Phycologia (2006) Volume 45 (4), 465–477
Published 5 July 2006
Solisphaera gen. nov. (Prymnesiophyceae), a new coccolithophore genus
from the lower photic zone
JÖRG BOLLMANN1*†, MARA Y. CORTÉS2, ANNELIES KLEIJNE3‡, JETTE B. ØSTERGAARD4
AND
JEREMY R. YOUNG5
1Geological Institute, Sonneggstrasse 5, ETH Zürich, CH-8092 Zurich, Switzerland
Departamento de Geologı́a Marina, Universidad Autónoma de Baja California Sur, UABCS, Carretera al Sur Km. 5.5,
C.P. 23080, La Paz, México
3
Department of Paleoecology and Paleoclimatology, Faculty of Earth Sciences, Vrije Universiteit, De Boelelaan NL-1985,
1081 HV Amsterdam, The Netherlands
4
Department of Phycology, Biological Institute, University of Copenhagen, Øster Farimagsgade 2D,
DK-1353 Copenhagen K, Denmark
5
Palaeontology Department, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
2
J. BOLLMANN, M.Y. CORTÉS, A. KLEIJNE, J.B. ØSTERGAARD AND J.R. YOUNG. 2006. Solisphaera gen. nov. (Prymnesiophyceae),
a new coccolithophore genus from the lower photic zone. Phycologia 45: 465–477. DOI: 10.2216/05-14.1
Solisphaera gen. nov. (Prymnesiophyceae) is described from the lower photic zone of the Pacific Ocean, the North Atlantic
Ocean and the Gulf of Mexico. Differences in coccolith morphology between Solisphaera and members of Rhabdosphaeraceae are certainly substantial enough to warrant the erection of a separate genus that should probably be categorised as
incertae sedis aff. Rhabdosphaeraceae. The new genus accommodates three new species, S. emidasia sp. nov., S. blagnacensis sp. nov. and S. helianthiformis sp. nov. and the presence of a corona of process-bearing coccoliths around the cell is
a key feature that unites the three species in the new genus Solisphaera, while the shape of these coronal coccoliths provides
the main character for separating them at species level. A remarkable feature of this genus is the tight interlocking of the
coronal coccoliths, in almost all collapsed coccospheres the circle of coronal coccoliths remains intact. This is evidently
due to the presence of notches at the base of the process into which the rims of adjacent coccoliths lock. All three species
are restricted to the lower photic zone in the areas studied and apparent preferences for different depth levels of S. emidasia
and S. blagnacensis, as well as their nutrient and light requirements, have to be confirmed by further analysis.
KEY WORDS: Solisphaera gen. et sp. nov, Atlantic Ocean, coccolithophores, Gulf of Mexico, lower photic zone, Pacific
Ocean, morphology, taxonomy
INTRODUCTION
Recent morphological and genetic studies have demonstrated
that the diversity of the coccolithophore community may be
considerably underestimated because fine scale morphological
variations in some species appear to be also reflected in genetic variations (Bollmann 1997; Knappertsbusch et al. 1997;
Sáez et al. 2003; Thierstein & Young 2004). In addition, the
number of known coccolithophore species appears to be underestimated because of the limited number of studies focussing on sampling in remote areas such as the subpolar regions
and the central gyres, or on detailed analysis of the vertical
distribution of coccolithophores (cf. Winter et al. 1994).
The diversity of coccolithophores is highest in low latitude
oceanic surface waters and more than 120 species have been
reported (Okada & Honjo 1973; Winter et al. 1994; Hagino
et al. 2000; Jordan et al. 2000; Cortés et al. 2001). In these
areas the coccolithophore assemblages often display depthrelated ecological zones, especially in the oligotrophic central
gyre environments (Okada & Honjo 1973; Winter et al. 1994;
Jordan & Chamberlain 1997; Cortés et al. 2001; Haidar &
* Corresponding author ([email protected]).
† Present address: Department of Geology, University of Toronto,
22 Russel Street, Toronto, ON, Canada M5S 3B1.
‡ Present address: Duinoord 11, 2224 CA Katwijk aan Zee, The
Netherlands.
Thierstein 2001). Typically there are well-developed upper
and lower photic zones, with consistently different assemblages. Characteristic species of the lower photic zone include
Florisphaera profunda Okada & Honjo and Gladiolithus flabellatus (Halldal & Markali) Jordan & Chamberlain. The top
of the lower photic zone varies between environments, often
corresponding to the depth of the deep chlorophyll maximum
(DCM) at which the photosynthetic available radiation is 1%
of that at the surface. The DCM is typically located between
80 to 120 m in the open ocean (Venrick 1973; Bienfang et al.
1984).
There are only a limited number of studies focussing on
the vertical community distribution which have sampled thoroughly below 100 m (e.g. Okada & Honjo 1973; Venrick
1988; Hagino et al. 2000; Cortés et al. 2001; Haidar & Thierstein 2001). As a consequence the lower photic zone coccolithophore community appears to be described incompletely,
although some new species from the lower photic zone have
been described during the last decade (Jordan et al. 1991;
Kleijne et al. 1991; Jordan & Chamberlain 1992, 1993; Hagino & Okada 1998).
In the present paper, we erect a new genus, accommodating
three new species that were found as a result of detailed sampling through the lower photic zone (100–200 m) in the central equatorial Pacific Ocean, the North Atlantic Ocean (Canary Islands region) and the Gulf of Mexico.
465
Of all North Atlantic data, only those for the type localities are listed. Additional data can be downloaded from http://www.pangaea.de.
Indicates that water samples from the respective depths were mixed before processing; ND, not determined; x, present; %, relative abundance; spp., all Solisphaera spp. were counted
together.
2
197
30%
140.008W
140.058W
140.028W
110.018W
100.008W
Equatorial Pacific Ocean
92/3
76
0.058S
92/3
78
0.018S
92/3
83
2.998N
92/3
94
0.018N
92/3
95
0.018N
29
29
2
12
15
Apr. 1992
Apr. 1992
May 1992
May 1992
May 1992
100/120
75
90/100
80/100
80/100
18.55/16.67
21.24
18.28/15.73
ND
ND
35.37/35.28
35.42
34.79/34.74
ND
ND
42%
16%
x
x
35%
1.50%
0.70%
45%
56%
x
x
1% spp.
x
36.42
ND
36.26
18.3
16.2
20.6
110
175
60
95.568W
89.978W
94.608W
25.408N
26.338N
26.418N
Gulf of Mexico
89G15
23
90G15
9
92G03
5A
1
33
80
455
232
65%
64%
x
7%
9%
3%
9%
15 Nov. 1989
14 Oct. 1990
17 Mar. 1992
Date
Longitude
36.56
35.46
Salinity
Temperature
(8C)
29.658N
29.658N
Nanoplanktonic organisms (, 20 mm fraction) were concentrated by prefiltration (mesh size 20 mm) followed by gravity
filtration using a 2.0 mm 47 mm cellulose filter membrane.
Latitude
Preparation for transmission electron microscopy (TEM)
Station no.
GULF OF MEXICO: Samples were collected by vacuum filtration onto 0.8–5 mm, 25 mm cellulose acetate filters. Filters
were air dried and stored in sealed Petri dishes prior to SEM
examination. Samples examined at the NHM were coated with
Gold-Palladium and examined in a FEI XL 30 field emission
SEM.
Cruise
NORTH ATLANTIC OCEAN (CANARY ISLANDS REGION): Up to 10
litres of seawater were filtered onto 47 mm diameter polycarbonate membrane filters using inline filter gaskets and a low
vacuum filtration device. Each filter membrane was rinsed
with NH4–buffered distilled water (pH 8.5) immediately after
filtration in order to remove all traces of sea salt. All membranes were stored in plastic petri dishes and oven-dried at
408 to 608C for several hours. For subsequent SEM analyses
a piece of filter membrane was mounted on an aluminium stub
using double sided tape and coated with 15 nm of Gold-Palladium or 2 nm of Platinum for subsequent analysis in various
SEMs at the ETH Zurich and EMPA [for details see Bollmann
et al. (2002)].
North Atlantic Ocean
P212/2
799
P212/2
799
Preparation for scanning electron microscopy (SEM)
Table 1. Data on abundance and environmental parameters of samples containing Solisphaera spp.1
EQUATORIAL PACIFIC OCEAN: The material originates from a
NOAA Spring Cruise during the EqPac Process Study as a
part of the Equatorial Pacific Ocean Climate Study/Joint Global Ocean Flux Study (EPOCS/JGOFS) of NSF/NOAA (Murray
et al. 1994). Water samples for taxonomy studies were collected from R.V. MALCOLM BALDRIDGE during Leg 3 from
Papeete, Tahiti (22 April 1992) via Balboa to Miami, USA
(24 May 1992). Most samples were collected from vertical
sampling profiles (0 to 200 m) at stations along the 1408W
meridian from 128S to 108N.
A summary of samples used in this study is given in Table
1 and details of the samples from the Canary Island region
can be downloaded from http://www.pangaea.de.
S.
emidasia
GULF OF MEXICO: Samples were obtained during the October 1990 and March 1991 cruises of the R.V. GYRE. Fifteen
stations with extended depth profiles (12 samples, from 5 to
200 m) were studied in detail, as described by Pariente (1997).
17.58
16.99
S.
blagnacensis
S.
helianthiformis
NORTH ATLANTIC OCEAN (CANARY ISLANDS REGION): Within the
EC-MAST III project CANIGO, a total of 132 samples were
analysed from several seasonal cruises (September 1995 to
July 1998). These samples cover an east–west temperature and
productivity gradient along a 298N transect from the African
coast to La Palma (Bollmann et al. 2000; Abrantes et al.
2002). Water samples were collected from vertical sampling
profiles at 9 different water depth levels (0, 10, 25, 50, 75,
100, 125, 150, 200, 300 m) at three locations near the mooring
stations LP1 (29845.79N, 17857.39W), JGOFS Time-series
Station ESTOC (298109N, 158309W) and EBC2 (28842.059N,
1389.039W).
125
150
Field sampling
21 Sep. 1995
21 Sep. 1995
MATERIAL AND METHODS
17.858W
17.858W
No. of
F.
specimens
profunda analysed
Phycologia, Vol. 45 (4), 2006
Sampling
depth (m)2
466
Bollmann et al.: Solisphaera gen. nov.
One to four litres of seawater were found to provide adequate
amounts of material. Organisms concentrated on top of the
filter were gently re-suspended and subsequently centrifuged
in order to form a pellet of material. Whole mounts for TEM
were prepared according to well-established procedures
(Moestrup & Thomsen 1980; Thomsen 1982). They were shadowcast with chromium at a low angle and examined on a
Transmission Electron Microscope (TEM) at the Dept. of Phycology, Biological Institute, University of Copenhagen. All
measurements were made on dried material.
Classification and terminology
We follow the classification of extant Haptophyta of Jordan
& Green (1994) and Edvardsen et al. (2000). Terminology
used is in accordance with Young et al. (1997) with the addition of some new terms to describe the peculiar features of
the new species:
● hemispherical coccosphere 5 coccosphere with two sides:
a domed side (or convex side) and flattened/planar side.
● domal-side body coccoliths 5 body coccoliths located on
the domed side of the coccosphere.
● planar-side body coccoliths 5 body coccoliths located on
the planar side of the coccosphere.
● coronal coccoliths 5 coccoliths with a distinctive protrusion, that form a circular ring, or corona, around the coccosphere.
RESULTS
While studying the vertical distribution of the coccolithophore
community from 0 to 200 m water depth in the central equatorial Pacific Ocean, the North Atlantic Ocean and the Gulf
of Mexico three new coccolithophore species were encountered. The specimens of the three different species possess
distinctive coccoliths, unlike those of any previously described species and genus. Therefore, they are assigned to a
new genus, Solisphaera gen. nov. The presence of a corona
of process-bearing coccoliths around the cell is a key feature
that unites the species in the genus Solisphaera, while the
shape of these coronal coccoliths provides the main character
for separating them at species level.
Division HAPTOPHYTA Hibberd 1972 ex Edvardsen &
Eikrem in Edvardsen et al. 2000
Class PRYMNESIOPHYCEAE Hibberd 1976; emend.
Cavalier-Smith in Cavalier-Smith et al. 1996
Order SYRACOSPHAERALES Hay 1977; emend. Young et
al. 2003
incertae sedis aff. Family RHABDOSPHAERACEAE
Haeckel 1894
Solisphaera Bollmann, Cortés, Kleijne, Østergaard &
Young gen. nov.
Coccolithophori parvi coccosphaeris monothecatis probabiliter
hemisphaericis, polymorphi, coccolithis et coronariis et corporis, his
in genera duo pluriave descriptis. Coccolithi coronarii coronam circularem circum coccosphaeram facientes; sunt planolithi, basi oblonga protrusione longitudinali ex elementis parvis rhombicis im-
467
bricantibus antihelicte dispositis constato; axibus longitudinalibus
ad coronam parallelis; extremitatibus coccolithorum contiguorum
superpositis, inter se extremitate huius in constrictionem illius tenuem connexis. Coccolithi corporis sunt planolithi elliptici vel multanguli, margine ex uno circulo elementorum tangentialium tigillatorum constato interdum instructi; valde aut leviter calcarei protusione interdum muniti.
Small coccolithophores with monothecate, probably hemispherical
coccospheres; polymorphic with coronal coccoliths and two or more
types of body coccoliths. The coronal coccoliths form a circular
corona around the coccosphere. They are planoliths with an oblong
base and a longitudinally-aligned protrusion, formed of small rhombic elements, arranged in an anticlockwise, imbricate pattern. The
coronal coccoliths are arranged with their long-axes parallel to the
corona; the ends of adjacent coronal coccoliths overlap and lock
into a small constriction at the base of the protrusion of the adjacent
coccolith. The body coccoliths are elliptical to polygonal planoliths;
they may have a rim constructed of a single cycle of tangential,
lath-shaped elements. They are heavily or lightly-calcified and may
bear a protrusion.
(designated here): S. emidasia Bollmann, Cortés,
Kleijne, Østergaard & Young.
TYPE SPECIES
ETYMOLOGY: sol 5 sun, sphaera 5 sphere; the collapsed coccosphere is reminiscent of a stylized sun.
REMARKS: Only collapsed coccospheres of these species
have been found and, therefore, no definite cell shape and cell
orientation can be given. However, the disposition of the coccoliths on the filters gives rather strong indications of the
shape of the living cells. The collapsed coccospheres nearly
always consist of a ring of protrusion-bearing coccoliths (the
coronal coccoliths) surrounding a field of simpler coccoliths.
However, the simpler coccoliths may be either (1) a low number of heavily-calcified non-overlapping planoliths, or (2) numerous lightly-calcified overlapping planoliths (Figs 1–4).
A possible explanation for these observations is that the
coccospheres are hemispherical, with the lightly-calcified coccoliths occurring on the domal side and the heavily-calcified
coccoliths on the planar side. This shape of a coccosphere
explains the smaller number of coccoliths on one side of the
coccosphere and the greater overlap of the coccoliths on the
other side in collapsed coccospheres.
In this structure, the continuous ring of interlocked coronal
coccoliths around the cell may function as a girdle that stabilizes a more or less hemispherical shaped coccosphere (Fig.
4).
Solisphaera emidasia Bollmann, Cortés, Kleijne,
Østergaard & Young sp. nov.
Figs 5–11
Coccosphaerae parvae polymorphae (diametro circa 7 mm) ex planolithis formarum trium constatae. Coccolithi coronarii coccosphaerae annulum circumdantes, basi oblonga, protrusione plana trapeziformi longitudinaliter orientata (circa 0.9 3 1.5 mm). Coccosphaera
a latere polari tholiformi visa formis duabus planolithorum ellipticorum leviter calcareorum (circa 1.2 3 0.9 mm) vestita. Planolithi
hi margine tenui manifeste distincto constato ex uno circulo elementorum (circa 0.05 3 0.2 mm) tangentialium bacilliformium plerumque instructi; area centrali ex elementis trapeziformibus (circa
0.1 3 0.4 mm) radialiter dispositis constata. Coccosphaera a latere
polari plano visa planolithis ellipticis (circa 1.5 3 1.0 mm), multiangulis valde calcareis vestita. Planolithi hi margine lato constato
ex uno circulo elementorum tangentialium rectangularium plerumque instructi, area centrali ex circulo irregulari elementorum 10–
14 oblongorum fere radialiter dispositorum constata.
Small polymorphic coccosphere (diameter c. 7 mm) formed of three
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Phycologia, Vol. 45 (4), 2006
Figs 1–4. Schematic reconstruction of the coccosphere shape and orientation of Solisphaera spp.
Figs 1–2. Collapsed coccospheres of Solisphaera spp. in domal-side pole view, showing the domal (‘antapical’) side with lightly-calcified
body coccoliths (Fig. 1) and the planar-side (‘apical’) pole with heavily-calcified coccoliths (Fig. 2). The three new species of the genus
Solisphaera are represented by the different shapes of the protrusions of the coronal coccoliths.
Fig. 3. Schematic side view of a collapsed coccosphere. The larger coccoliths in the lower part of the drawing represent the heavily-calcified
coccoliths of the planar (‘apical’) side.
Fig. 4. Tentative reconstruction of a complete coccosphere with flagella in side view; the planar (‘apical’) side is shown as bearing the flagellar
opening, see discussion.
types of planoliths. Coronal coccoliths form a ring around the coccosphere; they have an oblong base and a flat, longitudinally
aligned, trapezoid protrusion (size c. 0.9 3 1.5 mm). Coccosphere
in domed-side pole view shows two types of lightly-calcified, elliptical planoliths (size c. 1.2 3 0.9 mm) usually with a well-defined
narrow rim consisting of a single cycle of tangential, rod-shaped
elements (size c. 0.05 3 0.20 mm). The central area consists of c.
20 trapezoid elements (size c. 0.1 3 0.4 mm), arranged in a radial
pattern.
In planar-side pole view, the coccosphere shows heavily-calcified,
elliptical to polygonal planoliths (size c. 1.5 3 1.0 mm) usually with
a broad rim consisting of a single cycle of tangential, rectangular
elements. The central area consists of an irregular cycle of 10–14
elongate elements (size c. 0.30–0.50 3 0.10–0.30 mm), arranged in
an approximately radial pattern.
HOLOTYPE
(designated here): Figs 5, 6.
TYPE MATERIAL:
ETH SEM stub: P212 St799 150m, filter sample
collected at the type locality, 21 September 1995. Type repository:
Geological Institute, ETH Zürich.
TYPE LOCALITY: North Atlantic Ocean (29.658N, 17.858W, R.V.
POSEIDON Cruise P212, station 799 at a depth of 150 m).
ETYMOLOGY: Referring to EMIDAS, the Electronic Microfossil Database System (http://www.emidas.ethz.ch) where this form was illustrated first, leading to our collaborative description of this new
species.
DISTRIBUTION: Solisphaera emidasia was confined to the lower photic zone in the North Atlantic Ocean, the central equatorial Pacific
Ocean and the Gulf of Mexico (Table 1). The known ranges of
Bollmann et al.: Solisphaera gen. nov.
temperature and salinity of this species are at present c. 15.7–21.28C
and 34.7–37, respectively.
REMARKS: The diameter of the collapsed coccospheres
varies from 5 to 8 mm. The number of coronal coccoliths
varies from 13 to 24 and their protrusions are formed of small
rhombic elements (size c. 0.08–0.25 mm), arranged in an anticlockwise, imbricate pattern (Fig. 11). The apex of the protrusion appears to be formed of a single row of elements (Fig.
9). There are up to 13 heavily-calcified planar-side and 30–
50 lightly-calcified domal-side coccoliths. The rim elements
are often missing from both the lightly-calcified and heavilycalcified coccoliths, but this does not occur on all specimens
and coccoliths with partial rims occur. We do not know whether these coccoliths represent different types of coccoliths or
just variable preservation of body coccoliths. (Figs 5, 6, 8, 9).
Not all coccospheres of S. emidasia show the heavily-calcified planar coccoliths, which seems to be the result of the
orientation of the coccosphere on the filter (Fig. 7). If, for
example, coccoliths of the domal side of the coccosphere are
lying on top, they will entirely cover the fewer coccoliths of
the flat side. (See also the remarks on coccosphere shape in
the generic description; Figs 1–4.) When the heavily-calcified
planoliths are visible, so in planar pole view, they are often
arranged in a ring along the coronal coccoliths (Fig. 5). Figure
10 shows small elliptical unmineralised body-scales (0.17–
0.20 3 0.10–0.13 mm) with a raised beaded rim. The form of
the component elements of the coccoliths in SEM images suggests that they are formed of calcite and this was supported
by energy-dispersive X-ray analyses which revealed the presence of calcium carbonate in the periplast of S. emidasia. Polarising light microscopy observations confirmed this interpretation.
Solisphaera emidasia was first illustrated as Algirosphaera
sp. nov. on EMIDAS http://www.emidas.ethz.ch, Image ID:
443, 201, 173, 138 and subsequently as ‘Saturnulus emidasius’ (nomen nudum) in Young et al. (2003), p. 61, plate 27,
figs 8, 11.
Solisphaera blagnacensis Bollmann sp. nov.
Figs 12–21
Coccosphaerae parvae (diam. circa 7.5 mm) formis quattuor planolithorum: (1) coccolithis coronariis aspectu laterali protrusione rotundata instructis et (2–4) formis tribus coccolithorum corporis.
Coccolithi lateris tholiformis coccosphaerae leviter calcarei protrusionibus humilibus, basi elliptica ad oblonga (0.9–1.4 3 0.6–0.9
mm), margine angusto ex uno circulo elementorum bacilliformium
tangentialium constato, area centrali ex elementis 10–15 radialiter
dispositis trapeziformibus constanti; protrusiones magnitudine variabiles longitudinaliter orientatae aspectu laterali rotundatae. Coccolithi lateris plani coccosphaerae valde calcarei sine protrusionibus, illorum duae formae: (1) coccolithi minores aspectu distali
structura centrali elevata ex angulis se procurrentibus elementorum
constanti; (2) coccolithi maiores area centrali plana. In coccosphaera
conlapsa, coccolithi minores in centro positi, maiores circum marginem. Omnes coccolithi lateris plani elliptici ad multanguli (circa
1.4 3 1.0 mm), margine lato ex circulo uno elementorum tangentialiter dispositorum rectangularium constato, area centrali convexa
ex annulo irregulari elementorum 10–14 elongatorum radialiter dispositorum trapeziformium (circa 0.3–0.5 3 0.1–0.3 mm).
Small coccosphere (diameter c. 7.5 mm) with four types of planoliths: coronal coccoliths with a rounded protrusion in lateral view,
and three types of body coccoliths. The domal-side lightly-calcified
coccoliths have low protrusions. They have an elliptical to oblong
469
base (0.9–1.4 3 0.6–0.9 mm) with a narrow rim formed by a single
cycle of rod-shaped tangential elements and central plate of 10–15
radially-arranged trapezoidal elements. The protrusions are of variable size, are aligned longitudinally and are rounded in lateral view.
The planar-side heavily-calcified coccoliths lack protrusions and
are of two types: smaller coccoliths with an central, elevated structure in distal view, formed by the protruding edges of the elements
and larger coccoliths with a flat central area. The smaller coccoliths
occur in the centre of the collapsed coccosphere; the larger planar
coccoliths around the edge. All heavily-calcified planar coccoliths
are elliptical to polygonal discs (c. 1.4 3 1.0 mm) with a broad rim
of a single cycle of tangentially arranged rectangular elements. They
have a convex central part that consists of an irregular cycle of 10–
14 elongate radially-arranged trapezoidal elements (c. 0.30–0.50 3
0.10–0.30 mm in size).
HOLOTYPE
(designated here): Fig. 12;
SYNTYPE:
Fig. 13.
TYPE MATERIAL:
ETH SEM stub: P212 St799 150m, filter sample
collected at the type locality, 21 September 1995. Type repository:
Geological Institute, ETH Zürich.
TYPE LOCALITY: North Atlantic Ocean (29.658N, 17.858W, R.V.
POSEIDON Cruise P212, station 799 at a depth of 150 m).
ETYMOLOGY: Referring to Château de Blagnac in France, the venue
of numerous coccolithophore workshops during the CODENET and
previous coccolithophore related projects.
DISTRIBUTION: Solisphaera blagnacensis was found in the lower photic zone of the North Atlantic Ocean near the Canary Islands and
in the central equatorial Pacific Ocean (Table 1). Rare specimens
were also observed in samples from the Western Mediterranean,
Alboran Sea. At present this species has been found in water samples with a temperature of c. 15.7–21.28C and salinity of 34.7–37.
REMARKS: The number of coronal coccoliths varies between
11 and 18. The rim of their protrusions appears to be formed
by a single row of trapezoidal elements (Figs 18, 19; c. 0.15
3 0.25 mm). A few heavily-calcified planar coccoliths (10–
14) appear to cover the planar side of the coccosphere, while
numerous (40–50) lightly-calcified domal coccoliths, each
with a small rounded protrusion of varying size cover the
other, domed side of the coccosphere.
The most obvious difference between S. blagnacensis and
S. emidasia is the presence of rounded protrusions on the
lightly-calcified body coccoliths on the domal side of the coccosphere. Additional differences are:
● The coronal coccoliths of S. blagnacensis bear a protrusion
with a rounded, rather than trapezoid-shaped, profile and
are more variable in size (compare Figs 12, 14, 15 and Figs
5, 7, 8).
● The planar-side coccoliths have a more regular structure
than those of S. emidasia (Figs 17, 20, 21).
● Planar-side coccoliths consistently occur in the centre of the
coccosphere whilst they have often been observed around
the corona in S. emidasia, and these central planar-side coccoliths have a low central boss.
● The coronal coccoliths and body coccoliths are much more
similar to each other in S. blagnacensis, than they are in
S. emidasia (compare Figs 12, 14, 15 and Figs 5, 7, 8).
Energy-dispersive X-ray analyses and polarising light microscopy revealed the presence of calcium carbonate in the
periplast of S. blagnacensis. Unmineralised underlayer scales
were not observed.
S. blagnacensis was illustrated for the first-time as Algirosphaera sp. nov. on EMIDAS http://www.emidas.ethz.ch, Image ID: 270, 269 137, 136, 135 and 449 and subsequently as
470
Phycologia, Vol. 45 (4), 2006
Figs 5–11. Solisphaera emidasia sp. nov.
Fig. 5. Scanning electron microscope (SEM) image of a collapsed coccosphere in planar (‘apical’) pole view, displaying 5 types of planoliths:
coronal coccoliths [coccoliths with protrusions forming a ring around the coccosphere (cor)], lightly-calcified body coccoliths with (lcr) and
without (lc) a rim of rod-shaped elements, and heavily-calcified body coccoliths with (hcr) and without (hc) such a rim. Scale bar 5 2 mm.
Fig. 6. Detail of Fig. 5, showing lightly-calcified domal body coccoliths with and without a rim, and heavily-calcified planar coccoliths without
a rim. Scale bar 5 0.5 mm.
Fig. 7. SEM image of a collapsed coccosphere in domal (‘antapical’) pole view, showing coronal coccoliths and lightly-calcified body
coccoliths. Scale bar 5 2 mm.
Fig. 8. SEM image of a collapsed coccosphere in planar (‘apical’) pole view, showing coronal coccoliths (cor), a few heavily-calcified planar
coccoliths and the proximal sides of domal body coccoliths. See Figs 5, 6 for abbreviations. The arrows point to the constrictions at the base
of the coronal coccoliths where they interlock. Scale bar 5 2 mm.
Bollmann et al.: Solisphaera gen. nov.
‘Saturnulus blagnacensis’ (nomen nudum) in Young et al.
(2003), p. 61, plate 27, figs 7, 10.
Solisphaera helianthiformis Bollmann, Cortés, Kleijne,
Østergaard & Young sp. nov.
Figs 22–25
Coccosphaerae parvae polymorphae (diametro circa 8.5 mm) ex
planolithis formarum tribus constatae. Coccolithi coronarii protrusionibus elongatis tortis triangularibus muniti (usque ad 2.3 mm longis, 0.8 mm latis). Coccolithi lateris tholiformis leviter calcarei (circa 1.4 3 1.1 mm); sunt planolithi elliptici, margine angusto ex circulo uno elementorum bacilliformium tangentialium constato, area
centrali ex circa 20 elementis trapeziformibus (circa 0.1 3 0.4 mm)
in annulo radialiter dispositis. Coccolithi lateris plani valde calcarei
plani, elliptici ad multanguli (circa 1.5 3 0.1 mm).
Small, polymorphic coccosphere (c. 8.5 mm in diameter) formed of
three types of planoliths. Coronal coccoliths bear an elongate, twisted, triangle-shaped protrusions (up to 2.3 mm high 3 0.8 mm wide).
The domal-side lightly-calcified coccoliths (c. 1.4 3 1.1 mm) are
elliptical planoliths with a narrow rim of a single cycle of rodshaped tangential elements. The central area consists of c. 20 trapezoidal elements (c. 0.1 3 0.4 mm), arranged in a single, radial
cycle. The planar-side heavily-calcified coccoliths are elliptical to
polygonal and planar (size c. 1.5 3 1.0 mm).
HOLOTYPE
(designated here): Figs 22–24.
TYPE MATERIAL:
ETH SEM stub: P212 St799 150m, filter sample
collected at the type locality, 21 September 1995. Type repository:
Geological Institute, ETH Zürich.
TYPE LOCALITY: North Atlantic Ocean (29.658N, 17.858W, R.V.
POSEIDON Cruise P212, station 799 at a depth of 150 m).
From Latin helianthus 5 sunflower, formis 5 formed/
shaped, referring to the collapsed coccosphere resembling a sunflower.
ETYMOLOGY:
DISTRIBUTION: Solisphaera helianthiformis was found in the lower
photic zone of the North Atlantic Ocean near the Canary Islands,
the central equatorial Pacific Ocean and in the Gulf of Mexico (Table 1). At present this species has been found in water samples with
a temperature of 16.2–18.38C and a salinity of 34.7–37.
REMARKS: The number of coronal coccoliths varies between
18–28, while 30–50 lightly-calcified domal-side body coccoliths cover the remaining part of the coccosphere. The domalside body coccoliths resemble the lightly-calcified coccoliths
of Solisphaera emidasia in their shape, structure and size. In
addition, a few lightly-calcified coccoliths without rims are
often seen. It is unclear whether these coccoliths represent
another type of body coccoliths or lightly-calcified coccoliths
affected by carbonate dissolution or malformation. Heavilycalcified planar-side coccoliths, as observed for S. emidasia
and S. blagnacensis are clearly present in this species (see
arrow on Fig. 22). However, their ultrastructure and their distribution on the planar side of the coccosphere remains unknown because of the rareness of this species.
The coronal coccoliths of S. helianthiformis can be easily
distinguished from those of S. emidasia and S. blagnacensis
471
by their twisted, elongated triangular shape (Figs 22, 23, 25).
The base of the coronal coccoliths appears to be more or less
oblong (Fig. 23), similar to those of S. emidasia. The overall
structure of S. helianthiformis is similar to that of S. emidasia,
due to the absence of process-bearing body coccoliths (Figs
5–9, 22, 24). However, the twisted triangular shape of the
protrusions in S. helianthiformis provides an obvious difference (Figs 22, 23, 25).
Solisphaera helianthiformis was illustrated for the first-time
as ‘unknown’ coccolithophore by Pariente (1997), her Plate 3
fig. G and subsequently as ‘Saturnulus helianthiformis’ (nomen nudum) in Young et al. (2003), p. 61, plate 27, figs 9,
12.
Unmineralised underlayer scales were not observed and
neither energy-dispersive X-ray nor polarising light microscopy analysis could be performed because of the rarity of the
species. However, the appearance of the elements and the
close similarities of them in this species to those of the other
Solisphaera species lead us to predict that the coccoliths are
formed of calcite.
Ecology and coccolithophore community
The most detailed ecological information on the three new
species is available from the Canary Island region. Solisphaera spp. were frequent in most samples from 75 to 200 m
water depth and represented the second most abundant taxa
of the lower photic zone in this area with an average cell
density of about 800 cells l21, after Florisphaera profunda
with about 4000 cells l21 and before Gladiolithus flabellatus
with about 250 cells l21 (Figs 26–28). Although the data of
the three new species were lumped together while analysing
the samples, qualitative observations have shown that S. emidasia is the most abundant species, followed by S. blagnacensis. In contrast, S. helianthiformis was very rare. At the
type locality of S. blagnacensis and S. emidasia (R.V. POSEIDON Cruise 212 Station 799) the cell density of S. emidasia (2500 cells l21) was three times higher than that of S.
blagnacensis at 125 m water depth. However, at 150 m water
depth they were equally abundant (c. 1400 cells l21, each)
suggesting that S. emidasia is better adapted to ‘shallower’
depth levels within the lower photic zone. However, this hypothesis has to be proven by additional analysis.
Highest cell densities of up to 7500 cells l21 were encountered during summer and fall cruises, which suggests a seasonal distribution pattern. Solisphaera spp. occurred at 158C
to 208C, with highest cell densities between 178C to 198C (Fig.
29) and salinity from 36 to 37 (Fig. 30). Phosphate concentrations varied from 0 to 0.67 mmol l21, while cells densities
higher than 1000 cells l21 occurred only below 0.15 mmol l21
phosphate (Fig. 31). Nitrate concentrations varied from 0 to
13 mmol l21 nitrate and cells densities higher than 1000 cells
←
Fig. 9. Transmission electron microscope (TEM) image of a collapsed coccosphere, showing coronal coccoliths, numerous lightly-calcified domal
body coccoliths with a rim (lcr) and some heavily-calcified planar coccoliths with a rim (hcr); the arrow at the lower right points to the single
row of elements at the apex of a coronal coccolith. Scale bar 5 2 mm.
Fig. 10. TEM image of unmineralised underlayer scales (us), lightly-calcified coccoliths (lcr) and coronal coccoliths (cor). Scale bar 5 0.5 mm.
Fig. 11. Detailed SEM image of coronal coccoliths, showing the rhombic elements of the protrusion, the manner in which they interlock, and
the distal surface of the lightly-calcified, domal-side, rimmed body coccoliths. Scale bar 5 0.2 mm.
472
Phycologia, Vol. 45 (4), 2006
Figs 12–17. Solisphaera blagnacensis sp. nov.
Fig. 12. Scanning electron microscope (SEM) image of a collapsed coccosphere in domal (‘antapical’) pole view, showing the ring of coronal
coccoliths, lightly-calcified domal-side body coccoliths with a rounded protrusion (lcp) and proximal face of heavily-calcified planar body
coccoliths with rims (hcr). The unlabelled arrows point to the oblong base of the coronal coccoliths. Scale bar 5 2 mm.
Fig. 13. SEM image of a collapsed coccosphere in planar-side (‘apical’) pole view, showing the heavily-calcified non-overlapping planar-side
coccoliths. The arrow points to the proximal side of a lightly-calcified protrusion-bearing domal-side body coccolith (lcp). Scale bar 5 2 mm.
Fig. 14. SEM image of a collapsed coccosphere in domal-side (‘antapical’) pole view, showing the coronal coccoliths and the lightly-calcified
domal-side body coccoliths. Scale bar 5 2 mm.
Fig. 15. SEM image of a collapsed and distorted coccosphere, showing coronal coccoliths and lightly-calcified domal-side body coccoliths,
as well as the distal face of heavily-calcified planar coccoliths on the right side of the coccosphere. Scale bar 5 2 mm.
Bollmann et al.: Solisphaera gen. nov.
473
Figs 18–21. Solisphaera blagnacensis sp. nov.
Fig. 18. Detailed scanning electron microscope (SEM) image of a coronal coccolith. The arrow points to the slightly elevated narrow rim.
Scale bar 5 0.5 mm.
Fig. 19. Transmission electron microscope (TEM) image of a collapsed coccosphere, showing coronal coccoliths (in lateral view) with a single
cycle of trapezoidal elements along the distal margin of the protrusions (arrows). Scale bar 5 1 mm.
Fig. 20. Detailed SEM image of heavily-calcified planar-side body coccoliths in distal view, showing a central, elevated structure, formed by
the protruding edges of the elements. Scale bar 5 0.5 mm.
Fig. 21. Detailed SEM image of heavily-calcified planar-side body coccoliths in distal view and an underlayer of lightly-calcified coccoliths
apparently with the proximal expression of the protrusion (arrowed). Scale bar 5 2 mm.
l21 occurred only below a concentration of 1.4 mmol l21 nitrate
(Fig. 32).
During the Gulf of Mexico study Solisphaera spp. was only
present as a rare component of the assemblages (, 1% of the
total assemblage, see also Pariente 1997). The samples containing Solisphaera spp. were all from the lower photic zone,
where the assemblages were dominated by Florisphaera profunda, Emiliania huxleyi (Lohmann) Hay & Mohler and Gladiolithus flabellatus (Pariente 1997).
Abundance analysis of Solisphaera spp. in samples from
the equatorial Pacific Ocean was made using TEM replicas of
prefiltered sample material. Therefore, the results are difficult
to compare with the results obtained from filter samples analysed with the SEM. Nevertheless, in 7 out of 14 samples
from the middle and lower photic zone of the Pacific Ocean,
Solisphaera spp. were found, while 5 samples yielded a sufficient number of cells (. 30) to calculate the relative abundance of coccolithophore species. From these analyses it is
evident that S. emidasia, Florisphaera profunda and Gladiolithus flabellatus were by far the most abundant coccolitho-
←
Fig. 16. Detailed SEM image, showing coronal coccoliths and lightly-calcified domal-side body coccoliths with a protrusion. The arrows point
to the oblong base and the narrow rim of tangential elements. Scale bar 5 1 mm.
Fig. 17. Detailed SEM image of heavily-calcified planar-side coccolith in distal view, showing the rim of rectangular elements. Scale bar 5 0.5
mm.
474
Phycologia, Vol. 45 (4), 2006
Figs 22–25. Solisphaera helianthiformis sp. nov.
Fig. 22. Scanning electron microscope (SEM) image of a collapsed coccosphere with many lightly-calcified domal-side body coccoliths and
a ring of coronal coccoliths. The prominent protrusions of the coronal coccoliths are twisted through 6 458 relative to the domal face of the
coccosphere. The arrow points to a heavily-calcified planar-side body coccolith. Scale bar 5 2 mm.
Fig. 23. High magnification SEM image of Fig. 22 showing the interlocking, oblong base of the coronal coccoliths (arrows). Scale bar 5 1
mm.
Fig. 24. High magnification SEM image of the two types of domal-side body coccoliths, namely lightly-calcified coccoliths with a rim (lcr)
and coccoliths without rim (lc). Scale bar 5 1 mm.
Fig. 25. High magnification transmission electron microscope (TEM) image of the twisted coronal coccolith protrusions. Scale bar 5 1 mm.
phore species in the lower photic zone of these Pacific Ocean
samples (Table 1). Each whole mount examined in the TEM
contained numerous complete cells, while detached coccoliths
were scattered over the grid surface. Solisphaera blagnacensis
and S. helianthiformis were much more infrequently recorded
than S. emidasia, and these species always co-occurred with
S. emidasia. Furthermore, at the Pacific Ocean stations Solisphaera spp. occurred at lower salinities (down to a salinity of
34.7) than in the Atlantic Ocean.
DISCUSSION
So far, no obvious flagellar opening has been observed and
therefore, the relative orientation of the cell is not known.
However, there are some indications for the presence of a
flagellar opening in Solisphaera spp. A common feature in
coccolithophore taxa, for example in many species of the family Syracosphaeraceae or Rhabdosphaeraceae, is the occurrence of a few modified coccoliths surrounding the flagellar
opening (the apical or circum-flagellar coccoliths; Young et
al. 1997). The number of these circum-flagellar coccoliths is
always much lower than the number of body coccoliths.
This type of pattern could also be inferred from some specimens of Solisphaera spp. where a few heavily-calcified coccoliths are often arranged in a radial pattern on the planar side
of the coccosphere (e.g., on Fig. 13). These coccoliths are
located within the centre of a set of heavily-calcified coccoliths and they are always smaller than the planar coccoliths
covering the reaming planar side of the coccosphere (Fig. 13).
The smaller coccoliths (‘circum-flagellar coccoliths’) may surround a flagellar opening and therefore, the planar side of the
coccosphere may represent the apical side of the coccosphere,
as suggested in Figure 4.
Bollmann et al.: Solisphaera gen. nov.
475
Figs 26–28. Cell densities of the most abundant lower photic zone taxa in the north Atlantic (Canary Islands) region.
Figs 29–32. Cell densities of Solisphaera spp. with respect to environmental parameters (in Fig. 32 nitrates is the sum of NO2 and NO3).
Environmental parameters are from Knoll et al. (1998) and Abrantes et al. (2002).
Taxonomic affinity
Energy-dispersive X-ray analyses and polarising light microscopy revealed the presence of calcium carbonate in the periplast of S. emidasia and S. blagnacensis. Solisphaera helianthiformis could not be analysed because it was too rare. However, we are confident that all three species are coccolithophores from their general morphology and structure. The
genus Solisphaera is morphologically distinct, and its coccoliths do not closely resemble those of any recent or fossil coccolithophore genus. Therefore, the allocation of this genus to
any existing higher taxa is problematic.
In contrast to gross coccolith morphology, coccolith ultrastructure provides reliable indications of affinity (e.g. PerchNielsen 1985 a, b; Young et al. 2004). In particular base and
rim structures have proven consistently reliable indicators of
affinity. However, in Solisphaera the relatively simple structure of the base does not offer any obvious clues of affinity.
Conversely the protrusion structure is highly distinctive and
suggests an affinity to the Rhabdosphaeraceae. The family
Rhabdosphaeraceae was reviewed by Kleijne (1992) and Aubry (1999). The family is characterised by motile or nonmotile
cells, typically with both spine-bearing and non–spine-bearing
coccoliths. The spine-bearing coccoliths may be confined to
the poles or distributed around the coccosphere, greatly increasing its outer diameter. Polymorphic, varimorphic, dimorphic and monomorphic genera occur. The coccoliths are typically disc-shaped and usually formed of three components.
(1) The rim is narrow and slightly elevated and constructed
of two cycles of elements; the outer rim cycle is built of simple non-imbricate elements, whilst the inner rim cycle elements show strong obliquity. (2) The radial cycle consists of
laths, in an equal number to the rim units, running inwards
from the rim; openings are often present between the laths.
(3) The lamellar cycle is constructed of numerous small elements with a more or less clear anticlockwise helical arrangement that may end in a ‘cuneate cycle’ of a few well-formed
elements. In addition, many species have specialised rhabdoliths with a distal protrusion or process in the central area.
This process consists of spirally arranged lath-shaped elements of the lamellar cycle.
The base of the coccoliths of the three Solisphaera species
apparently lacks the characteristic Rhabdosphaeraceae features: it shows neither the rim with two cycles of elements
nor the radial cycle of rhabdoliths. The central-area of the
476
Phycologia, Vol. 45 (4), 2006
domal-side body coccoliths consists only of a central cycle of
irregularly shaped subradial elements (Figs 6, 12, 24). Generally, they have a narrow rim formed of a single cycle of
tangential elements (Figs 6, 10, 16, 22). The structure of the
protrusion among members of Solisphaera is highly distinctive, and although it shows some similarities to the coccolith
structure of Rhabdosphaeraceae, it is very different from all
other extant coccoliths. The detailed ultrastructure of the protrusion in Solisphaera species, with its anticlockwise imbricate rhombic elements, shows similarities to that of the sacculiform coccoliths of Algirosphaera robusta (Lohmann) Norris. However, it obviously lacks the complex internal structure
of that species (I. Probert, personal communication).
An additional similarity to Algirosphaera robusta is the
presence of body scales an order of magnitude smaller than
the coccoliths, whereas in most other coccolithophores body
scales are much closer in size to the coccoliths. If Solisphaera
is related to the Rhabdosphaeraceae then the rhabdolith rim is
represented by the peripheral cycle of elongate elements that
is visible in some coccoliths of Solisphaera. However, the
radial elements are missing and the elements that form the
protrusion may be comparable to the ‘lamellar cycle elements’. Radial cycle elements are also missing in all coccoliths of Rhabdosphaera and in the antapical spine coccoliths
of Acanthoica. Thus, a tentative hypothesis could be that the
species assigned to Solisphaera are members of Rhabdosphaeraceae in which, as a result of size reduction, the base
structure has become drastically simplified. However, further
detailed observations, especially of the arrangement of elements on the proximal face of the body coccoliths, will be
needed to fully describe the coccolith architecture and the future classification of this genus.
Ecology
The habitat of the three new species is the lower photic zone.
The apparent adaptation of S. emidasia to ‘shallower’ layers
and S. blagnacensis to ‘deeper’ layers within the lower photic
zone as shown for the two Florisphaera profunda varieties,
F. profunda var. elongata and F. profunda var. profunda
(Quinn et al. 2005) has to be proven by additional analysis.
Furthermore, it remains open whether the new species from
the lower photic zone are heterotrophic, as it has been suggested for other species from these layers, such as F. profunda
(Brand 1994).
ACKNOWLEDGEMENTS
We thank the captains and the crews of R.V. MALCOLM
BALDRIGE, R.V. METEOR and R.V. POSEIDON for their
efforts in facilitating the collection of data in the Pacific Ocean
and in the Atlantic Ocean. We are very grateful to Dr Vita
Pariente and many of her colleagues at Texas A&M University for providing samples from the Gulf of Mexico and for
much correspondence. Francisco P. Chavez and Kurt R. Buck,
from Monterey Bay Aquarium Research Institute, California,
organised JBØ’s participation in the JGOFS cruise in the Pacific Ocean. Andrea Spiedt sampled coccolithophores during
R.V. POSEIDON cruise 212. Philippe Gasser (EMPA) and
Martin Müller (IAP ETH Zürich) assisted in the examination
of the samples from the type locality in the Atlantic Ocean.
Silvia Clavadetscher provided the Latin translation and Peter
Zeeberg is thanked for suggestions for the Latin names.
This study was supported by a PhD-grant, funded by the
Faculty of Science, University of Copenhagen, and a travel
grant from the Fiedler Foundation to JBØ. This work is a
contribution to the EC-MAST project CANIGO (Subproject
3, ‘Particle Flux and Oceanography in the Eastern Boundary
Current system’), EC contract No. MAS-CT9-0060 and the
EC-TMR program CODENET, EC contract No ERB-FRMXCT97-0113. The Swiss Federal Office for Education financially supported JB (BBW No. 95.0355).
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Received 2 March 2005; accepted 23 January 2006
Associate editor: S. Sym