Scyphidium australiense Tabachnick, Janussen & Menschenina, 2008

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 australiense Tabachnick, Janussen & Menschenina, 2008

Figs 8 , 9

Note.

From the ending of its name, Scyphidium is a neuter noun, and thus S. australiensis (as originally named by Tabachnick et al. 2008) should be S. australiense . This is borne out by the names of conspecifics that are also adjectives (e.g., S. chilense , S. septentrionale , S. tuberculatum ) (J. Rosser, pers. comm.). We hereby make that change and use the corrected name throughout this work.

Type and locality (not examined).

Holotype - NIWA 155561, RV Sonne Stn SO17/80 (NZOI Stn Z3951B), Chatham Rise, 43.553°S, 179.457°E, 409 m, 10 Apr 1981 [Originally cited in Tabachnick et al. (2008) as WAM (p14), RV Soela Stn SO 17-80, 43°33.10'-33.05'S, 179°27.25'-27.08'E, depth unknown].

Material examined.

NIWA 126237, RV Sonne, Stn SO254/77ROV14_BIOBOX02, Pegasus Canyon slope, off Christchurch shelf, 43.2927361°S, 173.6066742°E, 853 m, 20 Feb 2017.

Distribution.

Chatham Rise and Pegasus Canyon slope, off Christchurch shelf Christchurch shelf, New Zealand (Fig. 8A ).

Habitat.

Attached to hard substratum; depth 409-853 m.

Description.

Body form is a heavy-looking, thick-walled, club-shaped, pendant sponge with a narrow basal attachment, widening gradually to a hemispherical rounded terminal end (Fig. 8B, C ) where a large osculum is centrally located. The osculum opens into a deep atrial cavity (Fig. 8D ). The margin is sharp-edged with indication of sparse marginalia that do not differ from prostal diactins of the lower body. The external surface of the upper body is fairly smooth, without prostalia, but the lower half is conspicuously conulose with long prostal diactins projecting in small groups from conules (Fig. 8E ). We did not have access to the basal attachment so we cannot comment on the basidictyonalia. Dimensions of the specimen are 27.6 cm in height, 11.7 cm in maximum width, 5.7-10.9 cm in diameters of the osculum, 10.0 mm in maximum wall thickness, 8.3 mm in length of projecting part of prostal diactins. Texture is firm but compressible and resilient, neither soft nor fragile. Surface of the dermal side is covered by an intact lattice of dermalia (Fig. 8G ) consisting mostly of pentactins (98% of 302 assayed), and a few stauractins and diactins (1% each). The upper body surface is fairly smooth, but the lower body is covered with conspicuous conules up to 3.2 mm high, from which prostal diactins project in small groups of one to four. One large pentactin was found but it was broken and assumed to be foreign. The atrial surface is covered by a felt-like layer of disarranged atrialia (Fig. 8H ) composed of hexactins (57% of 168 assayed), pentactins (20%), paratetractins (8%), diactins (6%), stauractins (5%), and triactins (3%). Colour in life is very pale brown, preserved in ethanol is medium brown.

Skeleton. Choanosomal skeleton consists of a tight series of macroscopic partitions of inhalant and exhalant channels running perpendicular to the body surfaces (Fig. 8F ). They consist of networks of choanosomal diactins and microscleres and in the lower body the proximal ends of the prostal diactins. A few small patches of fused choanosomal diactins occur but these are too rare to provide significant support to the body. Ectosomal skeleton of the dermal side consists of the robust lattice of pentactine dermalia and in the lower body the projecting prostal diactins. The atrial ectosomal skeleton consists of the felt-like lattice of atrialia and the supporting layer of hypoatrial diactins.

Spicules. Megascleres (Fig. 9 ; Table 4 ) are prostal diactins, choanosomal diactins, dermalia, and atrialia. Prostal diactins (Fig. 9A ) are large, curved, and smooth spicules with rounded proximal tips either smooth or bearing very low suggestions of obsolete spines. They have neither an axial cross nor central swellings. Distal tips are invariably broken off. Choanosomal diactins (Fig. 9B ) come in three distinct forms. The larger ones over 2 mm long are straight or slightly curved or sinuous and are smooth except for the patches of spines at the rounded or abruptly pointed tips. Those between 1 and 2 mm long have sharp tips and longer spines on the tip patches. The shortest, less than 1 mm long, are entirely spined with sharp tips and often with a central tyle or four knobs. Dermalia (Fig. 9C ) are thick stubby pentactins, entirely profusely spined without a knob of a sixth ray. Atralia (Fig. 9D ) are highly diverse; the most common hexactins have thinner and less densely spined rays than the dermalia. Pentactin atrialia are very similar to the dermal pentactins but have a knob in place of the sixth ray. Paratropal atrialia have rays similar to the hexactine atrialia. Spheres (Fig. 9E ) are common and here considered megascleres.

Microscleres (Fig. 9 ; Table 4 ) are two types of discohexasters and one type of oxyhexaster and its variants, rare hemioxyhexasters and oxyhexactins. Discohexasters 1 (Fig. 9F ) are spherical with very short smooth primary rays, each supporting 3.5 (2-5) thick secondary rays ornamented with reclined spines. Terminal discs invariably have six stout marginal teeth. Discohexasters 2 (Fig. 9G ) are smaller spherical forms with each smooth primary ray supporting 6.3 (5-8) thinner terminal rays; the terminal discs also invariably have 6 marginal teeth. Oxyhexasters (Fig. 9H ) are stout spherical forms with each short smooth primary ray supporting 3.2 (3-5) fully developed secondary rays ornamented with dense reclined spines and ending in sharp tips. Each oxyhexaster also has 2-12 poorly developed secondary rays only a few micrometres in length. Only one hemioxyhexaster and three oxyhexactins, all of a similar size and ray characters as the oxyhexaster, were discovered in microsclere surveys.

Remarks.

The characters of this new specimen agree with those in the original description of S. australiense by Tabachnick et al. (2008) except for the absence of prostal diactins and sphere megascleres in the latter, and absence of the rare discohexactins in the former. Absence of prostal diactins in the holotype is likely attributable to it being a distal fragment where we also found no prostalia in the new specimen. Spheres appear to be spicules of erratic occurrence in hexactinellids and are unlikely to be of phylogenetic significance. Absence of discohexactins in the new specimen is not considered an important difference. Sizes and shapes of the common microscleres are similar enough in both specimens to conclude that they are from specimens of the same species. It is somewhat surprising that the authors of this species assigned it to the genus Scyphidium without altering the generic diagnosis to encompass it; we have done so here.

Prior to the discovery of a second specimen of S. australiense here, there was considerable doubt as to the true type locality of the holotype described by Tabachnick et al. (2008). This work focused on hexactinellid sponges "sampled mainly off the Australian West Coast", and the holotype was named "after the type locality of this species", i.e., Australia. However, the latitude and longitude for RV Soela Stn SO 17-80 (43°33.10'-33.05'S, 179°27.25'-27.08'E) placed the type locality as on the north central Chatham Rise on the east coast of New Zealand. The Western Australian Museum (WAM) has confirmed that the RV Soela carried out fieldwork off western and northern Australia, and that the material covered in Tabachnick et al. (2008) was sent to the MNHN to be worked on taxonomically. Unfortunately, WAM has no details for "RV Soela Stn SO 17-80" (Jane Fromont, Western Australian Museum, pers. comm.), but interestingly, the specimen reported here, NIWA 126237, is also from Chatham Rise (Pegasus Canyon Slope, off Christchurch Shelf), intensifying the mystery surrounding the type locality of this species. Investigation of pre-2004 electronic records at NIC revealed that the specimen listed from station "RV Soela Stn SO 17-80", given in Tabachnick et al. (2008), was more likely to have been collected on the RV Sonne Cruise SO-17 on the Chatham Rise phosphorite deposits east of New Zealand ( Von Rad 1984), because the NZOI Stn Z3951B from that cruise, a large grab with Porifera listed in the Remarks column, has identical coordinates and similar station numbers. We are still unsure as to how the specimen reached Tabachnick’s attention at the MNHN, and indeed, the whereabouts of the holotype, but we know that errors were made in translation of the station data from the specimen labels to this publication, and it is possible that the authors assumed that the RV Sonne representation of "Stn SO17/80" was just another RV Soela Stn, represented as SO 17-80 in the publication. The MNHN was temporarily closed for most of 2020 and the early months of 2021 due to measures of the French government to prevent the spread of COVID-19 (novel coronavirus disease), so the repatriation of this specimen was not able to be completed at time of publication.

Figures

Figure 8. Scyphidium australiense Tabachnick, Janussen & Menschenina, 2008, NIWA 126237, distribution, skeleton and morphology A distribution in New Zealand waters, holotype as open circle, new specimen as filled circle B new specimen in situ (scale bar is approximate) C deck image (two sides, image by PJS) D osculum, deck image (by PJS) E preserved conulose outer surface of the lower body with prostal diactins F preserved wall section of the mid-body without conules G preserved dermal surface with intact pentactin lattice H preserved atrial surface with hexactins displaced from the atrial lattice. Image B captured by ROV Team GEOMAR, ROV Kiel 6000 onboard RV Sonne (voyage SO 254), courtesy of Project PoribacNewZ, GEOMAR, and ICBM.

Figure 9. Scyphidium australiense Tabachnick, Janussen & Menschenina, 2008, NIWA 126237, spicules A prostal diactin, whole and enlarged ends, one broken distal end and two intact proximal ends B choanosomal diactins, whole long and short versions at different scales plus enlarged tips and central swellings C dermalium: pentactin, whole and enlarged tips D atrialia, hexactin, whole and enlarged tip, pentactin, whole with enlarged tips, and paratetractin, whole; scales are the same as those for dermalium E spheres as small group of whole ones and one enlarged F Caulophacus discohexaster 1, whole and enlarged terminal ray end G Caulophacus discohexaster 2, whole and enlarged part of one ray tuft H oxyhexaster, whole and enlarged terminal ray end. Scales are the same for all whole microscleres and their enlarged parts.