Paisia, an Early Cretaceous eudicot angiosperm flower with pantoporate pollen from Portugal

16 Pages·2017·3.99 MB·English

by  Else Marie Friis

Grana
ISSN: 0017-3134 (Print) 1651-2049 (Online) Journal homepage: http://www.tandfonline.com/loi/sgra20
Paisia, an Early Cretaceous eudicot angiosperm
flower with pantoporate pollen from Portugal
Else Marie Friis, Mário Miguel Mendes & Kaj Raunsgaard Pedersen
To cite this article: Else Marie Friis, Mário Miguel Mendes & Kaj Raunsgaard Pedersen (2018)
Paisia, an Early Cretaceous eudicot angiosperm flower with pantoporate pollen from Portugal,
Grana, 57:1-2, 1-15, DOI: 10.1080/00173134.2017.1310292
To link to this article: https://doi.org/10.1080/00173134.2017.1310292
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Grana, 2018
Vol. 57, Nos. 1–2, 1–15, https://doi.org/10.1080/00173134.2017.1310292
Paisia, an Early Cretaceous eudicot angiosperm flower with
pantoporate pollen from Portugal
ELSEMARIEFRIIS 1,MÁRIOMIGUELMENDES 2,3&KAJRAUNSGAARDPEDERSEN 4
1Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden, 2Centre for Interdisciplinary
Development and Research on Environment, Applied Management and Space, Lusófona University of Humanities and
Technologies, Lisboa, Portugal, 3Centre for Marine and Environmental Research, University of Algarve, Campus de
Gambelas, Faro, Portugal, 4Department of Geosciences, University of Aarhus, Aarhus, Denmark
Abstract
A new fossil angiosperm, Paisia pantoporata, is described from the Early Cretaceous Catefica mesofossil flora, Portugal,
based on coalified floral buds, flowers and isolated floral structures. The flowers are actinomorphic and structurally
bisexualwithasinglewhorloffivefleshytepals,asinglewhorl offivestamensandasinglewhorl offivecarpels.Tepals,
stamens and carpels are opposite, arranged on the same radii and tepals are involute at the base clasping the stamens.
Stamens have a massive filament that grades without a joint into the anther. The anthers are dithecate and tetraspor-
angiate with extensive connective tissue between the tiny pollen sacs. Pollen grains are pantoporate and spiny. The
carpels are free, apparently plicate, with many ovules borne in two rows along the ventral margins. Paisia pantoporata is
the oldest known flower with pantoporate pollen. Similar pantoporate pollen was also recognised in the associated
dispersed palynoflora. Paisia is interpreted as a possibly insect pollinated, herbaceous plant with low pollen production
andlowdispersalpotentialofthepollen.ThesystematicpositionofPaisiaisuncertainandPaisiapantoporatamostlikely
belongs to an extinct lineage. Pantoporate pollen occurs scattered among all major groups of angiosperms and a close
match to the fossils has not been identified. The pentamerous floral organisation together with structure of stamen,
pollen and carpel suggests a phylogenetic position close to the early diverging eudicot lineages, probably in the
Ranunculales.
Keywords: Almargem Formation, apocarpous, basal eudicots, Ranunculales, SRXTM, synchrotron radiation x-ray
microtomography
Pantoaperturate(pantoporateandpantocolpate)pol- pollen type is almost globally distributed and repre-
lengrains occur scattered among allmajor groups of sented bya diversity of forms (Chlonova 1986;Ibra-
angiosperms and are reported both among early himetal.2017).Amongearlydivergingangiosperms
diverging lineages and in more derived groups. pantoporate pollen is reported for Trimeniaceae
Their occurrence in basal lineages is particularly (Austrobaileyales) and Chloranthaceae (Sampson &
interesting in the light of the diversity of this kind Endress 1984;Endress 1986),and in early diverging
of pollen in the Early Cretaceous, but the impor- monocots pantoporate pollen characterises allextant
tance of pantoaperturate pollen in early angiosperm Alismataceae and Limnocharitaceae (Argue 1973,
evolution has not yet been explored. The dispersed 1974, 1976; Chanda et al. 1988; Furness & Banks
pollen record documents pantoporate/polyporate 2010). Pantocolpate and pantoporate pollen grains
pollen already in the Aptian and by the Albian this are also common in early diverging lineages of
Correspondence:ElseMarieFriis,DepartmentofPalaeobiology,SwedishMuseumofNaturalHistory,Box50007,10405Stockholm,Sweden.
E-mail:[email protected]
(Received16August2016;accepted8March2017)
©2017TheAuthor(s).PublishedbyInformaUKLimited,tradingasTaylor&FrancisGroup
ThisisanOpenAccessarticledistributedunderthetermsoftheCreativeCommonsAttributionLicense(http://creativecommons.org/licenses/by/4.0/),which
permitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperlycited.
2 E. M. Friis et al.
eudicotsincludingtheRanunculalesandBuxales.In eous(lateBarremian–Albian)age,buttheexactstra-
theRanunculales,pantoaperturatepollenisrecorded tigraphic position of the Catefica deposits within the
for the Eupteleaceae, Papaveraceae (Fumarioideae AlmargemFormation isnotyetestablished.Accord-
and Papaveroideae), Berberidaceae and Ranuncula- ing to Jacques Rey (personal communication, June
ceae (e.g. Wodehouse 1936; Praglowski 1974; Now- 2012) the Almargem Formation at the Catefica
icke & Skvarla 1981, 1982; Blackmore et al. 1995; locality may be equivalent to the basal part of the
Emadzade et al. 2010). Euptelea, usually resolved as Figueira da Foz Formation and of late Aptian–early
sister to all other members of the Ranunculales, has Albian age, but although the Catefica mesofossil
mainly apolar and pantocolpate or sometimes partly flora does share some elements with the mesofossil
pantoporate pollen, while tricolpate pollen is rare floras of the Figueira da Foz Formation, there are
(Praglowski 1974). Nevertheless, Eupteleaceae and many taxa that are unique to the Catefica plant
all other families of Ranunculales were scored as assemblages, both among the mesofossils (EMF
having tricolpate pollen in the phylogenetic discus- and KRP, own observation) and the microfossils
sion of pollen characters by Doyle (2005) and pan- (MMM, own observation). There are also elements
toporate aperture configuration was not considered in the Catefica mesofossil flora that are shared with
in the character matrix of later phylogenetic discus- the probably older Torres Vedras mesofossil flora
sions by Doyle (e.g. Doyle & Endress 2014). (EMF; KRP, P. R. Crane, own observation) and
We here describe a new fossil flower, Paisia panto- that are not known for the slightly younger mesofos-
porata sp. nov., from the Early Cretaceous Catefica sil floras of the Figueira da Foz Formation.
mesofossil flora, Portugal, with pantoporate in situ Plant mesofossils were first reported from the
pollen. It shares the actinomorphic flower arrange- Catefica locality by Friis et al. (1994). They are
ment and free floral parts with many other Early typically small and three-dimensionally preserved
Cretaceous floral structures such as Kajanthus and either as charcoalifications or lignitised. The fossils
Kenilanthus (Mendes et al. 2014; Friis et al. 2017) were extracted from the sediments and prepared for
and Paisia adds to the diversity of Early Cretaceous examination following standard methods for Cretac-
floralstructures with an apocarpous gynoecium. Itis, eous mesofossils (Friis et al. 2011). The mesofossil
however, distinguished from all other Early Cretac- assemblages are rich in angiosperm flowers and
eousflowersrecordedsofarbyitspantoporatepollen inflorescences as well as isolated fruits, seeds and
and provides the first information of a flower produ- stamens of angiosperms, in addition to a diversity
cingpantoporate pollenin the Early Cretaceous. Pai- of seeds related to the Bennettitales–Erdtmanithe-
sia pantoporata is restricted to the Catefica mesofossil cales–Gnetales complex, conifer seeds and twigs of
flora and is another unique taxon for this flora. Cheirolepidiaceae as well as many fern fragments
The systematic position of Paisia pantoporata is and megaspores (e.g. Friis et al. 1994, 2009, 2010,
uncertain. It may represent an extinct lineage close 2013,2014b,2015a,2015b;Friis&Pedersen2014).
tothebaseoftheeudicotangiosperms,mostlikelyin About 60 specimens were studied. For scanning
the Ranunculales or among other early diverging electron microscopy (SEM), fossil specimens were
eudicots. This position is inferred from the penta- mounted on aluminium stubs with nail polish, sput-
merous and isomerous organisation of the flower, ter coated with gold and examined using a Hitachi
stamens with a massive filament and an apocarpous Field S-4300 FE-SEM at 2 kV. Organisation and
gynoecium with plicate carpels, as well as the com- internal details of 15 fossils (accession numbers:
mon occurrence of pantoaperturate pollen at this S101214, S118680, S171514, S171515, S171519,
grade. S171523-S171526, S171529, S171530, S174439,
S174743, P0298, P0338) were studied using syn-
chrotron radiation X-ray tomographic microscopy
Material and methods
(SRXTM) at the TOMCAT Beamline, Swiss Light
The fossil floral structures described here are from Source,atthePaulScherrerInstitute,Villigen,Swit-
the Lusitanian Basin, western Portugal, and were zerland (Stampanoni et al. 2006). The fossils were
collected at the Catefica locality (39° 3ʹ 16″ N; 09° mounted with nail polish on brass stubs and mea-
14ʹ 24″ W) situated near Torres Vedras on the wes- sured at 10 keV using a 10× objective with isotropic
tern margin of the Runa Basin. The plant bearing pixelsizeof0.65μm,asCMOSdetectoranda20μm
strata at the Catefica locality were previously thick LAG:Ce scintillator screen (for details on
assignedto the ‘Grésde Torres Vedras’(Carta Geo- SRXTM work on Cretaceous plant mesofossils at
lógica de Portugal, Folha 30-D Alenquer; Zbys- TOMCAT see Friis et al. 2014a). Virtual slices and
zewski & Torre de Assunção 1965) that is now reconstructions based on the SRXTM data were
included in the Almargem Formation (Rey 1992, made using Avizo software (versions 5–9.1.1). The
1993).TheAlmargemFormationisofEarly Cretac- specimens are housed in the palaeobotanical collec-
Paisia, Eudicot angiosperm from Portugal 3
Figure1.SEMimagesofPaisiapantoporatagen.etsp.nov.,flowersfromtheEarlyCretaceousCateficalocality,Portugal.A,B.Holotype;
antheticflowerwithpedicel,tepals(t)andcarpels(c)preserved;marginsoftepalsareincurvedatbaseandverythin(arrowheads)further
up(S101214;sampleCatefica49).C.Floralbudwithallfloralpartsandpartofpedicelpreserved;tepals(t)coverstamensandcarpels
(S118680;sampleCatefica49).D.Fragmentaryantheticflowerwithpedicelpreserved;onetepal(t)andtwocarpels(c)areexposedandthe
ventralsutureofonecarpelisvisible;asteriskmarksbaseofslit;facetsonreceptacle(arrows)showscarsfromtepalsandstamens(S174739;
sampleCatefica50).E.Antheticflowerwithpedicelpreservedshowingtepals(t)withincurvedmarginsandcarpels(c)(S170429;sample
Catefica342).F.Antheticflowershowingtepals(t)andcarpels(c);notethethinmarginsoftepals(arrowheads)(S174302;sampleCatefica
242). G. Anthetic flower with tepals (t) and carpels (c) preserved; base of tepals incurved; note downwards expanded base of tepals
(S171519;sampleCatefica342).H.Samespecimenasin(E)fromoppositesideshowingreceptaclewithscarsfromtepalsandstamens
(arrows);tepals(t)andcarpels(c)onlypartlypreserved;asteriskshowsbaseofventralslit(S170429;sampleCatefica342).I.Antheticflower
withtwocarpels(c)preservedandscarsfromtepalsandstamens(arrow)(S118679;sampleCatefica49).J.Isolatedpedicelwithswollen,
angularreceptacle(S171530;sampleCatefica151).Scalebars–500µm.
4 E. M. Friis et al.
tions of the Palaeobiology Department of the Swed- S171530 (Catefica 151); S174302 (Catefica 242);
ish Museum of Natural History, Stockholm (S) and S170429, S171519 (Catefica 342); S171514,
the Geological Museum of Lisbon, Portugal (P). S171515 (Catefica 343); S174743, S174344 (Cate-
fica361).Totally,about60specimens;severalspeci-
mens may be stored in box slides under the same
Systematic palaeontology
number.
Angiospermae
Type locality. — Catefica (39° 03ʹ 30ʺ N; 09°14ʹ 30ʺ
Eudicots
W), between the villages of Catefica and Mugideira,
Paisia gen. nov.
about 4 km south of Torres Vedras, Portugal.
Derivationofgenericname. — InhonourofProfessor
João Pais (1949–2016) for his contribution to the Type horizon and age. — Almargem Formation,
Early Cretaceous (late Barremian–early Albian).
palaeobotany and geology of Portugal.
Generic and specific diagnosis. — Flower small, pedi- Description and remarks. — The material includes
cellate, actinomorphic, pentamerous and isomerous several complete flowers (Figures 1A–C, F, G, 2A–
andfunctionalbisexualwithonewhorloffivetepals, G) or partly preserved flowers (Figures 1D, E, H, I,
one whorl of five stamens and one whorl of five free 3A–D, H-J, 4A–C) as well as isolated floral parts,
carpels, all opposite on the same radii. Receptacle such as tepals either empty or enclosing a single
distinctly five-angled. Perianth of a single whorl of stamen (Figure 5A), pedicels where all floral parts
five tepals; aestivation involute-valvate. Tepal base are shed (Figures 1J, 6A–D), young carpels and sta-
extendeddownwardsandmarginsincurved,clasping mens (Figure 3E–G) and mature follicles. Most
the stamens. Stamens with a single massive bundle flowersarepreserved in theanthetic or post-anthetic
extending from base to apex. Stamens differentiated stage, while a few are preserved in the pre-anthetic
into a short, stout filament and an elongated, basi- stage.
fixed anther.Anthers dithecateand tetrasporangiate; Flowers are pedicellate, small, about 1 mm long
sporangia minute, separated by a massive connec- without pedicel and up to 1.2 mm in diameter,
tive. Anther dehiscence latrorse by longitudinal actinomorphic, pentamerous and isomerous with an
slits. Pollen pantoporate, tectate-punctate, spiny. apocarpous and superior gynoecium (see floral
Gynoecium superior; carpels free, sessile, elongate, reconstruction and floral diagram Figure 8). Tepals
and plicate. Ovules many, borne in two longitudinal andtheenclosedstamensandcarpelsareinsertedon
rows on either side of the ventral suture. Stigma a five-angled receptacle with facetted sides with
sessile, decurrent, indistinct. tepals and stamens borne on the receptacle facets.
The floral organs are apparently arranged in whorls.
Type species designated here. — Paisia pantoporata sp. The perianth consists of a single whorl of parts,
nov. described here as tepals. Tepals are elliptical to
ovate in dorsal view (Figure 1A–C, E–H) with
Paisia pantoporata sp. nov.
pointed apex and rounded base that is distinctly
(Figures 1–6, 8)
separated from the pedicel and curving slightly
downwards forming a dorsal extension that is some-
Derivation of specific name. — From thepantoporate
timesprominent(Figures1A,B,E,G,2C).Incross-
pollen observed in situ in the stamens.
section, the tepals are more or less M-shaped with a
broad base and incurved, thinner margins (Figures
Specific diagnosis. — See combined generic and 2F–G, 3H–J). In young flowers, the tepal margins
specific diagnosis. are incurved along the full length of the tepals
(Figures 3B, H–J, C), while in more mature flowers
Dimensions. — Mature flowers without pedicel the margins are incurved only at the base (Figures
about 1 mm long and up to 1.2 mm wide. 1B, 2A, G) and in all specimens the tepal margins
are thinner than the middle part of the tepals
Holotype. — S101214 (Catefica sample 49; illu- (Figures 1A, B, F, 2A, E, F). The tepals are fleshy
strated here on Figures 1A, B, 2A–G). composed of equiaxial, rounded parenchyma cells
(Figures2C,3H–J).Therearethreebundlesextend-
Paratypes. — S118679, S118680, S118682, ing almost for the full length of the tepals
S171526, S174746, S174747 (Catefica 49); (Figure 3I). The inner surface of the tepals has
S174739, S174740, S174742 (Catefica 50); densely spaced bulging papillae (Figure 3C, H).
Paisia, Eudicot angiosperm from Portugal 5
Figure2.SRXTMvolumerenderings(A–D)andreconstructedtransverseorthoslices(E–G)ofPaisiapantoporatagen.etsp.nov.,anthetic
flower from the Early Cretaceous Catefica locality, Portugal (holotype, S101214; sample Catefica 49). A, B. Lateral views of flower at
differentanglesshowingwell-preservedtepals(t)withthinmargins(arrowheads)surroundingthecarpels(c).C.Cutlongitudinalvolume
renderingofflower(orthoslicesyz500–520)showingsectionsofcarpelswithnumeroussmallovules/seeds(arrowheads)thatdonotfillout
theovarycavity;stamens(asterisk)arepreservedbetweenthetepals(t)andcarpels.D.Apicalviewofflowershowingthefivetepals(t)and
fivecarpels(c).E–G.Sectionsthroughfloweratdifferentlevelsfromclosetoapex(E)tothebaseoftheflower(G)showingthefivetepals
(light green) clasping the five stamens (light yellow) and surrounding the five carpels (orange); tepal margins at base incurved, further up
extendedoutwards.Scalebars–500µm.
The androecium consists of five stamens opposite gradeswithoutajointintothebasallyattached,elon-
the tepals and the carpels. Stamens are elongate, gateanther(Figures3B,E,4A,B).Anthersinyoung
about 0.5–0.8 mm long, embraced by the incurved flowersareabout0.35mmlong,dithecateandtetra-
margins of the tepals. In young flowers, they consist sporangiate with small pollen sacs (Figures 3G, I,
of a short, stout filament, about 0.25 mm long that 4A–C). The two thecae are separated by a broad
6 E. M. Friis et al.
Figure3.SEMimages(A–F)andSRXTMreconstructedtransverseorthoslices(G–J)ofPaisiapantoporatagen.etsp.nov.,floralorgansfromthe
EarlyCretaceousCateficalocality,Portugal.A–D,H–J.Pedicelandfloralorgansisolatedfromthesamefloralbud(S171526;sampleCatefica
49).A.Pedicelinapicalviewshowingswollen,slightlyfive-angledreceptaclewithscarsfromthefloralorgans.B.Singletepalclaspingastamen
(asterisk);innersurfaceoftepalabovestamenispapillate(arrowhead).C.Papillateinnersurfaceoftepalenlarged.D.Youngcarpelwithalmost
straightandparalleldorsalandventralfaces.H–J.Transverseorthoslicesatdifferentlevelsthroughtwotepals;eachtepalclaspingastamen;tepals
fleshywiththreevascularbundles(arrowsinI);large,isodiametricparenchymacellsandincurvedmarginsfromapicalpart(H)tothebase(J);
stamens(asterisks)showmassiveconnectiveandtinypollensacs(I)andamassivefilamentwithasinglecentralstrand(J).E.Isolatedstamen
(asterisk) and adhering carpel (c) in lateral view showing longitudinal dehiscence line of anther (S171514; sample Catefica 343). F. Cut
longitudinalvolumerenderingofsamespecimenasshowninE(cutthroughmedianpartofcarpelandstamen)showingnumerous,tinyovules
notfillingtheovarycavity.G.Transverseorthoslice(orthoslicexy1300)ofthesamespecimenasshownin(E)showingstamen(asterisk)with
massiveconnectivewithasinglebundleandthefourtiny,lateralpollensacs(arrowheads)andsectionthroughmiddlepartofcarpel(c)withtiny
ovulesonbothsideoftheventralsuture.Scalebars–500µm(B),250µm(H–J),200µm(A–F),100µm(G),50µm(C).
Paisia, Eudicot angiosperm from Portugal 7
connective (Figures 3G, I, 4C). There is a single
bundle extending from base almost to apex. The
pollen sacs protrude and are laterally oriented with
lateral dehiscence by longitudinal slits.
Pollen grains are found in situ in the anthers of
severalflowersandinisolatedfragments(Figure5A–
I). They are pantoporate, spheroidal and minute,
about 11–14 µm in diameter, with tectate-punctate
pollenwallandasupratectalornamentationofspiny,
conicalelements,0.7–1.0µmlong,constrictedatthe
base, with a pointed or blunt tip, and with longitu-
dinal ridges that give the elements an appearance of
being compound of elongated elements (Figure 5I).
The elements form a dense ring around each aper-
ture, but are otherwise more irregularly scattered
over the tectum surface (Figure 5C, F–I). In some
specimens the pollen grains appear immature with
supratectal elements of adjacent grains coalesced
(Figure 5F, G). There are about six to eight pores,
about 3 µm in diameter, and globally distributed
over the grain. The aperture membrane is covered
by irregular sculptural elements (Figure 5C, H)
that are sometimes completely concealed by the
surrounding spiny elements (Figure 5I). Orbicules
were not observed.
There are five free carpels (Figures 1F, 2D–G).
Carpels are sessile and elongated, interpreted as pli- Figure4.SRXTMreconstructionsoftwotepalsandtwostamens
cate.Inyoungflowerstheyarenarrowandofalmost ofPaisia pantoporatagen. et sp. nov.,from the EarlyCretaceous
Cateficalocality,Portugal;floralorgansfromthesamefloralbud
the same width from base to apex and with almost
asinFigure3A–D,H–J(S171526;sampleCatefica49).A.Long-
straight ventral and dorsal margins (Figures 3D–F). itudinal voltex of tepals (t) and stamens (asterisk) and surface
In moremature floral structures they are elliptical to rendering(yellow) ofone stamenshowingfilament,massive con-
obovate with slightly convex ventral margin and nectiveandtinypollensacs.B.Transparentvoltexshowingthick
parenchymatissueoftepalsandstamensenclosedinthetepals.C.
rounded dorsal margin (Figures 1D, F, I, 2C). The
Cuttransversevoltexreconstructionatthelevelofthepollensacs
ventral slit extends for the full length of the carpel.
showingthetwotepalswithincurvedmarginsclaspingthestamens
Thisisobviousonbrokenspecimens(Figure1D,H) (asterisks); note massive connective with one central bundle and
as well as in some of the specimens studied using thetwolateralthecae withtiny pollensacs. Scalebars– 500µm
SRXTM.Thereisnoindicationofanascidiate zone (A,B);250µm(C).
in any of the specimen studied. The stigma is sessile
and indistinct. The carpel wall is smooth and con-
surrounding a small pith and surrounded by a
sists of almost equiaxial, rounded parenchyma cells.
broader zone of thick-walled parenchyma cells and
There are one dorsal and two ventral bundles. The
a thick epidermis (Figure 6A–D).
outer epidermis is composed of tiny, equiaxial cells,
apparently without stomata. ?Paisia sp.
Ovules are numerous per carpel (about 20–30) (Figure 7)
and tiny, apparently anatropous and both in young
stages (Figure 3E, F) and more mature flowers One specimen (P0292) from the Catefica locality
(Figure 2C) ovules do not fill the ovary cavity. (Figure 7A–E) consists of a small axis, about
They are borne in two longitudinal rows, one on 3.2mmlong,withaterminalapocarpousgynoecium
each side of the ventral suture extending from the andalateralbractfurtherdowntheaxissupportinga
carpel base to the apex. bud.Thebudisinanearlydevelopmentalstage and
The pedicel is about 0.2 mm in diameter below itisunknownwhetheritisvegetativeorafloralbud.
the receptacle. The preservation does not allow a Theaxisismoreorlesscircularintransection,about
detailed description of the stem anatomy and com- 0.2 mm in diameter. Vascular bundles are arranged
parison with extant plants, but in all specimens stu- in a ring around the small central pit and are sur-
diedbySRXTMitisclearthattherearefiveormore rounded by a tissue of thick-walled parenchyma
vascular bundles close to the centre of the pedicel cells.
8 E. M. Friis et al.
Figure 5. SEM images of stamens and pollen in situ of Paisia pantoporata gen. et sp. nov., from the Early Cretaceous Catefica locality,
Portugal.A.Isolatedtepalandenclosedstamenwithpolleninsitu(S170388;sampleCatefica50).B,C.Pantoporatepollenfromstamen
shownin(A);notethescatteredsupratectalelementsonthepollenbodyandtheconcentrationofelementsaroundtheapertures(S170388;
sampleCatefica50).D–H.FragmentoftepalenclosingstamenwithpantoporatepolleninsitufromfloralstructureshowninFigure1I;cell
wallthickeningsofantherwallareseenin(D)and(E)(arrowheads);thepollengrainsappeartobeimmature,sometimesgroupedintetrads
andsometimeswithsupratectalelementsofadjacentgrainscoalesced(F,G);supratectalelementswithbluntorspinyapex(H)(S118679;
sampleCatefica49).I.DetailofpollengrainfromfloralstructureinFigure1Gshowingapparentcompoundsupratectalelements;note
concentrationofelementsaroundtheaperture(S171519;sampleCatefica342).Scalebars:250µm(A),100µm(D),25µm(E),20µm(B),
10µm(C,F–H),5µm(I).
The terminal gynoecium appears to be in a post- facetted with a number of scars (Figure 7A, B) indi-
anthetic stage. There are no perianth parts or sta- catingthatotherfloralorganswereoriginallypresent
mens preserved. The receptacle below the carpels is intheflower,butshedafteranthesis.Thegynoecium
Paisia, Eudicot angiosperm from Portugal 9
consists of three free carpels (Figure 7A–C, E),
about 0.52 mm long and 0.34 mm wide, ovoid to
elliptic in shape, each with a distinct ventral suture
and an indistinct, sessile stigma (Figure 7C). No
pollen grains were observed in the stigmatic area.
There are about ten ovules/seeds borne in two long-
itudinal rows along the entire ventral suture
(Figure 7D, E). The ovules/seeds do not fill in the
ovary cavity. The epidermal cells of the carpels are
polygonal and more or less isodiametric in surface
view.
The fossil specimen is similar to Paisia pantopor-
ata in the facetted receptacle, large parenchymatic
cellsinpedicel,receptacleandcarpels,andaringof
vascularbundlesnearthecentreofthepedicel.The
fossil is, however, distinguished from Paisia panto-
poratabyitstrimerousgynoecium.Itispossiblethat
the specimen represents an aberrant tricarpellate
form of the otherwise pentacarpellate Paisia panto-
porata,butitismorelikelythatthe specimenrepre-
sents a new species, either of Paisia or a new fossil
genus. With the material currently available, a defi-
nite assignment of the specimen to Paisia is not Figure6.SRXTMreconstructionsofpedicelandreceptacleanat-
possible and we therefore refer to the specimen as omyinPaisiapantoporatagen.etsp.nov.,fromtheEarlyCretac-
?Paisia sp. eous Catefica locality, Portugal, same specimen as in Figure 1J
(S171530;sampleCatefica151).A–D.Longitudinal(A,B)and
transverse (C, D) orthoslices showing thick-walled cells towards
theperipheryandringofbundles(arrowheads)aroundthenarrow
Discussion central pith (A, orthoslice xz470; B, orthoslice xz640; C, ortho-
slicexy700;D,orthoslice1015).Scalebars–200µm.
Comparison of Paisia pantoporata with Early
Cretaceous flowers and pollen
Anumberofisolated plicatecarpels apparently from notfillouttheovaryspace.Kenilanthusmayalsohave
apocarpous gynoecia co-occur with Paisia pantopor- a single whorl of tepals as in Paisia pantoporata, but
ataand?Paisiasp.intheCateficamesofossilfloraand thenatureoftheperianthisnotfullydocumentedfor
may represent related forms. A diversity of fossils Kenilanthus. Kenilanthus differs in many other
with apocarpous gynoecia is also known from other respectsfromPaisiaandtheyareprobablynotclosely
Early Cretaceous mesofossil floras in Portugal and related. It has two whorls of apparently extrorse sta-
easternNorthAmerica(forLateCretaceousfollicular mensandpollengrainsaretricolpate-reticulate.Also,
fruitlets see later). Some of them are known from the epidermis of the Kenilanthus carpels have scat-
flowers and have beenassignedto eudicotsbased on teredstomatanotobservedforthecarpelsofPaisia.
their organisation and in situ tricolpate pollen. Teixeiraea lusitanica K.R.Pedersen et E.M.Friis is
Kajanthus lusitanicus E.M.Friis, M.M.Mendes et another early eudicot flower with in situ pollen from
K.R.Pedersen(Mendesetal.2014)fromtheChical- the Early Cretaceous Vale de Água locality (late
hão locality (late Aptian–early Albian) of Portugal, Aptian–early Albian) of Portugal. It is distinguished
andKenilanthusmarylandensisE.M.Friis,K.R.Peder- from Paisia in the multiparted nature of the androe-
sen et P.R.Crane from early–middle Albian strata of cium and the reticulate, tricolpate pollen. Further,
the Kenilworth locality, Maryland, USA (Friis et al. Teixeiraea lusitanica is apparently unisexual and cur-
2017),bothhavestructurallybisexualflowersandan rently only the staminate flower is known (von
apocarpousgynoeciumofthreetofiveplicatecarpels. Balthazar et al. 2005). Specimens with an apocar-
Kajanthus iscloselyrelatedto theextantSinofranche- pous gynoecium from the Early Cretaceous (late
tia of the ranunculalean family Lardizabalaceae Barremian–early Aptian?) Torres Vedras locality are
(Mendesetal.2014)andisdistinguishedfromPaisia multicarpellate, apparently with carpels in a helical
pantoporata by its trimerous flowers and tricolpate, arrangement (e.g. Friis et al. 2011).
reticulate pollen. Kenilanthus is similar to Paisia in Twopentacarpellateandapocarpousstructureswith
having a pentamerous and isomerous organisation freeplicatecarpelswerereportedfromtheEarlyCre-
with five free carpels and numerous ovules that do taceous (early–middle Albian) Puddledock locality,