Protosuberites novaezelandiae, 2019

Kelly, Michelle & Rowden, Ashley A., 2019, New sponge species from hydrothermal vent and cold seep sites off New Zealand, Zootaxa 4576 (3), pp. 401-438 : 418-424

Protosuberites novaezelandiae sp. nov.

( Figs 1 , 2 , 7 , 8 ; Table 4)

Material examined. Calypso hydrothermal vent field (Southern vent field), southwest of White Island, Bay of Plenty : Holotype — NIWA 32136 , University of Kiel Stn SO192-2/3, 37.688° S, 177.123° W, 192 m, collected by TV Grab , 27 April 2007 . Paratypes — NIWA 32135 , 32140 , University of Kiel Stn SO192-2/7, 37.688° S, 177.123° W, 191 m, collected by ROV, 28 April 2007 ; NIWA 52839 , IFM GEOMAR Stn SO135/110, 37.688° S, 177.122° E, 189–192 m, collected by rock dredge, 11 Oct 1998 .

Other material. NIWA 52838 , IFM GEOMAR Stn SO135/103, 37.695° S, 177.101° E, 179–181 m, collected by rock dredge, 10 Oct 1998 ; NIWA 52851 , IFM GEOMAR Stn SO135/110, 37.688° S, 177.122° E, 189–192 m, collected by rock dredge, 11 Oct 1998 .

Type location & distribution. Calypso hydrothermal vent field, Bay of Plenty, New Zealand, 179–192 m.

Description. Thickly encrusting on hard rocky substrate, appearing ‘stretched’ in places, about 5–10 mm thick, growing in patches of about 50–100 mm wide. Encrustations may give rise to low mounds, lobes, flabby expanses and finger-shaped projection, 5–10 mm diameter ( Fig. 7A, B ). Oscules are not obvious in life but appear to be at the ends of some fingers in in situ images. The surface is macroscopically smooth to undulating in life, with a stretched, slightly micro-knobbed appearance when out of water ( Fig. 7C ). Sediment catches in places where ectosomal spicules protrude beyond the surface rendering the texture slightly fuzzy ( Fig. 7D ). Texture in life slightly compressible, rubbery, corky, flexible. Colour in preservative ranges from light to dark cream yellow, to peach-coloured, to deep dull pink (NIWA 52838).

Skeleton. Choanosome composed of wavy tracts of large tylostyles aligned longitudinally through the axes of flabellate and finger-like portions of specimens ( Fig. 7E ), diverging towards the surface in encrusting portions ( Fig. 7F, G ). Tracts range from about 100–1100 µm wide and are interspersed with numerous free tylostyles. About 1000 to 1500 µm below the surface, tracts branch and diverge towards the surface, terminating below well separated surface bouquets of smaller tylostyles, the sharp tips of which project cleanly from the surface by about 60–150 µm.

Spicules. Megascleres ( Table 4; Fig. 8 ) are tylostyles with well-developed, spherical heads with a slight protrusion at the tip, ranging in length from about 150–920 µm long and 7–25 µm thick, slightly sinuous and unevenly thickened along the straight shaft, thicker in the upper half. Examination of histological sections of the ectosome and choanosome reveal at least two clear size categories of tylostyles, the smaller in the ectosomal brushes (170–350 µm long), the largest in the deep choanosomal tracts (500–920 µm long).

Substrate, depth range and ecology. Attached to volcaniclastic rock covered in sediment and associated with high densities of other sponges and an undescribed orange anemone, 179– 192 m.

Etymology. Named for the first record of the genus in the New Zealand region.

Remarks. In the Pacific Ocean region, two species were described from the Southern California Bight [ P. mexicensis (de Laubenfels, 1935) , P. sisyrnus (de Laubenfels, 1930) ], Australia [ P. epiphytum ( Lamarck, 1815) ; P. proteus ( Hentschel, 1909) , and Chile [ P. epiphytoides ( Thiele, 1905) ]. The most common species in this region, stretching from the Indian Ocean to Palau in the Central Pacific, is P. diversicolor Becking & Lim (as Suberites ), often found in land-locked marine lakes ( Kelly & Bell 2015).

In terms of spicule dimensions, the closest species to P. novaezelandiae sp. nov. are P. mexicensis from the South Californian Bight, with tylostyles up to 1000 µm long ( Table 5), and P. proteus from Shark Bay, southwestern Australia, with tylostyles ranging from 15 8–808 µm long ( Table 5). The Californian species has much larger megascleres than P. novaezelandiae sp. nov., and according to de Laubenfels (1935), the sponge is a thin encrustation on a large spicule of hexactinellid origin. The choanosome has a confused arrangement with bouquets at the surface, but there is no appreciable difference between the lengths of the tylostyles in the ectosome and choanosome. Protosuberites proteus from tropical Shark Bay in Western Australia, has very similar spiculation to P. novaezelandiae sp. nov., but is a shallow water sponge collected from estuaries and rocky reefs between 3 and 12 m deep. The sponge is much thicker (up to 6 cm thick) than the New Zealand species (5–10 mm thick) which is found in much deep waters (179–192 m). The two species are separated primarily on their disjunct geographic distributions (shallow tropical estuarine Western Australia vs deep-water hydrothermal vent field in temperate eastern New Zealand).

Most authors do not differentiate ectosomal and choanosomal categories of megascleres in species of Protosuberites from the South Pacific and Southern Ocean region ( Table 5). However, in those species with

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choanosomal tracts that diverge below the ectosome, such as in P. hendricksi ( Table 5) and in P. novaezelandiae sp. nov., there is a striking difference in the lengths of spicules in these species (e.g. Fig. 5F ; Table 4), and some evidence that, as in many Suberitidae genera, a subectosomal category may also be discernible, but difficult to measure (see Samaai & Gibbons 2005).

Protosuberites is well represented in the Atlantic Ocean and further north (13 species): North and Celtic Seas [ P. incrustans (Hansen) and sensu (Stephens) ; P. denhartogi Van Soest & de Kluijver ; P. durus (Stephens) ]; Western Mediterranean and Black Seas [ P. brevispinus (de Laubenfels) ; P. ectyoninus (Topsent) ; P. mereui Manconi ; P. modestus (Pulitzer-Finali) ; P. prototipus ; P. rugosus (Topsent) ]; North Atlantic [ P. capillitium (Topsent) ; P. ferrerhernandezi (Boury-Enault & Lopes) ]; Western Tropical Atlantic [ P. geracei (Van Soest & Sass) ], and across the Western Indian Ocean [ P. reptans (Kirkpatrick) and P. hendricksi Samaai & Gibbons from South Africa; P. longispiculus (Burton) from the Maldives] and Southeast Asia, where the earliest species were described from the brackish, land-locked Chilka Lake of eastern India [ P. aquaedulcioris (Annandale) ; P. lacustris (Annandale) ] and P. collaris Annandale from Krakatau, Indonesia. A sixth species has been described from Cheju Island, Korea, P. nestus (Sim & Kim) . A review of all species and their skeletal architecture and spicule dimensions would be very useful but is beyond the scope of this work.

Figures

FIGURE 1. Map showing type localities for new species described from the Calypso hydrothermal vent field in the Bay of Plenty and named seep sites on the Hikurangi Margin.

FIGURE 2. Photograph of seabed at Southern vent field of the Calypso hydrothermal vent field (NIWA Stn KAH1004/8: image 1119; 37.688° S, 177.123° E, 190 m), showing the three sponge species that dominate the epifauna assemblage at this site: Blue arrow—finely branched Haliclona (Soestella) battershilli sp. nov.; Red arrows—translucent white, cushion-shaped Haliclona (Halichoclona) sonnae sp. nov.; Green arrows—stubby fingered, peach-coloured Protosuberites novaezelandiae sp. nov. The orange anemone is undescribed. Image captured by NIWA’s DTIS (Deep Towed Imaging System) deployed from RV Kaharoa.

FIGURE 5. Haliclona (Halichoclona) sonnae sp. nov.: A. Encrusting, cushion-shaped specimens in situ (red arrows) intermingled with Haliclona (Soestella) battershilli sp. nov., at Southern vent field of the Calypso hydrothermal vent field (NIWA Stn KAH1004/8: image 1113; 37.688° S, 177.123° E, 190 m); B. Preserved holotype, NIWA 52859, showing cavernous interior and thick, flaky ectosome; C. Histological section of holotype showing the thick ectosome, dominated by an irregular, ladder-like reticulation, overlaid at the surface with a thin layer of paratangential oxeas. Also showing the highly cavernous subectosomal region separating the outer ectosome from the deeper choanosome; D. Histological section of the deep choanosome showing the loose, irregular, subisotropic to confused reticulation of oxeas in the choanosome, interrupted by large subdermal canals and spaces. Image in 4A captured by NIWA’s DTIS (Deep Towed Imaging System) deployed from RV Kaharoa.

FIGURE 7. Protosuberites novaezelandiae sp. nov.: A, B. Erect, peach-coloured knobs and low finger-forming clumps, scattered amongst orange anemones and Haliclona (Soestella) battershilli sp. nov., at Southern vent field of the Calypso hydrothermal vent field (NIWA Stn KAH1004/8: images 1119 & 1118; 37.688° S 177.123° E, 190 m); C. Preserved holotype NIWA 32136; D. Preserved paratype NIWA 32135; E. Longitudinal histological section through a finger of the holotype, NIWA 32136, showing the loose, divided axial skeleton that gives rise to loose extra-axial tracts which terminate in bouquets of smaller tylostyles in the ectosome; F. Extra-axial bundles of tylostyles give rise to bouquets of small tylostyles at the surface (paratype NIWA 32140); G. Another view of extra-axial bundles approaching the surface ectosome. Images in 5A and B captured by NIWA’s DTIS (Deep Towed Imaging System) deployed from RV Kaharoa.

FIGURE 8. Protosuberites novaezelandiae sp. nov., holotype NIWA 32136, spicules: A, Large choanosomal tylostyle with a slightly sinuous shaft, unevenly thickened along the shaft, thicker in the upper half; B, Small ectosomal tylostyle with a straight shaft; C. Large choanosomal tylostyle with a well-developed, spherical head and slight development of the apex; D, Tylostyles in two size categories.