Nubes poculiformis 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

Nubes poculiformis Reiswig, Dohrmann & Kelly sp. nov.

Figs 6 , 7

Material examined.

Holotype NIWA 126016, RV Sonne Stn SO 254/08ROV02_BIOBOX10, Seamount No. 114 in International Waters to the east of Three Kings Ridge and Norfolk Island, 31.301°S, 175.197°E, 1285 m, 31 Jan 2017.

Distribution.

Known only from the type locality, Seamount No. 114, in International Waters to the east of Three Kings Ridge and Norfolk Island (Fig. 6A ).

Habitat.

Attached to hard substratum; depth 1285 m (Fig. 6B ).

Description.

Morphology of the holotype body is a thick-walled tubular sponge, attached to hard substratum, by a moderately long, narrow stalk (Fig. 6B, C ). A moderately sized, round osculum is terminal and opens into a deep atrial cavity. The margin is blunt, bordered by a band of diactine marginalia (Fig. 6D, F ). The dermal surface has a dense covering of raised, prostal, hypodermal pentactins (Fig. 6D, E ), projecting up to 7 mm from the surface proper. Some of the deck images indicate long diactins projecting sparsely, up to 14 mm, from the dermal surface, but these may be foreign in origin; we have not found such large diactins in the material available for examination. Dimensions of the holotype are ~ 6 cm in total length, including the stalk of 1.8 cm length (Fig. 6G ), and 3.5 cm in width; the maximum body wall thickness is 13.9 mm. The osculum is 12.3 by 16.9 mm diameter in situ. Texture is soft, compressible, and resilient, neither hard nor fragile. Surface of the dermal side below the layer of projecting hypodermal pentactins is supported by an intact tight lattice of dermalia (Fig. 6H ). The atrial surface (Fig. 6I ), in contrast, is torn apart by removal from supporting fluids and the atrial lattice remains only as dismembered patches attached to underlying diactins. Colour in life is pale brown as is the specimen preserved in ethanol.

Skeleton. Choanosomal skeleton consists of a loose, vacuolar network of thin choanosomal diactins, large choanosomal hexactins and the thicker proximal rays of the hypodermal pentactins. There is no evidence of fusion between any spicules. Microscleres are scattered evenly throughout the choanosome. Ectosomal skeleton of the dermal side consists of abundant prostal pentactins providing good support for the sturdy lattice of stauractine (60.0% of 315 assessed), pentactine (38.4%), and rare hexactine (1.64%) dermalia. The atrial ectosome lacks hypoatrial pentactins but has bands of diactins that provide poor support for the atrial lattice of mainly hexactins (86.4% of 118 assessed), pentactins (7.5%), and stauractins (5.1%). Microscleres are present as in the choanosome.

Spicules. Megascleres (Fig. 7 ; Table 3 ) are prostal hypodermal pentactins, marginal diactins, choanosomal diactins of the body, choanosomal diactins of the stalk, dermalia and atrialia. Prostal hypodermal pentactins (Fig. 7A ) are large, raised orthotropal forms with long straight tangential rays. Tangential rays are ca. one half the length of the longer straight proximal rays. The spicules are smooth except for the rough sharp or round tips. Marginalia (Fig. 7B ) are long, slightly curved diactins; no intact tips were found in SEM surveys but an exhaustive survey with LM indicates tips taper to nearly invisible thinness and are quite distinct from the thick roughened tips of choanosomal diactins. Choanosomal diactins (Fig. 7C ) are straight or slightly curved with undetectable central swellings; they are smooth except for the rough, slightly inflated tips. Stalk diactins (Fig. 7D ) are longer and thicker than the choanosomal diactins, but otherwise similar. Dermalia (Fig. 7E ) are mainly entirely rough stauractins and pentactins with rounded ray tips. Atrialia (Fig. 7F ) are entirely rough hexactins with equal length rays and more acute ray tips.

Microscleres (Fig. 7 ; Table 3 ) are oxyhexasters, hemioxyhexasters, and anisodiscohexasters. Oxyhexasters (Fig. 7G ) and hemioxyhexasters have very short, sparsely spined or smooth, thick primary rays, ending in swollen hemispheres; 1-7, usually 3-4, rough, straight, terminal rays tapering to pointed tips emanate from the margins and occasionally from the centre of the hemisphere. Short to very short spur-like terminal rays are common. Anisodiscohexasters (Fig. 7H ) have smooth primary rays ending in ovoid strobila. Each strobilum supports ca. 20-30 rough, curved terminal rays that end in discs with 4-7 marginal discs. The tuft of terminal rays from each primary ray varies in length of rays, and with ray length the diameter of terminal discs, in a pattern that is not yet clear, but the whole spicule resembles a radially symmetrical starburst.

Etymology.

Named for the goblet shape of the sponge ( Nubes poculiformis , goblet-shaped; Latin).

Remarks.

This species differs from Nubes tubulata sp. nov. in having a short stalk and orthotropal hypodermal pentactins, but is otherwise similar enough to include it in the genus Nubes as its second species, Nubes poculiformis sp. nov.

Figures

Figure 6. Nubes poculiformis gen. nov., sp. nov., holotype NIWA 126016, distribution, skeleton and morphology A distribution in New Zealand waters B holotype in situ C holotype, deck image (by PJS); D longitudinal section of holotype, showing hypodermal pentactin veil E closer view of hypodermal pentactin veil F edge of osculum with tuft of marginalia G close view of stalk subdivided for spicule preparation of smaller sample H dermal surface with intact lattice of dermalia over inhalant canals I atrial surface with disrupted lattice of atrialia. Image B captured by ROV Team GEOMAR, ROV Kiel 6000 onboard RV Sonne (voyage SO 254), courtesy of Project PoribacNewZ, GEOMAR, and ICBM.

Figure 7. Nubes poculiformis gen. nov., sp. nov., holotype NIWA 126016, spicules A three prostal hypodermal pentactins, the lower one in plane of tangential rays, with enlarged ray ends B whole marginal diactins (ray ends unavailable) C two whole choanosomal hexactins with two enlarged ray ends and one centrum. Scale of whole spicules as in C; D four whole stalk diactins and enlarged end E dermalia, stauractin and pentactin with enlarged ray ends F atrialium and enlarged ray end G two oxyhexasters and enlarged terminal ray H whole anisodiscohexaster; an enlarged section showing disc diameter increasing in longer terminal rays; an enlarged side view of a terminal ray and end views of terminal ray discs.