taxonID	type	description	language	source
153B577AFF8AC03BFF6323B10FA61787.taxon	diagnosis	Diagnosis. Circular lenticular or hemispherical Polymastiidae. The skeleton of the basal surface of the sponge is composed of an envelope of principal subtylostyles or styles covered by a thin palisade of ectosomal tylostyles. The upper surface is composed of one or two layers of tylostyles. The choanosomal skeleton is composed of diverging tracts emanating from a central nucleus at the base of the sponge and by groups of fusiform tylostyles. The inhalant and exhalant apertures are grouped on papillae (Boury-Esnault 2002).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF8AC03FFF6321510E8615B5.taxon	description	Figures 1 – 3, Tables 1 & 3	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF8AC03FFF6321510E8615B5.taxon	materials_examined	Type material: Holotype QM G 337524, off Byron Bay, New South Wales, Australia, - 28.0544, 154.083 to - 28.097, 154.081, 999 – 1013 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 100 - 114, 9 / VI / 2017. Paratypes QM G 337530, same collection data as QM G 337524 sample 100 - 136; QM G 337532, same collection data as QM G 337524, sample 100 - 229; QM G 339452, Coral Sea Commonwealth Marine Reserve, Queensland, Australia, - 23.6312, 154.6597 to - 23.659, 154.6438, 1770 – 1761 m, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 128 - 117.2, 13 / VI / 2017. Other material: QM G 337558, Coral Sea Commonwealth Marine Reserve, Queensland, Australia, - 23.6312, 154.6597 to - 23.659, 154.6438, 1770 – 1761 m, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 128 - 117, 13 / VI / 2017; QM G 339453, same collection details as QM G 337558, sample 128 - 117.3, 13 / VI / 2017; QM G 316421, Lord Howe Plateau, Pacific Ocean Seamounts, - 32.445, 161.7825, 1130 – 1147 m, Beam Trawl, Coll. NORFANZ expedition on RV Tangaroa, TAN 308 / 77 - 039, MF 328, 25 / V / 2003; QM G 339455, same collection details as QM G 316421, 14 specimens. Etymology: named for its growth form, nidula L., small nest. Diagnosis: A fringed multi-papillate dish shaped Radiella, with tracts of tylostyles from the choanosome diverging into bouquets supporting a top palisade layer of tylostyles, producing a two layered upper ectosome. Morphology: The sponge is dish shaped varying from relatively flat to deeply conical, with a hispid concave upper surface, a convex smooth lower surface, and a marginal spicule fringe (Fig. 3 A – C). The holotype is 16.3 mm in width, including the 4.3 mm basal fringe, whilst the body height is 3.9 mm. The paratypes are identical in shape and similar in size i. e. 14 – 15.6 mm in width and 2.8 – 5.0 mm in height with the fringe of 3 – 4 mm. The holotype has three small papillae (1.4 mm in height), whilst 1 – 6 papillae could be discerned on the paratypes (Fig. 3 A). These may have been destroyed during collection as all of the specimens were covered by mud during the trawl collection. The sponge is white to cream in colour immediately after collection as well as in ethanol. The sponge is firm but flexible on the lower (basal) surface due to the later protective styles, but soft and compressible on the upper surface. Skeleton: The choanosomal skeleton consists of randomly orientated disorganised smaller tylostyles, located between the tracts of principal styles (Fig. 3 C, D). The principal tylostyles originate in the lower ectosome, rise and form bouquets in the upper choanosome. The upper ectosome is formed by another layer of principal tylostyles forming a palisade (Fig. 3 D). Detritus including sand is caught in the spicules emerging through the palisade. The lower ectosomal skeleton also contains the long fringe tyles on the lower (basal) surface, which radiate from the centre of the lower surface forming the fringe (Fig. 3 C, D). Spicules: The holotype has large, long, thin fringe styles 1990 – 4070 μm in length with slight central thickening and are 14.0 – 44.4 μm in width (Fig. 3 E – F). The principal tylostyles are much shorter, thicker, with a subtle tyle 779 – 1510 × 9.6 – 23.5 μm (Fig. 3 G – H). The smaller choanosomal tylostyles are thicker and have a more pronounced tyle and measure 220 – 658 μm in length and 4.8 – 19.4 μm in width (Fig. 3 I). The spicule measurements for the type material are tabulated in Table 1. Distribution: Coral Sea and Tasman Sea seamounts, bathyal depth. Ecology: Mud substrate Molecular data: 28 S-C region barcode of holotype QM G 337524 (ENA Accession number OY 741337), Paratypes QM G 337530 (OY 741338), QM G 337532 (OY 741339), forming a distinct and supported clade (Fig. 2). Remarks: This new species superficially resembles Radiella straticulata (Wilson, 1925), however it differs markedly in the skeleton by lacking the three-layered stratification in both the upper and lower ectosome. It also differs by having a smaller fringe of only 3 – 4 mm compared to 6 – 9 mm, corresponding to the shorter fringe spicules of up to 4.3 mm in the new species and up to 10 mm in R. straticulata. This specimen was previously listed as Radiella irregularis in O’Hara et al. (2020).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF8EC031FF63237B0FA11531.taxon	description	Figures 1, 2 & 4, Tables 2 & 3	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF8EC031FF63237B0FA11531.taxon	materials_examined	Type material: Holotype QM G 337516, Off Byron Bay, New South Wales, Australia, - 28.6765, 154.20327 to - 28.709, 154.1897, 2587 – 2562 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, Sample 90 - 202, 7 / VI / 2017. Paratypes: QM G 337515 same collection details as QM G 337516, Sample 90 - 180; QM G 337616 same collection details as QM G 337516, Sample 90 - 169; QM G 339368 same collection details as QM G 337516, Sample 90 - 169.3. Etymology: named for its substratum, pumix L., pumice. Diagnosis: Radiella species attached to pumice, lacking an obvious fringe, but expands by having new discrete hemispherical bouquets outside the ectosome. Morphology: A convex cream coloured sponge attached to drowned pumice stone (Fig. 4 A, B). The holotype QM G 337516, is 8.3 mm in diameter, and 1.2 mm in height. The paratype QM G 337616, is 6 mm in diameter and only 0.83 mm in height, whilst paratype, QM G 337515 is 5.8 mm in diameter and 1.4 mm in height. The upper surface is hispid, and the sponge lacks an obvious fringe (Fig. 4 C-E). The holotype has a single central papilla, the papillae could not be obviously seen on most of the paratypes (Fig. 4 E). Skeleton: The choanosomal skeleton is composed of confusedly arranged small tylostyles (Fig. 4 E). The ectosome consists of bouquets of the large principal tylostyles, many of which originate from the choanosome. These bouquets of the principal tylostyles also line the central oscular canal. The ectosome and the periphery of the specimen are characterised by the appearance of discrete bouquets (Fig. 4 C, D). In some cases, the bouquets on the surface appear as spheres giving the surface a papillate appearance. Spicules: The principal tylostyles vary greatly in length and may be possibly divided into two size categories with large overlapping sizes (640 – 2270 × 7 – 19 μm) (Tab. 2). There are smaller tylostyles arranged in disorder in the choanosome (100 – 300 × 3 – 15 μm) and intermediate tylostyles (339 – 660 × 5 – 13 μm) composing the bouquets of the main ectosomal skeleton. Distribution: Northern New South Wales, Australia, abyssal depth. Ecology: Found exclusively on submerged pumice stones. Molecular data: 28 S-C region barcode of holotype QM G 337516 (ENA Accession number OY 741336), paratype QM G 337616 (ENA Accession number OY 741340), forming a distinct and supported clade (Figure 2). Remarks: The new species resembles Spinularia australis Lévi, 1993 from bathyal depths off New Caledonia by the body shape and size and the substrate it grows on, the pumice stones. The individuals of S. australis are slightly larger in diameter, 7 to 12 mm, but similar in height, 1.4 to 3.7 mm. However, our new cream-coloured species differs from S. australis by lacking the lower fringe and associated large tylostyles, with the largest difference being the ectosomal skeleton with many independent small plumose bouquets which is the most distinctive character of this new species. The new species also lacks the radial skeleton seen in S. australis, and it also differs importantly from S. australis by having a new category of much smaller tylostyles and it also lacks raphides. These specimens were previously listed as Radiella irregularis in O’Hara et al. (2020).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF80C035FF6320730F4A151B.taxon	description	Figures 1 & 5, Table 3 Type material: Holotype QM G 316333, Lord Howe Plateau, Pacific Ocean Seamounts, Australia, - 34.2315, 162.6765, 515 – 700 m, Sherman Sled, Coll. NORFANZ expedition on RV Tangaroa, 85 - 014, MF 336, 26 / V / 2003. Etymology: named for its texture, sclera L., hard f. Diagnosis: A very hard Radiella species anchored to rock by choanosomal tracts of tylostyle forming root like processes. The sponge lacks a fringe and a purely radial skeleton, having instead a multilayered complex choanosomal skeleton. TABLE 3. (Continued) Morphology: The sponge is a hard incompressible, cream coloured low flat to convex cushion 23.5 mm in dimeter and 4.53 mm in height (Fig. 5 A). The sponge was presumably attached to some hard substrate (possibly sunken pumice), as stain marks are apparent on the lower surface and the base of spicule bouquets emerge from the body to form root-like processes (Fig. 5 B). There were no apparent papillae or oscular structures present on the upper surface. In cross section the choanosome is cream in colour, whilst the dense spicule ectosome is colourless (Fig. 5 B). The surface of the ectosome is cream in colour, but this is most likely due to sediment. Skeleton: The ectosomal skeleton is a dense palisade of principal styles arising from bouquets formed in the choanosome (Fig. 5 D). The choanosome is a confused array of the two smaller sizes of tylostyles, often in small bundles of the intermediate sized tylostyles (Fig. 5 C). Bouquets of the principal styles originate exterior to the underside of the sponge body where they function as root-like anchoring processes. These bouquets radiate up through the choanosome all the way up to the ectosome (Fig. 5 C, D). The principal tylostyles that form the bouquets on the upper ectosome are also the same spicules that form the radial thin lower ectosomal skeleton (Fig. 5 C), which ascends on the periphery to form another bouquet (Fig. 5 D). The small and intermediate tylostyles are present throughout the choanosome. Spicules: The megascleres are composed of three overlapping sizes of tylostyles, which all represent a gradation. As the tylostyles increase in length, they also proportionally decrease in width. The two smaller sizes of tylostyles are much thicker towards the point, whilst the largest tylostyles are slightly thicker towards the head. Principal tylostyles are 913 – (1140) – 1450 × 12.0 – (18.8) – 30.0 μm, n = 46 (Fig. 5 E, F). The intermediate tylostyles are 557 – (744) – 980 × 8.4 – (13.9) – 21.4 μm, n = 34 (Fig. 5 G, H), whilst the small tylostyles are 245 – (416) – 554 × 5.4 – (11.0) – 15.7 μm, n = 47 (Fig 5 I). Distribution: Known only from seamounts in the Lord Howe Plateau, bathyl depths. Ecology: Attached to a hard substrate, most likely rocks Molecular data: no unambiguous 28 S-C region barcode could be generated from this species. Remarks: This new species lacks the very large fringing styles that are normally obvious in species of the genus Radiella. This species differs from S. australis Lévi, 1993 in being much larger, lighter in colour, with a harder, denser and incompressible texture. Furthermore, our new species lacks the purely radial skeleton found in S. australis, but has a multilayered complex choanosomal skeleton instead. It also lacks the large fringe tylostyles as well as the raphides found in the New Caledonian specimens.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF84C035FF6322910E9614A7.taxon	diagnosis	Diagnosis: Small, usually more or less discoid Polymastiidae. Surface minutely hispid except at the edge where there is a strong hispidation present. Choanosomal skeleton composed of primary tracts of tylostyles between which trichodragmata are found. Ectosomal skeleton is composed of a palisade of ectosomal tylostyles. There are no true aquiferous papilla and the oscule is located at the upper part of the sponge and is slightly raised above the general surface (modified from Boury-Esnault 2002).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF84C036FF63204D089613CF.taxon	description	Figures 1, 2 & 6, Tables 3 & 4	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF84C036FF63204D089613CF.taxon	description	? Part Spinularia sarsii (Ridley & Dendy, 1887): 218 - 220	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF84C036FF63204D089613CF.taxon	materials_examined	Type material: Holotype QM G 337555, Coral Sea Commonwealth Marine Reserve, Queensland, Australia, - 23.587, 154.194 to - 23.617, 154.1947, 1013 – 1093 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 121 - 232, 13 / VI / 2017. Paratypes QM G 337175, off Byron Bay, New South Wales, Australia, - 28.0544, 154.083 to - 28.097, 154.081, 999 – 1013 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 100 - 114.1, 9 / VI / 2017; QM G 339363, same collection details as G 337175, sample 100 - 115; QM G 337548, same collection details as QM G 337555, sample 121 - 144. Other Material: QM G 316338, North Norfolk Ridge, Pacific Ocean Seamounts, - 26.43233333, 167.1811667, 750 – 774 m, Beam Trawl, Coll. NORFANZ expedition on RV Tangaroa, 43 - 016, MF 140, 18 / V / 2003, 5 specimens; QM G 339456, same collection details as QM G 316338; QM G 339454, Lord Howe Plateau, Pacific Ocean Seamounts, - 32.445, 161.7825, 1130 – 1147 m, Beam Trawl, Coll. NORFANZ expedition on RV Tangaroa, TAN 308 / 77 - 039, MF 328, 25 / V / 2003, 13 specimens. Etymology: named for the whip-like shape of the principal tylostyles, flagellum L. whip. Diagnosis: Discoid Spinularia with a small fringe, a single layer of bouquet forming tylostyles in the ectosome and long very thin whip like tylostyles. Morphology: Flattened discoid, with a hispid concave upper surface, a convex smooth lower surface (Fig. 6 A – D) and a marginal spicule fringe (Fig. 6 L). The holotype is 15 mm in width, including the 2.3 mm basal fringe, whilst the body height is 7.2 mm. The paratypes are identical in shape and similar in size i. e. 14 – 15.4 mm in width and 4.3 – 7.2 mm in height with the fringe of 3 mm. The holotype has a single central papilla (1 mm in height). The sponge is white to cream in colour immediately after collection and in ethanol. The sponge is firm, but flexible on the lower surface due to the protective styles, but soft and compressible on the upper surface. Skeleton: The choanosomal skeleton consists of randomly orientated disorganised smaller tylostyles (Fig. 6 D, K). The principal tylostyles originate below the ectosome, from bouquets in the upper choanosome, forming a palisade in the ectosome (Fig. 6 D, K). The lower ectosomal skeleton also contains the long fringe styles on the lower surface, which radiate from the centre of the basal surface forming the fringe (Fig. 6 D). Spicules: The large fringe tylostyles forming the fringe range from 1510 – 3500 μm in length and 14.7 – 48.8 μm in width (Fig. 6 E, F). The principal tylostyles have a very long drawn out thin sinuous tip resembling a whip, these are 696 – 2430 × 7.4 – 26.6 μm (Fig. 6 G, H). These whip-like tylostyles are very fragile, and can easily be overlooked as the fine ends are usually broken off during collection. The small tylostyles from the choanosome are prominently fusiform (Fig. 6 I). The uncommon raphides are also present lying loosely in the choanosome (Fig. 6 J). All spicule measurements are summarised in Table 4. Distribution: Coral Sea and Tasman Sea seamounts, bathyal depth. Ecology: Mud substrate. Molecular data: 28 S-C region barcode of holotype QM G 337555 (ENA Accession number OY 741343). This sample is genetically different from all other samples analysed in this study. Remarks: This new species is remarkably similar in morphology to Radiella nidula sp. nov., both being very small discs with fringing spicules and often occur together in the same habitats. The new species differs from R. nidula sp. nov., by the shape and size of the principal tylostyles, the wider smaller tylostyles, the whip like styles and the presence of raphides giving generic separation from Radiella. It also differs by having a simpler skeleton, i. e. it only has the single layer of bouquet forming tylostyles in the ectosome and by molecular differences in 28 S (see Fig. 3). This new species probably includes one of the specimens of Ridley & Dendy’s (1886), that was collected from Cape York Australia i. e. BMNH 1887.5.2.40. Ridley & Dendy (1887), indicate this Cape York specimen differs from the other specimens by the more convex shape and having shorter choanosomal tylostyles. It is also visibly different by the smaller more compact fringe and the presence of a single papillae from all Northern Hemisphere specimens of S. sarsii as illustrated in Fig. 29 E, F in Plotkin et al. (2018). However, examination of the spicules and skeleton of the paralectotype would be required to complete this determination, as the spicule measurements in Plotkin et al. (2018) have been pooled from 13 specimens and it is unclear if this contains any type material. These specimens were previously listed as Radiella irregularis in O’Hara et al. (2020). Specimen QM G 316338 also contain a small number of subtylostyles. Radiella straticulata has not infrequent subtylostyles as well. One of the five specimens of QM G 316338 and QM G 339456 also differ from the other specimens listed here by being attached to rock / coral fragments 3 – 5 mm in size (Fig. 6 M).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF87C036FF6324B20E3612BF.taxon	diagnosis	Diagnosis: Polymastiidae with columnar or globular growth form protected by a dense cylindrical sheath of longitudinally placed spicules which form a solid imperforate layer. The ectosomal skeleton contains bundles of smaller spicules arranged in a palisade and is limited to the upper surface of the cylinder. Ostia are present on the upper surface. The oscule at the top of a small papilla is on centre of the upper surface. Megascleres are subtylostyles and tylostyles (Boury-Esnault 2002).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF87C028FF6322420F62153F.taxon	description	Figures 1 & 7	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF87C028FF6322420F62153F.taxon	materials_examined	Material Examined: Holotype QM G 337614, Central Eastern Commonwealth Marine Reserve, New South Wales, Australia, - 30.0977, 153.8987 to - 30.1193, 153.8745, 2429 – 2518 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, 1 specimen, Sample 86 - 186, 5 / VI / 2017. Etymology: named after the lip like appearance of the sponge L. labium, n. lip. Diagnosis: Tentorium species, lacking the dense longitudinal sheath of tylostyles, with tracts of choanosomal principal styles not forming bouquets. Morphology: The sponge is cylindrical in shape, with a domed upper surface (Fig. 7 A – C). It is 10.6 mm in height and 30 mm in width. It is firmly attached to a piece of rock. It has three papillae located towards the apex of the smooth dome shaped upper surface (Fig. 7 A, B). Part of the ectosomal surface of the sponge was damaged, either during or before collection, so there may have been more papillae. The papilla is 4 mm in height and 1 mm in width. The sponge is cream in colour. The cortex is easily detachable and restricted to the upper surface, with the ectosomal skeleton composed of a palisade of tylostyles on the upper surface only (Fig. 7 A – D, I). Skeleton: The choanosomal skeleton is composed of longitudinal tracts of approximately 20 – 400 μm in width, composed mainly of the large tylostyles (Fig. 7 D, I). These tracts travel to the surface and provide support within the papillae. The ectosomal cortex is composed entirely of the small sub / tylostyles forming a palisade that also covers the papillae (Fig. 7 D, I). Spicules: The large principal styles that compose the longitudinal tracts in the choanosome are fusiform, with a subtle tylostyle head (Fig. 7 E – F). They are 743 – (1227) – 1931 × 13.9 – (21.3) – 32.1 μm (n = 97). The ectosomal palisade forming tylostyles, are of a uniform thickness of style and are much smaller and thinner than the choanosomal tylostyles with a more obvious tylostyle head. Sometimes subtylote (Fig. 7 G – H). These tylostyles are 194 – (237) – 303 × 2.9 – (4.8) – 6.4 μm (n = 34). Distribution: Continental slope of New South Wales, Australia, abyssal depth. Ecology: Attached to rocks. Molecular data: no unambiguous 28 S-C region barcode could be generated from this species. Remarks: The sponge lacks the basal fringe characteristic of Radiella species, but mentioned in some Tentorium descriptions (e. g. Boury-Esnault & van Beveren 1982). This species belongs to Tentorium, based on its columnar structure, with the longitudinally organised spicules and the palisade forming the upper ectosome. The genus is currently restricted to three species. Our specimen differs from T. papillatum (Kirkpatrick, 1908) (q. v. Plotkin & Janussen 2008), in lacking obvious papillae, but it bears a similarity to the latter species in that it lacks the dense cylindrical sheath of principal subtylostyles as in T. semisuberites (Schmidt, 1870) (q. v. Plotkin 2004) and T. levantinum Ilan, Gugel, Galil & Janussen, 2003, that was part of the original definition of Tentorium. Our specimen differs from the Arctic species Tentorium semisuberites (Schmidt, 1870) sensu stricto, in its gross morphology being an almost continuous dome structure, with an ectosome that can be easily detached. This individual specimen from the lower bathyal off the east coast of Australia, which has suffered some trauma to the superior surface, is closest to the as yet undescribed Tentorium cf. semisuberites sensu Plotkin & Janussen (2008), but differing from the latter in that the tracts in the choanosomal skeleton do not form obvious bouquets in the ectosomal skeleton – although this and the ectosomal sheath vary amongst specimens of Tentorium cf. semisuberites, as illustrated in Plotkin & Janussen (2008), suggesting there may be potentially several new species in this species complex. It is also almost three times larger at 30 mm in diameter, but of a similar height of 10.6 mm to Plotkin & Janussen’s (2008) material, and also differs in having three identical exhalant oscules and a cream colouration. Plotkin & Janussen (2008) also did not find differences in spicules between their specimens of T. semisuberites, collected from both hemispheres. However, due to the well-separated bipolar distribution of the Arctic and Antarctic faunas, it supports the possibility of being different species. Plotkin et al. (2016) showed that T. semisuberites is not a sister species to T. cf. semisuberites based on molecular data. Furthermore, Plotkin et al. (2018) showed that T. semisuberites is more closely related to Spinularia species than T. papillatum. Further molecular research may indicate sufficient differences for the erection of a separate genus and the placement of species within them. Tentorium semisuberites Boury-Esnault & van Beveren (1982) from the Kerguelen islands, has similar sized spicules, but differs by having fringing tylostyles at the base and only having a single papillae.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF99C028FF6322F50E2314FB.taxon	diagnosis	Diagnosis: Pedunculate egg-shaped sponge with an oscular papilla. Skeleton mainly confined to the ectosome. From outside to inside there is a palisade of ectosomal tylostyles, a layer of intermediary tylostyles and longitudinal tracts of principal tylostyles which lie on a collagenous layer. In the outermost region of the choanosome there is a tangential layer of ectosomal tylostyles. The spicules are tylostyles in three size categories. Choanocyte chambers are diplodal (Boury-Esnault 2002).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF99C02AFF6323B1088915F9.taxon	description	Figures 1 & 8	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF99C02AFF6323B1088915F9.taxon	materials_examined	Material examined: Holotype QM G 337550, Coral Sea Commonwealth Marine Reserve, Queensland, Australia, - 23.587, 154.194 to - 23.617, 154.1947, 1013 – 1093 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, sample 121 - 149, 13 / VI / 2017. Etymology: named for its spiky surface and its egg-like morphology reminiscent of the egg laying monotreme Echidna spp, L. ekinos, ‘ sea urchin’. Diagnosis: Egg shaped Ridleia with a dense palisade of very thin, long tylostyles making up more than 2 / 3 of the sponge thickness, embedded in the collagenous layer and a cavernous interior. Morphology: Growth form of the single known specimen so far is flattened egg-shaped, 12 mm in length, 9 mm in width, and 5 mm in height (Fig. 8 A). Papillae were not found and presumably were lost during collection. The sponge is firm but compressible with a fine hispid layer. Skeleton: This species is characterised by the massive palisade of large principal tylostyles almost 2 mm thick that makes up two thirds of the whole sponge body width (Fig. 8 A – C). These large ectosomal tylostyles are embedded in the collagenous layer. The small tylostyles also emerge from the collagenous layer and are orientated radially as the large tylostyles (Fig. 8 C, D). The lowest portion of the collagenous layer is characterised by the reduced and concentrated layer of tangential intermediate tylostyles. The inner choanosome has a cavernous interior with some residual tylostyle tracts (Fig. 8 B, C). Spicules: The ectosome is composed mainly of the long thin tylostyles that characterise this new species (994 – (1907) – 3200 × 9.9 – (15.6) – 24.2 μm (n = 54) (Fig. 8 E, F). The small tylostyles also make up the base of the ectosome (156 – (296) – 426 × 3.4 – (7.5) – 10.4 μm (n = 36) (Fig. 8 H). The intermediate tylostyles make up the tangential outermost layer of the choanosome (448 – (662) – 1000 × 6.5 – (10.5) – 13.8 μm (n = 22) (Fig. 8 G). Distribution: Coral Sea, bathyal depths. Ecology: Mud substrate. Molecular data: no unambiguous 28 S-C region barcode could be generated from this species. Remarks: The holotype of Ridleia echidna sp. nov., QM G 337550, is very different from the only two species remaining in this genus, i. e. R. oviformis Dendy, 1888 and R. dendyi de Laubenfels, 1934. It differs from both other known species by its massive ectosomal palisade of tylostyles and the very reduced and concentrated layer of paratangential tylostyles. The choanosome has a cavernous interior with some residual tylostyle tracts. It is assigned to Polymastiidae based on the possession of several sizes of tylostyles, a distinct cortex, ectosome and internal spicule free choanosome. But it differs sensu stricto due to its primary styles being radial and the secondary styles are tangentially distributed. Ridleia is the closest genus we consider to allocate this new species, requiring confirmation based on molecular data from other species presently allocated to this genus.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF9BC02AFF6322BC095D149C.taxon	diagnosis	Diagnosis: Polymastiidae of encrusting, massive, globular, hemispherical or discoid body shape, always bearing papillae with oscula at the summits. Main choanosomal skeleton composed of tracts of principal monactines radiating from the sponge base or forming a reticulation. Auxiliary choanosomal skeleton comprises smaller monactines, freescattered or grouped in little bundles. Cortical skeleton constituted at least by a superficial palisade of small smooth tylostyles or subtylostyles and an internal layer of larger monactines lying obliquely to the surface and may include middle layers. A fringe of extra-long monactines may be present at the edge of the body (Plotkin et al. 2018).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF9BC02CFF63206109821435.taxon	description	Figure 9, Table 5	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF9BC02CFF63206109821435.taxon	materials_examined	Material examined: QM G 315026, Casey Antarctic Research Base, Windmill Islands, Antarctica, - 66.2822, 110.5266, 30 m, SCUBA, Coll. M. Riddle & P. Goldsworthy, 10 / XI / 1997; QM G 335958, same collection details as QM G 315026; QM G 311143, Mc Murdo Base, Cape Armitage, Ross Island, Antarctica, - 77.85, 166.67, 20 m, north Jetty, Judy’s 1 st dome site, NCIS Q 66 C 3091 - Z, SCUBA, Coll. Australian Institute of Marine Sciences and National Cancer Institute, 18 / X / 1989. Morphology: Solitary circular sponge with a bulbous cushion base 52 – 83 mm wide and 25 – 40 mm in height (Fig. 9 A – G). Partially burrowing with a single large contractile and retractile central papilla, 13 – 19 mm wide, height 0 – 3 mm above the dermis in preservative, and judging by Fig. 9 A, B equal in height as width in vivo. There is a large single oscule at the top of the papillae (1 – 2 mm wide). The sponge is grey / brown in life and in ethanol, reflecting the colouration of the surrounding mud / silt. The papillae are ivory to cream in life and ethanol (Fig. 9 A – G). The sponge is firm but compressible, and is covered in a soft covering of fine hairs (except the papilla). Skeleton: The ectosomal skeleton is composed of an erect palisade of smaller tylostyles on the base, absent from the papilla, with larger styles protruding out from the choanosomal tracts (Fig. 9 H, I). There is abundant sand / detritus on the surface providing grey colouration to the ectosome. The choanosomal skeleton consists of huge multispicular tracts diverging and providing support to the smaller ectosomal tylostyles (Fig. 9 H, I). Stellate formations of smaller tylostyles occur between the tracts (Fig. 9 J). Spicules: Choanosomal principal styles tapering sight subtylostyle bases (hastate), tapering to sharp points (Fig. 9 K). Ectosomal tylostyles are straight to slightly curved and have a prominent tylote base (Fig. 9 L). Stellate tylostyles in the choanosome between the tracts, are indistinguishable from the tylostyles in the ectosome. Spicular measurements are given in Table 5. Distribution: Antarctic and Subantarctic waters Ecology: Partially burrowing in soft mud Molecular data: no unambiguous 28 S-C region barcode could be generated from this species. Remarks: These specimens match Kirkpatrick’s (1907) and subsequent authors’ descriptions of this species albeit with some variable spicule measurements between the publications. Plotkin & Janussen (2008) reviewed the various authors’ descriptions and measurements compared to their material, which is not repeated here. The location of this specimen from the Lord Howe Plateau is a range extension from the previous Antarctica and subantarctic records. In Plotkin & Janussen (2008), the P. invaginata samples from Antarctica deposited at the SMF, contain novel sceptre like spicules. Unfortunately, the P. invaginata specimens that were sequenced (Plotkin et al. 2017) were from a different cruise and are deposited at ZMBN. Plotkin et al. (2017) makes no mention of whether these samples have the sceptre like spicules. The morphology, skeleton and spicules match the original and more recent descriptions these new specimens also contain the stellate formations of tylostyles as reported by Kirkpatrick, (1907), Hentschel (1914), Koltun (1964), Boury-Esnault & van Beveren (1982), and Plotkin & Janussen (2008).	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF9DC020FF6323FB0E221449.taxon	description	Figures 1, 2 & 10, Table 5 Material examined: Holotype QM G 339367, Lord Howe Plateau, Pacific Ocean Seamounts, Australia - 34.2315, 162.6765, 515 – 700 m, Sherman Sled, Coll. NORFANZ expedition on RV Tangaroa, 85 - 014, MF 336, 26 / V / 2003. Etymology: named in honour of the NORFANZ expeditions which enabled the collection of these new species. Diagnosis: Polymastia with a single invaginated non-contractile papilla, choanosomal tracts of large tylostyles, forming bouquets below the ectosome. Smaller tylostyles also in the ectosome and scattered in the choanosome, lacking stellate bundles of tylostyles in the choanosome. Morphology: The sponge is dome shaped 11 mm in diameter and 5 mm in height. It was originally attached to a rock. It is cream in colour and has a hispid surface (Fig. 10 A). The upper surface bears a single non-contractile papilla 2 mm in length and approximately 0.5 mm in width, which is invaginated into the upper surface (Fig. 10 B, C). There is a single oscule on the summit of the papilla of 0.1 mm in diameter (Fig. 10 A – C). TABLE 5. (Continued) Skeleton: Aquiferous canals are obvious throughout the choanosome and continue up through the papillae (Fig 10 B, C). The choanosomal skeleton is composed of longitudinal tracts of principal styles, with smaller tylostyles scattered between the tracts (Fig. 10 C, D). These tracts originate in the base of the sponge and form bouquets beneath the ectosome and then protrude through the ectosome where they form the outer hispid layer. The walls and exterior face of the single papilla are protected and supported by the tylostyles (Fig. 10 C). The ectosomal skeleton is composed of the tightly packed bouquets of ascending styles forming a dense palisade along with the smaller tylostyles (Fig. 10 E). Spicules. Principal styles 499 – (1226) – 2560 × 6.1 – (17.4) – 30.2 μm, (n = 62) (Fig. 10 F, G), small tylostyles 92.7 – (140) – 272 × 2.9 – (4.5) – 8.7 μm, (n = 52) (Fig. 10 H). Molecular data: 28 S-C region barcode of holotype QM G 339367 (ENA Accession number OY 741341), This sample is genetically different from all other samples analysed in this study. It forms the sister to a supported P. invaginata clade. Remarks: This new species is different from P. invaginata firstly by the absence of the stellate bundles of the small tylostyles, that have been consistently referred to as occurring throughout the choanosome. This new species has scattered loose tylostyles in the choanosome and only at the termination of the aquiferous channels do there appear to be tylostyles formed into stellate clusters acting as filters (Fig. 10 I). Polymastia norfanzii sp. nov. is also differentiated from P. invaginata by the presence of strictly tylostyles in the choanosomal bundles, rather than the dominating larger styles of the central papillae, surrounded by the invagination caused by partial retraction of the papilla, lacks the contractile ability of the papillae in P. invaginata. This is corroborated by the large number of spicules both internally providing support for the papillae, and externally providing protection (Fig. 10 C). The contractile and retractile papilla on P. invaginata have a smooth exterior surface devoid of spicules. The differences in molecular results obtained in this study compared to previous studies along with the morphological differences mentioned above, separate this new species from P. invaginata. It also raises the possibility that several species may be currently under P. invaginata, as more specimens are recovered in the future, this will most likely elucidate more species.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF91C022FF6323DF0F3B17FF.taxon	description	Figures 1, 2 & 11.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
153B577AFF91C022FF6323DF0F3B17FF.taxon	materials_examined	Material examined: QM G 337502, Central Eastern Commonwealth Marine Reserve, New South Wales, Australia, - 30.0977, 153.8987 to - 30.1193, 153.8745, 2429 – 2518 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN 2017 _ V 03, 1 specimen, sample 86 - 150, 5 / VI / 2017; QM G 339438 same collection details as QM G 337502, sample 86 - 150.1. Morphology: The first specimen QM G 337502 is a grey-coloured anemone shaped cylindrical vase with medusoid papillae on the upper surface. There are about 22 papillae of tubular to tapering shape of up to 10 mm in length and 1 – 4 mm in width. There are terminal oscular apertures of less than 0.5 mm, diameter on the papillae. The sponge was attached to the substrate by a pedestal measuring 43 mm in height, 36 mm in width at the broadest part and only 25 mm wide at the base. The specimen has clearly flattened upon collection and preservation, and is now only 8 mm thick. The surface is macroscopically smooth, and velvety. The cortex is firm, detachable and cream in colour, the same colour as the papillae and the choanosome. On one side of the body there is a flattened depression, either from a previous injury or where the sponge has been overgrowing some structure. The second specimen QM G 339438 is a lighter cream in colour than specimen QM G 337502, but it has a similar morphology. It is 27 mm in height, 18 × 7 mm in width, and 17 papillae on the upper surface ranging from 2 – 4 mm in height and 1 – 2 mm in width. It also has a depression / injury on one side where part of the cortex has been removed. Skeleton: The cortical skeleton is composed of bouquets of the small subtylostyles, forming a palisade, producing a hispid surface 200 – 400 μm thick. The inner layer of the cortex is composed of a thin layer of tangential styles less than 100 μm thick. The choanosomal skeleton has a very cavernous open architecture with a loose reticulation formed by the tracts of principal styles, which lie against and are attached to the lower cortex layer, forming a porous wall on the outer layer of the choanosome. The majority of space within the choanosome is aquiferous canals, with occasional principal styles in a disorganised array. The papillae also have a very hispid palisade of small subtylostyles projecting directly outwards from the surface, with the large oxeote styles forming the skeleton paratangentially somewhat disorganised but mainly in columns, in a similar fashion to the rest of the sponge body. The choanosomal skeleton of the papillae is also very open and cavernous with aquiferous canals. Spicules: The oxeote fusiform styles provide the support of the skeleton, they are 613 - (964) - 1450 × 11.6 - (20.2) - 31.1 μm (n = 59). There was a continuous range in sizes of styles that could not be differentiated into principal and intermediate sizes. The thin slightly curved subtylostyles forming the hispid surface are 201 - (260) - 412 × 2.2 - (4.4) - 6.7 μm (n = 29). In the second specimen the spicules are of similar dimensions i. e. 613 - (1132) - 1830 × 10.6 - (18.3) - 29.3 μm (n = 57). The thin slightly curved subtylostyles forming the hispid surface are 173 - (231) - 329 × 2.3 - (4.2) - 6.0 μm (n = 27). Distribution: New South Wales, Australia and Antarctica, abyssal depths. Ecology: Mud substrate. Molecular Data: 28 S-C region barcode of G 337502 (ENA Accession number OY 741342). Recent sequencing of many Artic species (Plotkin et al. 2018) has allowed comparison with many species, although P. zitteli was not included in their data set. This sample is genetically different from all other samples analysed in this study. Remarks: This is the third record of P. zitteli after its first description from Port Jackson in Australia (Lendenfeld 1888; Hallmann 1914) and the later record from the Antarctic (Plotkin & Janussen 2008). Our specimens differ from the previously described sponges in lacking the extra small tylostyles mentioned by Hallmann (1914) and intermediately sized styles noted by Plotkin & Janussen (2008). Furthermore, our specimens are distinguished by a massive upright body resembling a sea anemone, while the previously described individuals are all thinly encrusting. In his original description Lendenfeld (1888) mentions 150 – 200 μm long tylostyles and 1 mm long styles. In his redescription of Lendefeld’s type specimen Hallmann (1914) lists 500 – 1200 μm long styles, choanosomal tylostyles, 145 – 210 μm long, and cortical tylostyles, 85 – 135 μm long. Additionally, he indicates that P. zitteli shares similar polytylote characteristics of the large styles with those of P. isidis Thiele, 1905, and P. affinis Thiele, 1898; none of which bear resemblance to our specimens. Plotkin & Janussen (2008) described large styles, 812 – 1315 μm long, intermediate styles, 340 – 598 μm long, and subtylostyles, 247 – 333 μm long, for their specimen. Furthermore, they also describe the choanosomal skeleton of P. zitteli as reticulated, also found in the two specimens described above. This feature is also found in P. crocea Kelly-Borges & Bergquist, 1997, from New Zealand, and P. boletiformis (Lamarck, 1815) from the North Atlantic. Polymastia boletiformis has been well redescribed by Plotkin et al. (2018), having only small and intermediate size categories of subtylostyles, and is a large yellow sponge with larger papillae. Polymastia crocea is another yellow shallow water species, with an unusual three layered cortex.	en	Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert, Hooper, John N. A. (2023): Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific. Zootaxa 5369 (1): 57-88, DOI: 10.11646/zootaxa.5369.1.3, URL: https://www.mapress.com/zt/article/download/zootaxa.5369.1.3/52229
