The biodiversity and biogeography of komokiaceans and other enigmatic foraminiferan-like protists in the deep Southern Ocean

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Deep-Sea Research II 54 (2007) 1691–1719 www.elsevier.com/locate/dsr2

The biodiversity and biogeography of komokiaceans and other enigmatic foraminiferan-like protists in the deep Southern Ocean Andrew J. Goodaya,, Tomas Cedhagenb, Olga E. Kamenskayac, Nils Corneliusa a

National Oceanography Centre, Southampton, Empress Dock, European Way, Southampton SO14 3ZH, UK Department of Marine Ecology, Biological Institute, University of Aarhus, Finlandsgade 14, DK-8200 Aarhus N, Denmark c Laboratory of Ocean Benthic Fauna, P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovsky Pr., 36, Moscow 117997, Russian Federation b

Accepted 4 July 2007 Available online 2 August 2007

Abstract We present a survey of komokiaceans and other relatively large, stercomata-bearing testate protists, presumed to be foraminifera, based on extensive ship-board sorting of samples collected at 13 sites (depth range 1820–4930 m) in the Weddell Sea and two sites in the SE Atlantic (Cape and Aguilas basins, north of the Antarctic Convergence) during the ANDEEP III expedition. Thirty-nine species occurred in the Weddell Sea and a further 11 in the SE Atlantic basins. Of these 50 species, 35 are undescribed. We assign, with a greater or lesser degree of certainty, 26 and 13 species to the komokiacean families Komokiidae and Baculellidae, respectively, and another 2 to the Komokiacea incertae sedis. We include in the Baculellidae an undescribed species in which very fine hair-like fibres, similar to those seen in some species currently included in this family, arise from the segments that make up the chain-like test. A further 11 chain-like species lack these fibres and we therefore exclude them from the Komokiacea. A final group of species includes a mixture of different forms, some of which exhibit komokiacean-like features. These assemblages were most diverse at abyssal sites in the central Weddell Sea (27–30 species per site). Above 4000 m, 1–8 species were present at individual sites and only two species, Normanina conferta and Septuma brachyramosa, occurred at depths o2000 m. One of these, N. conferta, was the most widely distributed species, occurring at 11 stations south of the Antarctic convergence as well as the Aguilas Basin. Many (31–61%) of the Southern Ocean ANDEEP species are recognised in the North Atlantic and 6 were previously described from the central North Pacific. Our results suggest that some komokiacean and chain-like species are widely distributed at abyssal depths in the oceans. They also support other evidence that many undescribed komokiacean species exist and highlight some of the difficulties involved in defining the morphological limits of this difficult taxon. r 2007 Elsevier Ltd. All rights reserved. Keywords: Biodiversity; Biogeography; Deep water; Polar waters; Komokiacea; Protista

1. Introduction

Corresponding author. Tel.: +44 2380 596353; fax: +44 2380 596 247. E-mail address: [email protected] (A.J. Gooday).

0967-0645/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.dsr2.2007.07.003

Foraminifera are probably the best studied taxon in the deep Southern Ocean (SO), largely as a result of taxonomic publications based on major national expeditions conducted in the first half of the 20th Century and geological studies undertaken during

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the second half of last century (reviewed by Cornelius and Gooday, 2004; Mikhalevich, 2004; Brandt et al., 2007a, b). Although some of the earlier publications included a number of delicate agglutinated species, among them monothalamous (single-chambered) forms such as Vanhoeffenella, the main focus of foraminiferal studies in the deep SO has concerned hard-shelled foraminifera. Gooday and Pawlowski (2004) and Gooday et al. (2004) described new monothalamous species from the Weddell Sea, but only the recent publication of Cornelius and Gooday (2004) provides a qualitative account of the soft-bodied, single-chambered foraminifera which are often an important component of deep-sea assemblages. The Komokiacea are an important, but frequently overlooked group of large (typically 41 mm), deep-sea, soft-bodied protists with a test that comprises a system of branching tubules. These enigmatic organisms are usually classified in the foraminiferan order Astrorhiziina (Loeblich and Tappan, 1987, 1989; Kaminski, 2004), although there is no conclusive evidence that they are related to the other members of this group of monothalamous agglutinated foraminifera. The Komokiacea and its two constituent families, the Komokiidae with four genera and seven species and the Baculellidae with two genera and four species, was formally described by Tendal and Hessler (1977) based on box-core samples from the central North Pacific. These authors also examined material from the Atlantic, Pacific and Indian oceans in which they determined komokiaceans to generic level. All Tendal and Hessler’s samples were from temperate latitudes, with the exception of several around 601N in the Atlantic and Pacific oceans. Since this landmark publication, only five papers (Mullineaux, 1988; Schro¨der et al., 1989; Kamenskaya, 1993a, b; Shires et al., 1994) have described new komokiacean species. A few other studies provided information on komokiaceans from the Pacific Ocean (Kamenskaya, 1987, 1988, 1989), Atlantic Ocean (Gooday and Cook, 1984; Tendal, 1985; Gooday, 1987, 1990, 1994; Kaminski and Schro¨der, 1987; Kuhnt and Collins, 1995), and Arctic Ocean (Wollenburg and Mackensen, 1998). Most species occupy flocculent surface sediments (Kaminski et al., 1988) but some are infaunal (Tendal and Hessler, 1977; Kuhnt and Collins, 1995), while a few live on hard substrates (Mullineaux, 1988). During the 1980s, Russian investigations, reviewed below, established the occurrence of komokiaceans

in the Weddell Sea and adjacent areas. However, apart from an abstract by Gooday et al. (2006), there has been no other treatment of this group in the SO. This is not surprising given the fact that the deep-water benthos around Antarctica remained relatively unknown until recently. The ANDEEP project was the one of the first to undertake a concerted study of benthic organisms in this remote region (Brandt et al., 2004, 2007a, b). The first and second ANDEEP cruises (I and II) took place in 2002 (R.V. Polarstern Cruise ANT XIX/3–4) and the third campaign (III) in 2005 (R.V. Polarstern Cruise ANT XXII/3). During the ANDEEP III cruise, numerous komokiaceans and other foraminiferanlike protists were picked out from the fresh sieved residues of samples collected with a box corer, multiple corer, epibenthic sledge, and Agassiz trawl. These collections form the basis of the present study. Our aim in this paper is to (1) provide an overview of the extensive komokiacean material collected during ANDEEP III and (2) compare the species found in these SO samples with those in samples collected in the North Atlantic and literature records from other oceans. Brief descriptions of each species are given in a taxonomic appendix and many of them are illustrated in Figs. 1–6. Selected species, including three that are new, are described elsewhere (Gooday et al., in press). First, however, we review the history of komokiacean studies, with an emphasis on Russian work, which is largely unfamiliar to western scientists. 2. Notes on the literature 2.1. Early records of Komokiacea and komokiaceanlike protists The literature on komokiaceans that has appeared in western journals since the publication of Tendal and Hessler (1977) is briefly referred to above. However, records of the group date back to Victorian times with the description by Norman (1878) of Halyphysema conferta Norman, 1878. This species was transferred to a new genus Normanina by Cushman (1928) and was placed in the Komokiacea by Tendal and Hessler (1977). Gooday (1990) drew attention to several possible komokiaceans in an obscure publication by the French naturalist, the Marquis Leopold de Folin. One of Brady’s plates from his Challenger Report (Brady 1884, Plate 27A, Fig. 2) shows an organic-walled

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Fig. 1. ANDEEP komokiaceans (Family Komokiidae). (A) Sp. 208, Lana sp. F, Stn. 88#7; (B) Sp. 208a, Lana sp. F1, Stn. 94#5; (C) Sp. 195, Lana sp. F2, Stn. 88#12; (D) Sp. 15, Lana aff. neglecta sp. 1, Stn. 16#8; (E) Sp. 301, Lana aff. neglecta sp. 2, Stn. 153#8; (F) Sp. 216, Lana sp. A1, Stn. 102#8; (G) Sp. 50, Lana sp. 1, 21#5. All scale bars ¼ 1 mm.

chain similar to the specimen illustrated by Gooday (1990, Plate 3, Fig. C therein). Brady’s Fig. 3 on the same plate shows what appears to be a specimen of Crambis conclavata Schro¨der et al., 1989. Brady identified both his figured specimens as Aschemonella catenata and his Fig. 3 has the additional caption: ‘specimen incrusted with mud and with (?) filose pseudopodia extended’. We follow Kuhnt and Collins (1995) in regarding Crambis, a genus that Schro¨der et al. (1989) referred to as foraminifera insertae sedis, as a likely komokiacean. Brady’s third figure of A. catenata (Brady, 1884, Plate 27A, Fig. 1), resembles one of the ‘agglutinated chains’

recognised in ANDEEP material (Chain 5; Fig. 3F). As discussed below, some of the organic-walled chains may be related to komokiaceans, whereas the agglutinated chains are almost certainly not members of this group. 2.2. Komokiaceans in Russian literature Komokiaceans were recognised by Russian scientists in the 1950s. During the 14th cruise of Russian research vessel R.V. Vityaz (1953), 19 specimens resembling branching lumps were recovered from four Okean grab samples at 4850–5570 m water

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Fig. 2. ANDEEP komokiaceans (Family Komokiidae). (A) Sp. 164, Reticulum sp. C, Stn. 88#7; (B) Sp. 19, Reticulum sp. D, Stn. 16#8; (C) Sp. 259, elongate Lana, Stn. 121#7 (shipboard photograph); (D) Sp. 227, Reticulum sp. E, Stn. 102#13; (E) Sp. 207, Reticulum pingue Schro¨der, Medioli and Scott, 1989, Stn. 94#11; (F) Sp. 226, ball with filaments, Stn. 102#13 – this species is not a komokiacean; (G) Sp. 181, ?Reticulum sp. H, Stn. 94#11. All scale bars ¼ 1 mm.

depth in the northwest Pacific to the east of the Kurile-Kamchatka Trench. Similar organisms, named ‘vetvistye komochki’ (‘fluffy balls’ or ‘soft foraminiferans’) also were found at eight stations (4800–5930 m depth) in the NW Pacific and to the west of the Hawaiian islands during the 19th cruise of the R.V. Vityaz (1954). Subsequent cruises of the R.V. Vityaz, and the first cruises of R.V. Dmitry Mendeleev and R.V. Akademik Kurchatov, yielded

many specimens of ‘komochki’ from bathyal to hadal depths in different areas of Pacific and Atlantic oceans. Their greatest diversity, density and biomass occurred at abyssal depths (Filatova, 1960, 1969; Filatova and Levenstein, 1961). Several were described as new species of foraminiferans in the genera Dendrophrya and Normanina by Saidova (1975) (Table 1). Later, some of these records were used by Belyaev (1989) in his analysis of the hadal

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Fig. 3. ANDEEP komokiaceans (Family Baculellidae) and other forms. (A–B) Sp. 213, Arbor multiplex Schro¨der et al., 1989, Stn. 94#11; (C) Sp. 177, Arbor hispida Schro¨der, Medioli and Scott, 1989, Stn. 88#8; (D) Sp. 200, Arbor floccularis Schro¨der, Medioli and Scott, 1989, Stn. 94#11; (E) Clados-like form A, Stn. 88#8; (F) chain sp. 5, Stn. 102#13; (G) Sp. 203, chain sp. 6, Stn. 102#13. All scale bars ¼ 1 mm.

fauna of the World Ocean. So, even before they were assigned to a formally described taxon, ‘komochki’ were known to be a very widespread and important component of deep-sea communities. After the publication of Tendal’s (1972) ‘A monograph of the Xenophyophoria’, some ‘komochki’ were attributed to this group of giant agglutinated protists by Vinogradova et al. (1978) and Zezina (1978). These authors emphasised the very important role of large agglutinated protists in deep sea communities. The taxon was formally described in 1977 by Tendal and Hessler (1977), who introduced

the informal term ‘komoki’ based on the original Russian word. Thus, ‘‘yit took more than twenty years to understand the systematic position of these exceptionally interesting protozoansy’’ (Filatova, 1982). The quantitative distributions of komokiaceans and xenophyophores, treated as two separate groups, were first studied systematically in grab samples from Pacific cruises of the R.V.s Vityaz, Dmitry Mendeleev and Akademic Kurchatov (Kamenskaya, 1987). Komokiaceans were found at more than 75% of stations at the depths

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Fig. 4. ANDEEP komokiaceans (Family Baculellidae) and other forms. (A–B) Sp. 193, branched Baculella, Stn. 88#8; (C) Sp. 112, Edgertonia sp. 1, Stn. 88#8; (D) Sp. 161, Edgertonia argillispherula Tendal and Hessler, 1977, Stn. 88#5; (E) Sp. 206, Gen. nov. A & sp. nov. B, Stn. 94#11; (F) Sp. 191, ?Baculella sp. 1, Stn. 88#8; (G) Sp. 204. coiled chain, Stn. 102#13; (H) Sp. 99, Staphylion sp., Stn. 94#11. All scale bars ¼ 1 mm, except where indicated.

43000 m, and in 490% of grab samples in abyssal basins. Their biomass (wet weight including test) and percentage contribution to total benthic biomass increased towards the central parts of the ocean. A similar pattern was reported in the abyssal basins of the Atlantic Ocean (Vinogradova et al., 1982; Kamenskaya, 1988, 1990, 1993a; Vinogradova

et al., 1990a, b, 1993a). Some species were found to have very wide geographical distributions, at least at the morphospecies level. For example, Septuma ocotillo, described from the northeast Pacific by Tendal and Hessler (1977), also occurs in the North and South Atlantic (Kamenskaya, 1993a, 1996) while Septuma brachyramosa was reported from the

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Fig. 5. ANDEEP chain-like species. (A) Sp. 16, delicate chain sp. 4, Stn. 16#8; (B) Sp. 91, delicate chain sp. 2, Stn. 59#11; (C) Sp. 209, ragged chain, Stn. 94#7; (D) delicate chain sp. 3, Stn. 142#5; (E) Sp. 47, chain sp. 4, Stn. 21#5; (F) Sp. 201, chain sp. 3, Stn. 102#13; (G) large grey chain, Stn. 21#7; (H) chain sp. 1, Stn. 88#8. All scale bars ¼ 1 mm.

SE Atlantic and from hadal trenches in the West Pacific (Kamenskaya, 2006). The bathymetric distribution of komokiaceans was studied in Pacific and Atlantic material by Kamenskaya (1989, 1990, 1993a). Samples from bathyal depths (1000–2000 m) yielded single specimens assigned to the genera Septuma, Lana (Reticulum) and Edgertonia, but komokiaceans only appeared in large numbers below 3000 m, with maximal occurrences in the central parts of the abyssal basins (3500–5000 m). Komokiaceans were

also one of the main components of hadal faunas below 6000 m (Kamenskaya, 2006). The genera with the widest bathymetric ranges were Septuma, Lana (Reticulum) and Edgertonia. Russian scientists discovered komokiaceans in the SO in the 1980s. They were found in 1985 during the 43th cruise of the R.V. Akademik Kurchatov near Mordvinov Island (South Shetland Islands) between 3110 and 4190 m depth (Vinogradova et al., 1990c). In this area, the biomass (wet weight with test) of komokiaceans was about 8–10% of total benthic

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Fig. 6. ANDEEP chain-like and other species. (A) Sp. 105, fuzzy chain, Stn. 59#7; (B) Sp. 59, branched test with dense stercomata, Stn. 21#6; (C) Sp. 205, pale lobed mudball, Stn. 94#11; (D) Sp. 2, Tuber-like species, Stn. 16#5; (E) Sp. 179, thick fluffy tubules, Stn. 88#8 (shipboard photograph). All scale bars ¼ 1 mm except where indicated.

Table 1 Komokiacean species described by Saidova (1975) Name (Saidova, 1975)

Figure in Saidova (1975)

Comments

Occurrence

Dendrophrya abyssalicaa

Pl V fig. 3

37142.50 N, 156123.60 E; 5790 m

D. derosa D.(?) kermadecensisa Normanina fruticosa

Pl V fig. 4 Pl V fig. 5 Pl V fig. 6

N.? elongataa N. ultrabyssalicaa

Pl. V, fig. 7 Pl VI, fig. 1

Possibly a new komokiacean genus Lost, possibly a species of Lana Reticulum sp. Specimen lost. Not Normanina, possible a species of Komokia Chain-like species Possibly a new komokiacean

a

31125.60 N, 150147.80 E; 5526 m 281530 S, 1761010 E; 8928–9174 m 331180 N, 149145.70 E; 6126 m 12130 S, 1721350 W; 4732 m 311500 S, 1771140 W; 9995–10,002 m

Indicates that original specimens have been re-examined.

biomass. Later, Vinogradova et al. (1993b, 2000) found komokiaceans at 6164-m depth in the Orkney Trench during the 43rd cruise of R.V. Dmitry

Mendeleev (1989). Finally, species of Septuma (200 specimens/m2) and Normanina (200 specimens/m2) were recorded in grab samples from the Weddell Sea

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(depth 2925 m) and species of Lana and Edgertonia (300 specimens/m2) were found at 1170-m depth in the Bransfield Strait, in both cases during the 43rd cruise of R.V. Dmitry Mendeleev (Vinogradova et al., 1993b). Galtsova et al. (1997) explored the relation between different meiobenthic and macrobenthic taxa and various environmental factors, including depth, sediment type, concentration of Corg, lipids and proteins, in the Angola and Cape basins and on the Valdiva seamount (SE Atlantic). The strong negative correlation between the density of komokiaceans on the one hand, and densities of macrobenthic polychetes and meiobenthic harpacticoids, on the other hand, were related to trophic conditions and the bioturbation of the upper layer of sediment. Strong positive correlations were found between the density of komokiaceans and water depth and sediment type. They increased in abundance with depth and were associated with silty (alevrito-pellite) carbonate sediment. However, there was no correlation between komokiacean abundance and Corg concentrations. 2.3. Fossil komokiacean-like foraminifera Komokiaceans and similar soft-bodied foraminifera have little fossilisation potential (Schro¨der, 1986). Nevertheless, foraminifera said to resemble komokiaceans occur in Late Cretaceous abyssal sediments of the North Atlantic Plantagenet Formation (Kuhnt et al., 1989) and pelagic limestones (‘Scaglia facies’) of similar age in Italy (Kuhnt, 1990; listed as Tolypammina(?) spp. 1–3). As far as we are aware, these species have not been illustrated. In addition, both the Scaglia facies (Kuhnt, 1990) and the Plantagenet Formation (Kuhnt and Moullade, 1991) yield a number of chain-like

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foraminifera that are rather similar to some of those illustrated in the present paper. These include Aschemocella carpathica (Neagu 1964), A. grandis (Grzybowski 1898), Subreophax aff. splendidus (Grzybowski 1896) and Subreophax sp. 1. The type figures of A. carpathica (reproduced in Kaminski and Gradstein, 2005, Fig. 38), a species originally described from the late Cretaceous of the Romanian Carpathians, are strikingly similar to some modern chain-like deep-sea species. In addition, Rhizammina-like tubes are known from these and other deep-water, Late Cretaceous deposits (e.g. Kuhnt and Kaminski, 1989; Kuhnt, 1990), although at least some may be better placed in the genus Nothia (Kaminski and Gradstein, 2005). Whether any of these fossil species are related to modern Komokiacea or komokiacean-like foraminifera is difficult to determine since the internal structures, particularly stercomata, are apparently not preserved. 3. Materials and methods All the Antarctic samples were collected during the R.V. Polarstern Cruise ANTXXII-3 (21 January–6 April 2005), in most cases using either an epibenthic sledge or an Agassiz Trawl (Table 2). The epibenthic sledge was equipped with two nets, a lower epibenthic net (500 mm mesh size) and an upper suprabenthic net (300 mm mesh size), each 1 m in width. The 3 m wide Agassiz trawl was equipped with a cod end mesh size of 500 mm, except at Stns. 74#7, 78#11 and 81#9, where a 10-mm mesh size was used. Both gears were trawled for 10 min across the seafloor with a mean velocity of 1 knot. The epibenthic sledge usually yielded a fairly clean catch whereas the trawl often recovered large quantities of mud. In both cases, small subsamples of the catches

Table 2 Positions of ANDEEP sites Station and deployment

Position

Depth (m)

Gear

1S

1E or W

Cape Basin Stn. 16 16#5 16#8

41107.410 41107.510 41107.820

09155.550 E 09156.300 E 09156.110 E

4712 4723 4726

GKG MUC

Anguilas Basin Stn. 21 21#5

47139.360 47139.370

04115.710 E 04115.650 E

4559 4566

GKG

Comments

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1700 Table 2 (continued ) Station and deployment

Position

Depth (m)

Gear

1S

1E or W

21#7

47138.660

04115.140 E

4552–4555

EBS

Neumayer slope 57#2

69124.470

05119.280 W

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AT

E. Weddell Sea Abyssal Plain, south of Maud Rise 0101.470 E Stn. 59 67130.540 59#7 67131.050 0100.270 E 59#11 67130.960 0100.020 W

4651 4654 4653

MUC MUC

Kapp Norvegica continental slope transect Stn. 74 71118.460 Stn. 78 71159.430 Stn. 80 70139.390 Stn. 81 70131.970

13157.900 W 13159.720 W 14143.550 W 14134.900 W

1047 2162 3071 4397

Weddell Abyssal Plain transect Stn. 88 68103.650 88#5 68103.680 88#7 68103.610 88#8 68103.640 Stn. 94 66137.680 94#5 66137.430 94#7 66137.370 94#11 66138.070 Stn. 102 65134.970 102#8 65134.370 102#13 65134.350 Stn. 110 64159.500

20127.390 W 20127.750 W 20127.990 W 20131.710 W 27108.780 W 27109.770 W 27109.780 W 2715.680 W 36130.710 W 36130.930 W 36131.200 W 43102.000 W

4931 4933 4934 4929–4931 4893 4894 4892 4893–4894 4803 4803 4803–4818 4700

Peninsula slope Stn. 121 Stn. 133

63137.430 64158.950

50145.110 W 53101.720 W

2603 1549

Powell Basin Stn. 142 142#5 Stn. 150 Stn. 151

62110.820 62111.300 61148.620 61145.460

49129.350 W 49129.070 W 47128.030 W 47107.160 W

3405 3404–3408 1989 1181

Bransfield Strait Stn. 152

62120.020

57153.750 W

1198

Off Anvers Island Stn. 153 153#8 Stn. 154

63119.330 63119.150 64131.540

64136.960 W 64137.100 W 64139.550 W

2091 2069–2131 3803

NE Atlantic sites Stn. 12174 Stns. 11908, 52701 Stn. 11262 9128#10 9129#1

1N 311050 481500 311100 28118.10 23106.00

1W 211100 161300 251100 30127.70 27158.10

4940 4810 5432 6059 5590

Comments

Only biological sample taken at this site

No Komokiacea

GKG GKG EBS MUC MUC AT GKG EBS

AT EBS

EBS No Komokiacea No Komokiacea No Komokiacea

EBS No Komokiacea

EBS EBS EBS

Madeira Abyssal Plain Porcupine Abyssal Plain Great Meteor East

For each site, a mean position based on all biological samples (GKG, MUC, AT and EBS) is given, together with precise positions of deployments mentioned in figure captions. Also given are mean positions for stations in the NE Atlantic mentioned in Table 4. Sampling gears indicated as follows: AT ¼ Agassiz Trawl; EBS ¼ epibenthic sledge; GKG ¼ large box corer (Grosse Kastengreifer); MUC ¼ multicorer.

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were removed as soon as possible after recovery and transferred to a 1-mm sieve submerged in seawater. All subsequent sieving was done using sieves of mesh sizes 500, 300, 125, and 64 mm, always submerged in chilled sea water (1–2 1C) in a cool room. Because of the fragility of the organisms, the agitation of the sieves was always gentle and fairly slow. The sieve residues were placed in a Petri or similar dish that in turn was put in an outer dish with ice in order to keep it cold during sorting. All komokiaceans and other foraminifera were picked from the samples with a pair of flexible forceps (‘‘entomological forceps’’), a brush, or a fine pipette under a stereomicroscope (Wild M5 or Leica MZ6). Larger samples of sediment (5–10 L) from the Agassiz trawl were treated in a slightly different way in order to find large, rare forms. The sediment was placed in a bucket and a saltwater hose was inserted. The water was allowed to flow over the edge and was collected in a series of sieves (2-, 1-, 0.5-mm mesh size). The residue was then treated as described above. Additional komokiacean material was obtained from core samples. In each case, the upper 1 cm layer of sediment collected using a multiple corer equipped with 57-mm internal diameter tubes or square subcores (10  10 cm) from a subdivided box corer, was sieved as described above on 300- and 125-mm meshes and sorted for foraminifera. Picked specimens were treated in various ways. Some were frozen in liquid nitrogen or fixed in guanidine buffer for molecular analyses and a few were fixed in gluteraldehyde for ultrastructural work. The remainder were fixed in 10% seawater formalin buffered with borax for morphological study. The present paper is based on this formalinfixed material. The ANDEEP species were compared directly with komokiaceans from the NE Atlantic, collected during various cruises conducted by the Institute of Oceanographic Sciences, Wormley. Details of the main stations are summarised in Table 2, except for those in the Porcupine Seabight which were given by Gooday (1990). The type material of Tendal and Hessler (1977), housed in the Zoological Museum, Copenhagen, also was examined. Shipboard photographs were taken using a Nikon Coolpix 4500 digital camera attached to a Leica MZ6 binocular microscope. Most specimens illustrated in this paper were photographed in the laboratory using a Canon EOS 350D digital camera attached to a Leica MZ75 binocular microscope.

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4. Results 4.1. Diversity and taxonomic composition of ANDEEP komokiaceans A feature common to all the species treated in this paper is the accumulation of stercomata within the test. A total of 41 species can be assigned to the Komokiacea. The majority of these (26) belong to the Komokiidae and include typical members of the genera Septuma, Komokia, Ipoa and Normaninia. The remaining Komokiidae comprise species of the closely related genera Lana and Reticulum (Figs. 1 and 2). The distinction between these two genera is unclear since it depends on the ‘mesh-size’ of the reticulated network of tubules that comprise the test. A sediment core filling the interstices between the tubule network is sometimes present. Thirteen species can be referred, with greater or lesser degrees of confidence, to the Baculellidae. As well as Arbor (Fig. 3A–D), Baculella and Edgertonia (Fig. 4A–D), we include here a species of Staphylion (Fig. 4H) and a chain-like species (Fig. 5G) in which tuberclelike processes give rise to tubular, very fine hair-like fibres. These filaments are very similar to those seen on other species of Baculellidae, notably Edgertonia floccula (Shires et al., 1994). A further two species belonging to a new genus which is described elsewhere (Gooday et al., in press) are regarded as Komokiacea incertae sedis. Following Gooday (1983, 1990), we group together a further 11 chain-like species with tests consisting of a series of rounded to elongate ‘segments’ separated by constrictions or necks. These are placed together for convenience and probably do not constitute a natural grouping. They include two main types. In the first type, the test is delicate, flexible with a finely agglutinated wall (Fig. 5A–D). The segments are sometimes elongate to a point where the test resembles a tube interrupted by constrictions. In Sp. 91 (delicate chain 2), globular or droplet-shaped chambers are linked by very delicate, flexible, tapered stolons (Fig. 5B). In the second type, the test is more rigid and comprises a sequence of chambers with either partially or completely agglutinated walls (Figs. 3F,G and 5E,F,H). The hair-like fibres present in the ‘large grey chain’ and some other species of the Baculellidae, are not clearly developed in any of these species, although flaccid, organic-walled tubular filaments often arise from tubercles on the sides of the chambers in some species. We do not consider

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any of these species to be komokiaceans. Those with more rigid, agglutinated walls and somewhat rounded chambers resemble the xenophyophore genus Aschemonella. Several other large, stercomata-bearing organisms with some komoki-like features were recognised in the ANDEEP samples (Fig. 6). In three of these, the test comprises a few, relatively wide branches arising from a central region and shows some resemblance to the genus Tuber Schro¨der, Medioli and Scott, 1989. In two species, the test is basically tubular and resembles the genus Clados Schro¨der, Medioli and Scott, 1989. Another species forms a flat, reticulated network of branches with a poorly defined, ‘fuzzy’ surface. The last species in this heterogeneous category is a ball-shaped structure composed of fairly large mineral grains bound together by an organic matrix forming transparent filaments that project from the surface of the ball (Fig. 2F).

4.2. Species richness and distribution in the Weddell Sea and SE Atlantic Of the 50 species recognised during this study, 39 occur in samples from the SO to the south of the Antarctic Convergence (Table 3). They were most abundant and diverse in the deepest part of the central Weddell Sea. A total of 30, 27 and 28 species were found at depths X4800 m (Stns. 88, 94, 102) where the species richness of Komokiidae, Baculellidae and chain-like taxa reached maximum values (Table 3). Diversity was lower at two other stations deeper than 4000 m; 17 species were present at Stn. 110 in the central Weddell Sea (4700 m), 11 at Stn. 59 to the south of the Maud Rise (4650 m), and 5 at Stn. 81 on the continental rise off Kapp Norvegica (4410 m). Stations located at depths below 4000 m yielded between 0 and 8 species. Only 2 species, Normanina conferta and S. brachyramosa, were encountered above 2000 m. S. brachyramosa was found only at sites on the continental margin, but N. conferta was the most widely distributed species, occurring at 12 stations south of the Antarctic convergence. Other widely distributed species included Reticulum sp. C, Septuma ocotillo, Septuma sp. nov. and ‘Edgertonia’ floccula (6 stations each). Many other species were confined to the central part of the Weddell Sea. No komokiaceans were observed during shipboard sorting at Stns. 74, 150, 151, 152 and 154 (Table 2).

The single stations sampled in the Cape Basin (Stn. 16, 4730 m) and Aguilas Basin (Stn. 21, 4550 m) yielded 9 and 6 species, respectively. In each case, only one of these species (S. brachyramosa at Stn. 16 and N. conferta at Stn. 21) was also present in the SO. 4.3. Wider distributions We have compared directly the ANDEEP species with those recognised during campaigns in the NE Atlantic, as well as records published by Schro¨der et al. (1989) from the Nares Abyssal Plain (Table 4). Of the 35 komokiaceans (Komokiidae and Baculellidae) that occur at stations south of the Antarctic Convergence, 25 are also known from the North Atlantic. A further 3 species occur in the SE Atlantic (Cape or the Aguilas Basin) and the North Atlantic. More than half (6) of the 11 chain-like species are also known from the North Atlantic. However, none of the other komokiacean-like species recognised in ANDEEP samples are known from the North Atlantic. Six of the species in the ANDEEP samples, Ipoa fragila, S. ocotillo, Baculella globofera, B. hirsuta and Edgertonia argillispherula, were described by Tendal and Hessler from the central North Pacific. These identifications are based on a comparison of our material with type specimens. 5. Discussion 5.1. Systematic position of the Komokiacea There have been several opinions concerning the taxonomic position of komokiaceans. The first species to be described, Halyphysema ( ¼ Normanina) conferta, was always been regarded as a foraminiferan (e.g. Cushman, 1948; Loeblich and Tappan, 1964, 1987). Tendal and Hessler (1977) placed the komoki in a new superfamily, the Komokiacea ( ¼ Komokioidea of Tappan and Loeblich, 1982) within the foraminiferan suborder Textulariina and recognised two constituent families, the Komokiidae and Baculellidae. However, in her classification of class Astrorhizata, Mikhalevich (1995) established a new family Normaninidae for the genera Septuma and Normanina in which the test interior is subdivided by septae perforated by foramina. She placed this family within the superfamily Schizamminoidae, at the same time attributing the families Komokiidae and Baculellidae to another superfamily of foraminifera, the

Table 3 Distribution of komokiacean and komokiacean-like species at ANDEEP III stations CB

AB

NM

MR

KN slope

Station

16

21

57

59

78

80

81

88

94

102

110

121

Water depth (m)

4730

4560

1820

4650

2100

3000

4400

4930

4890

4800

4700

2630

X X

X X

X X

X

X X

X X

X X

X X

PB

AI

133

142

153

1580

3400

2080

X X

X

X

X

X

X

X

X X

X X X X X

X

X

X X

X

X X

X X X

X

X

X X

X

X

X

X X

X

X X X

X

X

X X

X X X

X X X

X X

X X

X X

X X

X

X

X

X

X X

X X X

X

X

X

X

X X

X

X

X X X X X

X X X X

X X X

X X

X

X

1703

Baculellidae 213. Arbor multiplex 177. Arbor hispida 200. Arbor floccularis 155. Baculella globofera 52. Baculella hirsuta 193. Branched Baculella 191. ?Baculella sp.1 161. Edgertonia argillispherula 51. ‘Edgertonia’ floccula

X

APS

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Komokiidae 161. Ipoa fragila 163. Ipoa sp. nov. ?Ipoa sp. 169. Komokia multiramosa 49. Normanina conferta 282. Normanina sp. 15. Lana aff. neglecta 1 301. Lana aff. neglecta 2 50. Lana sp. 1 22. Lana sp. 2 216. Lana sp. A1 9. Lana sp. B 208. Lana sp. F 208a. Lana sp. F1 195. Lana sp. F2 259. Elongate Lana 207. Reticulum pingue 164. Reticulum sp. C 19. Reticulum sp. D 227. Reticulum sp. E Reticulum sp. G 181. ?Reticulum sp. H 94. Septuma ocotillo 79. Septuma brachyramosa 84. Septuma komokiformis 165. Septuma sp. nov.

WS Transect

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Area

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Table 3 (continued ) Area

CB

AB

NM

MR

KN slope

Station

16

21

57

59

78

80

81

88

94

102

110

121

Water depth (m)

4730

4560

1820

4650

2100

3000

4400

4930

4890

4800

4700

2630

X X X

X

X X X

X X

X X

X X

112. Edgertonia sp. 1 99. Staphylion sp. 100. Lobed mudball Large grey chain

X X

PB

AI

133

142

153

1580

3400

2080

X

X X X

X

X X

X

X

X X

X

X X

X

X

X X

X X

X

X

X

X

X X X

X X

X X X

CB ¼ Cape Basin; AB ¼ Anguillas Basin; NM ¼ off Neumayer; MR ¼ South of Maud Rise; KN ¼ Kapp Norvegia; WS ¼ Weddell Sea; APS ¼ Antarctic Peninsula slope; PB ¼ Powell Basin; AI ¼ slope off Anvers Island, Bellingshausen Sea. The taxa indicated as new are described by Gooday et al. (in press).

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X

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Komokiacean-like species Clados-like sp. A 17. Clados-like sp. B 205. Pale lobed mudball 179. Thick fluffy tubules 59. Branched tube, dense stercomata 2. Tuber-like branched cluster 226. Ball with filaments

APS

X

Komokiacea incertae sedis 180. Gen. nov. A & sp. nov. A 206. Gen. nov. A & sp. nov. B Chain-like taxa Delicate chains 91. Delicate chain sp. 2 Delicate chain sp. 3 16. Delicate chain sp. 4 209. Ragged chain Robust agglutinated chains Chain sp. 1 201. Chain sp. 3 47. Chain sp. 4 Chain sp. 5 203. Chain sp. 6 Other chains 105. Fuzzy chain 204. Coiled chain

WS Transect

Table 4 Distribution of komokiacean and komokiacean-like species in the Southern, Atlantic and Pacific Oceans SO

Water depth (m)

NE Atlantic

Pacific

CB

AB

NAP

MAP

9128

9129

GME

PAP

NWA

PSB

4730

4560

5775

4950

6059

5590

5432

4845

3053–4050

2040–4100

X

X

X

X

X

X

X

X

X

X

X Xb

Ka

X X X X

X X

X X X

X

X

X

X X

X X X X X X X X

X X

X X X X

X X

X X

X

X

X

X

X

X

X

X

X X

X X

X X

X

X

X X X X X X X X X X X

X

Ka X, Ka Kc

X

K X

X X X X

X X X X K&C

X X

X

X

X

X

X X

X

X X

X X

X

X

X

X

X

X X

X X

X X

X X

X X

X X

X

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X X

1705

Baculellidae 213. Arbor multiplex 177. Arbor hispida 200. Arbor floccularis 155. Baculella globofera 52. Baculella hirsuta 193. Branched Baculella 191. ?Baculella sp. 1 161. Edgertonia argillispherula 51. ‘Edgertonia’ floccula

X X X X X X

NW Atlantic

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Komokiidae 161. Ipoa fragila 163. Ipoa sp. nov. ?Ipoa sp. 169. Komokia multiramosa 49. Normanina conferta 282. Normanina sp. 15. Lana aff. neglecta 1 301. Lana aff. neglecta 2 50. Lana sp. 1 22. Lana sp. 2 216. Lana sp. A1 9. Lana sp. B 208. Lana sp. F 208a. Lana sp. F1 195. Lana sp. F2 259. Elongate Lana 207. Reticulum pingue 164. Reticulum sp. C 19. Reticulum sp. D 227. Reticulum sp. E Reticulum sp. G 181. ?Reticulum sp. H 94. Septuma ocotillo 79. Septuma brachyramosa 84. Septuma komokiformis 165. Septuma sp. nov.

SE Atlantic

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Table 4 (continued ) SO

Water depth (m) 112. Edgertonia sp. 1 99. Staphylion sp. 100. Lobed mudball Large chain

Komokiacean-like species Clados-like chain A 17. Clados-like chain B 205. Pale lobed mudball 179. Thick fluffy tubules 59. Small, branched, complete 2. Tuber-like branched cluster 226. Ball with filaments

NE Atlantic

Pacific

CB

AB

NAP

MAP

9128

9129

GME

PAP

NWA

PSB

4730

4560

5775

4950

6059

5590

5432

4845

3053–4050

2040–4100

X X X

X

X

X

X X X X

X

X X

X X

X X

X X

X X X

X X

X

X

X X X

X

X X X X X X

X

X X X

SO ¼ Southern Ocean. CB ¼ Cape Basin, records from Kamenskaya (1993a, b) indicated by ‘K’. AB ¼ Aguilas Basin; NAP ¼ Nares Abyssal Plain (from Schro¨der et al., 1988 – a record of Kuhnt & Collins from the nearby NW Sargasso Sea is indicated as K&C); MAP ¼ Madeira Abyssal Plain; GME ¼ Great Meteor East area; PAP ¼ Porcupine Abyssal Plain; NWA ¼ NW African margin; PSB ¼ Porcupine Seabight. Pacific records are from Tendal and Hessler (1977) and Kamenskaya (2006). a The Cape Basin records of Kamenskaya (1993a, b) are from depths around 4915 m (4920 m for Ipoa fragila, 4912 m for Septuma ocotillo and 4910 m for S. brachyramosa). b As Normanina tyloda. c Septuma komokiformis also occurs in the Angola basin (water depth 1758–4770 m) (Kamenskaya, 1993a, b).

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Chain-like taxa Delicate chains 91. Delicate chain sp. 2 Delicate chain sp. 3 16. Delicate chain sp. 4 209. Ragged chain Robust chains Chain sp. 1 201 Chain sp. 3 47. Chain sp. 4 Chain sp. 5 203. Chain sp. 6 Other chains 204. Coiled chain 105. Fuzzy chain

NW Atlantic

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Komokiacea incertae sedis 180. Gen. nov. A & sp. nov. A 206. Gen. nov. A & sp. nov. B

SE Atlantic

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Dendrophryoidea. Kaminski (2004) also recognised the family Normaninidae. This arrangement implies that the komoki are polyphyletic. Other authors have either ignored the Komokiacea (Saidova, 1981) or considered it as a separate taxon, close to the foraminifera (Kamenskaya, 1993b, 2000). Recent efforts to analyse DNA gene sequences from komokiaceans have provided some support for this position (Lecroq et al., 2006). However, until this result can be replicated in other species, it seems best to adopt a conservative approach and retain these puzzling organisms within the foraminifera. 5.2. Limits of the Komokiacea The uncertain taxonomic position of the Komokiacea is matched by difficulties in defining the limits of the group. Tendal and Hessler (1977) provide the following diagnosis of the superfamily: ‘Test consists of complex system of fine, branching tubules of even diameter. Test wall simple; agglutinated particles argillaceaous. Stercomata (faecal pellets) accumulate within tubules’. This definition embraces a group of ‘core’ komokiaceans that includes the genera described by Tendal and Hessler (Edgertonia, Ipoa, Komokia, Lana, Normanina, Septuma, Baculella) as well as Cerebrum Schro¨der, Medioli and Scott, 1989, Reticulum Schro¨der, Medioli and Scott, 1989 and the attached genus Chrondrodapis Mullineaux, 1988 (Lee et al., 2002). For reasons discussed below, we follow Schro¨der et al. (1989) in including Arbor Schro¨der, Medioli and Scott, 1989 in the Komokiacea. However, we exclude several genera that have been placed here by various authors (Kaminski, 2004, p. 243, therein). Catena Schro¨der, Medioli and Scott, 1989 is a flexible, chain-like species with a transparent (presumably organic) test containing stercomata. However, the fine, hair-like fibres of the kind found in some other chain-like species, which we believe to be komokiaceans (see below) are not described. Globopelorhiza Cedhagen and Mattson, 1991 is a ‘mudwalled astrorhiziid’ of the kind illustrated by Gooday (1983, 1990). This genus lacks stercomata and forms a mudball test occupied by randomly winding, anastomosing strings of protoplasm which extend into branches arising from the surface of the test (Cedhagen and Mattson, 1991). These branches are much wider than typical komokiacean tubules. One of us has drawn attention previously to features of the large, tubular foraminiferan Rhizammina algaeformis Brady, 1879, particularly the

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wall structure and accumulations of stercomata, which suggest an affinity with the komokiacean family Komokiidae (Gooday and Cartwright, 1987; Cartwright et al., 1989). Based on these observations, Kaminski (2004) transferred the Family Rhizamminidae, including the genera Rhizammina and Testulorhiza Avnimelech, 1952, to the Komokiacea. However, Rhizammina globigeriniforme Hofker 1930, the type species of Testulorhiza, lacks stercomata (Gooday, unpublished observation) and probably does not belong in this group. The transfer of R. algaeformis in the Komokiacea has a stronger basis but would involve an extension of the diagnosis to include this large species in which the test consists of a sparsely branching tube, a few hundred microns in diameter. Schro¨der et al. (1989) described two monotypic genera, Crambis and Staphylion, which they regard as being of uncertain affinity (incertae sedis). As discussed in the taxonomic appendix, we regard Staphylion as a likely komokiacean. Crambis conclavata Schro¨der, Medioli and Scott, 1989 is not present in the ANDEEP III samples but is common at Stn. 9129 in the NE Atlantic. It was included without comment in the Komokiacea by Kuhnt and Collins (1995). Schro¨der et al. (1989) noted that the internal structures are obscured but believed they could see ‘stercomata which appeared to be aligned with dark lines’ within the test. In the Atlantic material, the test is composed largely of fine sediment. Delicate, dark grey tubules are evident when the sediment mass is carefully broken up. There appears to be a central tubule which gives rise to irregular side branches, although these structures disintegrate when attempts are made to excavate them. Small mounds with dark centres, visible on the surfaces of many specimens, may be the surface expression of these tubules. The tufts of fine filaments that arise from the ends of some branches include wider tubules, which are probably equivalent to those seen within the test structure. Further study is required in order to establish whether this curious organism is a komokiacean. The diverse array of stercomata-bearing foraminifera in the ANDEEP material further demonstrates the problems involved in defining the Komokiacea. The chain-like forms include species of Arbor, which possess hair-like tubular filaments. Similar structures are reported in some other organic-walled, chain-like species (Gooday 1983, 1990); one such species (‘large grey chain’) was found in an ANDEEP sample from Stn. 21

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(Fig. 5G). Because the filaments are identical to those described by Shires et al. (1994) in ‘Edgertonia’ floccula, and probably correspond to the ‘very fine fibres between which sediment is trapped’ in Baculella hirsuta Tendal and Hessler (1977, p. 188 therein), we interpret these fibre-bearing species as komokiaceans. Others chain-like forms, however, are almost certainly not related to the Komokiacea. These include the delicate chains with elongate finely agglutinated segments (Fig. 5A–D) and the more robust, rather coarsely ‘agglutinated chains’ (sensu Gooday, 1990) (Figs. 3F,G and 5E,F,H). Another problematic group comprises species with a few short, finger-like tubules packed with stercomata. Three species of this type, ‘branched test with dense stercomata’ (Sp. 59), ‘pale lobed mudball’ (Sp. 205) and ‘Tuber-like species’ (Sp. 2), are included in the present survey (Fig. 6B–D). Their general appearance is rather komoki-like, but they lack a ‘fine tubule of even diameter’ considered by Tendal and Hessler (1977, p. 171) to be a ‘basic element in the morphology of komoki’. 5.3. Taxonomic problems within the Komokiacea The Komokiacea present further challenges at the species level. Within the Lana/Reticulum group, numerous different types can be recognised, based on small differences in the width of the tubules and the frequency of branching (Gooday and Cook, 1984). Tendal and Hessler (1977) remark that their diagnosis of Lana ‘covers an exceedingly large number of species’. Specimens are often fragmentary, making the overall shape of the test impossible to determine. It is often very difficult to discriminate between different forms and to recognise them consistently in different samples. Species that form mudball structures are also problematic since the arrangement of tubules within the mudball cannot be easily determined. Undescribed mudball species are particularly common in the North Atlantic (Gooday, 1990) but less important in ANDEEP material, where they are represented mainly by certain well-known species such as ‘E.’ floccula. Some komokiacean species exhibit a considerable degree of intraspecific variability. This is particularly apparent in S. ocotillo, where two test types can be distinguished in ANDEEP samples: (1) those with with relatively compact, bushy tests composed of fairly broad tubules having fairly thick, semiopaque walls and length:width ratios generally o15, and (2) ‘spidery’ test consisting of tubules

with long branching intervals and thinner, often semi-transparent walls and length:width ratio often 420 (Gooday et al., in press). N. conferta exhibits considerable variation in the number of tubules with terminal swellings. These number p10 in some individuals; in others from the same sample, they are more numerous. Such differences could lead to the establishment of spurious species. In the case of S. ocotillo and N. conferta, the ANDEEP samples yielded enough specimens for the intraspecific nature of the variation to be apparent (Gooday et al., in press). 5.4. Species distributions Tendal (1985) commented that there were clear differences at both the species and generic levels in komokiaceans from ‘slope and near slope’ sites in the Bay of Biscay and those from the central North Pacific gyre. Gooday (1990) distinguished between a ‘slope assemblage’ and an ‘abyssal assemblage’ of komokiaceans in the NE Atlantic; the former comprising large mudballs and Lana/Reticulum morphotypes, the latter small delicate taxa such as Ipoa, Komokia, Septuma and Normanina. A rather similar distinction is evident in the Weddell Sea. Mudballs are not as prevalent as on NE Atlantic margins, but the slope stations yield more robust species of Septuma (S. brachyramosa, S. komokiformis) and some Reticulum and Lana species, whereas the central Weddell Sea Abyssal Plain is occupied by delicate species such as S. ocotillo, N. conferta, I. fragila and Ipoa sp. nov. Komokiaceans are also more diverse on the abyssal plain than they are on the continental margin of the Weddell Sea. The ANDEEP data, although largely qualitative, are consistent with earlier evidence that komokiaceans and other stercomata-accumulating foraminifera are a dominant faunal group in oligotrophic, central oceanic settings (Hessler, 1974; Tendal and Hessler, 1977; Gooday et al., 1997, in press; Wollenburg and Mackensen, 1998). Knowledge about the geographical ranges of species is important for understanding the relationship between local and regional diversity and global-scale patterns in biodiversity. Wide distributions are common amongst deep-sea foraminifera, including hard-shelled (Murray, 1991), agglutinated (Schro¨der et al., 1988) and soft-shelled (Gooday et al., 2004) species. Komokiaceans seem to conform to the same pattern. Our comparison of komokiaceans in the deep Weddell Sea and the North Atlantic suggests

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the existence of strong parallels between assemblages in these two regions. An important caveat is that it is often difficult to be sure that one is dealing with the same morphospecies, particularly in the case of relatively featureless taxa such as Lana. Except in the case of the Nares Abyssal Plain, where we have relied on illustrations and descriptions in Schro¨der et al. (1989), all records of ANDEEP species in North Atlantic samples are based on the direct comparison of specimens placed side-by-side in the same Petri dish. This suggests that 22 of the 40 species found in samples from south of the Antarctic convergence, and 4 of the 11 species recorded from the Cape and Aguilas basins, also occur in the NE or NW Atlantic. Based on a similar direct comparison with the holotypes, we conclude that at least seven of the 11 species described by Tendal and Hessler (1977) from the central North Pacific occur in the ANDEEP samples. Species such as B. globofera, E. argillispherula, I. fragila, S. ocotillo, and N. conferta may constitute widely distributed ‘core species’ of the kind familiar in other deep-sea taxa (Glover et al., 2002; Gage, 2004). Although the relationship between dispersal ability and range is not always straightforward (Gaston, 2003), marine animals that are easily dispersed tend to have large geographic ranges (Young et al., 1997; Gage 2004). In the case of foraminifera, wide species distributions are probably facilitated by the long-distance transport of microbe-sized propogules by currents (Alve and Goldstein, 2003). In contrast, Mikhalevich (2004) emphasised the high degree of endemism amongst foraminifera on the Antarctic shelf (up to 80% at depths from 2 to 50 m) and, to a lesser extent, at bathyal depths. Some abyssal komokiacean species, for example, the new species of Ipoa and Septuma described by Gooday et al. (in press), have only been found in ANDEEP SO samples. The problem of undersampling, however, makes it very difficult to establish whether these species have limited geographical ranges. It is important not to over-interpret apparent absences, and therefore we do not claim that such species are endemic to the SO. However, there are some apparent differences between assemblages in the different Hemispheres. Komokiacean and other mudball species seem to be much less common in the deep Weddell Sea than in NE Atlantic. Shires (1995) distinguished between 21 morphologically distinct, undescribed types of mudballs from the Porcupine and Madeira Abyssal

1709

Plains; many, although not all of these were komokiaceans. In addition, Shires et al. (1994) described a new mudball species, ‘E.’ floccula, as being very common and widespread in the NE Atlantic. Of these species, only ‘E.’ floccula occurs in ANDEEP samples and it is much less common than in the North Atlantic. 5.5. How many komokiaceans species exist In their introduction to the Komokiacea, Tendal and Hessler (1977, p. 166 therein) write that ‘single samples contain dozens of species and we suspect that the total number of species in just our few hadal, abyssal and bathyal samples may be in the hundreds.’ They also recognized that ‘there will be many important morphologies that will need future treatment’. Tendal (1985) estimated there to be at least 30 species, most of them undescribed, in his BIOGAS material from the Bay of Biscay. There are numerous undescribed komokiaceans, many belonging to the difficult Lana/Reticulum group, in NE Atlantic samples collected by the Institute of Oceanographic Sciences in the 1970s and 1980s (e.g. Gooday and Cook, 1984; Gooday, 1990). For example, Shires (1995) recognised 61 species, only 13 of which were assigned to described species, in her survey of komokiaceans from the Porcupine Abyssal Plain; these included 15 undescribed species assigned to Lana. She also distinguished 29 species of chain-like foraminifera, which may include some komokiaceans. Schro¨der et al. (1989) described one important morphotype consisting of chain-like species not treated by Tendal and Hessler, under the generic name Arbor. The existence of many additional genera and species of komokiaceans is suggested by recent analyses of small sediment samples from the abyssal Equatorial Pacific which have yielded numerous remains, many of them fragmentary, of novel komokiaceans (Nozawa et al., 2006). The ANDEEP SO samples support the impression from other oceans that numerous undescribed komokiacean species exist. The survey presented here is not exhaustive and is based on samples sorted onboard ship during the ANDEEP III campaign. In many samples, a residue of komokiaceans, consisting of specimens and fragments that could not be easily assigned to species, remained after the obvious species had been removed. These undoubtedly include additional species. The scale of komokiacean diversity is difficult to assess and

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presently we cannot improve on Tendal and Hessler (1977) estimate of ‘hundreds’. However, it is becoming clear that some morphospecies are widely distributed and thus the level of global komokiacean diversity is probably lower than their diversity in single sample would suggest. 5.6. Ecological significance In a review of the trophic biology of deep-sea foraminifera, Gooday et al. (in press) suggest that stercomata-bearing taxa subsist largely on fine sediment particles and associated organic material, including bacteria (see also Nozawa et al., 2006). It is likely that they have lower metabolic rates than, for example, the predominately calcareous herbivorous (‘bloom-feeding’) foraminiferal species that exploit labile organic matter deposits such as phytodetritus. Although they probably process organic carbon at a slower rate than the herbivores, the great abundance of komokiaceans and similar forms over vast areas of the ocean floor implies that they are important in carbon cycling on a global scale. We conclude from our study of the ANDEEP samples, particularly those from the central Weddell Sea, that the ecological role of these remarkable protists may be as great in the abyssal SO as it is elsewhere in the deep ocean. Acknowlegements We thank Prof. Angelika Brandt for inviting three of us (A.J.G., N.C., T.C.) to participate in the ANDEEP III expedition and making available material from the epibenthic sledge and Agassiz trawl, Dr. Eberhard Fahrbach for his efficient running of the R.V. Polarstern ANT XXII/3 cruise and the Captain, officers and crew of the R.V. Polarstern for their help during the cruise. Other cruise participants, notably Simone Branda˜o, Stacey Doner, Drs. Bhavani Narayanaswamy and Marina Malyutina kindly donated the komokiaceans from their samples. The paper was improved by comments from David Scott and an anonymous reviewer. Dr. Ole S. Tendal generously made available komokiacean type material housed in the collections of the Zoological Museum, Copenhagen. Mrs. Kate Davis provided valuable help with the figures. The work of O.E.K., including two visits to Southampton, was funded by a grant from the Census of Abyssal Marine Life (CeDAMar) and by the Swiss National Science Foundation SCOPES

Program (Grant no. IB73A0-111064 to Dr. Jan Pawlowski). T.C. was supported by the Danish Research Agency (Project no. 9509 1435). Taxonomic appendix Species numbers are those assigned during shipboard sorting. Species without numbers were recognised later during examination of material at the National Oceanography Centre, Southampton. (A) Superfamily Komokiacea Tendal and Hessler, 1977 Family Komokiidae Tendal and Hessler, 1977 Sp. 161. Ipoa fragila Tendal and Hessler, 1977 Tendal and Hessler (1977, p. 181, Pl. 9, fig. D; Pl. 11, figs. C–D). A distinctive species first described by Tendal and Hessler (1977) from the central North Pacific. ANDEEP specimens are identified by direct comparison with type specimen (Gooday et al., in press). Ipoa fragila is also reported by Schro¨der et al. (1989) from the Nares Abyssal Plain and by Kamenskaya (1993a, b) from the Cape and Angola basins. Sp. 163. Ipoa sp. nov. A species in which the narrower peripheral branches follow a more or less crooked course and give rise to short side branches, which are either basically tubular or, less commonly, bead-like in shape. Described by Gooday et al. (in press). ?Ipoa sp. Four small specimens from Stn. 142 that form distinctive clusters of branching tubules. They resemble some of the tiny, delicate, branched komokiacean morphotypes illustrated by Kuhnt and Collins (1995, particularly morphotype 3, Pl. 5, figs. 6–8, 12). Sp. 169. Komokia multiramosa Tendal and Hessler, 1977 Tendal and Hessler (1977, p. 179, Pl. 9, fig. A–B; Pl. 11, figs. A–B; Pl. 19, fig. F; text-fig. 3). Described by Tendal and Hessler (1977) from the central North Pacific and reported by Gooday (1990) from the NE Atlantic. ANDEEP specimens

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are identified by direct comparison with the type specimen (Gooday et al., in press). Sp. 15. Lana aff neglecta 1. Fig. 1D Dark grey mass of parallel-sided tubules forming a loose, open meshwork without a sediment filling. The tubules are 25–45 mm in diameter. This species is possibly conspecific with Lana neglecta. Unfortunately, the type specimen of L. neglecta is very poorly preserved and seems to have dried out at some point in its history. A direct comparison was therefore not very informative. However, the tubules in L. neglecta are narrower (20–25 mm diameter according to Tendal and Hessler (1977)) than in the ANDEEP species and we therefore avoid a firm identification. Sp. 301. Lana aff neglecta 2. Fig. 1E Similar to sp. 15, but light tan in colour with slightly narrower tubules (25–37 mm), which have a rather shorter branching interval and form a tighter meshwork.

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the figured specimen have closed, rounded ends, suggesting that it is fairly intact. Sp. 9. Lana. B The specimens have been lost, but shipboard photographs show rather irregular clumps of fine anatomising tubules which are distinct from Lana F, F1 and F2. Sp. 208. Lana F Fig. 1A Small clumps up to 1.5 mm wide, consisting of a fairly tight meshwork of tubules which are 60–100 mm diameter. Wall light tan in colour, finely agglutinated and rather thick with a slightly fuzzy surface. Sp. 208a. Lana F1. Fig. 1B Species represented by small fragments consisting of branching tubules, 50–65 mm diameter. Wall finely agglutinated and light tan in colour. In larger pieces, the tubules form reticulations with a mesh size varying widely from 120 to 750 mm.

Sp. 50. Lana sp. 1. Fig. 1G Mass of tubules, 35–65 mm diameter, protruding from an elongate sediment core that incorporates large globigerinacean shells.

Sp. 195. Lana F2. Fig. 1C This species is also represented by small fragments comprising branching tubules but the tubules are distinctly narrower (30–45 mm diameter) than in Lana F1. They sometimes form reticulations with a mesh size varying from 150 to 400 mm.

Sp. 22. Lana sp. 2. Tubule fragments, up to 2 mm long, and 130–175 mm wide. Tubule walls are fairly thick and loosely agglutinated with a rather uneven surface and protruding quartz grains and sponge spicules. One fragment has a central tubule with alternating side branches; in others, branching is dichotomous.

Sp. 259. Elongate Lana. Fig. 2D Distinctive, elongate structures composed of fine sediment incorporating delicate, fragile, thin-walled tubules, 25–32 mm diameter.

Sp. 216. Lana A1 Fig. 1F Test light tan in colour, forming flattened clumps several millimetres in diameter, each consisting of a fairly tightly reticulated meshwork of narrow tubules, 25–30 mm in diameter. Size of openings in meshwork similar to that seen in holotype of Lana reticulata Tendal and Hessler, 1977, the type species of the genus Reticulum. However, the tubules in R. reticulata are wider (30–50 mm) than in the ANDEEP species. Many of the peripheral branches of

Sp. 207. Reticulum pingue Schro¨der, Medioli and Scott, 1989 Reticulum pingue Schro¨der, Medioli and Scott (1989, p. 31, Pl. 2, fig. 4; text-fig. 10). Fig. 2E The ANDEEP specimens exhibit the characteristic elongate ‘caterpillar-like’ morphology described by Schro¨der et al. (1989) in NW Atlantic specimens. Sp. 164. Reticulum sp. C Fig. 2A

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Test up to 3 mm or more in diameter, ball-shaped with a low, bluntly pointed conical projection. It is composed of tightly reticulated tubules, 30–40 mm diameter, exposed only on the test exterior where they are pressed fairly tightly onto surface. Ends of tubules closed and rounded. Interstices usually occupied by fine sediment to form a mudball but a few specimens are devoid of an obvious infilling. This species closely resembles Lana sp. 1 of Gooday (1990, Pl. 1, fig. F). Sp. 19. Reticulum sp. D Fig. 2B Test up to 2.5 mm diameter, rounded to oval and composed of tightly reticulated tubules without sediment filling the interstices. Ends of tubules project for short distance beyond periphery, giving the test a rather fuzzy appearance. Sp. 227. Reticulum sp. E Fig. 2C Test similar to Reticulum C, but generally smaller (0.8–1.5 mm diameter) and round to oval without a conical projection. Reticulum sp. G A delicate species consisting of a small, tightly reticulated ball of fine tubules. Sp. 181. ?Reticulum sp. H Fig. 2G Rounded to oval mudball, ranging in size from 750 to 150 mm. Narrow, rather twisted tubules project for a short distance across the entire surface, resulting in ‘hairy’ appearance. Mudball obscures branching pattern and arrangement of tubules. Sp. 79. Septuma brachyramosa Kamenskaya 1993 Septuma brachyramosa Kamenskaya 1993, p. 78, fig. 3. Fairly compact, bush-like test, composed of relatively short tubules. It was first described from the Cape Basin (Kamenskaya, 1993a, b) and later reported from hadal trenches in the Pacific Ocean (Kamenskaya, 2006). Septuma sp. of Gooday (1990) from the Madeira and Porcupine Abyssal Plains, NE Atlantic, represents the same species. ANDEEP specimens are described by Gooday et al. (in press). Sp. 84. Septuma komokiformis Kamenskaya 1993 Septuma komokiformis Kamenskaya 1993, pp. 78, 79, fig. 4.

This species has relatively longer and more crooked tubules than S. brachyramosa, although the number of tubules and the degree of ‘bushiness’ varies. Many tubules terminate in fairly long, unbranched sections. Reported from the flanks of the Valdivia Seamount (1758 m) and the Angola Basin (2370–4770 m) (Kamenskaya, 1993a, b). The ANDEEP material is described by Gooday et al. (in press). Sp. 94. Septuma ocotillo Tendal and Hessler, 1977 Septuma ocotillo Tendal and Hessler, 1977, p. 180, text-fig. 4; Pl. 9, fig. C Pl. 10, figs. A–B; Pl. 12, figs. A–B; Pl. 19, fig. A; Pl. 20, fig. A–F; Pl. 21, fig. A–D. ANDEEP specimens are identified by direct comparison with the type specimen (Gooday et al., in press). The bush-like test consists of tubules of essentially even diameter, which usually radiate out from the central region. This species was first described by Tendal and Hessler (1977) from the central North Pacific. It is reported the Nares Abyssal Plain (Schro¨der et al., 1989), the Barents Sea (Kamenskaya, 1996), the Cape Basin (Kamenskaya, 1993a, b) and from hadal trenches in the Pacific Ocean (Kamenskaya, 2006). Sp. 165. Septuma sp. nov. A small species with tubules radiating out from central region, which is usually obscured by sediment. Most tubules are characterized by bead- or knob-like lateral swellings and protuberances, sometimes extending into short side-branches. A number of longer tubules extend for variable distance beyond the main tubules. Described by Gooday et al. (in press). Sp. 49. Normanina conferta (Norman, 1878) ¼ Normanina tylota Tendal and Hessler, 1977 Gooday et al. (in press) compared the type specimens of Haliphysema ( ¼ Normanina) conferta and N. tyloda and judged them to be conspecific. The ANDEEP specimens are similar to these types, except for their more delicate construction and an absence of sediment in the central part of the test. N. conferta is also reported by Schro¨der et al. (1989) from the Nares Abyssal Plain, by Gooday (1994) and Shires (1995) from the Porcupine Abyssal Plain, and by Kamenskaya (2006) from hadal trenches in the Pacific Ocean.

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Sp. 282. Normanina sp. A single individual from Stn. 142 has distinctly thicker tubules than other specimens of Normanina in our ANDEEP III material. Illustrated by Gooday et al. (in press).

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Baculella globofera Tendal and Hessler (1977, pp. 187, 188, Pl. 15, figs. A and B; Pl. 16, fig. A; Pl. 19, fig. D; Pl. 24, figs. A and B). The ANDEEP specimens are very similar to those described by Tendal and Hessler. This species is uncommon in our material.

(B) Family Baculellidae Sp. 213. Arbor multiplex Schro¨der, Medioli and Scott, 1989. Schro¨der et al. (1989, pp. 36–38, Pl. 3, figs. 1–4; Pl. 9, fig. 2; text-fig. 16). Figs. 3A and B The specimens illustrated in Figs. 3A–B show the complex structure of the test most clearly; other examples in the ANDEEP material have a mudballlike morphology. Schroder et al.’s illustrations show elongate morphotypes but their description mentions that the test can curve in on itself and accumulate sediment to form a mudball. Sp. 177. Arbor hispida Schro¨der, Medioli and Scott, 1989 Arbor hispida Schro¨der, Medioli and Scott (1989 p. 36, Pl. 4, figs. 1–2; text-fig. 15). Fig. 3C The early segments are globular but later ones are dominated by large conical tubercles. Occasionally, these give rise to short tubular extensions, but hairlike fibres are not developed. The wall is finely agglutinated and the tiny grains are visible individually under a dissecting microscope. The test is often twisted, but a sediment infilling is never present. This species was illustrated as a ‘tectinous chain’ by Gooday (1990, Pl. 3, fig. D) from the Madeira Abyssal Plain. Sp. 200. Arbor floccularis Schro¨der, Medioli and Scott, 1989 Arbor floccularis Schro¨der, Medioli and Scott (1989 p. 36, Pl. 4, figs. 3–4). Fig. 3D A smaller and more delicate species than A. hispida. The segments are rounded with conical to finger-like tubercles, which are smaller and more numerous than in A. hispida. Some tubercles produced into tubular organic-walled extensions, which in a few cases are fairly long. Sp. 155. Baculella globofera Tendal and Hessler, 1977

Sp. 52. Baculella hirsuta Tendal and Hessler, 1977 Baculella hirsuta Tendal and Hessler 1977 (pp. 188–190, Pl. 14, figs. E and F; Pl. 19, fig. E; Pl. 24, fig. C; Pl. 25, Fig. A; Pl. 26, fig. A; text-fig. 9). Several specimens from Stn. 21 have tightly packed, bead-like side branches and taper from a broader end with a cover of fine sediment to a narrower end. Apart from being rather narrower with more clearly visible side branches, they resemble the holotype of B. hirsuta with which they have been compared directly. Sp. 193. Branched Baculella Fig. 4A and B This species resembles B. hirsuta in having numerous bead-like side branches but is dichotomously branched. Sp. 191. ?Baculella sp. 1 Fig. 4F A small, elongate species with short, irregular tubules arising from an axial region. There appears to be no distinct axial tubule, making a placement in Baculella uncertain. Sp. 161. Edgertonia argillispherula Tendal and Hessler, 1977 Fig. 4D Edgertonia argillispherula Tendal and Hessler (1977, pp. 190–192; Pl. 9, Fig. F; Pl. 18, figs. A and B; Pl. 25, fig. B; Pl. 26, fig. D). The ANDEEP specimens form a mudball-like structure and are similar to the type specimen. Very long, thin-walled tubules extending out from the test surface are highly developed in some cases. Sp. 51. ‘Edgertonia’ floccula Shires, Gooday and Jones, 1994 The ANDEEP specimens are identical to those described by Shires et al. (1994) from the NorthEast Atlantic. The lack of distinct tubules and the presence of very fine fibres suggests an affinity with Staphylion rather than with Edgertonia.

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Sp. 112. Edgertonia sp. 1 Fig. 4C Small, possibly fragmentary pieces consisting of small, spherical chambers, 50–100 mm diameter, arising from branching tubules. The chambers and tubules resemble those of Edgertonia tolerans Tendal and Hessler, 1977 (based on direct comparison with holotype), although this species forms a much larger ball-like structure, for which there is no evidence in our samples. The chambers are also similar to the ‘difflugiform bodies’, 100 mm in diameter, described by Schro¨der et al. (1989) in Staphylion compactum Schro¨der, Medioli and Scott, 1989. However, as in the case of E. tolerans, these bodies form part of a much larger spherical structure. Sp. 99. Staphylion sp. 1 Fig. 4H The ANDEEP specimens resemble the type species, S. compactum Schro¨der, Medioli and Scott, 1989 in having droplet-shaped, chamber-like structures (‘difflugiform bodies’) which ‘float’ in the flocculent surface layer of the spherical, mudball test. However, these structures are rather larger than those of the type species (125–150 mm compared to 100 mm in S. compacta). In some cases, they form large aggregations, which are not associated with a mudball. Schro¨der et al. (1989) regarded Staphylion as a taxon ‘whose affinities with the Foraminiferida are still questionable.’ We place it within the Komokiacea based on the presence of very fine, twisted, hair-like fibres, which entangle the ‘chambers’ and provide coherence to the aggregations. As indicated above, similar fibres are present in ‘Edgertonia’ floccula. Sp. 100. Lobed mudball Small mudballs, up to 1.5 mm long, with elongate, sometimes slightly lobed shape and internal layering that causes the structure to break along curved surfaces. Surface smooth, but giving rise to a few flaccid, thin-walled tubules. Large grey chain Fig. 5G Chain-like species consisting of elongate, approximately triangular chambers, usually with several conical tubules developed at the wider end. The tubercles give rise to very fine, hair-like fibres similar to those seen in ‘E.’ floccula and Staphylion. The

wall is more or less transparent and predominantly organic with a sprinkling of very fine surface particles. The interior is occupied by dark stercomata. The ANDEEP specimen is similar to the ‘tectinous chain from Sta. 8521’, illustrated by Gooday (1983, fig. 7), except that the tubules are more prominent. We believe that fibre-bearing chains of this type are probable komokiaceans. (C) Komokiacea incertae sedis Sp. 180. Gen. nov. A & sp. nov. A The test comprises a series of relatively wide, stiff, crooked tubular processes, up to 140 mm wide, which arise from either side of a longitudinal axis and increase in length from the proximal to the distal end. Described by Gooday et al. (in press). Sp. 206 Gen nov A & sp. nov. B Fig. 4E Larger specimens (1.0–1.1 mm) resemble species A in having tubular processes (75–100 mm wide) extending to both sides of the longitudinal axis. In smaller specimens, they tend to radiate from a central area. The wall is fairly thick and composed of finer-grained material than species A. (D) Chain-like taxa (D.1) Delicate chains Sp. 91. Delicate chain 2 Fig. 5B The test consists of a chain of globular to dropletshaped ‘chambers’ (segments) linked by delicate necks that taper towards the next chamber. The segments are sometimes attached to, or incorporate, large mineral grains. This is probably the same as the delicate, chain-like species from the Madeira Abyssal Plain illustrated by Gooday (1994, Fig. 2a). It superficially resembles some members of the Hormosinacea, particularly Subreophax distans, but is distinguished by the flexible test which is filled with stercomata rather than cytoplasm. Delicate chain 3 Fig. 5D The test is delicate and flexible. It is divided into rather inflated, approximately subtriangular to

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droplet-shaped segments, 250–600 mm long and 150–175 mm wide, separated by narrow constrictions or necks. Some segments have one or more conical processes extending into short, translucent, organicwalled filaments. Sp. 16. Delicate chain 4 Fig. 5A The test is delicate and flexible. It is divided into elongate segments, 0.5–1.2 mm long and 0.12–0.18 mm wide, each increasing gradually in width from the proximal to the distal end. Each segment bears 1–2 short, conical processes that often extend into short, translucent, organic-walled filaments. The wall is finely agglutinated, light tan in colour. Test interior with stercomata. Sp. 209. Ragged chain Fig. 5C The test is delicate and flexible, basically tubular but divided by relatively weak constrictions into rather poorly defined segments. Individual segments are elongate, subcylindrical to subtriangular in shape, often with short, conical tubercles, some of which are produced into organic-walled filaments. The wall is tan in colour, fine-grained with occasional larger mineral grains. Test interior with stercomata. (C.2) More robust ‘agglutinated chains’ (sensu Gooday 1990) Chain sp. 1 Fig. 5H The test consists of a fairly rigid chain of dropletshaped to subtriangular chambers which often incorporate conical elements and are joined by narrow necks. The conical parts are sometimes produced into short, flaccid, organic extensions, but fine, hair-like fibres are not developed. The test interior is filled with brownish stercomata. The shape of the test in this species closely resembles the illustration of Catena pyriformis Schro¨der, Medioli and Scott, 1989 given by Schro¨der et al. (1989) but it is clearly agglutinated rather than transparent and presumably organic. Sp. 201. Chain 3 Fig. 5F Fairly flexible chain composed of variably shaped segments, 350–650 mm long, generally subtriangular

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to droplet-shaped and joined by narrow necks. Most have a short conical process, which is sometimes produced into a delicate, thin-walled, organic extension. The wall is light brownish, composed of small (20–25 mm) quartz grains and scattered larger grains set in a fine-grained matrix. Sp. 47. Chain 4 Fig. 5E A large, fairly robust, dichotomously branching chain (the single specimen, coiled after being confined in a vial, is 7 mm from side to side) consisting of a series of approximately globular to oval segments, 0.75–1.1 mm diameter, separated by constrictions or short necks. The unbroken ends of the terminal segments are drawn out into delicate, tubular organic extensions, but the segments lack the tubercles found in other chain-like species. The wall incorporates large particles, a mixture of mineral grains, globigerinacean shells and shell fragments, set in a fine-grained matrix. Dark contents are visible through the test wall, particularly where quartz grains create a transparent window. Chain 5 Fig. 3F A complete individual, 3.5 mm long, forms a fairly rigid, dichotomously branching chain of segments, each of which is 0.3–0.5 mm long and generally subtriangular to droplet shaped. Segments located at the ends of branches terminate in short necks, but tubercle-like processes are not developed on any segments. The wall is fairly coarse grained, consisting of smaller quartz grains and larger particles, which project to give the surface a rough finish. This specimen is strikingly similar to the one that Brady (1884, Pl. 27A, fig. 1) illustrated as Aschemonella catenata (Norman 1876). Sp. 203. Chain 6 Fig. 4G A fairly robust species forming a branching chain of large segments, each up to 1 mm long. The segments are irregular in shape and dominated by long, tubular or conical processes. The wall is rather coarsely agglutinated; most particles are quartz grains 20–30 mm in size, but others are larger, up to 100 mm or more in diameter. The lack of finegrained matrix between the grains gives the wall a granular appearance. The interior contains large

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stercomata. This species superficially resembles Arbor cuspidata, as illustrated by Schro¨der et al. (1989, particularly their Text Fig. 14), but is easily distinguished by the more coarsely agglutinated wall.

Sp. 17. Clados-like form B This species from Stn. 16 is very similar to form A. The main difference is that the wall is more loosely agglutinated and incorporates larger grains, which project from the surface, in addition to finer particles.

(C.3) Other chain-like species Sp. 105. Fuzzy chain Fig. 6A A chain of up to 10 or more rounded, usually more or less flattened segments. It usually either branches once or twice or gives rise to a single lateral segment. The segments are 250–450 mm in diameter, without any of the tubercle-like structures seen in other chain-like species. Instead, the surface is covered with small, tuft-like structures, which give it a fuzzy appearance. The wall is thick and opaque, composed of fine-grained sediment with occasional larger particles. Sp. 204. Coiled chain Fig. 4G The test consists of short series of segments that coil round to form a rather compact structure, 0.45–1.00 mm in diameter. At first sight, it resembles a lobed mudball, although there is no interstitial sediment. The segments are more or less globular, 0.20–0.45 mm in size, and increase in diameter along the series. The segments lack tubercles, but are covered in short, tuft-like filaments that give the test a ‘hairy’ appearance. The wall is greyish in colour, composed of fine sediment and occasionally incorporates larger particles. (E) Other komokiacean-like species Clados-like form A Fig. 3E Two complete individuals from Stn. 88 measure 1.75 and 2.90 mm long. The basically tubular test branches dichotomously with each main branch giving rise to short, stub-like side branches. The width is irregular and varies from 0.15 to 0.22 mm, in one specimens broadening into a flattened section, 0.40 mm wide. Weak constrictions occur. The wall is thick, opaque and composed of fine sediment with occasional larger grains. The most similar species is Clados floridus Schro¨der, Medioli and Scott, 1989, particularly the specimens illustrated in Schro¨der et al. (1989, text-fig. 3).

Sp. 205. Pale lobed mudball Fig. 6C Test consists of relatively few lobes or short finger-like processes that arise, often asymmetrically, from a central or basal region. As few fine, delicate filaments arise from the ends of the processes. Wall thick; interior with large stercomata. 179. Thick fluffy tubules Fig. 6E Test up to 1.6 mm long, comprising a few poorly defined branches which anastomose to form a meshed structure. Wall loosely agglutinated and composed of a jumble of sediment particles of varying sizes; most are o25 mm but some are larger. Outer surface very irregular with many protruding, angular grains visible under a high power microscope. Test lumen poorly defined, containing what appear to be large stercomata. 59. Branched test with dense stercomata Fig. 6B Single specimen with a stiff tubular test, 2 mm long, which branches dichotomously twice and has two additional short side branches. Tube is 0.15–0.20 mm wide and loosely agglutinated from fine sediment, which encloses a dense core of black stercomata. 2. Tuber-like species Fig. 6D Test fragile, 0.5–1.5 mm diameter, consisting of relatively wide tubular processes radiating from a central region in various planes. The tubes may give rise to short lateral branches or protuberances. They are rather irregular in width (110–180 mm) and the ends are often slightly swollen. Test interior with stercomata, often forming compact masses. 226. Ball with filaments Fig. 2F Two specimens from Stn. 142 measure 1.0 and 1.45 mm diameter and consist of a conglomeration of large mineral grains, mainly clear quartz but also

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scattered darker grains. Twisted organic filaments emerge from between the grains and project for a short distance beyond the test surface. The test is occupied by a large cavity filled with small (10 mm diameter) brown stercomata.

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