New sponge species from hydrothermal vent and cold seep sites off New Zealand Author Kelly, Michelle Author Rowden, Ashley A. text Zootaxa 2019 2019-04-03 4576 3 401 438 journal article 10.11646/zootaxa.4576.3.1 abceb121-c58e-4028-94eb-e0fba328e440 1175-5326 3715654 CB2EFF9C-E670-44F2-AA7A-8415FC896C45 Pseudosuberites thurberi sp. nov. ( Figs 1 , 9–12 ; Table 6 ) Pseudosuberites sp., Baco et al ., 2010 : 255 , 256, fig 2b. Pseudosuberites sp., Thurber et al ., 2010 : 260 , 265–268, fig. 3, table 3. Pseudosuberites sp., Bowden et al ., 2013 : 5 –11. FIGURE 9. Photograph of the seabed at the North Tower seep site on Opouawe Bank (NIWA Stn TAN0616/85: image 100; 41.781° S, 175.401° E, 1049 m) showing the conspicuous finger-shaped sponge, Pseudosuberites thurberi sp. nov. , growing from the sediment-covered rock surface (red arrows). Image captured by NIWA’s DTIS (Deep Towed Imaging System) deployed from RV Tangaroa . Scale = 20 cm. Material examined. South and North Tower Seeps, Opouawe Bank, Hikurangi Margin : Holotype — NIWA 27044 , NIWA Stn TAN0616/79, North Tower , 41.783° S , 177.399° E , 1040–1053 m , collected by epibenthic sled, 13 Nov 2006 . Paratypes — NIWA 27043 , 27045 , 27047 , 27060 , NIWA Stn TAN0616/79, North Tower , 41.783° S , 177.399° E , 1040–1053 m , collected by epibenthic sled, 13 Nov 2006 ; NIWA 27055 , NIWA Stn TAN0616/83, South Tower , 41.783° S , 175.399° E , 1050–1053 m , collected by epibenthic sled, 13 Nov 2006 . LM-3 Seep, Rock Garden, Hikurangi Margin : NIWA 32043 , IFM GEOMAR Stn SO 191-3/238, 39.977° S , 178.236° E , 907–908 m , collected by TV grab, 6 Mar 2007 . LM-9 Seep, Omakere Ridge, Hikurangi Margin : NIWA 32063 , IFM GEOMAR Stn SO 191-2/164, 40.054° S , 177.822° E , 1097–1110 m , collected by TV grab, 22 Feb 2007 . Other material. South and North Tower Seeps, Opouawe Bank, Hikurangi Margin : NIWA 27046 , 27048 , NIWA Stn TAN0616/79, North Tower , 41.783° S , 177.399° E , 1040–1053 m , collected by epibenthic sled, 13 Nov 2006 ; NIWA 27051 , NIWA Stn TAN0616/80, South Tower , 41.790° S , 175.405° E , 1055– 1050 m , collected by epibenthic sled, 13 Nov 2006 ; NIWA 27052 , 27054 , NIWA Stn TAN0616/83, South Tower , 41.783° S , 175.399° E , 1053– 1050 m , collected by epibenthic sled, 13 Nov 2006 ; NIWA 35004 , IFM GEOMAR Stn SO 191-2/149, South Tower , 41.789° S , 175.407° E , 1055 m , collected by TV grab, 19 Feb 2007 . LM-9 Seep, Omakere Ridge, Hikurangi Margin : NIWA 27034 , NIWA Stn TAN0616/45, 40.013° S , 177.860° E , 1127–1160 m , collected by epibenthic sled, 7 Nov 2006 ; NIWA 32040 , 32061 , 35008 , IFM GEOMAR Stn SO191-2/87, 40.053° S , 177.735° E , 1106– 1098 m , collected by TV grab, 12 Feb 2007 ; NIWA 32062 , IFM GEOMAR Stn SO191-2/164, 40.054° S , 177.822° E , 1097–1110 m , collected by TV grab, 22 Feb 2007 . Type location. South and North Tower Seeps , Opouawe Bank , Hikurangi Margin . Distribution. Opouawe Bank at southern entrance to Cook Strait, south of Wairarapa coast, North Island, 907– 1160 m , north to Omakere and Ritchie’s Ridge on the Hikurangi Margin. Description. Thickly encrusting, widely spreading, mounded sponge, giving rise to multiple, finely divided branches, that form a highly fragmented mass ( Figs 9 , 10 ) about 4–5 cm high and wide. Sponges on hard substrate tend to form encrusting mounds, while those partially buried in sediment produce fine tendrils ( Figs. 9 , 10B ). Branches may be relatively thick with incipient branching, up to 1 cm diameter (e.g. Figs 10A, C ), to finely divided tendrils 2–3 mm diameter (e.g. Fig. 10B ). Oscules are not visible in life or in the preserved state. Texture is corky, slightly granular to the touch, overall firm, compressible, and flexible. Colour in life, dull greyish white; in preservative, dull tan to light orange brown. FIGURE 10. Pseudosuberites thurberi sp. nov. : A. Preserved holotype NIWA 27044; B. Preserved paratype NIWA 32043; C. Preserved paratype NIWA 27043; D. Preserved paratype NIWA 27045. FIGURE 11. Pseudosuberites thurberi sp. nov. , histological sections showing skeleton: A. Paratangential section of holotype NIWA 27044, showing subectosomal fans and marked tangential ectosome; B., C. Longitudinal sections of paratype NIWA 27055, showing the long, thin axial tracts diverging beneath the tangential ectosome. Skeleton. Choanosome composed of loose, divaricating bundles of tylostyles, aligned longitudinally in surface projections, running parallel with the base of the sponge in encrustations ( Fig. 11A ), ranging from about 100–150 µm wide. Free spicules are interspersed between tracts, criss-crossing the primary tracts as single spicules or forming deep, diverging, subectosomal brushes ( Figs 11B, C ). Tracts or subectosomal brushes emerge at the surface as a dense palisade of bouquets of tylostyles, through which lies a relatively thin layer of predominantly, tangentially disposed tylostyles. The whole forms a dense, thick, continuous palisade. Spicules. Megascleres ( Table 6 ; Fig. 12 ), tylostyles with well-developed, spherical heads, 291 (134–530) µm long × 8 (7–15) µm thick, with slight protrusion of the apex, shaft uniform along the length and slightly bent off centre in the upper third. No obvious difference in the lengths of the tylostyles between the ectosome and choanosome. Substrate, depth range and ecology. Attached to authigenic carbonate rock, 907–1160 m . Thurber et al . (2010) hypothesise that this species may be chemoautotrophic and play a significant role in facilitating the transfer of methane into the metazoan food web in hard substrata habitats at the seep sites. Etymology. The species is named in honour of Dr Andrew Thurber, Department of Microbiology, Oregon State University, U.S. A, for his leadership in the discovery and first description of a unique sponge-dominated community that is largely fuelled by methane from the seeps ( Thurber et al . 2010 ). Remarks. A general survey of presently accepted species in Pseudosuberites ( Van Soest et al . 2018b ) reveals a range of choanosomal architectures, seemingly dependent upon whether the species is encrusting (confused skeleton with loose tracts) or lobate/digitate (some axial compression of tracts with subectosomal divergence towards ectosomal bouquets), indicating a progression in tract and axial compression in the skeleton as the sponge thickens and attains height. Megascleres in the choanosomal skeleton also vary considerably in their overall length, ranging from about 350 µm in P . andrewsi Kirkpatrick and P . exalbicans Topsent , to 1200 µm in P . hyalinus and 2000 µm in P . nudus Koltun. Four species are known from the northern hemisphere: P . montiniger (Carter) from the North and East Barents Sea; P . sadko Koltun from the Russian Arctic Ocean; P . mollis Topsent from the Western Mediterranean; P . sulphureus , a thin encrusting sponge from the North Sea. Eight species are known from the Indo-Pacific: three from Japan [( P . incrustans (Thiele) , P . kunisakiensis Hoshino , and P . perforates (Thiele) ], one from Easter Island ( P . vakai Desqueyroux-Faundez ) and one from the Marshall Islands [( P . purpureus (de Laubenfels) ]. Pseudosuberites andrewsi Kirkpatrick , is perhaps the best known tropical species, from Christmas Island in the Western Indian Ocean; P . cava Sollas was recorded from the Malay Peninsula, and P . lobulatus (Lévi) from Vietnam . However, most species have been recorded from Antarctica and the southern-most reaches of the South Pacific Ocean ( Chile and the Patagonian Shelf), and the South Atlantic Ocean ( Tristan Gough) ( Table 7 ). TABLE 6. Spicule dimensions (µm) of Pseudosuberites thurberi sp. nov. , given as length [mean (min–max)] × width [mean (min–max)], n=20 unless stated otherwise.

Specimen	Tylostyles
Holotype NIWA 27044	309 (134–453) × 9 (6–10)
Paratype NIWA 27043	280 (174–352) × 8 (6–11)
Paratype NIWA 27045	340 (161–467) × 10 (7–15)
Paratype NIWA 27047	277 (177–365) × 9 (5–12)
Paratype NIWA 27055	303 (224–401) × 8 (5–12)
Paratype NIWA 32063	290 (153–444) × 7 (5–9)
Paratype NIWA 32043	224 (156–306) × 8 (5–11)
Paratype NIWA 27034	255 (153–428) × 8 (6–10)
Paratype NIWA 27046	289 (165–414) × 9 (6–14)
Paratype NIWA 27048	313 (211–398) × 9 (6–15)
Paratype NIWA 27051	306 (174–369) × 8 (6–17)
Paratype NIWA 27052	252 (176–324) × 7 (4–10)
Paratype NIWA 27054	292 (200–383) × 8 (6–11)
Paratype NIWA 32040	292 (207–385) × 9 (5–12)
Paratype NIWA 32061	283 (176–419) × 8 (5–13)
Paratype NIWA 32062	345 (180–530) × 10 (7–14)

Bergquist (1968: 24–26) ascribed several sponges from Auckland’s Waitemata Harbour, and the Hauraki Gulf’s North Channel, to Pseudosuberites sulcatus ( Thiele, 1905 ) which was first described from waters off Cabo de Espiritu Santo ( 53.783° S , 67.500° W ) on the Patagonian Shelf in the South Atlantic Ocean ( Table 7 ). Bergquist’s specimens are similar to P . sulcatus , as originally described by Thiele (1905) and Bergquist (1968) , including the spicule dimensions [Cabo de Espiritu Santo: choanosomal tylostyles 370 µm long, 12 µm thick, ectosomal tylostyles 175 µm long, 5 µm thick; Narrow Neck: tylostyles 284 (170–386) µm long, 9.6 (6.0–12.7) µm thick; North Channel tylostyles 272 (140–387) µm long and 7.3 (4.6–8.4) µm thick]. The sponges are small and thinly encrusting [Cabo de Espiritu Santo: about 15 mm high with surface processes; New Zealand : 0.8–1.4 mm thick with irregular surface processes (2.8–4.0 mm high, 1.2–1.6 mm wide)], both with a ‘choanosome composed of a confused mat of large tylostyles with a tendency towards vertical disposition, and the ectosome was composed of vertically arranged tylostyles of large and small size, with a tendency for small spicules to predominate in the dermal region ( Bergquist 1968 ). Thiele (1905) described some ‘bundle’ formation in the choanosome, tylostyles being bound by spongin, and the same ‘radial’ arrangement of spicules in the ectosome. What is quite clear from these descriptions and recent descriptions of P . sulcatus from Easter Island ( Desqueyroux-Faúndez, 1990 ), is that P . sulcatus (and the New Zealand specimens assigned to this species) does not conform to our current understanding of the genus Pseudosuberites , i.e. being the only suberitid genus with an ectosome of tangentially orientated megascleres of a comparable size to those in the choanosome. Rather, P . sulcatus (and the New Zealand specimens) conform more closely to the genus Protosuberites , as diagnosed by Van Soest (2002) and recently revisited in Van Soest & Kluijver (2003) and Samaai & Gibbons (2005) , as possessing a ‘surface skeleton of brushes of tylostyles, which are often somewhat smaller than those of the choanosome. Choanosomal skeleton consists variably of single spicules erect on the substrate or bundles running from the substrate to the surface, usually parallel to each other, without any form of anastomosing’ ( Van Soest 2002 : 235). FIGURE 12. Pseudosuberites thurberi sp. nov. , holotype NIWA 27044, spicules: A, Choanosomal tylostyle, straight shafted; B, Choanosomal tylostyle, acutely bent in the upper proximal end of the spicule; C, Small, possibly ectosomal tylostyle; D, Choanosomal and ectosomal tylostyles of different lengths. TABLE 7. Comparison of species of Southern Ocean Pseudosuberites Topsent , as accepted currently in World Porifera Database (WPD) (Van Soest et al . 2018b). Dimensions are taken from the original description of the species; spicule dimensions given as length [mean (min–max)] × width [mean (min–max) µm].

Locality & depth	Morphology & colour	Skeleton	Spicule dimensions	Comment
P . hyalinus (Ridley & Dendy, 1887)
Southern Chile	Massive, amorphous, fragments,	Ectosome distinctive, tylostyles	Tylostyles of variable size with no	The authors questioned whether it was
with a glassy or translucent	strewn throughout dermal	evidence of differentiation between	“worthwhile to describe a new species on such
appearance; soft, spongy,	membrane, glassy and	ectosome and choanosome: “the	fragmentary evidence,” but they found it
cavernous; where not encrusted by	translucent. Choanosome	different sizes are throughout mixed	interesting that the spiculation was, “almost
other organisms, smooth	irregular with loosely disposed	up with one another.”	exactly that of the genus Suberites , while other
tylostyles of various sizes; a	About 1100 µm long, 25 µm thick	characters, e.g., the arrangement of the skeleton
few indications of fibres	300–1136 µm long (Hentschel	and nature of the ectosome, are totally
running vertically towards the	1 914: 52)	different” (Ridley & Dendy, 1887: 168).
surface
P . exalbicans Topsent, 1913
Tristan Gough, 183 m	Irregular encrusting, spreading form	Ectosome translucent,	Tylostyles, two size categories
incorporating many foreign bodies,	detachable in large flakes.	recognised:
sometimes massive with shrivelled	Choanosomal tylostyles are	340 µm long x 10 µm thick
lobes and thin, bumpy, obtuse	loosely arranged in bundles	130 µm long x 4.5 µm thick
branches that anastomose with their	which lie obliquely,
neighbours. Oscules not visible	terminating in surface bouquets
that pierce the surface
P . hyalinus var. compactus Hentschel, 1914
Antarctica, 350–385 m	Massive, uniformly rounded, with	Ectosome with tylostyles	Tylostyles or styles:
foreign bodies, comparatively dense	tangentially disposed,	300–1136 µm long
structure, up to 7 cm long. Smooth	choanosomal tylostyles
surface. Color dirty white. Oscules	randomly disposed, loose
4 mm wide, with wide membranous
edge

TABLE 7. (Continued)

Locality & depth	Morphology & colour	Skeleton	Spicule dimensions	Comment
P. sulcatus (Thiele, 1905)
Cabo de Espiritu Santo,	Thinly encrusting mass about 15	Choanosomal tylostyles form	Tylostyles, two size categories	Pseudosuberites sulcatus does not conform to
Patagonian Shelf	mm thick, with surface processes	loose bundles that may be held	recognised:	our current understanding of the genus
and wrinkles, surface translucent,	together in the base by some	370 µm long, 12 µm thick	Pseudosuberites , the only suberitid genus with
body cavernous	spongin. At the surface the	175 µm long, 5 µm thick	an ectosome of tangentially orientated
spicules are distributed more	megascleres. Rather, P . sulcatus conforms more
evenly, mostly with the tip	closely to Protosuberites Swartschewsky, 1905 ,
turned towards the surface; at	as diagnosed by Van Soest (2002) and recently
the ectosome a smaller	revisited in Van Soest & Kluijver (2003) and
tylostyle is disposed chiefly in	Samaai & Gibbons (2005).
a radial position, the tips
protrude only slightly through
the surface
P . digitatus (Thiele, 1905)
Admiralty Sound, Chile	Irregular encrustation on algae,	Ectosomal tylostyles are similar	Tylostyles, two size categories	Pseudosuberites digitatus conforms more
partly branched with frequently	to the previous species ( P.	recognised:	closely to Protosuberites Swartschewsky, 1905 ,
curved, finger-like projections	sulcatus ), i.e., disposed chiefly	400 µm long, 7 µm thick	as diagnosed by Van Soest (2002) and recently
in a radial position, arranged	170–190 µm long, 5 µm thick	revisited in Van Soest & Kluijver (2003) and
between the pores in strongly	Samaai & Gibbons (2005).
diverging bushes. Choanosome
is more structured than in P .
sulcatus , especially in the
branches, and the skeleton is
denser and less cavernous
P . nudus Koltun, 1964
Antarctica	Body globular, lobate, surface	Ectosome composed of small	Styles to subtylostyles:
smooth. Ectosome is thin,	tangential tylostyles;	1300–2000 µm long
parchment-like, easily separable.	choanosome composed of	27–52 µm wide
Sponge flaccid, elastic, cavernous	branched fibres of large styles,	Tylostyles:
among which isolated	400–1200 µm long
tylostyles bundles are scattered	8–20 µm wide
in a disorderly way

Bergquist (1968) followed Burton (1930) in also relegating the New Zealand species Suberites ramosus , S . anastomosus and S . incrustans , in synonymy with P . sulcatus . These three species were first described by Brøndsted (1924) from the shallow subtidal in Perseverance Harbour on Campbell Island, Subantarctic Island region of New Zealand . Burton’s 1930 concept of Pseudosuberites was that the ectosomal skeleton could vary from tangential to oblique to a palisade, all three dispositions being visible in a single specimen of what he called P . sulcatus from Campbell Island and South Georgia ( Burton 1930 ). However, Suberites ramosus and S . anastomosus strongly confirm to the genus Protosuberites as described above and should be transferred there: The surface of both species is described by Brøndsted (1924) as having ‘a dermal membrane (that) seems to be sustained by a layer of smaller spicules at an oblique angle, lying with the apices outwards directed, often appearing as tufts, continuing the spicule fibres’ ( S . ramosus ), and ‘a dermal membrane sustained by rather compact and closely placed spicule tufts, directed more or less perpendicular to the surface; the small tylostyles compose mainly the tufts, the bigger one mainly the fibres’ ( S . anastomosus ). Suberites incrustans , currently accepted as a synonym of P . sulcatus ( Van Soest et al . 2018a ) , is quite different from the other two species, and P . sulcatus , as it lacks a discernible ectosomal skeleton. Without direct examination of the specimen, this species is unrecognisable within Suberitidae , except for possible affinity with Prosuberites Topsent, 1893 whose species are very thinly encrusting with no ectosomal specialisation. Pseudosuberites thurberi sp. nov. differs considerably from the shallow-water sponges described as P . sulcatus by Bergquist (1968) : the tylostyles in P . thurberi sp. nov. are about 200 µm longer, the ectosome is strongly tangential (vertically disposed in Bergquist’s specimens), and they are restricted geographically to the Hikurangi Margin where they occur between depths of 900–1100 m . The new species is also differentiated from the type species, P . hyalinus and P . hyalinus var. compactus Hentschel, 1914 (both from Chile ), and P . nudus from Antarctica , on the much larger size of the spicules in these three species, being well over 1000 µm long ( P . thurberi sp. nov. : max 530 µm long). The only species that approaches P . thurberi sp. nov . , at least in terms of spicule length, is P . exalbicans Topsent, 1913 from the South Atlantic Ocean, with spicules that range from 130–340 µm long ( P . thurberi sp. nov. : 291 (134–530) µm long), but it has a thickly encrusting, spreading form with a deeply wrinkled, furrowed surface. The only other New Zealand species known (with certainty) to inhabit deep New Zealand and South Atlantic waters is Cercicladia australis Rios, Kelly & Vacelet, 2011 , a remarkable carnivorous sponge that has been found in only two subpolar locations on either side of the globe, on the Macquarie Ridge to the southwest of New Zealand ( 1060–1408 m ) and off the Argentine coast of Patagonia ( 1145–1728 m ). The authors expressed confidence in the disjunct distribution because the diagnostic spicules are unique globally and very easily recognizable. This is not the case for Pseudosuberites thurberi sp. nov. and P . albicans , which have identical megasclere types , no diagnostic microscleres and non-specialised skeletons. Pseudosuberites thurberi sp. nov. is the first accurate record of the genus in New Zealand waters and inhabits a highly specialised environment. Pseudosuberites species are thinly to thickly encrusting with lobes and digits. The skeletons of encrusting species are usually confused, or with loosely constructed tracts of megascleres diverging from the base, spreading at the surface and extending just beyond the dermal membrane, which consists of a layer of tangentially disposed spicules. The development of lobes is usually accompanied by some degree of axial compression in the lobe. The thinner the specimen, the simpler the skeleton. Megascleres are always subtylostyles to tylostyles in two loosely differentiated categories, the larger forming the choanosomal tracts and the smaller forming the tangential ectosome. It will be important in the future to conduct a careful study of the species in this broadly defined genus, in which subgroups are currently not clear, but such a study is beyond the scope of this contribution.