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Erdtmanitheca portucalensis, a new pollen organ from the Early Cretaceous (Aptian–Albian) of Portugal with Eucommiidites-type pollen

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A new lignitised, slightly compressed pollen organ, Erdtmanitheca portucalensis, with affinities to extinct Erdtmanithecales from the Early Cretaceous (Aptian-Albian) of Vale de Agua (Lusitanian Basin, western Portugal), is described. The pollen organ is composed of loosely arranged microsporophylls radiating from a central core. The estimated number of microsporophylls is about 100-150. The microsporophylls are sessile and ellipsoidal to barrel-shaped with a flattened or slightly apically depression containing about ten narrow sporangia. The sporangia enclose abundant well-preserved pollen grains of Eucommiidites-type. Pollen grains found in situ are elliptical in equatorial outline, about 16.0-27.2 m long and 11.9-16.4 m wide. The main (distal) colpus is long with expanded rounded ends. It is flanked by two subsidiary colpi in an almost equatorial position. The surface of the pollen wall is psilate and occasionally punctate. The ektexine is composed of a distinct tectum, granular infratectal layer and a thin foot layer. The endexine is thick and laminar. The new Early Cretaceous Portuguese pollen-organ is similar in several respects to that of Erdtmanitheca texensis described from the Late Cretaceous of Texas, USA. The new fossil species further documents the importance of the Bennettitales-Erdtmanithecales-Gnetales group in the Early Cretaceous floras of Portugal extending the stratigraphic and geographical distribution of the genus with regard to systematic and phylogenetic significance of the Eucommiidites-producing plants that may have been co-occurring with the Early Cretaceous diversification of angiosperms. It is ascertained that perforate tectum occurs in pollen grains with a well-developed foot layer as well as in pollen grains in which a foot layer is poorly developed or lacking, and that pollen features do not support a separation of the Erdtmanithecales seeds and pollen organs.
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Erdtmanitheca portucalensis
, a new pollen organ from the Early
Cretaceous (Aptian-Albian) of Portugal with
Eucommiidites
-type pollen
Mário Miguel Mendes
ab
; João Pais
a
; Kaj Raunsgaard Pedersen
c
; Else Marie Friis
d
a
CICEGe, Earth Sciences Department, Technology and Sciences College, New University of Lisbon,
Caparica, Portugal
b
Geosciences Department, University of Évora, Portugal
c
Department of Geology,
University of Århus, Århus C, Denmark
d
Department of Palaeobotany, Swedish Museum of Natural
History, Stockholm, Sweden
Online publication date: 17 March 2010
To cite this Article Mendes, Mário Miguel, Pais, João, Pedersen, Kaj Raunsgaard and Friis, Else Marie(2010) '
Erdtmanitheca
portucalensis
, a new pollen organ from the Early Cretaceous (Aptian-Albian) of Portugal with
Eucommiidites
-type
pollen', Grana, 49: 1, 26 — 36
To link to this Article: DOI: 10.1080/00173130903442826
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ISSN 0017-3134 print/ISSN 1651-2049 online © 2010 Collegium Palynologicum Scandinavicum
DOI: 10.1080/00173130903442826
Grana, 2010; 49: 26–36
SGRA
Erdtmanitheca portucalensis, a new pollen organ from the Early
Cretaceous (Aptian–Albian) of Portugal with Eucommiidites-type
pollen
Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen
MÁRIO MIGUEL MENDES
1,2
, JOÃO PAIS
1
, KAJ RAUNSGAARD PEDERSEN
3
&
ELSE MARIE FRIIS
4
1
CICEGe, Earth Sciences Department, Technology and Sciences College, New University of Lisbon, Caparica, Portugal,
2
Geosciences Department, University of Évora, Portugal,
3
Department of Geology, University of Århus, Århus C, Denmark,
4
Department of Palaeobotany, Swedish Museum of Natural History, Stockholm, Sweden
Abstract
A new lignitised, slightly compressed pollen organ, Erdtmanitheca portucalensis, with affinities to extinct Erdtmanithecales
from the Early Cretaceous (Aptian–Albian) of Vale de Água (Lusitanian Basin, western Portugal), is described. The pollen
organ is composed of loosely arranged microsporophylls radiating from a central core. The estimated number of microsporo-
phylls is about 100–150. The microsporophylls are sessile and ellipsoidal to barrel-shaped with a flattened or slightly api-
cally depression containing about ten narrow sporangia. The sporangia enclose abundant well-preserved pollen grains of
Eucommiidites-type. Pollen grains found in situ are elliptical in equatorial outline, about 16.0–27.2
μm long and 11.9–16.4
μm wide. The main (distal) colpus is long with expanded rounded ends. It is flanked by two subsidiary colpi in an almost equato-
rial position. The surface of the pollen wall is psilate and occasionally punctate. The ektexine is composed of a distinct tec-
tum, granular infratectal layer and a thin foot layer. The endexine is thick and laminar. The new Early Cretaceous Portuguese
pollen-organ is similar in several respects to that of Erdtmanitheca texensis described from the Late Cretaceous of Texas, USA.
The new fossil species further documents the importance of the Bennettitales-Erdtmanithecales-Gnetales group in the
Early Cretaceous floras of Portugal extending the stratigraphic and geographical distribution of the genus with regard to
systematic and phylogenetic significance of the Eucommiidites-producing plants that may have been co-occurring with the
Early Cretaceous diversification of angiosperms. It is ascertained that perforate tectum occurs in pollen grains with a well-
developed foot layer as well as in pollen grains in which a foot layer is poorly developed or lacking, and that pollen features
do not support a separation of the Erdtmanithecales seeds and pollen organs.
Keywords: Early Cretaceous, Erdtmanithecales, Eucommiidites, Figueira da Foz Formation, mesofossils, pollen,
pollen organ, Portugal
Lower Cretaceous strata from the Estremadura and
Beira Litoral regions (Lusitanian Basin, western
Portugal) have yielded rich fossil floras including
exquisitely preserved angiosperm flowers. These floras
are pivotal for understanding vegetational structure
and changes in the region during the earliest phases
of angiosperm diversification. Previous studies of
plant fossils from this region focused on macrofossil
floras mostly containing leaves (Heer, 1881;
Saporta, 1894; Romariz, 1946; Teixeira, 1948,
1950, 1952) and microfossil floras containing dis-
persed palynomorphs (Hasenboehler, 1981; Pais &
Reyre, 1981; Pais & Trincão, 1983; Leereveld et al.,
1989; Trincão, 1990; Heimhofer et al., 2007). More
recently, the discovery and study of well-preserved
mesofossil floras with abundant angiosperm reproduc-
tive organs such as inflorescences, flowers, stamens,
fruits and seeds, has greatly increased our know-
ledge on the reproductive biology and organisation
of Cretaceous angiosperms (Friis et al., 1994, 1997,
Correspondence: Mário Miguel Mendes, CICEGe, Earth Sciences Department, Technology and Sciences College, New University of Lisbon, Quinta da
Torre, 2829-516 Caparica, Portugal. E-mail: mmmendes@mail.telepac.pt
(Received 29 July 2009; accepted 19 October 2009)
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Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen 27
1999, 2000, 2001, 2004, 2006). The same mesofossil
floras also include well-preserved and informative
remains of other plant groups. Most notably, the
recognition of a new complex of seeds with a unique
seed structure otherwise only found in Bennettitales,
Erdtmanithecaes and Gnetales (the BEG group of
Friis et al., 2007) is of importance for understanding
the total vegetation structure and is of potentially
great importance for understanding phylogenetic
relationships among seed plants. Some of the seeds
are closely related to extant Ephedra L. of the Gnet-
ales (Rydin et al., 2004, 2006) and one seed type,
Erdtmanispermum juncalense Mendes, Friis & Pais
can be placed in the extinct order Erdtmanithecales
(Mendes et al., 2008a). The Erdtmanithecales are
also represented in the Early Cretaceous floras of
Portugal by the microsporangiate organ Eucommiitheca
hirsuta Friis & Pedersen (Friis & Pedersen, 1996).
Other seeds are of uncertain position in the BEG
group and have been assigned to extinct genera such as
Buarcospermum Friis, Pedersen & Crane, Lignierisp-
ermum Friis, Pedersen & Crane and Lobospermum
Friis, Pedersen & Crane (Friis et al., 2007, 2009). A
further seed type, Raunsgaardispermum Mendes, Pais
& Friis, combines distinct ephedroid seed characters
with bennettitalean and erdtmanithecalean pollen
features (Mendes et al., 2008b).
In this article, we describe a new Erdtmanithecales
microsporangiate organ from Portugal that we assign
to the genus Erdtmanitheca Pedersen, Crane & Friis
first described from the Late Cretaceous (Early Ceno-
manian) of Texas, USA (Pedersen et al., 1989). This
new finding further documents the importance of the
BEG group in the Early Cretaceous floras of Portugal
and adds to the diversity of the group.
Materials and methods
The fossil pollen organs described here were
extracted from sediment samples collected from the
Vale Farelo opencast clay pit complex, near the
small village of Vale de Água (39º 37’ 13.1’’ N; 08º
51’ 57.2’’ W), in the Estremadura region, western
Portugal (Figure 1).
The fossil specimens were isolated from dark-grey
mudstone deposits previously assigned to the “Com-
plexos Gresosos da Nazaré e Cós-Juncal” (Carta
Geológica de Portugal, Folha 26-B Alcobaça,
Zbyszewski et al., 1961) and subsequently included
in the Figueira da Foz Formation (Dinis, 1999,
2001). According to Dinis (pers. comm., 2009) the
fossil-bearing horizons belong to the Famalicão
Member, which is the basal part of the Figueira da
Foz Formation (Dinis, 1999, 2001; Rey et al., 2006).
A late Aptian age was suggested by Dinis et al.
(2002) for the Figueira da Foz lower boundary, using
mainly macrofossils, pollen and spores as well as
sedimentological and lithofacial correlations
(Teixeira, 1950; Dinis & Trincão, 1991; Friis et al.,
1999; Heimhofer et al., 2005), and Rey et al. (2006)
indicated a late Aptian to early Albian age for the
Famalicão Member of the Figueira da Foz Formation.
In general, the fossils are lignitised with the original
three-dimensional form slightly compressed. Bulk
matrix samples were dried in the laboratory, disag-
gregated in water and sieved using a shower
through a 125
μm screen. The fossils described in
this paper were isolated from one sediment sample
(sample VF-141) collected by M. M. Mendes and
J. L. Dinis in 2008. The species diversity is low,
but the sample yielded some seeds, twigs and
leaves of conifers, as well as several angiosperm
fossils such as possible nymphaealean seeds, seeds
assignable to the extinct genus Anacostia Friis,
Crane and Pedersen, as well as other seeds and a
variety of endocarps. A preliminary palynological
analysis of the same sample has documented a pal-
ynoflora mainly characterised by fern spores, gym-
nosperm pollen, including pollen grains of
Eucommiidites-type, and a few angiosperm pollen
grains.
Figure 1. Map illustrating the studied area in western Portugal
(square). The approximate location of the Vale Farelo clay pit
complex where the specimens were collected is indicated by an
asterisk.
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28 M. M. Mendes et al.
The fossils were cleaned in hydrofluoric (40%
HF) and hydrochloric (10% HCl) acids, thoroughly
rinsed in water and air dried. The specimens were
observed with a Nikon SMZ800 stereomicroscope.
The specimens selected for scanning electron
microscopy were mounted on polished aluminium
stubs and coated with gold for 60 seconds in a sputter
coater, and examined using a Hitachi Field S-4300
scanning electron microscope (FE-SEM) at 2 kV, at
the Swedish Museum of Natural History, Stockholm.
Pollen for TEM was removed from specimen P0185
after SEM, embedded in Epon (TAAB 812) after
dehydration in a grade of acetone and acetone/Epon
solutions. Sections were cut with a diamond knife on
a RMC MT7 Ultramicrotome, triple stained with
lead citrate and uranyl acetate (following Daddow,
1983), and examined using a Leo 912 AB Omega
transmission electron microscope (with a high volt-
age of 80 kV) at the Swedish Museum of Natural
History. Pollen grains for light microscopy (LM)
were removed from specimen P0185 and glycerine
was used for mounting permanent slides. LM studies
were performed using an ECLIPSE E600 Nikon
microscope and specimens were photographed using
a Nikon DS-L2 digital camera.
Dimensions of the pollen organs were measured
under the stereomicroscope and the dimensions of
the pollen grains embedded in glycerine were meas-
ured using LM; dry pollen grains were measured
from SEM-micrographs, and the layers of the pollen
wall were measured on TEM-micrographs.
LM, SEM- and TEM-micrographs were improved
using Photoshop software to enhance contrast and
remove stain from the background.
The specimens formally described in this paper
are deposited in the Earth Sciences Department,
Technology and Sciences College, New University
of Lisbon, Portugal.
Results
Systematic description
Spermatophyta
Erdtmanithecales Friis & Pedersen, 1996
Erdtmanithecaceae Friis & Pedersen, 1996
Erdtmanitheca Pedersen, Crane & Friis, 1989
Erdtmanitheca portucalensis Mendes, Pais, Pedersen
& Friis sp. nov. (Figures 2–5)
Specific diagnosis. Pollen organ bearing loosely
arranged microsporophylls radiating from a central
core. Microsporophyll ellipsoidal to barrel-shaped with
a flattened or slightly depressed peltate apical head;
each microsporophyll with about ten narrow sporangia
in a radial arrangement. Pollen of Eucommiidites-type
with long main (distal) colpus flanked by two lateral
colpi in almost equatorial position; tectum psilate,
occasionally with small puncta proximally. Tectum
thick, infratectal layer and foot layer thin. Pollen length
(L) to width (W) ratio about 3:2.
Derivation of the specific name. The specific epithet
portucalensis is derived from Portugal, where the fos-
sils were collected.
Dimensions. Pollen organs about 1.9 mm long and
1.97–2.65 mm wide. Pollen grains about 20.5–21.8
μm long and 14.5–16.1 μm wide.
Holotype. P0186 (Vale de Água – Vale Farelo clay
pit, sample VF-141) (Figures 3A–D, 4E, J–L).
Paratype. P0185 (Vale de Água – Vale Farelo clay
pit, sample VF-141) (Figures 2, 3E–F, 4A–D, F–I).
Type locality. Vale de Água – Vale Farelo open-
cast clay pit complex, Estremadura region, western
Portugal (39º 37’ 13.1’’ N; 08º 51’ 57.2’’ W).
Stratigraphic position. Famalicão Member of the
Figueira da Foz Formation.
Age. Early Cretaceous (late Aptian–early Albian).
Description and remarks on the species. The mate-
rial studied here includes two dispersed lignitised
and slightly compressed pollen organs. None of the
specimens are complete and there are no remains of
stalk or dehiscence scar. The shape of the fragments
indicates that the pollen organ was originally spherical
(best seen in specimen P0185), consisting of numerous
microsporophylls borne in a radial arrangement
around a central receptacle. The specimens are
Figure 2. Erdtmanitheca portucalensis sp. nov. from the Early Creta-
ceous of Portugal. LM-micrographs of Eucommiidites-type pollen
grains isolated from the paratype (P0185). Scale bar – 10
μm.
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Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen 29
Figure 3. Erdtmanitheca portucalensis sp. nov. from the Early Cretaceous of Portugal. SEM-micrographs of pollen organs. A. Holotype
showing sessile microsporophylls loosely arranged in a radial pattern from a central core (P0186). B, C. Detail of holotype showing the
ellipsoidal to barrel-shaped microsporophyll (P0186). D. Detail of microsporophyll showing sporangia with pollen grains (P0186).
E. Fragment from paratype showing microsporophyll arranged in radial pattern (P0185). F. Detail of paratype showing pollen grains in
elongated pollen sacs (P0185). Scale bars – 1 mm (A, E); 500
μm (B); 250 μm (C); 50 μm (D); 100 μm (F).
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30 M. M. Mendes et al.
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Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen 31
about 1.89 mm long and 1.97–2.65 mm wide
(Figure 3A–F). The most complete specimen con-
sists of about 20 microsporophylls and the other
specimen consists of six microsporophylls. The
estimated diameter of the pollen organs is about
2.0 mm and the estimated number of microsporo-
phylls in each pollen organ is about 100–150. The
microsporophylls are sessile and loosely arranged in
Figure 5. Erdtmanitheca portucalensis sp. nov. from the Early Cretaceous of Portugal. Eucommiidites-type pollen grains isolated from the
paratype (P0185). TEM-micrographs of pollen wall ultrastructure. A, B. Transverse sections of pollen grains perpendicular to the main
colpus (mc) and lateral colpi (lc). C. Detail of grain in Figure 5B showing stratification of pollen wall with thick homogenous tectum (t),
thin granular infratectal layer (it), foot layer (fl) and thick laminar endexine (end). D. Detail of Figure 5B showing apertural region of one
lateral colpus enlarged with thinning of tectum towards the aperture and tectal verrucae on the margins to the aperture. Scale bars – 3
μm
(A, B); 2
μm (C, D).
Figure 4. Erdtmanitheca portucalensis sp. nov. from the Early Cretaceous of Portugal. SEM-micrographs of Eucommiidites-type pollen
grains isolated from holotype and paratype. A, B & D. Group of pollen grains isolated from the paratype showing well-defined distal col-
pus flanked by two subsidiary colpi in the equatorial plane (P0185). C. Orbicules (Ubisch bodies) spaced on the sporangium wall
(P0185). E. Pollen grain isolated from the holotype showing wall with perforations on the proximal surface between the lateral colpi.
F–I. Pollen grains isolated from paratype showing psilate wall surface and margins of apertures (P0185). J. Pollen grain isolated from the
holotype showing perforations along the margins of the main colpus (P0186). K. Pollen grain, isolated from the holotype, in equatorial
view showing colpi (P0186). L. Fragmented pollen grain isolated from the holotype showing wall stratification and details of aperture
structure (P0186). Scale bars – 20
μm (A, J); 25 μm (B, D); 5 μm (C, L, M); 10 μm (E–I).
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32 M. M. Mendes et al.
a radial pattern from the central receptacle, separate
from each other for most of their length. The micro-
sporophylls are ellipsoidal to barrel-shaped, about
1.1 mm long and 0.6 mm wide, with a rounded pel-
tate apical head that is flattened or with a shallow
central depression.
The microsporophylls are apparently synangiate
with about ten radially arranged sporangia embedded
in a common tissue, but the number of sporangia in
each microsporophyll and the exact organisation of
the sporangia on the microsporophyll is unclear.
Dehiscence is by longitudinal slits that extend for
almost the full length of the sporangia from the base
to the margin of the apical head (Figure 3B–D).
In situ pollen is of the Eucommiidites-type, elliptical
in equatorial outline, rounded at both ends, and
about 16 (20.5) 27.2
μm long and 11.9 (13.9) 16.4
μm wide (15 specimens measured). Length to width
ratio is about 3:2. The pollen wall is typically invagi-
nated in the aperture regions (Figures 2, 4A, B, D–I)
and details of the aperture region and membrane are
only seen in a few specimens in SEM, but can also
be observed in TEM. The invagination also indicates
that the pollen grains were probably more spherical
in hydrated, living state. The aperture arrangement is
distinct. There is a well-defined distal colpus, with
slightly expanded rounded ends (Figure 4A, B, D–I).
The distal colpus is flanked by two lateral colpi
placed more or less in the equatorial plane. They are
slit-like with pointed ends and longer than the distal
colpus and almost meet at either end (Figure 4A, B,
D), although none of them merge to form a ring col-
pus. Margins of the apertures are irregular and the
aperture membrane is verrucate-granular (Figures
4F, H, I, 5A, B, D).
The pollen wall is tectate and psilate. In some speci-
mens, small holes (puncta), 0.1–0.4
μm in diameter,
occur on the proximal surface between the lateral colpi
(Figure 4A, E) or occasionally along the margins of the
main colpus (Figure 4A, J). The puncta were not
observed in the TEM-sections and were apparently not
continuous through the tectum. Some pollen are
slightly contracted over the proximal pole to form a
faint regular pattern. We ascribe the differences in the
appearance of the tectum surface to differences in pre-
servation, where increased degradation of the pollen
wall causes more prominent holes.
The pollen wall is about 1
μm thick in non-apertural
regions and thinner over the apertures. Pollen wall
stratification and details of aperture structure were
observed by SEM in a fragmented pollen grain
(Figure 4L) and by TEM in ultrathin sections
(Figure 5). The ektexine (outer layer, lighter staining
in ultrathin sections) is composed of a distinct tectum,
a thin granular infratectal layer, and a thin foot layer.
The tectum is homogenous, about 0.60
μm thick in
non-apertural regions, but gradually thinning in the
apertural regions and lacking over the aperture
(Figure 5A, B, D). It is granular to verrucate on the
margins of the lateral colpi (Figure 5D) and apparently
smooth on the margins of the main colpus (Figure
5A). The granular infratectal layer is about 0.1
μm
thick. It is more distinct in SEM (Figure 4L) than in
TEM (Figure 5C) and may be compressed during
fossilisation. The foot layer is of approximately the
same thickness as the infratectal layer, about 0.1
μm.
It is also homogenous as the tectum, but with
uneven outer and inner surface (Figure 5C).
The endexine (inner layer, darker staining in
ultrathin sections) is about 0.25
μm thick, laminar,
and of more or less even thickness in apertural and
non-apertural regions (Figure 5).
Small orbicules (Ubisch bodies), about 0.5–1.5
μm in diameter, and with an almost smooth surface
are densely spaced on the inner surface of the spo-
rangia wall and scattered on the surface of the pollen
grains (Figure 4C). They are solid in TEM.
Discussion
Eucommiidites and Erdtmanithecales
The organisation of the fossil pollen organs
described here and their distinctive Eucommiidites-
type pollen unequivocally place the fossils in the
Erdtmanithecales, an extinct order established to
accommodate fossil seeds and microsporangiate
organs containing Eucommiidites-type pollen (Friis &
Pedersen, 1996).
The pollen genus Eucommiidites Erdtman was
established on the base of dispersed pollen from the
Early Jurassic of Påls, Sweden (Erdtman, 1948).
The pollen is characterised by an unusual aperture
configuration typically with a main colpus in a distal
position flanked either by two subsidiary colpi or a sin-
gle ring colpus in an almost equatorial position (Erdt-
man, 1948; Couper, 1956, 1958). Pollen grains of
Eucommiidites-type are widespread in palynofloras in
the Northern Hemisphere, from the Late Triassic to
the Late Cretaceous (Erdtman, 1948; Kuyl et al.,
1955; Couper, 1956, 1958; Groot & Penny, 1960;
Hughes, 1961, 1994; Brenner, 1963, 1967; Rey-
manówna, 1968; Scheuring, 1970, 1978; Pedersen
et al., 1989; Batten & Dutta, 1997).
Eucommiidites pollen found in situ in seeds and
microsporangiate structures have a distinct tectate
pollen wall with a homogenous, sometimes punctate-
perforate tectum and a granular infratectal layer
(Pedersen et al., 1989; Friis & Pedersen, 1996; Tekleva
et al., 2006). The perforations are prominent in the pol-
len found in the micropyles of Erdtmanispermum
balticum Pedersen, Crane and Friis and are also present
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Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen 33
in the pollen of Erdtmanitheca texensis Pedersen, Crane
and Friis, although the perforation is less pronounced.
A punctate tectum was also documented for dispersed
pollen grains assigned to Eucommiidites troedssonii
Erdtman from the Early Jurassic of Grojec, Poland
(Scheuring, 1978) and from the Hettangian–Sinemurian
of Sose Bugt, Bornholm, Denmark (Batten & Dutta,
1997); perforation is particularly pronounced in the
latter.
The infratectal layer is interspaced either
between tectum and endexine (Erdtmanitheca texen-
sis) or more common between tectum and foot
layer (Erdtmanispermum balticum, Eucommitheca hir-
suta and Bayeritheca hughesii Kvacek & Pacltová).
The foot layer, when present, is thin (Eucommi-
itheca hirsuta) or thicker (Bayeritheca hughesii, Erdt-
manispermum balticum) (Pedersen et al., 1989; Friis
& Pedersen, 1996; Tekleva et al., 2006). A granu-
lar infratectal layer was also reported for Eucommi-
idites troedssonii from Sose Bugt (Batten & Dutta,
1997), but it is unclear from the description and
figures whether the foot layer is present or not. The
ultrastructure of Eucommiidites troedssonii from
Grojec is illustrated by line drawings only and is
unclear for the infratectal layers.
A variety of other grains assigned to the Eucommii-
dites complex by Tekleva et al. (2006) based on
comparable aperture arrangement have a distinctly
different wall structure and cannot be included in
Erdtmanithecales as currently circumscribed.
The pollen organs have peltate microsporophylls,
each with several elongate sporangia. The microspo-
rophylls are arranged on elongated axes or in spherical
heads (Pedersen et al., 1989; Friis & Pedersen, 1996;
Kvacek & Pacltová, 2001). Seeds assigned to the
Erdtmanithecales are characterised by having a nucel-
lus enclosed by two layers; a thin membranous inte-
gument that is extended into a long narrow micropyle
and a hard three-valved outer seed envelope that
completely encloses the integument except for the
apical micropylar opening (Pedersen et al., 1989).
New studies of Erdtmanithecales and other Early
Cretaceous seed plants concluded that Erdtmanithe-
cales are most closely related to Bennettitales and
Gnetales, and the term BEG (Bennettitales-Erdtma-
nithecales-Gnetales) group was coined for this con-
stellation of seed plants (Friis et al., 2007, 2009).
Four new genera, Buarcospermum, Lignierispermum,
Lobospermum and Rugonella Friis, Pedersen and
Crane, were assigned to this complex, but their
more precise systematic affinity within the group
was not resolved (Friis et al., 2009).
Rothwell et al. (2009) recently questioned the Erdt-
manithecales concept. In their studies of the phyloge-
netic position of Erdtmanithecales seeds and pollen
organs were analysed separately based on differences in
morphology and ultrastructure between pollen in situ
in seed micropyles (tectum punctate, foot layer dis-
tinct) and pollen in situ in the pollen organs (tectum
typically psilate, foot layer absent or indistinct). In this
analysis the seeds were resolved as most closely related
to the Gnetales and the pollen organs most closely
related to the Bennettitales. The new fossil described
here shows, however, a range in pollen wall structure
that encompasses the structure observed for pollen in
situ in the seeds and that for pollen in situ in the pollen
organs. Several grains have a punctate tectum,
although the holes are not continuous, and there is a
distinct foot layer. Dispersed Eucommiidites pollen
grains also show distinctly punctate tectum combined
with the absence or poorly developed foot layer. This
together with the otherwise very similar pollen wall
structure of pollen in seeds and pollen in sporangia
indicate that seeds and pollen organs were produced
by the same kind of plants.
Comparison with other Eucommiidites producing pollen
organs
Three genera and species of pollen organs with
Eucommiidites pollen have been included in the
Erdtmanithecales: Erdtmanitheca texensis (Late Cre-
taceous of Texas, USA), Eucommiitheca hirsuta
(Early Cretaceous of Beira Litoral, Portugal) and
Bayeritheca hugesii (Late Cretaceous of Bohemia,
Czech Republic). These pollen organs are united by
having sporangia arranged in a radial pattern on a
peltate microsporophyll and by their characteristic
Eucommiidites pollen. Pollen grains resembling Euco-
mmiidites were also found in situ in cones of Hastyos-
trobus muirii Van Konijnenburg-van Cittert from the
Middle Jurassic of Hasty Bank, Yorkshire, England.
Although the wall ultrastructures of these grains
(Tekleva et al., 2006) show some similarities to
other Eucommiidites grains, the infratectal layer
described by Tekleva et al. (2006) as spongy appears
alveolar rather than granular. The pollen cone is
poorly preserved and there are no details of spor-
angia or their organisation on the axis (Van Koni-
jnenburg-van Cittert, 1972) and further comparison
with this fossil is currently not possible.
Eucommiitheca hirsuta and Bayeritheca hughesii are
distinguished from the new Portuguese fossil in hav-
ing microsporangiate units arranged along an elon-
gate axis. In E. hirsuta, the arrangement of
microsporophylls is opposite and decussate; in
B. hughesii, the arrangement is less clear. Pollen
grains in B. hughesii are smaller than in the new
Portuguese fossils and the foot layer slightly thicker.
Pollen grains observed in E. hirsuta are also smaller
(15.0–20.0
μm × 10.0–12.0 μm in contrast to 16.0–
27.2
μm × 11.9–16.4 μm in the new fossil).
Downloaded By: [Mendes, Mário Miguel][B-on Consortium - 2007] At: 16:27 17 March 2010
34 M. M. Mendes et al.
Erdtmanitheca texensis has microsporophylls
arranged in spherical heads radiating from a central
receptacle very similar to the arrangement in the
new Portuguese fossils. Further similarities between
our new fossils and E. texensis are the synangiate
nature of the microsporophylls with about ten nar-
row, elongate sporangia extending from the margin
of the peltate apex to the base of the microsporo-
phyll, and dehiscence of the sporangia by longitudi-
nal slits. A generic assignment of the Portuguese
fossils to Erdtmanitheca is therefore well-supported.
The new fossils differ, however, from E. texensis in
several details and are therefore assigned to a new
species, E. portucalensis. Most significantly, the Por-
tuguese fossils have fewer microsporophylls (about
100–150 in contrast to about 300 in E. texensis) and
the microsporophylls are more loosely arranged.
Although none of the specimens is preserved com-
pletely, their organisation strongly suggests that they
were spherical heads as in E. texensis. The mode of
attachment on the plant is unknown for both the
new fossil and for E. texensis.
The pollen grains of Erdtmanitheca texensis and
E. portucalensis are very similar in general shape and
size and in the distribution of apertures. The only
difference is that the lateral furrows in E. portucalensis
are slightly longer. Tectum perforations are more
distinct in some grains of E. portucalensis, but not in
all, and the variations observed in pollen wall surface
between E. portucalensis and E. texensis are probably
mostly due to variation in preservation. In pollen wall
ultrastructure the two species are closely similar and
both have distinct orbicules. There are, however,
minor differences that also support assignment of the
two fossils to different species. In E. texensis the pol-
len wall is markedly thinner on the proximal side,
while in E. portucalensis does not show such thinning.
Also in E. texensis the granular infratectal layer rests
directly on the endexine, and foot layer is lacking,
while in E. portucalensis the granular infratectal layer
is interspaced between the tectum and foot layer with
a distinct delimitation to both.
Erdtmanithecales in Portugal
Pollen grains of Eucommiidites-type have been
reported from many Early Cretaceous palynofloras
of western Portugal, such as Lagosteiros, Forte de
Santa Susana, Forte da Crismina and S. Julião
beach ranging in age from Berriasian to Albian
(Trincão, 1990).
Recently, Eucommiidites pollen was also recovered
in the Lower Cretaceous strata of the Nossa Senhora
da Luz clay pit complex, the Juncal locality, and in
the Vale Farelo clay pit complex, the Vale de Água
locality, ranging in age from the Aptian to Albian
(Mendes, work in progress). None of the dispersed
grains was studied in greater detail using SEM or
TEM and they may not all belong to the Erdtma-
nithecales. The presence of Erdtmanithecales in
Portugal is, however, well-established for the Early
Cretaceous.
From the Lusitanian Basin in western Portugal
two different kinds of pollen organs with Eucommii-
dites pollen in situ are currently known from the
younger part of the Early Cretaceous, including
Eucommiitheca hirsuta (Friis & Pedersen, 1996) and
Erdtmanitheca portucalensis (this work), and one kind
of seeds, Erdtmanispermum juncalense (Mendes et al.,
2008
a), has been reported from the earliest Creta-
ceous. No pollen organs were found associated with
Erdtmanispermum juncalense and no pollen was found
inside the micropyles of the seeds. However, the
assignment of Erdtmanispermum juncalense to Erdt-
manithecales is ascertained by the close similarity to
the coeval Erdtmanispermum balticum from the earli-
est Cretaceous of Bornholm (Denmark) that has
Eucommiidites pollen in situ (Pedersen et al., 1989).
Seeds that could be associated with Erdtmanitheca
portucalensis have not yet been found from the Vale
Farelo clay pit complex – Vale de Água locality, and
no other seeds of the BEG group were identified
from this locality.
Seeds of Raunsgardispermum from the Early Creta-
ceous of Portugal combine ephedroid seed characters
with bennettitalean and erdtmanithecalean pollen
features (Mendes et al., 2008b) and are also assignable
to the BEG group. The pollen grains are similar to
those of Erdtmanitheca portucalensis in their psilate-
perforate tectum, but they differ in being monocolpate
and the perforation of the tectum is denser and
occasionally coarser, although the size of the perfo-
rations varies from grain to grain and may also for
this taxon be linked to preservation.
Conclusions
The new pollen organ Erdtmanitheca portucalensis
and its in situ Eucommiidites-type pollen described
here is clearly assignable to the extinct order
Erdtmanithecales. The Portuguese Early Cretaceous
pollen organ shares key characters with the Late
Cretaceous Erdtmanitheca texensis. The new fossil
findings provide more knowledge on the morpholo-
gical variation in Eucommiidites-pollen-producing
plants. This finding extends the geographical and
stratigraphic range of Erdtmanitheca that was previ-
ously known only from the Early Cenomanian (Late
Cretaceous) of eastern North America. The new
finding also provides additional support for the
presence of a diverse complex of plants, e.g. the
Downloaded By: [Mendes, Mário Miguel][B-on Consortium - 2007] At: 16:27 17 March 2010
Erdtmanitheca portucalensis, a new pollen organ with Eucommiidites-type pollen 35
Bennettitales-Erdtmanithecales-Gnetales group, in
the Early Cretaceous vegetation co-occurring with
the early diverging angiosperms. The presence of
psilate pollen with more coarsely perforate grains in
Erdtmanitheca portucalensis shows that this feature
may be related to preservation and may not be a useful
systematic character.
It is also clear that a punctate tectum occurs both
in pollen with a distinct foot layer and in pollen with
a foot layer that is poorly developed or lacking and
that these pollen features (punctate tectum/distinct
foot layer contra psilate tectum/absent or indistinct
foot layer) cannot be used to place the Erdtmanithe-
cales pollen organs and seeds in separate clades.
Acknowledgements
We thank Jorge Dinis, Coimbra, for valuable assis-
tance in field work and for information on the geo-
logy of the Figueira da Foz Formation. We also
thank Eduarda Ferreira, Caparica, for technical
assistance in the laboratory, Yvonne Arremo, Stock-
holm, for technical assistance with the scanning
electron microscope, Carina Svensson and Lena M.
Gustavsson, Stockholm, for technical assistance
with sections for ultrastructural studies and with the
TEM investigations. Patrick Herendeen, Chicago,
and Johanna van Konijnenburg-van Cittert, Leiden,
are thanked for helpful comments on the manu-
script. This work was supported by a fellowship
from the “Fundação para a Ciência e a Tecnologia”
(SFRH/BD/24849/2005) to Mário Miguel Mendes
and a grant from the Swedish Natural Science
Research Foundation (VR) to Else Marie Friis.
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The Iberian Peninsula formed a connecting bridge between Laurasia and northern Gondwana during the Early Cretaceous, making it a very important study area for palaeoecology and palaeobiogeography. Since few Early Cretaceous fossil wood records are currently known in the Iberian Peninsula, the discovery of new remains from this period is of major significance for postulating or strengthening palaeoecological hypotheses. In this work we document the presence of conifers assigned to the genus Protocupressinoxylon Eckhold for the first time in Portugal. The new fossil suggests that the palaeoclimatic conditions had no marked seasonality and confirms that although the wood flora of the Iberian Peninsula is much poorer than in western Europe in the same period, it is clearly Laurasian. © 2014 LNEG – Laboratório Nacional de Geologia e Energia IP.
... In their first point, Bao et al. argue that the pollen grains associated with P. vivificus do not belong to eudicots but to the extinct gymnosperm order Erdtmanithecales that produced superficially angiosperm-like pollen 4,5 . To support this assertion, Bao et al. point out similarities between the pollen associated with Pelretes and Eucommiidites pollen, the latter of which is trisulcate and possesses a broad main sulcus flanked by two narrower slit-like sulci located at the equator or on the proximal pole. ...
... This pollen has been found in the micropyle of several dispersed seeds that share an ovoid form, triangular cross-section, similar wall structure, and prominently extended micropyle. The microsporangiate organs are small spherical cone-like structures with a central receptacle bearing numerous radiating microsporophylls with a peltate tip sheltering several pollen sacs (Mendes et al., 2010;Fig. 28). ...
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Gymnosperms represent a broad range of seed-bearing plants that differ from flowering plants in not having seeds enclosed within carpels. Gymnosperms are probably monophyletic, having arisen among ‘progymnosperm’ stock in the Devonian. Key adaptations involving retention of the megagametophyte within a protective coating to form a seed on the parent sporophyte, dissemination of the microgametophyte in durable pollen, production of complex root systems, and extensive development of secondary xylem in the stem, provided gymnosperms with opportunities to exploit upland and drier habitats in the late Paleozoic that had not been occupied by earlier free-sporing plant groups. Gymnosperms diversified in the late Paleozoic and were prime contributors of organic matter to some of the world's largest coal deposits, which accumulated at that time. After suffering widespread extinctions at the close of the Permian, gymnosperms re-radiated in the Triassic and dominated the global floras until the mid-Cretaceous, after which they were progressively supplanted by angiosperms. Gymnosperms are represented in the modern flora by over 1000 species, but their diversity and distribution have contracted greatly since the Mesozoic. They still dominate large tracts of the Northern Hemisphere boreal forests, and are locally dominant in more restricted vegetation types in other parts of the world. Extant gymnosperms provide a range of food, industrial and medical resources to modern society.
... Durante o Cretácico a Península Ibérica passou por significativas alterações paleogeográficas e paleoclimáticas, e a vegetação também sofreu fortes modificações. A reconstrução da vegetação cretácica por Diéguez et al. (2010) Estudos de diversas floras apontam para que o clima na margem ocidental portuguesa (Mendes et al., 2010;Heimhofer et al., 2012) seria quente e húmido durante a maior parte de Barremiano-Aptiano, tornando-se mais quente e seco durante o Albiano, condições que prevaleceram durante a maior parte do Cretácico Superior. Ao estudar a palinologia de depósitos continentais localizados a Sul da Bacia Lusitaniana, Heimhofer et al. (2012) deduziram existir floresta dominada por cupressáceas e taxodiáceas em combinação com plantas higrófilas. ...
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No Cretácico Inferior, a Península Ibérica estabeleceu uma ponte entre a Laurásia e o Norte de Gondwana. Por isso é uma área muito importante para estudos paleoecológicos e paleobiogeográficos. Desde que alguns registos de troncos fósseis do Cretácico Inferior passaram a ser conhecidos na Península Ibérica, a descoberta de novos restos fossilíferos correspondentes a este período tem grande importância para inferir e estabelecer interpretações paleoecológicas. Neste trabalho documenta-se pela primeira vez a ocorrência de conífera atribuível ao género Protocupressinoxylon Eckhold. O fóssil sugere que as condições palaeoclimáticas apresentavam marcada sazonalidade e confirma que a flora da Península Ibérica é muito mais pobre do que a da Europa ocidental durante o mesmo intervalo e tem claramente características da Laurásia. Abstract: The Iberian Peninsula formed a connecting bridge between Laurasia and northern Gondwana during the Early Cretaceous, making it a very important study area for palaeoecology and palaeobiogeography. Since few Early Cretaceous fossil wood records are currently known in the Iberian Peninsula, the discovery of new remains from this period is of major significance for postulating or strengthening palaeoecological hypotheses. In this work we document the presence of conifers assigned to the genus Protocupressinoxylon Eckhold for the first time in Portugal. The new fossil suggests that the palaeoclimatic conditions had no marked seasonality and confirms that although the wood flora of the Iberian Peninsula is much poorer than in western Europe in the same period, it is clearly Laurasian.
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Iniciou a carreira docente na Faculdade de Ciências de Lisboa mas pouco depois foi transferido para a UNL, onde foi um dos membros iniciais do DCT/FCT. Aqui, doutorouse em Geologia (Estratigrafia e Paleobiologia) e terminou a carreira como Professor Catedrático e Presidente do DCT. Foi um especialista da estratigrafia do Miocénico das bacias do Tejo e do Algarve e respectivas associações de macrorrestos, pólenes e esporos. Num curriculum vitae muito rico destaca-se a contribuição dada à cartografia geológica do País.
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Numa publicação desta índole, não se justifica, naturalmente, um inventário exaustivo do património arqueológico conhecido na área ocupada pela presente folha, mas tão-somente uma caracterização das principais ocorrências registadas, evidenciando deste modo a importância arqueológica da região, cujo conhecimento, até época recente, em boa parte, decorreu dos trabalhos de campo de índole geológica. Encontram-se publicadas as cartas arqueológicas de três dos quatro municípios abrangidos pela folha: Oeiras (CARDOSO & CARDOSO, 1993); Cascais (CARDOSO, 1992), concelho que, desde 1943, possuía já um esboço de carta arqueológica (PAÇO & FIGUEIREDO, 1943); e Amadora (MIRANDA et aI. , 1999): nelas os mais interessados encontrarão informação detalhada que completará o presente contributo, sem esquecer a existência de diversas sínteses regionais, das quais a mais completa se reporta á área ocupada pelo actual concelho de Oeiras (CARDOSO, 2000 a).