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61

Gladiolithus adeyi sp. nov.: a new deep photic coccolithophore species and new molecular genetic and crystallographic observations on *ODGLROLWKXVÀDEHOODWXV.
Jeremy R. Young
Earth Sciences, University College London, Gower Street, London WC1E 6BT

Kyoko Hagino
Research and Education Faculty, Natural Sciences Cluster, Sciences Unit, Kochi University, Akebono-cho 2-5-1, Kochi-city, Kochi Prefecture,
780-8520 Japan

Alex J. Poulton
National Oceanography Centre, Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH

Abstract: Gladiolithus is a distinctive and unusual genus of deep photic coccolithophores which has recently beenshown to have a fossil record extending back to the mid Paleocene (ca 60Ma). We describe here a new species of GladiolithusZLWKORQJQDUURZWXEHFRFFROLWKVDQGGHPRQVWUDWHLWVDIÀQLW\WRRWKHUGladiolithusVSHFLHVWKURXJKGHWDLOHG
PRUSKRORJLFDODQGFU\VWDOORJUDSKLFFRPSDULVRQLQFOXGLQJQHZREVHUYDWLRQVRQG. ‡abellatus:HDOVRSUHVHQWQHZ
molecular genetic data which suggests that Gladiolithus is deeply diverged from other coccolithophores and likely
originated from different Mesozoic ancestors.
Keywords: Gladiolithus, coccolithophores, molecular phylogeny, deep photic
1. Introduction
One of the interesting aspects of coccolithophore ecology
is the existence of a distinctive deep photic assemblage
occurring in oligotrophic waters beneath the deep chlorophyll maximum, in the lower part of the thermocline
and below (Winter et al. 1994, Young 1994). The mostcharacteristic species of this assemblage are )ORULVSKDHUD
profunda and *ODGLROLWKXVÁDEHOODWXV but a diverse rangeof rare taxa also occur. These include one other species of
Gladiolithus, G. striatus, described by Hagino & Okada(1998) and sporadically recorded since: we have observed
it in deep photic samples from the South Atlantic, the Indian
2FHDQDQG1RUWK3DFLÀFDQGLQ0HGLWHUUDQHDQVHGLPHQWVGladiolithus is less common in Quaternary sediments than
)ORULVSKDHUD but has been discovered in high abundancesin the Paleogene of Tanzania as described in Bown et al.
(2008, 2009). These fossil assemblages contain abundantspecimens indistinguishable from modern * ÁDEHOODWXV
but also distinctly different morphotypes and three further
species have been described - G. contus, G. ornatus and*EUHYLV.
The morphology of*ODGLROLWKXVÁDEHOODWXV and G. striatus is illustrated here in Plate 1 and has been described indetail by Halldal & Markali (1955), Jordan & Chamberlain (1992), and Hagino & Okada (1998). All described
Gladiolithus species are characterised by tube coccoliths formed of six elongate calcareous plates forming
an approximately hexagonal tube with one end closed.
Modern coccospheres of * ÁDEHOODWXV and G. striatus
are dimorphic also including simple disc-like coccoliths
termed lepidoliths (Plate 1 Figs. E-H). Complete coccospheres are bowl-shaped, partially enclosing the cell,with a rather large opening. The lepidoliths form the baseof the bowl and the tube coccoliths the rim. Collapsed
coccospheres can, however, appear rather different. The
tube coccoliths of both *ÁDEHOODWXV and G. striatus are
curved lengthwise. In G. striatus the inner concave surface

is smooth whilst the outer convex surface is ornamented
with striations. In * ÁDEHOODWXV ornamentation is morevariable although pitting and tooth-like projections fromthe sutures, occur in some specimens and tend to be morestrongly developed on the outer surfaces. The lepidolithsof G. striatus also show striations on their outer surface,whilst those of *ÁDEHOODWXV are smooth. In both species,
the lepidoliths are formed of two elements joined along a
medial suture.
A research student, Tim Adey (NOC), encountered an
XQLGHQWLÀHGFRFFROLWKRSKRUHLQGHHSSKRWLF]RQHVDPSOHV
from the South Atlantic, characterised by long, spinelike coccoliths (plates 2, 3). We have now obtained highresolution scanning electron microscope (SEM) imagesof a few specimens of this species and these indicatethat it is a new species of Gladiolithus, which we namehere G. adeyi. This discovery prompted further comparative studies of Gladiolithus including molecular genetic
LQYHVWLJDWLRQRILWVDIÀQLWLHVDQGQHZREVHUYDWLRQVRQWKH
crystallography of the coccoliths. These results are also
reported here.
2. Material and methods
2.1 Plankton sampling
We have found specimens of G. adeyi sp. nov. in two
samples from the South Atlantic gyre deep-photic zone,
collected during Atlantic Meridional Transect cruises;
respectively samples AMT14 CTD 26 120m (11.73°S,
25°W, 8/5/2004) and AMT18 CTD 75 165m. (19.12°S,
25.00°W, 29/10/2008). Two specimens were imaged athigh resolution from the AMT14 sample and one from the
AMT18 sample. Additional specimens have been seen inthese samples in low-resolution SEM images and in thelight microscope. Also, one specimen has been illustrated
in the literature, as Thorosphaera sp. L, by Reid (1980)
IURP WKH 1RUWK 3DFLÀF J\UH &UXLVH7DVDGD\  VWDWLRQ62&RFFROLWKRSKRUHV$EVWUDFWV

Plate 1Gladiolithus flabellatus and G. striatus.

A. * ÁDEHOODWXV, complete specimen showing form of intact coccosphere. Image NHM219-27, HOTS 169 cruise, Hawaii May 2005.
B. *ÁDEHOODWXVgroup of tube coccoliths. Image NHM310-076, KH90-3
FUXLVH13DFLÀFC. G. striatus, collapsed coccosphere, note that only outer surfaces oftube coccoliths show striations. Image NHM310-084, KH90-3
FUXLVH13DFLÀF
D. G. striatus, group of tube coccoliths. Image NHM310-082, KH90-3
FUXLVH13DFLÀF

E. * ÁDEHOODWXV lepidoliths proximal view showing baseplate scales.
Image NHM304-052, AMT 18 cruise, CTD89, 108m, S. Atlantic.
F. * ÁDEHOODWXV lepidoliths in distal view. Image NHM223-02, HOTS
169 cruise, Hawaii May 2005
G. *ÁDEHOODWXV base of tube coccolith. Image NHM310-076, KH90-3
FUXLVH13DFLÀF
H. G. striatus base of tube coccolith. Image NHM310-081, KH90-3
FUXLVH13DFLÀF
1%7KHPVFDOHEDUDWWKHEDVHRIWKHSODWHLQGLFDWHVWKHVFDOHRIÀJVE to H.

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63

Plate 2Gladiolithus adeyi sp. nov.

A-D Holotype specimen, from cruise AMT18, CTD station 075, 165m.
A. complete specimen, NHM322-08; B. the single lepidolith visible,
proximal view with baseplate scale visible, NHM322-09; C. detailof tips of tube coccoliths, NHM322-07; D. detail of bases of tube
coccoliths, NHM322-09.
E-F Specimen from cruise AMT14 CTD station 26 120m. E. complete specimen, NHM225-19; F. detail of bases of tube-coccoliths,
NHM225-20.

G-H Second specimen from same sample as E-F. G. complete specimen,
NHM225-09; H. detail of bases of tube-coccoliths, NHM225-10.
NB The 10µm and 1µm scale bars at the bottom of the plate indicate the
PDJQLÀFDWLRQVRILPDJHV$( *DQG') +UHVSHFWLYHO\64&RFFROLWKRSKRUHV$EVWUDFWV

Plate 3
Light micrographs

A-C Gladiolithus adeyi coccospheres in cross polars and cross polars
with 1ƪ gypsum plate.
D. Two large isolated tube coccoliths of *ÁDEHOODWXV.
E. *ÁDEHOODWXVFRFFRVSKHUH&KORURSODVWVDUHYLVLEOHLQWKHEULJKWÀHOG
image. Lepidoliths appear to be visible at the base of the coccosphere.

F. Light micrographs of the two Gladiolithus specimens from which
DNA sequences were collected. Top VFsp24, bottom VFsp26. Bothcollected at Villefranche sur mer.
$OOVSHFLPHQVH[FHSW)IURPVDPSOH$07&7'P

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1, 28°N, 150°W,140-160m, March 1974). Comparative material studied for other Gladiolithus species
included a further sample from cruise AMT 18 (CTD89,
108m, 28.9°S, 26.0W, 1st Nov 2008); two samples from
Hawaiian Ocean Time Series Cruise HOT-169, May
2005 (both samples from station 2, 22.75°N, 158.0°E) ;one sample from cruise KH90-3 of R/V Hakuho-Maru(Station AQ11, Nov. 1990, 4.0°S, 179.0°E, 173m, typematerial of G. striatus). Samples were collected from&7' ERWWOHV FRQFHQWUDWHG E\ YDFXXP ÀOWUDWLRQ RQWR
PHPEUDQH ÀOWHUV DQG H[DPLQHG E\ HOHFWURQ PLFURVFRS\
at the Natural History Museum London. For light microsFRS\ SRUWLRQV RI FHOOXORVH DFHWDWH ÀOWHUV ZHUH PRXQWHG
using Norland Optical Adhesive 74 and examined in crosspolarised light.

65

assumed to be invariable = 0.6211; and rates for variable
sites assumed to follow a gamma distribution with shapeparameter = 0.5222, were estimated by Modeltest 3.7.
The ML analysis was performed using the heuristic search
option with a branch swapping algorithm Tree bisectionreconnection (TBR) with the NJ tree as a starting tree.
Bootstrap analyses with 1000 replicates for the ML analysis were applied to examine the robustness and statistical reliability of the topologies (Felsenstein, 1985). For
the BI analysis, the GTR+I+G model was selected by the
MrModeltest. Markov chain Monte Carlo iterations werecarried out to 5.5 million generations, when the average
standard deviations of split frequencies were below 0.01,
indicating convergence of the iterations.
The rest of the concentrated seawater sample used
IRU WKH LVRODWLRQ RI FHOOV ZDV ÀOWHUHG RQWR D Millipore
2.2 Molecular genetic analysis
HAWP04700 membrane. Specimens of Gladiolithus were
10L of subsurface seawater sample (100 m) were
LGHQWLÀHG XQGHU WKH 6(0 LQ RUGHU WR FRQÀUP LWV SUHVFROOHFWHG IRU ÁRULVWLF DQG PROHFXODU VWXGLHV RI FRFFRence and determine the species - *ODGLROLWKXVÁDEHOODWXV
lithophores using a Niskin bottle equipped to the boat La
was present but G. striatus and G. adeyi were not seen.
Sagitta of the Villefranche-sur-mer Oceanological ObserSince it is not possible to distinguish *ÁDEHOODWXV andYDWRU\ )UDQFH IURP%D\RI9LOOHIUDQFKH   1
G. striatus in the LM the sequences have been deposited  ( RQWK6HSWHPEHU7KHVDPSOHZDVin GENBANK as Gladiolithus sp., however, it is highly
concentrated using a 1 µm mesh-size plankton net. A total
likely they come from *ODGLROLWKXVÁDEHOODWXV.
of 10 Gladiolithus cells (VFsp- 23-26 and 31-36) wereisolated using a micropipette under an inverted LM, and
3. Systematic taxonomy
WKHQVXEMHFWHGWRVLQJOHFHOO3&5DPSOLÀFDWLRQIROORZLQJ*ODGLROLWKXVDGH\LVSQRY<RXQJ+DJLQR 3RXOWRQ
Takano and Horiguchi (2005). The primers used for PCR
Synonymy7KRURVSKDHUDVS/5HLG  SODWHDPSOLÀFDWLRQ 3&5 FRQGLWLRQV SURFHGXUH IRU VHTXHQFH
ÀJVS
determination and the sequencers, were the same as
those described in Hagino et al. (2009). The results Diagnosis: A species of Gladiolithus with long narrow
ZHUHFRQÀUPHGE\VHTXHQFLQJERWKIRUZDUGDQGUHYHUVH tube-coccoliths tapering continuously from the base to thestrands. Partial 18S rDNA sequences were successfully tip. Lepidoliths are formed of a single calcite plate with aobtained from two specimens, VFsp24 and VFsp26 (Plate narrow rim.
Derivation of name: In honour of Tim Adey, biological3F), independently from each other.
For the phylogenetic analysis, a total of 40 18S rRNA RFHDQRJUDSKHUZKRÀUVWREVHUYHGWKHVSHFLHV
gene sequences of the Division Haptophyta, including a Type specimen: Specimens illustrated in SEMs NHM
sequence of the Pavlovophyceae as an out-group, were 322-05 to 322-09.
obtained from GenBank. Since 18S rDNA sequences Type material: 3ODQNWRQ ÀOWHU FROOHFWHG DW DP
of the specimens VFsp24 (GenBank Accession number on 29/10/2008, from 165m water-depth, at 19.12°S,
AB983344, 1660-bp) and VFsp26 (GenBank Acces- 25.00°W, from CTD station 75 of cruise AMT18.
sion number AB983345, 1693-bp) were identical to Type repository: Palaeontology Department, The Natural
each other in the region in which they overlapped (1660- History Museum, London.
bp), we used the sequence of VFsp24 as representative
4. Resultsof them. The sequences were aligned together with thesequences obtained in this study using Clustal W (http:// 4.1 Description of G. adeyi
www.genome.jp/tools/clustalw/). Phylogenetic trees were Coccosphere. The four coccospheres observed in theconstructed based on the Maximum Likelihood (ML) SEM are all similar, consisting of 15 to 22 very long
method and Bayesian inference (BI) using PAUP version coccoliths (~20 µm) apparently radiating from a small
4.0b10 (Swofford, 2002) and Mr. Bayes v3.1.2 (Ronquist central body. The specimen illustrated by Reid (1980) also
KDVVHYHUDOOHSLGROLWKVLHÁDWERG\FRFFROLWKV2QO\RQH
and Huelsenbeck, 2003), respectively.
For ML analysis, a likelihood score (-lnL = 8997.8809) lepidolith is visible on the specimens we have imaged. It
was obtained under the GTR+I+G model with the is possible that all the imaged specimens are incomplete
following parameters: assumed nucleotide frequen- and that the similarity in coccolith numbers on the specicies A= 0.2395, C= 0.2194, G= 0.2801, and T=0.2611; mens observed to date is a coincidence. Likewise the way
substitution-rate AC= 1.0977, AG= 1.4576, AT= 0.6624, the tube coccoliths radiate from a small central body may
CG= 0.9323, CT= 4.4195, GT= 1; proportion of sites prove to be misleading since these are clearly collapsed

66&RFFROLWKRSKRUHV$EVWUDFWV

225-9

225-19322-06

Reid 1980

Number of tube coccoliths

22

17

17

17

Length of tube coccoliths

20.8-22.4µm

20.1-22.1µm

21.5-23.8µm

18.5-21µm

0.7-0.8µm

0.8-0.9µm

0.7-0.8µm

0.7-0.9µm

0.34-0.47µm

0.33-0.52µm

0.36-0.55µm/

75-82°

78-83°

77-83°

/

/

/

1.2µm

1.1-1.2µm

Basal width of tube coccoliths
Height of basal elements
Angle of inclination of basal elements
Lepidolith length

Table Dimensions of observed G. adeyi specimens, including the one imaged by Reid 1980.

coccospheres. Most specimens seen in the light microscope were isolated tube coccoliths or radial scatters witha few coccoliths (e.g. Plate 3, Fig. B). Two coccospheres
were seen, however, with all the tube-coccoliths in a
FRQHVKDSHGPDVV 3ODWHÀJV$DQG& DQGE\DQDORJ\with * ÁDEHOODWXV, these may be closer to the original
coccosphere form, but neither lepidoliths nor chloroplasts
could be seen.
Tube coccoliths. These are 19-22µm long (see Table)
WDSHULQJXQLIRUPO\IURPDEDVHPZLGHWRDÀQH
SRLQW7KH\DUHKROORZWXEHVZLWKDÁDWWHQHGKH[DJRQDO
cross-section formed of six laths, running the entire lengthof the coccolith. The sutures between the laths appear tobe slightly irregular giving a beaded appearance. At thebase of the coccoliths there is a low cycle of additional
elements, these are clockwise imbricate, sloping at ca 80°
to the base and consist of pairs of alternating short andlong elements joined at the base but with a gap between
them for most of their length. Each joined pair of basal
elements overlies the suture between a pair of elongate
laths. The base of the coccoliths appears to be covered bya calcareous plate, but it is not perfectly imaged in anyof our specimens. At the apex of the coccoliths the tube
is only ca. 0.2µm wide and all six laths are terminated at
the same level leaving a small opening with minute spines
extending from the sutures.
Lepidoliths. The specimen imaged by Reid (1980) has
at least seven elliptical disk-shaped coccoliths 1.1 to 1.2µm long, most of which have a low rim suggesting thatthey are seen in distal view. We agree with her in identifying these as lepidoliths. We observed one similar coccoOLWK 3ODWH)LJ% 7KLVLVÁDWWHQHGKH[DJRQDOLQVKDSH
1.2µm long and 0.5 µm wide. It has an ornamentation
RIÀQHFXUYHGUDGLDWLQJULGJHVWKLVLVDOPRVWFHUWDLQO\
DQ RUJDQLF EDVHSODWH VFDOH ZLWK UDGLDWLQJ PLFURÀEULOV
Around the edge of the coccolith is a narrow rim cycle,
this appears to surround a single plate, with no sign of amedian suture as seen in the lepidoliths of *ÁDEHOODWXVand G. striatus.
4.2 Crystallographic orientation of Gladiolithus coccoliths
The crystallographic orientation of the calcite crystals

which form coccoliths has been shown to be a conservaWLYHIHDWXUHRIPXFKYDOXHIRUFODVVLÀFDWLRQ HJ<RXQJHW
al. 1991, 1998). Hence we would expect all Gladiolithus
coccoliths to have similar crystallographic orientation.
There are few detailed crystallographic observations on*ÁDEHOODWXV so we re-examined it for this comparison.
On isolated *ÁDEHOODWXV tube coccoliths (e.g Plate 3 Fig
F) the central lath is bright when the coccolith is at 45°
and use of a 1ƪplate indicates that the c-axis is parallelwith the coccolith length. When the coccolith is parallelwith one of the polarization directions the central lathis dark but the side laths are strongly birefringent andwith a 1ƪ plate they show opposite colours (one is blue
the other yellow), this is due to the c-axes being inclined
about 45° from the vertical (see diagram). The lepidoliths of * ÁDEHOODWXV can sometimes be clearly seen on
complete coccospheres in side view (e.g. Plate 3 Fig E)
and it is then clear that they are formed of crystal units
ZLWKVXEYHUWLFDOFD[HVWKLVDOVRPHDQVWKH\DUHGLIÀFXOW
to observe in plan view.
Observations on G. adeyi tube-coccoliths are slightly
trickier since they are narrower and the birefringence ofthe side laths often dominates over that of the central lath
but they show the same c-axis orientations (Plate 3 Figs
A-C). Interestingly whilst isolated coccoliths typicallyshow two parts with contrasting orientations (e.g Plate 3
Figs. B, C), when a mass of coccoliths are aligned then asingle birefringence colour dominates (Plate 3 Fig A). We
have not been able to clearly identify any lepidoliths of G.
adeyi in the light microscope.
4.3 Baseplate scales in Gladiolithus
Organic baseplate scales have not previously been
described from Gladiolithus. Our observation of such ascale on the lepidolith of G. adeyi prompted us to lookfor examples in * ÁDEHOODWXV and one specimen withapparent baseplate scales was found (Plate 1 Fig.E). On
WKLV VSHFLPHQ VRPH OHSLGROLWKV GR SRVVHVV ÀQH ULGJHV
resembling a baseplate scale, though others do not. Thosewith possible scales also show different curvature of themedian suture to those without. This curvature of thesuture is a general feature of *ÁDEHOODWXV lepidoliths andcan be used to distinguish the distal (or outer) and prox-

&RFFROLWKRSKRUHV$EVWUDFWV

imal (or inner) surface ofthe lepidolith. The putative scales appear on theproximal surface as would
be expected for base-platescales, so we conclude thatthese almost certainly areorganic baseplates scales.
4.4 Phylogenetic
position of Gladiolithus
As described in themethods section partial
18S DNA sequences wereobtained from two Gladiolithus cells collectedfrom Villefranche-sur-mer.
Comparison of these with
Figure 1 Drawings of G. adeyi other haptophyte sequencesand *ÁDEHOODWXV tube coccoliths. allows derivation of theArrows indicate the c-axis orien- maximum likelihood tree
tations as inferred from the obser(Fig. 2). In this tree Gladivations with the1ƪ plate.
olithus falls at the base of
the coccolithophore clade. This suggests that it is a truecoccolithophore, but possibly only distantly related to anyof the extant groups. It should be noted, however, that67

bootstrap values in this part of the tree are low so there
LV ORZ FRQÀGHQFH LQ WKH SUHFLVH WRSRORJ\ DQG LQGLFDWHG
relationships.
5. Discussion
The combination of six-sided tube coccoliths and simple
body coccoliths, lepidoliths, allows us to place the new
species in Gladiolithus with some certainty. This placePHQWLVFRQÀUPHGE\WKHLGHQWLFDOFU\VWDOORJUDSKLFRULHQtation of the tube coccoliths. It is also evidently a deep
photic species like the other described extant species andthe beaded sutures of the tube coccoliths is reminiscentof the ornamentation seen on * ÁDEHOODWXV. The very
elongate shape of the coccoliths is reminiscent of thefossil species G. contus, however in the current species
the coccoliths taper uniformly from the base to the tip
whilst in G. contus they appear to taper toward both ends.
The coccoliths are clearly different to any of the otherdescribed species. So this is a new species of Gladiolithus.
G. adeyi GRHV KRZHYHU GLIIHU VLJQLÀFDQWO\ IURP WKHother extant species. The tube-coccoliths are much longer
and do not show any curvature, or differentiation of an
inner smooth concave face and outer ornamented convex
face. Also, the basal cycle is distinctive: there are basal
elements in G. striatus, as described by Hagino & Okada(1998) and shown in Plate 1 Figs D and H, but they are
not obviously similar, and regular basal elements are notevident in * ÁDEHOODWXV
although small irregularelements are sometimes
VHHQ 3ODWH  ÀJV % DQGG). Finally the lepidolithsof G. adeyi have a rim of
VPDOO HOHPHQWV 3ODWH  ÀJB), which are not present on* ÁDEHOODWXV or G. striatus
lepidoliths. Actually, the G.
adeyi lepidoliths resemble
the baseplates of * ÁDEHOlatus and G. striatus coccoOLWKV FRPSDUH3ODWHÀJV*+ DQG 3ODWH  ÀJ %  7KLV
range of rather strong differences suggests that G. adeyi
is well-separated from theother species, and possibly
Figure 2
Maximum likelihood tree indicating
possible phylogenetic relationships
between the sampled haptophyte
species based on the 18S ribosomal
DNA gene. The numbers on eachnode indicate the bootstrap values
from ML analysis and posterior
probability of BI analysis. Higher
values indicate that the node is better supported.

68&RFFROLWKRSKRUHV$EVWUDFWV

the differences between the extant species * ÁDEHOlatus, G. striatus and G. adeyiUHÁHFWWKHORQJHYLW\RIWKH
genus, which we now know extends back to the Paleocene(Bown et al., 2009).
Our molecular phylogenetic results place the origin of
Gladiolithus in the basal divergence of the coccolithophore clade, and this divergence is generally interpreted
as corresponding to the Early Jurassic radiation of coccolithophores (e.g. Saez et al. 2004, Medlin et al. 2007). On
this basis it is perhaps more likely that Gladiolithus had an
independent origin in the Mesozoic than that it is closely
related to any of the well-established Cenozoic families. This is further supported by our detailed crystallographic and structural observations, which do not suggest
any extant coccolithophores as likely close ancestors.
This is a rather surprising result but is supported by the
recent observations of abundant Gladiolithus specimens
in exceptionally preserved Paleogene sediments from
Tanzania (Bown et al. 2009). The results suggest that it
will be well worth studying the origins of Gladiolithus
in well-preserved Palaeocene sections and attempting toisolate it into culture.
Acknowledgements
We are grateful to fellow scientists and crew of the James
Clark Ross for assistance in sampling during the Atlantic
Meridional Transect cruises, and especially to Tim Adeyfor his initial observations. The sampling for molecularphylogenetics was facilitated by Jean-Pierre Gattuso andcolleagues at Villefranche and by Colomban de Vargas.
7KHÀOWHUVDPSOHXVHGIRU6(0REVHUYDWLRQRIG. striatus
was provided by Hiromi Matsuoka. We thank Takeo Horiguchi for help with molecular phylogenetic experiments.
This is contribution number 256 of the AMT programme.
References
Bown, P.R., Dunkley Jones, T., Lees, J.A., Randell, R.,
Mizzi, J.A., Pearson, P.N., Coxall, H., Young, J.R.,
Nicholas, C.J., Karega, A., Singano, J. & Wade, B.
2008. A Paleogene calcareous microfossil KonservatLagerstätte from the Kilwa Group of coastal Tanzania Bulletin of the Geological Society of America,
120(1/2): 3-12.

Bown, P.R., Young, J.R., Dunkley Jones, T. & Randell, R.
2009. A Paleogene record of extant lower photic zone
calcareous nannoplankton. Palaeontology, 52(2): 457469.
)HOVHQVWHLQ-&RQÀGHQFHOLPLWVRQSK\ORJHQLHVDQ
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