 - (3.7 ± 1.1) - 5.2 µm. Sigmas C-shaped, sometimes with a part of the shaft almost straight (Fig. 8F). They measure 13 - (17.0 ± 3.18) - 23.4 µm × 1 µm.

Etymology.

The name refers to the lamellate shape of the sponge.

Remarks.

The new species clearly belongs to the family Niphatidae for the presence of multispicular fibres in the ectosome and to the genus Niphates for the skeletal organisation. The genus Niphates includes sponges with "Surface conulose to spiny [ ….] produced by primary longitudinal fibres ending on surface" ( Desqueyroux-Faúndez and Valentine 2002). The ectosomal skeleton is a tangential network of secondary fibres, obscured by protruding tufts of primary fibres. Microscleres are rare sigmas ( Desqueyroux-Faúndez and Valentine 2002). However, other species of the genus (e.g. Niphates nitida Fromont, 1993) have a smooth surface as the new species.

Niphates laminaris sp. n. is characterised by a non-spiny, rather irregular, microconulose surface and by a choanosomal skeleton with a reticulation of primary and secondary tracts. Microscleres are numerous. In the Indo-Pacific area, only N. nitida has sigmas. However, N. nitida is a sponge with repent habit, with oscula located at the top of small erect lobes; a choanosomal fibrous reticulation with round or triangular meshes (104-146 µm) and oxeas measuring 128 × 5.6 µm. Therefore, it substantially differs from Niphates sp. n; all other Niphates in the area differ from the new species for the absence of sigmas and for other significant features listed below. Niphates olemda (de Laubenfelds, 1954) is a blue, or pink tubular sponge with small oxeas (92-100 × 2-3 µm), while N. aga (de Laubenfelds, 1954) is ramose with superficial projections, a confused ectosomal skeleton and straight and large oxeas (175-180 × 5 µm). Niphates cavernosa Kelly-Borges & Bergquist, 1988 is a massive, creeping and branching sponge, violet in life, with two categories of oxeas differing in thickness (oxeas I: 5-10 µm thick; oxeas II: 2-4 µm); N. furcata (Keller, 1889) is green, erect, branching, with rather short oxeas (100 × 12 µm). Niphates hispida Desqueyroux-Fáundez, 1984 is a hard and incompressible sponge with very small oxeas (60-80 × 2-4 µm), consisting of a series of coalescent, cylindrical tubes arising from a massive common base. Niphates mirabilis (Bowerbank, 1873) is an ochre-pinkish sponge with a unispicular ectosomal reticulation, while N. obtusispiculifera (Dendy, 1905) is a branching, cylindrical sponge with strongyles as megascleres. Niphates plumosa (Bowerbank, 1876) is fawn-coloured and has a peculiar, stipitate and fan-shaped growth form with only oxeas as spicules. Niphates rowi Ilan et al., 2004 is the species most similar to the new species. Its ectosomal skeleton is a reticulation of fibres creating quadrangular meshes which are smaller than those of Niphates laminaris sp. n. (70-115 µm). In addition, the choanosomal reticulation of N. rowi has rectangular meshes which are smaller (115-200 µm) than those of Niphates laminaris sp. n., whereas the oxea size is similar (115 - (140) - 170 × 5.5 - (6.5) - 7.5 µm). In conclusion N. rowi , which is an encrusting sponge, differs from Nipahtes laminaris sp. n. in the growth form, the absence of sigmas and sinuous oxeas and in the size of the ectosomal and choanosomal meshes.