Marine Biodiversity

Xenophyophores (Protista, Foraminifera) from the Clarion-Clipperton Fracture Zone with description of three new species --Manuscript Draft--

Manuscript Number: Full Title: Xenophyophores (Protista, Foraminifera) from the Clarion-Clipperton Fracture Zone with description of three new species Article Type: Original Paper Keywords: Protista, xenophyophores, megabenthos. polymetallic nodules, eastern equatorial Pacific, abyssal Corresponding Author: Olga Kamenskaya, PhD P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences Moscow 117997, RUSSIAN FEDERATION Corresponding Author Secondary Information: Corresponding Author's Institution: P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences Corresponding Author's Secondary Institution: First Author: Olga Kamenskaya, PhD First Author Secondary Information: Order of Authors: Olga Kamenskaya, PhD Andrew Gooday, Professor Ole Tendal, Professor Vjacheslav Melnik, Dr Order of Authors Secondary Information: Abstract: We describe three new and one poorly-known species of psamminid xenophyophores (giant foraminifera), all of which were found attached to polymetallic nodules in the Russian claim area of the Clarion-Clipperton Fracture Zone (CCFZ; abyssal eastern equatorial Pacific, 4716 - 4936 m water depth). Semipsammina licheniformis sp. nov. is the second species of the genus to be formally described. The test encrusts the surface of the host nodule forming a flat structure with a rounded outline and rather irregular concentric zonation. The wall comprises a single layer, composed mainly of radiolarian skeletons, covering granellare branches and stercomata strings that lie directly adjacent to the nodule surface. Psammina multiloculata sp. nov. has an approximately semi-circular, upright test with a weak concentric zonation that is attached to the nodule by a short stalk. The outer test layer comprises radiolarian fragments, sponge spicules and mineral grains; the interior is divided into small compartments containing the stercomare and granellare. Psammina limbata sp.nov. has a plate-like, sometimes curved, semi-circular test attached to the nodule surface by basal root-like structures. The composition of the test is similar to that of P. multiloculata but the interior is not compartmentalised. The most distinctive feature is the lighter colour of the curved outer margin compared to other parts of test. With the addition of these and other species described during recent decades, Psammina has become a rather unwieldy taxon that requires revision. Spiculammina delicata Kamenskaya 2005, previously known from a single specimen, is the most abundant species in our collection. The test exhibits considerable morphological variation, particularly in terms of the degree of branching. The new specimens confirm the placement of this species in the family Psamminidae rather than the Syringamminidae, which it superficially resembles, as well as its sessile mode of life. Two additional species in our material, Stannophyllum radiolarium Haeckel, 1889 and Stannophyllum sp., belong to the order Stannomida. Like the psamminid species, both were found attached to nodules. Xenophyophores are a dominant megafaunal taxon within the

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1 1 2 2 3 3 Xenophyophores (Protista, Foraminifera) from the Clarion-Clipperton 4 5 4 Fracture Zone with description of three new species 6 7 5 8 9 6 O.E.Kamenskaya1, A.J.Gooday2, O.S.Tendal3, V.F.Melnik4 10 11 7 12 1 13 8 - P.P.Shirshov Institute of Oceanology RAS, 117997 Moscow, Nakhimovsky prosp. 36, 14 15 9 Russia; e-mail: [email protected] 16 10 2- National Oceanography Centre, University of Southampton, Waterfront Campus, European 17 18 11 Way, Southampton SO 14 3ZH, United Kingdom; e-mail: [email protected] 19 20 12 3- State Natural History Museum of Denmark (Zoological Museum), University of 21 22 13 Copenhagen, Universitetsparken 15, 2100 Copenhagen O, Denmark; e-mail: 23 24 14 [email protected] 25 4 26 15 - Yuzhmorgeologiya State Scientific Centre, 353461, Gelendzhik, Krymskaya St., 20, 27 16 Russia; e-mail:[email protected] 28 29 17 30 31 18 32 33 19 Abstract We describe three new and one poorly-known species of psamminid 34 35 20 xenophyophores (giant foraminifera), all of which were found attached to polymetallic 36 37 21 nodules in the Russian claim area of the Clarion-Clipperton Fracture Zone (CCFZ; abyssal 38 22 eastern equatorial Pacific, 4716 - 4936 m water depth). Semipsammina licheniformis sp. nov. 39 40 23 is the second species of the genus to be formally described. The test encrusts the surface of 41 42 24 the host nodule forming a flat structure with a rounded outline and rather irregular concentric 43 44 25 zonation. The wall comprises a single layer, composed mainly of radiolarian skeletons, 45 46 26 covering granellare branches and stercomata strings that lie directly adjacent to the nodule 47 48 27 surface. Psammina multiloculata sp. nov. has an approximately semi-circular, upright test 49 28 with a weak concentric zonation that is attached to the nodule by a short stalk. The outer test 50 51 29 layer comprises radiolarian fragments, sponge spicules and mineral grains; the interior is 52 53 30 divided into small compartments containing the stercomare and granellare. Psammina 54 55 31 limbata sp.nov. has a plate-like, sometimes curved, semi-circular test attached to the nodule 56 57 32 surface by basal root-like structures. The composition of the test is similar to that of P. 58 33 multiloculata but the interior is not compartmentalised. The most distinctive feature is the 59 60 61 62 63 64 65 2

34 lighter colour of the curved outer margin compared to other parts of test. With the addition of 1 2 35 these and other species described during recent decades, Psammina has become a rather 3 4 36 unwieldy taxon that requires revision. Spiculammina delicata Kamenskaya 2005, previously 5 37 known from a single specimen, is the most abundant species in our collection. The test 6 7 38 exhibits considerable morphological variation, particularly in terms of the degree of 8 9 39 branching. The new specimens confirm the placement of this species in the family 10 11 40 Psamminidae rather than the Syringamminidae, which it superficially resembles, as well as 12 13 41 its sessile mode of life. Two additional species in our material, Stannophyllum radiolarium 14 15 42 Haeckel, 1889 and Stannophyllum sp., belong to the order Stannomida. Like the psamminid 16 43 species, both were found attached to nodules. Xenophyophores are a dominant megafaunal 17 18 44 taxon within the CCFZ. Although limited, our new material suggests that this region hosts 19 20 45 many novel taxa. 21 22 46 23 24 47 Key words. Protista, xenophyophores, megabenthos. polymetallic nodules, eastern 25 48 equatorial Pacific, abyssal 26 27 49 28 29 50 30 31 51 Introduction 32 33 52 34 35 53 Xenophyophores are giant marine, agglutinated deep-sea protists (Tendal, 1972) that are 36 54 confined to regions below about 500 m water depth. Since the first species were described in 37 38 55 the 1880s, (Brady, 1883; Haeckel, 1889), they have been variously classified as foraminifera, 39 40 56 sponges or as a distinct protistan group (Tendal, 1972). However, recent molecular analyses 41 42 57 place at least some species within the radiation of basal monothalamous foraminifera 43 44 58 ('monothalamids') (Pawlowski et al., 2003, 2013; Lecroq et al., 2009; Gooday et al., 2011). 45 46 59 Xenophyophores are particularly abundant in areas where the food flux is enhanced, for 47 60 example, on seamounts and ridges, in submarine canyons and under productive surface 48 49 61 waters, including the eastern equatorial Pacific (Tendal, 1972; Tendal and Lewis 1978; 50 51 62 Levin and Thomas 1988; Levin, 1994). 52 53 63 Interest in xenophyophores has been heightened recently by their abundance in the 54 55 64 Clarion-Clipperton Fracture Zone (CCFZ), a large tract of the equatorial Pacific where 56 57 65 polymetallic nodules ('manganese nodules') are particularly abundant. The International 58 66 Seabed Authority (ISA) has awarded contracts to countries and companies to exploit nodules 59 60 67 in designated claim areas within the CCFZ. Our previous investigations have revealed that 61 62 63 64 65 3

68 xenophyophores are a key megafaunal group within the Russian claim area in the central part 1 2 69 of the Clarion-Clipperton nodule field (Kamenskaya et al., 2013). They were seen in 70% of 3 4 70 sea-floor photographs and were found in 30% of box-cores samples collected during a 2007 5 71 cruise of Research Vessel Yuzhmorgeologia. Their average density was 1600 specimens per 6 7 72 hectare, with a maximal value of 120,000 specimens per hectare (= 12 specimens per m2); the 8 9 73 next most common group, the Actiniaria, did not exceed a density of 170 specimens per 10 11 74 hectare. According to earlier studies on eastern equatorial Pacific seamounts, the abundance 12 13 75 and species diversity of macro- and meiobenthos is elevated in sediments beneath and close 14 15 76 to xenophyophore tests compared to sediments where no xenophyophores are present (Levin 16 77 et al.,1986; Levin and Thomas, 1988). Diverse assemblages of metazoans and foraminifera 17 18 78 also inhabit the cavities and interstices of xenophyophore tests (Levin and Thomas, 1988; 19 20 79 Levin 1994; Hughes and Gooday, 2001). Therefore, in the areas where these giant protists 21 22 80 dominate, they probably play an important role in the structuring of benthic communities. 23 24 81 Their study is especially important in the light of likely future polymetallic nodule mining 25 82 within the CCFZ. 26 27 83 Following Tendal (1972), we recognize two main xenophyophore groups: stannomids 28 29 84 (order Stannomida of Tendal, 1972) and psamminids (order Psamminida of Tendal 1972). 30 31 85 Both groups are present in the central part of the Clarion-Clipperton nodule field, either 32 33 86 attached to the nodules (species of the genera Psammina, Semipsammina, Stannophyllum and 34 35 87 Spiculammina) or living on soft sediment between the nodules (species of Psammina and 36 88 Reticulammina). About 60% of these xenophyophores have a leaf-like test shape and 37 38 89 probably belong to genera Psammina and Stannophyllum. The tree-like species 39 40 90 Spiculammina delicata was seen in 10% of bottom photographs. Here, we analyze the 41 42 91 taxonomic composition of the xenophyophore fauna attached to nodules from the central part 43 44 92 of the CCFZ and describe three new species in the genera Psammina and Semipsammina. In 45 46 93 the absence of material suitable for molecular analyses, our descriptions are based on 47 94 morphological characters. 48 49 95 50 51 96 Material and methods 52 53 97 54 2 55 98 The material was obtained using a box corer (cross-sectional area 0,25cm ) from different 56 57 99 parts of the Russian claim area of the Clarion-Clipperton nodule field (13-14°N, 130-135°W) 58 100 during four cruises of the Research Vessel Yuzhmorgeologia in 2003, 2006, 2009 and 2010 59 60 101 (Table 1). Nodules with xenophyophores were collected from the surface of the box-core 61 62 63 64 65 4

102 samples. Xenophyophores were carefully removed from the nodules and preserved in 70% 1 2 103 ethanol. For SEM study fragments of specimens were mounted on aluminium stubs and 3 4 104 coated with Au. Analysis of chemical constituents (Ba) was performed with an energy- 5 105 dispersive X-ray spectrographic analyzer (EDS) connected to a scanning electron microscope 6 7 106 (CamScan and Zeiss EV050). The holotypes are deposited in the collection of the Zoological 8 9 107 Museum of the Moscow State University. 10 11 108 12 13 109 Systematics 14 15 110 16 111 Recent molecular analyses place several xenophyophore species within the radiation of 17 18 112 'basal'' monothalamous foraminifera (Pawlowski, et al., 2003, 2013; Lecroq et al., 2009; 19 20 113 Gooday et al., 2011). Unfortunately, DNA sequences are not available for most 21 22 114 xenophyophores, and the higher-level taxonomy of monthalamids generally is in a state of 23 24 115 flux (Pawlowski et al., 2013). We therefore avoid assigning our species to taxa beyond genus 25 116 level and simply divide them into psamminids and stannomids. 26 27 117 28 29 118 Psamminid group of species: 30 31 119 32 33 120 Semipsammina licheniformis sp. nov. Kamenskaya. Gooday, Tendal 34 35 121 Fig. 1 a-f 36 122 Semipsammina sp. Kamenskaya, Melnik, Gooday 2013: 391-392, Fig. 6d 37 38 123 39 40 124 Material examined. The holotype was from St. 60-1 of R/V Yuzhmorgeologia cruise 4-06, 41 42 125 13.26° N, 134.41° W; depth 4777 m. The holotype is deposited under registration number F- 43 44 126 16 45 46 127 47 128 Diagnosis. Encrusting test covering part of nodule surface. Outline more or less rounded with 48 49 129 irregular margin that includes occasional elongate extensions. Test surface with concentric 50 51 130 pattern of linear, step-like features. Maximum test dimension up to ~ 6 cm; thickness 52 53 131 decreasing from ~3 mm in central part to ~1 mm near margin. Agglutinated test wall 54 55 132 composed of radiolarian skeletons with occasional diatom frustules and sponge spicule 56 57 133 fragments; test wall covers interior space that contains strings of granellare and stercomare 58 134 lying directly adjacent to nodule surface. 59 60 135 61 62 63 64 65 5

136 Description of holotype. The test of the single available specimen is light greyish in colour 1 2 137 and forms a flattened structure that encrusts the surface of a polymetallic nodule. It has an 3 4 138 approximately circular outline, measuring 6.1 x 4.9 cm, and covers about half of the nodule 5 139 surface, following the curved contours of the substrate (Fig. 1 a). The thickness in the central 6 7 140 part is about 3 mm, decreasing to 1 mm near the margins. The surface of the test has distinct, 8 9 141 concentric step-like features, most clearly developed in the central part and probably 10 11 142 reflecting episodic growth. The margin of the test is irregularly rounded and often displays 12 13 143 small lobate features. Several long narrow extensions of the margin, having the form of a 14 15 144 flattened tube, are also developed; they are up to 1 cm long, sometimes branching, and 16 145 consist of either naked granellare or granellare covered with xenophyae. 17 18 146 The test forms an upper layer that covers the granellare and stercomare. The xenophyae 19 20 147 (agglutinated particles) comprise a jumble of complete and fragmentary radiolarian skeletons, 21 22 148 with scattered micronodules and occasional diatom frustules and small fragments of sponge 23 24 149 spicules, creating a fairly rough surface texture (Figs. 1 b, c). There are some internal 25 150 xenophyae. The granellare and stercomare lie directly adjacent to the nodule surface; some 26 27 151 parts are also attached to the inner surface of the test wall, as seen when parts of the test wall 28 29 152 are detached (Fig. 1 d). The granellare are light in colour and form strands, 50 to 100 µm in 30 31 153 diameter, which branch but do not anastomose (Fig.1 d). The strands contain numerous 32 33 154 granellae, 3-4 µm in length with the ovate shape typical of xenophyophore barite crystals 34 35 155 (Fig.1 e). The stercomare masses form branching structures, ranging from less than 50 µm to 36 156 more than 100 µm in diameter, containing stercomata with a diameter <10 µm (Fig. 1). 37 38 157 39 40 158 Etymology. From Latin and English “lichen” 41 42 159 43 44 160 Distribution. Currently know only from one site in the Russian license area of the Clarion- 45 46 161 Clipperton Fracture Zone, Eastern Pacific, depth 4777 m (Table 1). 47 162 48 49 163 Remarks. The only previously described species of the genus, Semipsammina fixa Tendal 50 51 164 1975, is known from two specimens and some fragments attached to turtle grass rhizomes 52 53 165 from the Puerto Rico Trench (depth 6000-5890 m). The plate-like body of S. fixa is 54 55 166 irregularly rounded in outline, up to 5.5 mm in diameter and ~ 0.5 mm in thickness. The 56 57 167 xenophyae comprise sponge spicules and mineral particles. Our new species differs from S. 58 168 fixa mainly in the much larger size of the test and the nature of the xenophyae. There also 59 60 169 appear to be differences in the shape of stercomare system. 61 62 63 64 65 6

170 Mullineaux (1987) reported two species (designated 'sp. a' and 'sp. b') of Semipsammina 1 2 171 living on the surfaces of polymetallic nodules from the equatorial North Pacific (5°N, 3 4 172 125°W; 4500 m depth) and the central North Pacific (30°N, 157°W; 5800 m depth). 5 173 Semipsammina sp. a occurred at the equatorial site while S. sp. b occurred at both sites. These 6 7 174 represent the first records of Semipsammina in the Pacific Ocean. No further information is 8 9 175 available about these species. 10 11 176 12 13 177 14 15 178 Genus Psammina Haeckel, 1889 16 179 17 18 180 Remarks. The genus was established by Haeckel (1889) based on three species, Psammina 19 20 181 nummulina, P. globigerina and P. plankina. According to the diagnosis given in Tendal 21 22 182 (1972), the main features of Psammina are 1) a discoidal test with large pores around the 23 24 183 margin, 2) firmly cemented xenophyae forming hard, upper and lower plates, 3) internal 25 184 xenophyae forming pillar-like structures between the two plates, and 4) granellare branches 26 27 185 and stercomare strings strongly developed between the pillars. Gooday and Tendal (1988) 28 29 186 added three further species, P. delicata, P. fusca, and P. sabulosa, These conform more or 30 31 187 less to the diagnosis of Tendal (1972), although none has a clearly discoidal shape, marginal 32 33 188 pores are evident only in P. sabulosa, and P. fusca lacks internal pillars as well as pores. 34 35 189 Tendal (1994) described P. zonaria, a bathyal species from the western Pacific with an 36 190 elongate test that widens towards its distal end and is subdivided internally into transverse 37 38 191 compartments. Finally, Kamenskaya and Saidova (1998) redescribed Psammina planata 39 40 192 (Saidova) 1970, a hadal species from the western Pacific that was originally placed in the 41 42 193 genus Astrorhizinella. 43 44 194 Here, we assign two additional species to the genus Psammina. They also deviate 45 46 195 from the original concept of Psammina in certain respects. In the future it may be necessary 47 196 to divide this now rather heterogenous group of species into two or more distinct genera. 48 49 197 50 51 198 Psammina multiloculata sp. nov. Kamenskaya, Gooday, Tendal 52 53 199 Figs. 2, 3 54 55 200 Material examined. The holotype was from St. 28 of R/V Yuzhmorgeologia cruise 4-06, 56 0 0 57 201 13.28 N, 134.41 W; depth 4843 m. The holotype is deposited under registration number F- 58 202 17. Other material: one specimen from St. 8726, one specimen from St. 8655, one specimen 59 60 203 from St. 204. . 61 62 63 64 65 7

204 1 2 205 Diagnosis. More or less semicircular, plate-like test, sometimes with additional side plate, 3 4 206 attached to hard substrate by short, wide, basal stalk. Outer layer of test consisting of small 5 207 fragments of radiolarian skeletons, sponge spicules and mineral grains. Surface is granular at 6 7 208 base and with weakly developed concentric zonation most evident close to margin. Inner 8 9 209 space divided into numerous compartments containing strings of granellare and stercomare . 10 11 210 12 13 211 Description. Holotype (Fig. 2 a-c): The test is flat, plate-like, and was attached to a nodule 14 15 212 by its longest side without the development of a stalk. The dimension of the intact specimen 16 213 is 24x18 mm but the test was broken into several fragments during preparation. One of these 17 18 214 fragments includes the base of a side plate (Fig. 2 c). The surface of the test is noticeably 19 20 215 granular at the base and shows concentric zones, which are most clearly visible near the 21 22 216 outer margin (Fig. 2 a, b). The outer layer of the test is composed of small fragments of 23 24 217 radiolarian skeletons, sponge spicules and mineral grains (external xenophyae). The test 25 218 interior is divided into compartments by internal xenophyae; along the abraided margin the 26 27 219 compartments appear as open spaces filled with dark stercomata (Fig. 2 c). 28 29 220 Specimen from St. 204 (Figs 2 d, 3 a-g): The specimen broke into fragments during 30 31 221 preparation (Fig.2d). The undamaged test formed a more or less flat structure with a 32 33 222 relatively smooth, semi-circular outline, 31 mm wide and 24 mm high, originally attached to 34 35 223 the host nodule by a short flattened stalk about 9 mm wide. The thickness varied from 3 mm 36 224 at the basal part of the test to 2 mm close to margins. As in the holotype, the test surface is 37 38 225 granular near the base, becoming more smooth towards the margin, and the xenophyae are 39 40 226 small fragments of radiolarian skeletons, sponge spicules and mineral grains (Fig. 3 a, b). The 41 42 227 inner space of the test is divided into numerous small compartments, each measuring about 43 44 228 600 x 400 µm (Fig. 3 c). These spaces are occupied by granellare and stercomare . The 45 46 229 granellare branches are up to 50-100 µm wide and extend through several compartments (Fig. 47 230 3 c, f). They contain numerous barite crystals (granellae), no more than 2 µm in length. (Fig. 48 49 231 3 g, h). The stercomare masses may be oval in shape and occupy one chamber (Fig.3-d), or 50 51 232 arranged in strings and extend between several compartments The oval masses are typically 52 53 233 400-500 µm long and ~200 µm wide (Figs.3 c-d). They consist of stercomata with maximum 54 55 234 dimensions of ~10-15 µm. 56 57 235 Other material (Fig 2 e-f): Two more or less intact tests have differing morphologies. The 58 236 specimen from St. 8655 was originally attached to a nodule. It measures 23 by 13 mm and 59 60 237 consists of three well-developed plates, the angles between them varying from ~90° to ~170° 61 62 63 64 65 8

238 (Fig. 2 f). The test surface exhibits a clear concentric zonation and the internal compartments 1 2 239 are clearly visible in places through the test wall. The specimen from St. 8726 is smaller, 3 4 240 measuring 15 by 11 mm (Fig. 2 g). The test is fan-like with a short (~2 mm), wide (~5 mm) 5 241 stalk that was originally attached to the surface of a nodule. Concentric zones and internal 6 7 242 compartments are visible close to the margin (Fig. 2 g, h).. 8 9 243 10 11 244 Etymology: From Latin “loculata”-divided into small volumes. 12 13 245 14 15 246 Distribution: Currently know from four sites in the Russian license area of the Clarion- 16 247 Clipperton Fracture Zone, Eastern Pacific, depth 4841-4936 m (Table 1). 17 18 248 19 20 249 Remarks. Psammina multiloculata differs from other species of the genus in the presence of 21 22 250 an elaborate system of small internal compartments. In Psammina zonaria, the test interior is 23 24 251 also partitioned into compartments, but these spaces are relatively large and are delimited by 25 252 transverse bars that occupy the entire width of the test, rather than the tiny cell-like spaces 26 27 253 that characterise the new species. In both of these species, the internal structure of the test 28 29 254 probably represents an elaboration of the pillars present in species such as P. nummulina, P. 30 31 255 globigerina, and P. plankina. 32 33 256 The basically plate-like test of P. multiloculata shows some variability, particularly 34 35 257 regarding the degree of development of side plates. The shape is somewhat reminiscent of the 36 258 foraminiferal genus Jullienella, particularly J. foetida Schlumberger, 1890 and J. zealandica 37 38 259 Hayward and Gordon, 1984, in which the test interior is partly subdivided by parallel ridges. 39 40 260 However, these are not sufficiently developed to create internal compartments (Buchanan 41 42 261 1960; Nørvang 1961; Hayward and Gordon 1984). Moreover, Jullienella foetida and J. 43 44 262 zealandica are not xenophyophores. lacking the typical granellare and stercomare systems, 45 46 263 and are confined to sublittoral to upper bathyal depths. 47 264 48 49 265 50 51 266 Psammina limbata sp.nov. Kamenskaya, Gooday, Tendal 52 53 267 (Fig.4 a-i) 54 55 268 Psammina sp. Kamenskaya, Melnik, Gooday 2013: 391-392, Fig. 6 b 56 57 269 58 59 60 61 62 63 64 65 9

270 Material examined. The holotype was from St. 25 of R/V Yuzhmorgeologia cruise 4-06, 1 0 0 2 271 13.28 N, 134.45 W; depth 4724 m. The holotype is deposited under registration number F- 3 4 272 18. 5 273 Etymology. From Latin “limbata”- bordered. 6 7 274 8 9 275 Diagnosis. Flattened, plate-like semi-circular test attached to nodule surface by basal stalk 10 11 276 and root-like structures. Outer layer of test composed of firmly cemented fragments of 12 13 277 radiolarian skeletons, mineral grains and sponge spicule fragments with weakly developed 14 15 278 concentric zonation. Curved outer margin distinctly lighter than other parts of test. Interior 16 279 friable with strings of granellare and masses of stercomare interwoven with loosely- 17 18 280 agglutinated spicule fragments; stercomare absent from outer margin. Weakly-developed 19 20 281 concentric ridges on inner surface of outer test layers. 21 22 282 23 24 283 Description of holotype. The single collected specimen has a curved, approximately semi- 25 284 circular, plate-like test that was attached to the surface of a nodule by a basal stalk and 26 27 285 several long, branched, root-like structures (Fig.4 a, b). It is ~ 40 mm wide, ~31 mm high and 28 29 286 ~1 mm thick. The external xenophyae that form the outer test layer comprise firmly cemented 30 31 287 fragments of radiolarian skeletons, small mineral grains and small fragments of sponge 32 33 288 spicules (Fig. 4 c). A weakly-developed concentric zonation on the surface of the test 34 35 289 presumably reflects episodic growth (Fig. 4 b). A narrow zone around the outer margin 36 290 comprises only transparent sponge spicule fragments and appears lighter than other parts of 37 38 291 the test. Small concentric ridges are developed on the inner surface of the outer test layers 39 40 292 (Fig. 4 g), but they do not partition the interior space into compartments. (Fig. 4 h). The 41 42 293 interior of the test has a friable consistency and contains larger, loosely organized spicule 43 44 294 fragments between which are situated granellare branches, 50-100 µm diameter and masses 45 46 295 of stercomare, up to 300 x 600 µm in size (Fig. 4 d). The absence of the dark stercomare from 47 296 the marginal zone of the test is responsible for its lighter colour (Fig. 4 i). Stercomata range 48 49 297 in size from 7 to 20 µm (Fig. 4 e) and the granellae crystals are typically 3 µm long (Fig. 4 50 51 298 f). 52 53 299 54 55 300 Etymology. From Latin “limbata”- bordered. 56 301 57 58 302 Distribution. Currently know from one site in the Russian license area of the Clarion- 59 60 303 Clipperton Fracture Zone, Eastern Pacific, depth 4724 m (Table 1). 61 62 63 64 65 10

304 1 2 305 Remarks. Psammina limbata sp. nov. resembles P. multiloculata in the general shape and 3 4 306 composition of the test but is not divided into compartments internally, and it has basal root- 5 307 like structures that are not present in P. multiloculata. The new species resembles P. zonaria 6 7 308 in the zonation of outer and inner surfaces of the outer test layers, but this zonation does not 8 9 309 affect the test interior. The two species also have different test shapes as well as different 10 11 310 kinds of xenophyae, namely planktonic foraminiferal shells in P. zonaria and siliceous 12 13 311 particles in P. limbata. 14 15 312 The pale outer margin of the new species is a distinctive feature that, together with its 16 313 plate-like form, makes it easily recognisable in bottom photographs from the CCFZ. Based 17 18 314 on photographic surveys, it appears to be one of the more common species in this region. 19 20 315 21 22 316 23 24 317 25 318 Spiculammina delicata Kamenskaya, 2005 26 27 319 Fig.5, 6 28 29 320 Spiculammina delicata Kamenskaya 2005: 23-27, Fig. 1-2 30 31 321 Spiculammina delicata Kamenskaya, Melnik, Gooday 2013: 391- 393, Fig. 6 c 32 33 322 34 35 323 Material examined: A total of 19 specimens collected during R/V Yuzhmorgeologia cruise 36 324 4-06, Stns 25, 34, 39, 43, 49, 52, 85, 94, 95, 118, 119, 122, 133, 150, 151, 159, 164, 166, 167. 37 38 325 39 40 326 Remarks. Spiculammina.delicata was described by Kamenskaya (2005) based on a single 41 0 0 42 327 specimen from the central part of the Clarion-Clipperton Fracture Zone (11.52 N, 136.06 43 44 328 W). Our new material demonstrates the wide distribution of this species within the Russian 45 46 329 CCFZ claim area (Table 1). The test varies from several mm to 5-6 cm in size and exhibits 47 330 considerable morphological variation (Fig. 5). Some specimens have a relatively simple 48 49 331 tubular form (Fig. 5 d) but in most cases the test is tree-like with a basal trunk giving rise to 50 51 332 variable numbers of branches that range from long and relatively slender to short and 52 53 333 relatively wide. The test is composed almost exclusively of sponge spicule fragments (Figs 6 54 55 334 a-b). Although in some respects it resembles members of the family Syringamminidae (e.g. 56 57 335 the genus Aschemonella), Kamenskaya (2005) assigned Spiculammina to the family 58 336 Psamminidae Haeckel, 1889, based on the presence of sparse xenophyae in the lumen of the 59 60 337 tubular test. This placement is supported by examination of the new material, which has 61 62 63 64 65 11

338 revealed that the test interior is occupied by numerous internal xenophyae, creating a rigid 1 2 339 framework (Fig. 6c). Kamenskaya (2005) suspected that the original specimen, which was 3 4 340 fragmented, had been attached to a hard substrate. The new specimens were all growing on 5 341 polymetallic nodules, confirming the sessile nature of this species. 6 7 342 Spiculammina delicata is easily recognisable in bottom photographs. It was visible in 8 9 343 10% of the images from the Russian claim area and was collected in many box corer samples 10 11 344 (Kamenskaya et al. 2013). 12 13 345 14 15 346 Distribution. In the present study, this species was found at 19 sites in the Russian license 16 347 area of the Clarion-Clipperton Fracture Zone, Eastern Pacific, depth range 4716-4824 m 17 18 348 (Table 1). It was previously known from a single specimen obtained at 11. 520N, 136. 060W, 19 20 349 5400 m depth (Kamenskaya 2005). 21 22 350 23 24 351 25 352 Stannomid group of species: 26 27 353 28 29 354 Stannophyllum radiolarium Haeckel, 1889 30 31 355 Fig. 7 32 33 356 Stannophyllum radiolarium Haeckel 1889: 65, pl. I, 2A-C; 9, 53, 61, 66, 68, 70 34 35 357 Stannophyllum radiolarium Schulze 1907a: 36, 41, 42, 49, 50, 52, 53, 54 36 358 Stannophyllum radiolarium Schulze 1907b: 160, 162 37 38 359 Stannophyllum radiolarium Laubenfels 1948: 185 39 40 360 Stannophyllum radiolarium Tendal 1972: 13, 15, 44, 45, 54-55, 57, 61, 62, 69, 70, 74, 76, 77, 41 42 361 81, 85, 90, pl. 10F; 43 44 362 Stannophyllum radiolarium Tendal 1973: 26, 28-29 45 46 363 Stannophyllum radiolarium Tendal 1994: 91 47 364 Stannophyllum radiolarium Kamenskaya, Melnik, Gooday 2013:392, Fig.6a 48 49 365 50 51 366 Material examined. R/V Yuzhmorgeologia cruise 4-08, St.8639, depth 4750 m (specimen 1); 52 53 367 R/V Yuzhmorgeologia cruise 4-06, St. 31, depth 4785 m (specimen 2). 54 55 368 56 57 369 Remarks. Both specimens were originally attached to nodules. Specimen 1 from St. 8639 58 370 (Fig. 7 a) has a fan-like test, measuring 22 x 15 mm, with long and thin tubular processes 59 60 371 developed at the base. Specimen 2 from St. 31 (Fig.7 b) has a more elongate, drop-like test 61 62 63 64 65 12

372 measuring 32 x 25 mm. Both have a concentric surface zonation, more pronounced in the 1 2 373 case of specimen 1. The colour is brownish and the consistency is soft. The xenophyae are 3 4 374 radiolarian tests (Fig. 7 c). The linellae have a diameter of 1-2 µm and do not anastomose 5 375 (Fig. 7 d, e). The granellare branches are up to 40 µm in diameter and the granellae crystals 6 7 376 1-3 µm long. The stercomare are sparsely developed but are sometimes visible as oval masses 8 9 377 up to 200 µm in length (Fig. 7 d). 10 11 378 The features of these two tests are generally consistent with the description of 12 13 379 Stannophyllum radiolarium given by Tendal (1972), which was based on a re-examination of 14 15 380 the original Challenger material supplemented by two additional specimens collected during 16 381 the Galathea Expedition and a Vityaz cruise. However, our specimens (particularly #1) have 17 18 382 a clearly developed surface zonation, a feature not evident in the material examined by 19 20 383 Tendal (1972). The Challenger and Galathea specimens were also whitish in colour 21 22 384 compared to the brownish appearance of our material, although the Vityaz specimen is 23 24 385 described as 'yellow-brown'. 25 386 26 27 387 Distribution. Northern, eastern, western and central areas of the Pacific Ocean. Depth 3570- 28 29 388 5515 m. In the present study it was recorded at two sites in the Russian license area of the 30 31 389 Clarion-Clipperton Fracture Zone, Eastern Pacific, depth 4750-4785 m (Table 1). 32 33 390 34 35 391 36 392 37 38 393 Stannophyllum sp. 39 40 394 Fig. 8 41 42 395 Material examined: Single specimen from R/V Yuzhmorgeologia cruise 18-01, St. 197, 43 44 396 depth 4845 m. 45 46 47 397 Description. The single specimen, originally attached to a nodule, was approximately 48 398 semicircular in shape, resembling bracket fungus and measured approximately 6 by 3 cm 49 50 399 (Fig. 8 a). The width was about 1 mm near the outer margin, increasing towards the base. 51 52 400 Unfortunately, the test was damaged during collection and lost much of its original 53 54 401 morphology when placed in a Petri dish (Fig. 8 b). The colour is brownish and the 55 56 402 consistency is flexible. The xenophyae consists largely of complete and fragmentary 57 58 403 radiolarian skeletons (Fig. 8 c). The test interior is penetrated by numerous dichotomously 59 404 branching granellare strands (Fig.8 d, e), about 20µm in diameter and full of granellae 60 61 62 63 64 65 13

405 crystals about 2 µm in length (Fig. 8 f, g). Stercomata are quite small (about 5 µm) and 1 2 406 organized in oval masses of stercomare covered with organic sheath (Fig. 8 h). Linellae are 3 4 407 simple, not anastomosed, 2 µm in diameter and form a distinct layer. 5 6 408 Remarks. Our specimen shares some characters with other Stannophyllum species (Tendal, 7 8 409 1972), although it differs in certain respects from all of them. It resembles S. zonarium in the 9 10 410 type of xenophyae, but lacks the surface zonation of the test typical of this species. The test is 11 12 411 soft and flexible as in S. mollum, but the linellae are simple rather than anastomosing. It has 13 14 412 the same type of xenophyae (radiolarians) as S. radiolarium, but differs from this species in 15 16 413 possessing a distinct layer of linellae. The closest match to a known species appears to be 17 414 with S. granularium. The shape and consistence of the test are similar, but in contrast to S. 18 19 415 granularium, the xenophyae consist almost entirely of radiolarians rather than a mixture of 20 21 416 mineral grains and sponge spicules, with a varying proportion of radiolarians (Tendal, 1972). 22 23 417 24 25 418 Distribution. Recorded at one site in the Russian license area of the Clarion-Clipperton 26 27 419 Fracture Zone, Eastern Pacific, depth 4845 m (Table 1). 28 29 420 30 31 421 Concluding remarks 32 33 422 34 35 423 Our relatively small collection of xenophyophores, obtained at depths between 4716 and 36 37 424 4936 m in the central part of the CCFZ (13-14°N, 130-135°W), reveals the occurrence of at 38 39 425 least six species, three new and one poorly-known species belonging to the order Psamminida 40 426 and two species belonging to the order Stannomida. All of the specimens were found attached 41 42 427 to polymetallic nodules. Previous studies have demonstrated that some xenophyophores are 43 44 428 sessile on hard substrates, including rocks and plant material (Pearcey, 1914; Tendal 1975; 45 46 429 Levin and Thomas 1988), as well as on and in soft sediments. Mullineaux (1987) reported 47 48 430 the genera Semipsammina, Stannoma, Stannophyllum and Syringammina living on nodules 49 50 431 from the central (30°N, 157°W) and equatorial (5°N, 125°W) North Pacific. Similarly, 51 432 Veillette et al. (2007) found two xenophyophore-like organisms, one a fan-shaped 52 53 433 morphotype and the other lacking agglutinated particles, on nodules from the western (9°N, 54 55 434 150°W) and more central (14°N, 130°W) parts of the CCFZ. Our new material confirms that 56 57 435 where nodules are present, they represent an important habitat for these large testate protists, 58 59 60 61 62 63 64 65 14

436 which constitute a major element of the megafauna in the CCFZ. We anticipate that 1 2 437 additional undescribed species will be discovered in this part of the Pacific Ocean. 3 4 438 5 439 6 7 440 Acknowledgments. The study of xenophyophores is supported : OEK by Russian 8 9 441 Foundation for Basic Research (RFBR) grant 12-05-33049 and partly by the European 10 11 442 Union Seventh Framework Programme (FP7/207-20130 under the MIDAS project, grant 12 0 13 443 agreement n 603418; VFM by RFBR grant 12-04-01253a; AJG conducts similar work in the 14 15 444 CCZ through a commercial arrangement with Seabed Resources Development Ltd. 16 445 17 18 446 19 20 447 21 22 448 References 23 24 449 Brady HB (1883) Syringammina, a new type of arenaceous Rhizopoda, Proc. R. Soc. Lond. 25 450 35: 155–161 26 27 451 28 29 452 Buchanan JB (1960) On Jullienella and Schizammina, two genera of arenaceous foraminifera 30 31 453 from the tropical Atlantic, with a description of a new species. J. Linn. Soc. London. Zool. 32 33 454 44: 270-277 34 35 455 36 456 Gooday AJ, Aranda da Silva A, Pawlowski J (2011) Xenophyophores (Rhizaria, 37 38 457 Foraminifera) from the Nazaré Canyon (Portuguese margin, NE Atlantic). Deep-Sea Res II 39 40 458 58: 2401–2419 41 42 459 43 44 460 Gooday AJ, Tendal OS (1988) New xenophyophores (Protista) from the bathyal and abyssal 45 46 461 north-east Atlantic Ocean. J. Nat. Hist. 22: 413-434 47 462 48 49 463 Haeckel E (1889) Report on the deep-sea Keratosa collected by H.M.S. Challenger during the 50 51 464 years 1873-76. Report of the Scientific Results of the Voyage of H.M.S. Challenger during 52 53 465 the years 1873-76, Zoology 82:2 54 55 466 56 57 467 Hayward BW, Gordon DP (1984) A new species of the agglutinating foraminifer Julienella 58 468 (Schizamminidae) from New Zealand. J. Foram, Res. 14: 111-114 59 60 469 61 62 63 64 65 15

470 Hughes JA, Gooday AJ (2001) Association between living benthic foraminifera and dead 1 2 471 tests of Syringammina fragilissima (Xenophyophorea) in the Darvin Mounds region (NE 3 4 472 Atlantic). Deep-Sea Res I 51:1741-1758 5 473 6 7 474 Kamenskaya OE (2005) Spiculammina delicata gen. et sp. n., a new xenophyophore from the 8 9 475 eastern Pacific (Psamminidae). Invertebr. Zool. 2, 1: 23–27 10 11 476 12 13 477 Kamenskaya, OE, Saidova KhM (1998) Redescription of Psammina planata (Saidova, 14 15 478 1970), a hadal xenophyophore from the Kurile-Kamchatka Trench. In: A.P. Kuznetsov and 16 479 O.N. Zezina (eds.) Benthos of the High Latitude Regions. Moscow.:137 17 18 19 480 Kamenskaya OE, Melnik VF, Gooday AJ (2013) Giant protists (xenophyophores and 20 21 481 komokiaceans) from the Clarion-Clipperton ferromanganese nodule field (Eastern Pacific). 22 23 482 Biology Bulletin Reviews 3, 5: 388-398 24 25 483 26 27 484 Laubenfels MV (1948) The order Keratosa of the phylum Porifera - a monographic 28 485 study. - Occ. Pap. Allan Hancock Fdn. 3: 1-217. 29 30 486 31 32 487 Lecroq B, Gooday AJ, Tsuchiya M, Pawlowski J (2009) A new genus of xenophyophores 33 34 488 (Foraminifera) from the Japan Trench: morphological description, molecular phylogeny and 35 36 489 elemental analysis. J. Linn. Soc. London. Zool. 156: 455–464. 37 490 38 39 491 Levin LA (1994) Paleoecology and ecology of xenophyophores. Palaios. 5: 32–41. 40 41 492 42 43 493 Levin LA, Thomas CL (1988) The ecology of the xenophyophores (Protista) on eastern 44 45 494 Pacific seamounts. Deep-Sea Res 35, 12: 2003–2027. 46 47 495 48 496 Levin LA, DeMaster DJ, McCann LD, Thomas CL (1986) Effects of giant protozoans (class: 49 50 497 Xenophyophorea) on deep seamount benthos, Mar. Ecol. Prog. Ser. 29: 99–104 51 52 498 53 54 499 Mullineaux LS (1987) Organisms living on manganese nodules and crusts: Distribution and 55 56 500 abundance at three North Pacific sites. Deep-Sea Res 34: 165-184 57 58 501 59 60 61 62 63 64 65 16

502 Nørvang A (1961) Schizamminidae, a new family of foraminifera. Atlantide Report 6: 169- 1 2 503 201, Pls I - IX 3 4 504 5 505 Pawlowski J, Holzmann M, Fahrni J, Richardson SL (2003) Small subunit ribosomal DNA 6 7 506 suggest that xenophyophorean Syringammina corbicula is a foraminiferan. J. Eukaryotic 8 9 507 Microbiol. 50: 483–487 10 11 508 12 13 509 Pawlowski J, Holzmann M, Tyszka J (2013) New supraordinal classification of 14 15 510 Foraminifera: Molecules meet morphology. Marine Micropaleontology 100: 1-10 16 511 17 18 512 Pearcey FG (1914) Foraminifera of the Scottish Antarctic Expedition. . Transactions of the 19 20 513 Royal Society of Edinburgh 49: 991 - 1044. 21 22 514 23 24 515 Saidova KhM (1970) Benthic foraminifers in the Kurile-Kamhatka Region based on the data 25 516 of the 39th cruise of the R/V Vityaz. Trudy Instituta Okeanologii 86: 134-161 26 27 517 28 29 518 Schlumberger C (1890) Note sur un foraminifere nouveau de la côte occidentale d’Afrique. 30 31 519 Mémoires de la Société zoologique de la France 3: 211-213 32 33 520 34 35 521 Schulze FE (1907a) Die Xenophyophoren, eine besondere Gruppe der Rhizopoden. -Wiss. 36 522 Ergebn. dt. Tiefsee-Exped. Valdivia 11: 1- 55 37 38 523 39 40 524 Schulze FE (1907b) Die Xenophyophoren. Bull. Mus. comp. Zool. Harv. 51: 143-162 41 42 525 43 44 526 Tendal OS (1972) A monograph of the Xenophyophoria (Rhizopoda, Protozoa). Galathea 45 46 527 Report 12: 7-99. 47 528 48 49 529 Tendal OS (1975) A new xenophyophore, living on solid substratum, and its significance. 50 51 530 Deep-Sea Res 22: 45-48. 52 53 531 54 55 532 Tendal OS (1973) Xenophyophoria (Protozoa, Rhizopoda) from the collections of the R/V 56 57 533 “Vitiaz”. Zoologichesky Zhurnal 52: 25-30 58 534 59 60 61 62 63 64 65 17

535 Tendal OS (1994) Protozoa Xenophyophorea Granuloreticulosa: Psammina zonaria sp.nov. 1 2 536 from the Wester Pacific and some aspects of the growth of xenophyophores. In: A. Crosnier 3 4 537 (ed.). Resultats des Campagnes MUSORSTOM. Vol. 12. Mém. Mus. Nat. Hist. 161: 49-54 5 538 6 7 539 Tendal OS (1996) Synoptic checklist and bibliography of the Xenophyophorea (Protista), 8 9 540 with a zoogeographical survey of the group. Galathea Report 17: 79-101 10 11 541 12 13 542 Tendal OS, Lewis KB (1978) New Zealand xenophyophores: upper bathyal distribution, 14 15 543 photographs of growth position, and a new species. N.Z. J. Mar. Freshw. Res. 12: 197-203 16 544 17 18 545 Veillette J, Sarrazin J, Gooday AJ, Galéron J, Caprais J-C, Vangriesheim A, Juniper SK 19 20 546 (2007). Ferromanganese nodule fauna in the equatorial north Pacific ocean: species richness, 21 22 547 faunal cover and spatial distribution. Deep-Sea Research I 54: 1912-1935. 23 24 548 25 549 26 27 550 28 29 551 30 31 552 32 33 553 34 35 554 36 555 37 38 556 39 40 557 41 42 558 43 44 559 45 46 560 47 561 48 49 562 50 51 563 52 53 564 54 55 565 56 57 566 58 567 59 60 568 61 62 63 64 65 18

569 Figure captions 1 2 570 3 4 571 Fig. 1. Semipsammina licheniformis sp. nov., Stn.60-1, cruise 4-06, holotype, registration 5 572 number F-16; a, b, d, light micrographs; c, e, f, scanning electron micrographs. 6 7 573 a- Intact specimen on the surface of the host nodule 8 9 574 b- Fragment of the surface of the test 10 11 575 c- Surface of test showing xenophyae (mainly radiolarian skeletons) 12 13 576 d- Underside of outer test layer showing granellare branches and dark masses of 14 15 577 stercomare 16 578 e- Granella (barite crystal) on the surface of a granellare branch 17 18 579 f- Strings of stercomare composed of stercomes 19 20 580 Scale bars: a- 1 cm; b- 1 mm; c- 100 µm, d- 1 mm; e- 10 µm; f- 30 µm 21 22 581 23 24 582 25 583 Fig. 2. Psammina multiloculata sp.nov.; light micrographs. 26 27 584 a – Holotype from Stn. 28, cruise 4-06, registration number F-17 28 29 585 b – Fragment of holotype 30 31 586 c – Fragment of holotype with base of secondary plate 32 33 587 d – Fragments of specimen from Stn. 204, cruise 18-01 34 35 588 e - Specimen from Stn. 8655, cruise 4-09, side view 36 589 f _ Specimen from Stn. 8655, cruise 4-09, top view 37 38 590 g – Specimen from Stn.t.8726, cruise 4-09, side view 39 40 591 h – Specimen from Stn. 8726, cruise 4-09, margin of the test showing internal 41 42 592 compartments. 43 44 593 Scale bars: a, e, g – 10 mm, b – 5 mm, c-1,5 mm 45 46 594 47 595 48 49 596 Fig. 3. Psammina multiloculata sp.nov., specimen from Stn.204, cruise 18-01; scanning 50 51 597 electron micrographs. 52 53 598 a – Surface of the test 54 55 599 b - Detail of surface showing xenophyae (fragments of sponge spicules and radiolarians) 56 57 600 c – Test interior showing compartments 58 601 d – Oval stercomare mass within compartment 59 60 602 e – Stercomare strings (left) and granellare branch (right) 61 62 63 64 65 19

603 f - Granellare branch 1 2 604 g – Detail of granellare branch containing numerous granellae (barite crystals) 3 4 605 h – Single granella 5 606 Scale bars: a, c - 1000 µm, b, d, f – 100 µm, e – 30 µm, g – 10 µm, h – 3 µm 6 7 607 8 9 608 Fig. 4. Psammina limbata sp.nov., Stn. 25, cruise 4-06, 4724 m, holotype, registration 10 11 609 number F-18. 12 13 610 , a - Intact test attached to host nodule. 14 15 611 b - Test detatched from nodule showing concentric zonation. 16 612 c - Surface of the test showing xenophyae. 17 18 613 d - Outer layer of test underlain by internal xenophyae (mainly sponge spicules), 19 20 614 stercomare and granellare 21 22 615 e - Stercomare mass 23 24 616 f - Single granella (barite crystal) 25 617 g - Small ridge on underside of outer test layer 26 27 618 h - Weakly-developed zonation on underside of outer test layer inside test 28 29 619 i - Margin of test consisting of sponge spicules 30 31 620 Scale bar: a, b - 1 cm, g – 1 mm, d, i -200µm, c, h - 100µm, e- 20µm, f – 3 µm 32 33 621 34 35 622 Fig. 5. Spiculammina delicata, variation in test morphology of specimens attached to nodules 36 623 (cruise 4-06). 37 38 624 a - Stn. 118 39 40 625 b - Stn. 166 41 42 626 c – Stn. 159 43 44 627 d – Stn. 43 45 46 628 e – Stn. 119 47 629 f – Stn. 164 48 49 630 50 51 631 52 53 632 Fig. 6. Test structure of Spiculammina delicata, from Stn. 25, cruise 4-06; scanning electron 54 55 633 micrographs. 56 57 634 a - Surface of the test 58 635 b - Detail of test wall showing xenophyae (sponge spicules) 59 60 636 c - Test interior containing stercomare, granellare and xenophyae 61 62 63 64 65 20

637 d – Strings of stercomare between inner xenophyae 1 2 638 Scale bar: a – 200 µm; b, – 100 µm; d – 20 µm; c-10 µm 3 4 639 5 640 6 7 641 Fig. 7. Stannophyllum radiolarium; a,b, light micrographs; c - f, scanning electron 8 9 642 micrographs. 10 11 643 a- Specimen from Stn. 8639; dimensions 22x15 mm 12 13 644 b- Specimen from Stn.31 attached to host nodule; dimensions 32x25 mm 14 15 645 c- Surface of the test showing xenophyae (radiolarians). 16 646 d- Linellae and stercomare mass 17 18 647 e- Detail of linellae 19 20 648 f- Granellare branch with granellae 21 22 649 Scale bar: c,d-100 µm; e, f, 10 µm 23 24 650 25 651 Fig. 8. Stannophyllum sp. from Stn 197, cruise 18-01; a,b, light micrographs; c - i, scanning 26 27 652 electron micrographs. 28 29 653 a- Specimen as originally found in box core, attached to a nodule 30 31 654 b- Damaged fragment in Petri dish 32 33 655 c- Test surface showing xenophyae (radiolarians) 34 35 656 d, e- Test interior with granellare branches and internal xenophyae 36 657 f- Single granella (barite crystal)e 37 38 658 g- Mass of granellae within granellare branch 39 40 659 h- Stercomare 41 42 660 i- layer of linellae 43 44 661 Scale bar: b- 1 cm; d- 300 µm; c, e- 100 µm; i- 30 µm; h- 10 µm; f, g- 3 µm 45 46 662 47 663 48 49 664 50 51 665 52 53 54 666 55 56 57 667 58 668 59 669 60 61 62 63 64 65 21

670 1 671 2 672 3 4 673 5 674 6 675 7 676 8 677 9 10 678 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Figure

Fig.1

Fig.2

Fig.3

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8 Table

Table 1. List of stations from cruises of R/V Yuzhmorgeologiya with xenophyophores from the Clarion-Clipperton nodule field.

Station Cruise Year Coordinates Depth Species N N, W m 25 4-06 2006 13.280 134.450 4724 Psammina limbata, Spiculammina delicata 28 4-06 2006 13.290 13.410 4843 Psamina multiloculata 31 4-06 2006 13.310 134.410 4785 Stannophyllum radiolarium 34 4-06 2006 13.310 134.320 4742 Spiculammina delicata 39 4-06 2006 13.260 134.470 4716 Spiculammina delicata 43 4-06 2006 13.280 134.420 4753 Spiculammina delicata 49 4-06 2006 13.290 134.340 4755 Spiculammina delicata 52 4-06 2006 13.240 134.530 4787 Spiculammina delicata 60-1 4-06 2006 13.260 134.420 4777 Semipsammina licheniformis 85 4-06 2006 13.270 134.320 4820 Spiculammina delicata 94 4-06 2006 13.230 134.440 4772 Spiculammina delicata 95 4-06 2006 13.230 134.430 4786 Spiculammina delicata 118 4-06 2006 13.240 134.340 4778 Spiculammina delicata 119 4-06 2006 13.240 134.330 4825 Spiculammina delicata 122 4-06 2006 13.190 134.510 4820 Spiculammina delicata 133 4-06 2006 13.220 134.370 4788 Spiculammina delicata 150 4-06 2006 13.270 134.430 4778 Spiculammina delicata 151 4-06 2006 13.270 134.430 4776 Spiculammina delicata 159 4-06 2006 13.260 134.450 4755 Spiculammina delicata 164 4-06 2006 13.260 134.430 4769 Spiculammina delicata 166 4-06 2006 13.260 134.420 4777 Spiculammina delicata 167 4-06 2006 13.260 134.420 4789 Spiculammina delicata 197 18-01 2003 13.550 129.020 4845 Stannophyllim sp. 204 18-01 2003 13.900 129.140 4896 Psammina multiloculata 8639 4-08 2009 12.770 133.410 4750 Stannophyllum radiolarium 8655 4-09 2010 12.720 133.590 4841 Psammina multiloculata 8726 4-09 2010 13.540 133.420 4936 Psammina multiloculata