Scyphidium variospinosum Reiswig, Dohrmann & Kelly, 2021

Reiswig, Henry M., Dohrmann, Martin, Kelly, Michelle, Mills, Sadie, Schupp, Peter J. & Woerheide, Gert, 2021, Rossellid glass sponges (Porifera, Hexactinellida) from New Zealand waters, with description of one new genus and six new species, ZooKeys 1060, pp. 33-84 : 33

Scyphidium variospinosum Reiswig, Dohrmann & Kelly sp. nov.

Figs 10 , 11

Material examined.

Holotype NIWA 126279, RV Sonne Stn SO254/78ROV15_BIOBOX3-5, Wairarapa Slope, 41.619°S, 175.788°E, 1630.5 m, 21 Feb 2017. Paratype NIWA 126274, RV Sonne Stn SO254/78ROV15_BIOBOX1, Wairarapa Slope, 41.619°S, 175.788°E, 1675.1 m, 21 Feb 2017.

Distribution.

Known only from two locations on the Wairarapa Slope, New Zealand (Fig. 10A ).

Habitat.

Attached to hard substratum; depth 1631-1675 m (Fig. 10B ).

Description.

Morphology of the holotype and paratype is a thick-walled, club-shaped sponge with a narrow basal attachment, widening gradually to a hemispherical rounded terminal end where a large osculum is centrally located (Fig. 10B-E ). The osculum opens into a deep atrial cavity. The margin is sharp-edged with indication of sparse marginalia that do not differ from prostal diactins of the general body wall. The external surface of the entire body is clean and conulose, with prostal diactins and hypodermal pentactins emanating from conules in small groups of 1-10. Dimensions of the holotype and paratype are, respectively, length 16.5 and 15.8 cm, width 9.5 and, excluding the lateral bulge, 9.5 cm, diameter of the osculum 6.4 and 6.6 cm, wall thickness 11.1 and 10.0 mm. Texture is soft, compressible, and resilient, but not fragile. Surface of the dermal side is conulose and bears a layer of prostal diactins projecting 12.5 (6.5-19.3) (n = 9) mm above the dermal surface, intermingled with a veil of prostal, hypodermal, thorned, paratropal pentactins (Fig. 10F, G ) projecting 8.6 (7.2-10.0) (n = 9) mm above the surface. On the surface below is a lattice of overlapping dermalia of mostly pentactins (94% and 82% of 160 and 101 assessed) (Fig. 10H ). The atrial surface bears a poorly preserved atrial lattice of mostly hexactins (94.7% and 94% of 133 and 131 assessed) (Fig. 10I ) forming a cover over the exhalant apertures. Colour in life and preserved is very pale brown.

Skeleton. Choanosomal skeleton is composed of choanosomal diactins without detectable macroscopic or microscopic organisation. No evidence of spicule fusion was noted in either specimen. Microscleres are scattered throughout the choanosome. Ectosomal skeleton of the dermal side consists of the prostal diactins and projecting veil of thorned pentactins. The dermal surface is covered by a robust lattice of mostly pentactine dermalia. The atrial ectosome consists of the felt-like disorganised lattice of mostly hexactine atrialia and the supporting layer of hypoatrial diactins.

Spicules. Megascleres (Fig. 11 ; Table 5 ) are prostal diactins, prostal hypodermal pentactins, choanosomal diactins, dermalia, and atrialia. Prostal diactins (Fig. 11A ) are large, curved, and smooth spicules with rough subterminal patches and round tips. They have neither axial crosses nor central swellings. Prostal hypodermal pentactins (Fig. 11B ) are large spicules with proximal rays ~ 1.4 times the length of tangential rays; the tangential rays are mainly paratropal, occasionally orthotropal. Both tangential and proximal rays have smooth rounded tips, but only tangential rays bear large thorns on the middle halves of the rays. Choanosomal diactins (Fig. 11C ) occur in two distinct forms. Large ones> 2 mm in length are straight, slightly curved or sinuous, and are smooth except for rough subterminal areas; tips are rounded or abruptly pointed. Small forms <2 mm in length are entirely spined, have sharp tips and often four central knobs or a single tyle. Dermalia (Fig. 11D ) are thick stubby pentactins, entirely and profusely spined without a knob of a sixth ray. Atralia (Fig. 11D ) are most commonly hexactins, with rays longer, thinner, and less profusely spined than those of dermalia.

Microscleres (Fig. 11 ; Table 5 ) are three types of discohexasters and two types of oxyhexasters and their variants, rare hemioxyhexasters and oxyhexactins. The centrum in all categories tends to be varyingly swollen to the extent that the spicules approach asteroid forms. The oxyhexasters are extremely difficult to separate into types due to presence of intermediates. Discohexasters 1 (Fig. 11F ) are semi-stellate with very short smooth primary rays, each supporting 4-8 gently curved secondary rays ornamented with reclined spines; terminal discs invariably have eight stout marginal teeth. Discohexasters 2 (Fig. 11G ) are very slightly smaller spherical forms with each smooth primary ray supporting 2-4 straight thick terminal rays ornamented with reclined spines; the terminal discs have 5-9 marginal teeth. Discohexasters 3 (Fig. 11H ) are small semi-stellate forms like discohexasters 1, with very short, smooth primary rays, each supporting 7-11 thin, curved, rough secondary rays, each ending in a terminal disc with 4-9 marginal teeth. Oxyhexasters 1, including hemioxyhexasters (Fig. 11H ), are stout spherical forms with each short smooth primary ray supporting 1-3 secondary rays ornamented with dense reclined spines and ending in sharp tips. Oxyhexasters 2 (no SEM image available) are forms with very thin secondary rays and often broken; they have diverse characters but are not considered immature forms of oxyhexasters 1. The centres are very small or swollen to globular form and the distal ends of the primary rays are either very thin or globular, each primary end supports two or three thin secondary rays that appear totally smooth. We are not confident in recognising this as a spicule category since the only practical character in defining it is the thinness of the secondary rays and size. Oxyhexactins (no SEM available) are rare: only four have been verified in spicule surveys. They have characteristics of oxyhexasters 1 in the stoutness and ornamentation of their rays.

Etymology.

Named for the large, irregularly thorned hypodermal pentactins, that project from the body of this species ( Scyphidium variospinosum , with irregular thorns; Latin).

Remarks.

The characters of these new specimens agree with the revised diagnosis of Scyphidium (see above) but differ from those of all eight recognised species of that genus. None has raised, thorned, hypodermal pentactins as prostalia. Only three species, S. tuberculatum (Okada, 1932), S. jamatai Tabachnick, 1991, and S. australiense Tabachnick, Janussen & Menschenina, 2008 (see above) have dermalia as mostly pentactins and atrialia as mostly hexactins, in agreement with the two new specimens. The sizes of the discohexasters are considerably smaller in all three than those in the new forms described here. On the basis of these and other differences, we are confident that the two new specimens described here represent a new species, here designated as Scyphidium variospinosum sp. nov.

Figures

Figure 10. Scyphidium variospinosum sp. nov.: A distribution in New Zealand waters, location of both holotype NIWA 126279 and paratype NIWA 126274 on Wairarapa Slope B holotype NIWA 126279 in situ (green laser spots are 6.24 cm apart) C holotype, deck image, torn open on the left side. Note the distinct pentactin veil around body D holotype, superior end, deck image, where torn wall is obvious, and osculum is partly intact on the upper left side. Scale bar unavailable E paratype, NIWA 126274 (deck images by PJS) F close view of the prostal pentactins forming the veil of the holotype G Closer view of the thorns on the prostal pentactin tangential rays H dermal surface of preserved holotype with partly damaged lattice of dermalia I atrial surface of the preserved holotype with no lattice evident. Image B captured by ROV Team GEOMAR, ROV Kiel 6000 onboard RV Sonne (voyage SO 254), courtesy of Project PoribacNewZ, GEOMAR, and ICBM.

Figure 11. Scyphidium variospinosum sp. nov., holotype NIWA 126279, spicules A prostal diactins, two whole and enlarged end and near-end segment B prostal pentactins, two whole spicules, inside and end views and parts including a tangential ray end (top), a thorned part and a proximal end (lower). Scale bars of whole and parts are same as in A C choanosomal diactins, three whole long and short versions plus enlarged tips D one pentactine dermalium and enlarged tangential and proximal ray tips E one hexactine atrialium and enlarged ray end F Caulophacus discohexaster 1 and enlarged terminal ray end G Caulophacus discohexaster 2 with enlarged terminal ray end H Caulophacus discohexaster 3 I hemioxyhexaster with enlarged terminal ray end. All microscleres and their enlarged parts are at same scale bars.