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Erdtmanispermum juncalense sp. nov., a new species of the extinct order Erdtmanithecales from the Early Cretaceous (probably Berriasian) of Portugal

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... O excelente estado de preservação em que se encontram muitas destas estruturas reprodutivas, recolhidas nas diferentes mesofloras do Cretácico, tem possibilitado não só a realização de comparações com táxones da flora moderna, como também, o estabelecimento de análises de relações sistemáticas e filogenéticas, o que se reveste de elevada importância na medida em que se torna possível tirar algumas ilações sobe aspectos da biologia reprodutiva das angiospérmicas durante o Cretácico. Nas mesofloras do Cretácico Inferior português encontramse muito bem representados outros restos de vegetais fósseis que correspondem a sementes e a órgãos produtores de pólenes atribuíveis a plantas extintas pertencentes ao grupo das gimnospérmicas (Pedersen et al., 1989; Friis & Pedersen, 1996, 2009 Rydin et al., 2006; Mendes et al., 2008a Mendes et al., , 2008b Mendes et al., , 2010 Mendes et al., , 2011). É de salientar que, algumas destas gimnospérmicas já desaparecidas parecem estar mais próximas das angiospérmicas do que das coníferas, das cicadófitas ou das Gnetales (). ...
... Além disso, estas plantas com semente têm interesse pelo importante significado paleoecológico, por terem sido contemporâneas das primeiras angiospérmicas, ocupando ambientes terrestres com características semelhantes ou até fazendo parte dos mesmos ecossistemas. Neste artigo apresentam-se e discutem-se em conjunto várias ocorrências de sementes e de órgãos produtores de pólenes atribuíveis a novo grupo de gimnospérmicas extintas, já previamente descritas em Mendes et al. (2008a Mendes et al. ( , 2008b Mendes et al. ( , 2010 Mendes et al. ( , 2011), provenientes de jazidas do Cretácico Inferior da Bacia Lusitânica. As jazidas são aqui enquadradas com informações litostratigráficas, cronostratigráficas e paleoambientais. ...
... Nas mesofloras do Cretácico Inferior provenientes das jazidas de Vale Painho (Juncal), Casal do Borracho (Torres Vedras), Catefica e Vale Farelo (Vale de Água) foram identificados restos de vegetais fósseis bem preservados atribuíveis a plantas afins das Bennettitales, Erdtmanithecales e Gnetales, nomeadamente, sementes e órgãos masculinos produtores de pólenes de tipo Eucommiidites Erdtman (Mendes et al., 2008aMendes et al., , 2008bMendes et al., , 2010Mendes et al., , 2011). As sementes estudadas, de pequena dimensão, são caracteristicamente constituídas por três tecidos distintos. ...
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Resumo: Neste artigo faz-se uma síntese sobre a ocorrência de gimnospérmicas extintas, com características típicas do grupo das Bennettitales, Erdtmanithecales e Gnetales e discute-se o enquadramento estratigráfico de um conjunto de espécimes, previamente descritos. Estas plantas encontram-se representadas por sementes de pequena dimensão recolhidas em unidades fluviais siliciclásticas do Cretácico Inferior (Berriasiano a Albiano inferior) da Bacia Lusitânica, Oeste de Portugal, e, provavelmente, constituem grupo monofilético designado por complexo BEG. As sementes fósseis são constituídas por um tecido interno, o nucelo, preservado sob a forma de uma membrana delicada. O nucelo é envolvido por tecido fino de natureza membranosa, o tegumento interno, circundado por invólucro externo constituído por tecido esclerenquimatoso. As plantas do complexo BEG foram contemporâneas das primeiras angiospérmicas, tendo partilhado ecossistemas com características ambientais semelhantes, o que reforça o seu interesse paleoecológico. Abstract: This paper presents a synthesis of the occurrence of extinct gymnosperms related to the Bennettitales, Erdtmanithecales and Gnetales group and discusses the stratigraphic setting of previously described specimens. These plants are represented by small fossil seeds collected from Lower Cretaceous (Berriasian to Lower Albian) fluvial siliciclastic deposits of the Lusitanian Basin, western Portugal, and probably constitute a monophyletic group, the BEG complex. The fossil seeds are composed of an innermost membranous nucellus preserved as a delicate cuticle. The nucellus is evolved by a membranous integument surrounded by a sclerenchymatic outer envelope. Plants from the BEG complex were contemporary of the earliest angiosperm having shared ecosystems with similar environmental characteristics, what reinforces its paleoecological importance.
... Most assemblages are dominated by angiosperms, and studies have mainly focused on the angiospermous component of these mesofossil assemblages (Friis et al., 1994(Friis et al., , 1997(Friis et al., , 1999(Friis et al., , 2000(Friis et al., , 2001Pedersen et al., 2007). However, reproductive organs of extinct gymnospermous plants have also been identified in the Portuguese Cretaceous floras, and it is clear that some of these gymnosperms also played an important role in the vegetation, particularly during the Early Cretaceous (Friis & Pedersen, 1996;Rydin et al., 2004Rydin et al., , 2006Friis et al., 2007;Friis et al., submitted;Mendes et al., 2008). ...
... It is now clear that this complex of plants constituted an important part of the vegetation and was much more diverse that previously thought. In Portugal the Bennettitales-Erdtmanithecales-Gnetales-type seeds includes several different kinds of ephedroid seeds (Rydin et al., 2004(Rydin et al., , 2006, different kinds of small square and lobed seeds Friis et al., submitted), and two different fossils assignable to the Erdtmanithecales: the microsporangiate structure, Eucommiitheca hirsuta (Friis & Pedersen 1996; Early Cretaceous of Beira Litoral, Portugal) and the seeds of Erdtmanispermum juncalense (Mendes, Friis & Pais 2008;Early Cretaceous of Estremadura, Portugal). In this study we describe a further member of this plant complex. ...
... The formation is not formally described, but it is laterally equivalent to the Lourinhã and Farta Pão formations dated as Berriasian based on foraminifera, ostracods and charophytes (Ramalho, 1971;Rey, 1972), and the Porto da Calada and Serreira formations, also dated as Berriasian based on dinocysts (Berthou & Leereveld, 1990). Further information on the geology of the Bombarral formation and a map of the site are provided by Mendes et al. (2008). ...
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A new genus and species, Raunsgaardispermum lusitanicum, is described from the Bombarral formation, Early Cretaceous (probably Berriasian) of Portugal. The new taxon is based on small well‐preserved, lignitised seeds, about 1.2 – 2.1 mm long and 0.9 – 1.26 mm wide, ovoid to broadly elliptic in outline with a distinct pointed micropylar region. The seed wall is composed by a thin membranous integument extended apically into a long tubular micropyle. The integument is enclosed almost completely by an outer envelope except for a small circular opening for micropylar region. The outer envelope is bivalved and sclerenchymatous, ornamented by narrow longitudinal ridges. Papillae are present apically on the inner surface of the seed envelope adjacent to the micropylar tube. Monocolpate, tectate‐psilate‐punctate pollen grains, about 26 – 29 µm long and 14 – 16 µm wide, were observed in situ in the micropyle of one seed and on the outer surface of several others. The seeds show an interesting character combination of distinct ephedroid seed characters coupled with pollen characters of Bennettitales and Erdtmanithecales and add further evidence to the link between Bennettitales, Erdtmanithecales and Gnetales.
... Nas mesofloras do Cretácico Inferior português encontramse muito bem representados outros restos de vegetais fósseis que correspondem a sementes e a órgãos produtores de pólenes atribuíveis a plantas extintas pertencentes ao grupo das gimnospérmicas (Pedersen et al., 1989;Friis & Pedersen, 1996, 2009Rydin et al., 2006;Mendes et al., 2008aMendes et al., , 2008bMendes et al., , 2010Mendes et al., , 2011. ...
... Neste artigo apresentam-se e discutem-se em conjunto várias ocorrências de sementes e de órgãos produtores de pólenes atribuíveis a novo grupo de gimnospérmicas extintas, já previamente descritas em Mendes et al. (2008aMendes et al. ( , 2008bMendes et al. ( , 2010Mendes et al. ( , 2011, provenientes de jazidas do Cretácico Inferior da Bacia Lusitânica. As jazidas são aqui enquadradas com informações litostratigráficas, cronostratigráficas e paleoambientais. ...
... Nas mesofloras do Cretácico Inferior provenientes das jazidas de Vale Painho (Juncal), Casal do Borracho (Torres Vedras), Catefica e Vale Farelo (Vale de Água) foram identificados restos de vegetais fósseis bem preservados atribuíveis a plantas afins das Bennettitales, Erdtmanithecales e Gnetales, nomeadamente, sementes e órgãos masculinos produtores de pólenes de tipo Eucommiidites Erdtman (Mendes et al., 2008a(Mendes et al., , 2008b(Mendes et al., , 2010(Mendes et al., , 2011. ...
Article
This paper presents a synthesis of the occurrence of extinct gymnosperms related to the Bennettitales, Erdtmanithecales and Gnetales group and discusses the stratigraphic setting of previously described specimens. These plants are represented by small fossil seeds collected from Lower Cretaceous (Berriasian to Lower Albian) fluvial siliciclastic deposits of the Lusitanian Basin, western Portugal, and probably constitute a monophyletic group, the BEG complex. The fossil seeds are composed of an innermost membranous nucellus preserved as a delicate cuticle. The nucellus is evolved by a membranous integument surrounded by a sclerenchymatic outer envelope. Plants from the BEG complex were contemporary of the earliest angiosperm having shared ecosystems with similar environmental characteristics, what reinforces its paleoecological importance.
... While this hypothesis needs to be tested by a new generation of more rigorous phylogenetic analyses of living and fossil seed plants, the evidence presented here provides further support for this grouping by further documenting clear structural similarities between the seeds of Buarcospermum, Lignierispermum , Lobospermum , and Rugonella, and those of Bennettitales, Erdtmanithecales, andGnetales. Buarcospermum, Lignierispermum, Lobospermum, Rugonella, and, Pedersen et al., 1989b, Mendes et al., 2008b; discussed later), but most are currently unassigned within the BEG group and remain to be formally named. Especially common and widespread are small fourangled seeds ( " square seeds " ) very similar to those described and illustrated recently (Friis et al., 2007). ...
... The inner surface of the seed envelope is smooth, including where it surrounds the micropylar tube. The outer surface is smooth or sometimes slightly rugulate with irregular transverse ridges (Mendes et al., 2008b). Seeds of Erdtmanithecales are similar in general structure to those of Buarcospermum , Lignierispermum , Lobospermum , and Rugonella. ...
Article
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Four new genera and six new species of fossil seed (Buarcospermum tetragonium, Lignierispermum maroneae, Lobospermum glabrum, L. rugosum, L. stampanonii, Rugonella trigonospermum) are described from five Early Cretaceous mesofossil floras from Portugal and eastern North America. The four genera are distinguished by differences in size, shape, and details of seed anatomy, but all are unusual in having an outer seed envelope with a distinctive anatomical structure that surrounds the nucellus and the integument. The integument is extended apically into a long, narrow micropylar tube. The four new genera are part of a diverse, but previously unrecognized, complex of extinct plants that was widespread in Early Cretaceous vegetation and that coexisted in similar habitats with early angiosperms. The distinctive structure of these seeds, and the strong similarities to other fossil seeds (Ephedra, Ephedripites, Erdtmanispermum, Raunsgaardispermum, and some Bennettitales) already known from the Early Cretaceous, suggests that this newly recognized complex of extinct plants, together with Bennettitales, Erdtmanithecales, and Gnetales (the BEG group), is phylogenetically closely related.
... 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 Gnetales (Rydin et al., 2004(Rydin et al., , 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). ...
... From the Lusitanian Basin in western Portugal two different kinds of pollen organs with Eucommiidites 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., 2008a), has been reported from the earliest Cretaceous. No pollen organs were found associated with Erdtmanispermum juncalense and no pollen was found inside the micropyles of the seeds. ...
Article
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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.
... This value is similar to the Upper Jurassic "marly-sandy-carbonate" and "red muddy-sandy" series in outcrops about 40 km to the NNE, also in the syncline axis, confirming a probable high preservation of the original thickness. Thus, a Berriasian age was suggested for the upper part of the unit (Mendes et al., 2008a). ...
... Two of these are formally described. Erdtmanispermum juncalense (Mendes et al., 2008a) includes 7 seeds corresponding to about 3% of the mesofossils. The seeds are well-preserved, about 1.05-1.5 mm long and 0.75-1.1 mm wide, more or less ovoid to guttiform in outline with a rounded base and apically tapering into an elongated narrow micropylar region (Plate V, 1, 2). ...
Article
Mesofossil and palynomorphs of probable Berriasian age is described from Cretaceous sediments exposed in the Bombarral formation near the village of Juncal in the Estremadura region (western Portugal). Both the palynoflora and mesofossil flora are poor in species diversity and in number of specimens. The palynological assemblage is dominated by pteridophytes and gymnosperms. The mesofossil flora is dominated by conifer seeds and seeds assigned to the Bennettitales-Erdtmanithecales-Gnetales group. The associations indicate the presence of a coniferous forest dominated by Cheirolepidiaceae with a grown cover and understory vegetation of ferns and other pteridophytes as well as members of the BEG group. The fossil floras indicate a warm, seasonally dry climate. The local and regional sedimentological data also point to a seasonal climate with a prolonged dry season. The vegetational and environmental signal from the Portuguese flora is in accordance with that of other, contemporaneous floras of northern Europe (southern England, Bornholm/Denmark and Germany).
... Seeds of Erdtmanithecales have been intensively studied recently (Pedersen et al. 1989b;Friis and Pedersen 1996;Friis et al. 2007Friis et al. , 2009Mendes et al. 2008). A variety of isolated seeds (including Rugonella, Erdtmanispermum, square seeds, and many others) with long micropylar tubes have been reported from the Early Cretaceous in Portugal and eastern North America (Pedersen et al. 1989b;Friis et al. 2007Friis et al. , 2009Mendes et al. 2008). ...
... Seeds of Erdtmanithecales have been intensively studied recently (Pedersen et al. 1989b;Friis and Pedersen 1996;Friis et al. 2007Friis et al. , 2009Mendes et al. 2008). A variety of isolated seeds (including Rugonella, Erdtmanispermum, square seeds, and many others) with long micropylar tubes have been reported from the Early Cretaceous in Portugal and eastern North America (Pedersen et al. 1989b;Friis et al. 2007Friis et al. , 2009Mendes et al. 2008). All of these seeds have a similar construction, and they are related to Erdtmanithecales, Gnetales, and perhaps also Bennettitales (the BEG group) (Friis et al. 2007(Friis et al. , 2009, although recently Rothwell et al. (2009) cast doubt on this group. ...
Article
Problematospermum is a distinctive but enigmatic seed known mainly from the Jurassic and Cretaceous sediments. Numerous new specimens of Problematospermum ovale from two localities in the Middle Jurassic Jiulongshan Formation of China (Sanjiaocheng Village in western Liaoning and Daohugou Village in eastern Inner Mongolia) provide improved information on the structure of Problematospermum. It has an ovoid body with a long apical tube and bears a tuft of filamentous appendages at the base. While Problematospermum was interpreted previously as a disseminule of an angiosperm or angiosperm-like plant, the new specimens show closer similarities to seeds of the Bennettitales, Erdtmanithecales, and Gnetales. However, the unusual features of Problematospermum imply pollination and dispersal biology different from what has so far been known for key lineages of seed plants.
... This value is similar to the Upper Jurassic "marly-sandy-carbonate" and "red muddy-sandy" series in outcrops about 40 km to the NNE, also in the syncline axis, confirming a probable high preservation of the original thickness. Thus, a Berriasian age was suggested for the upper part of the unit (Mendes et al., 2008a). ...
... Two of these are formally described. Erdtmanispermum juncalense (Mendes et al., 2008a) includes 7 seeds corresponding to about 3% of the mesofossils. The seeds are well-preserved, about 1.05-1.5 mm long and 0.75-1.1 mm wide, more or less ovoid to guttiform in outline with a rounded base and apically tapering into an elongated narrow micropylar region (Plate V, 1, 2). ...
... On the other hand, the Tithonian-Berriasian floras are scarce in Europe, and they are really unusual in the Iberian Peninsula. In Portugal, the floras of this age are restricted to micro and meso-fossils [44][45][46]. While in Spain, there are only three references to the flora of this age: (1) Early Berriasian macro and microflora from the Villar del Arzobispo Fm. in the Galve area (Eastern Spain) [47], deposited in a deltaic environment and mainly dominated by pteridophytes; (2) Berriasian to Barremian? ...
Article
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Hydrothermal palaeoenvironments are very uncommon in Upper Jurassic and Lower Cretaceous deposits worldwide. We present new plant and insect remains from travertines formed during the Jurassic-Cretaceous boundary in northern Spain (Aguilar Fm., Palencia province). A total of 136 plant specimens and three insect wings were collected and studied. This entomofauna consists of dragonfly (Odonata) wings including Cymatophlebiidae and an undetermined new genus and species of Aktassiidae, representing the first report of these families for the Iberian Peninsula. The fossil flora shows different morphotypes of plants, which have been tentatively assigned to three different genera. The taphocoenosis of the flora was dominated by Bennettitales (98.5%) including cf. Pterophyllum sp., Ptilophyllum cf. acutifolium, Ptilophyllum cf. pecten, Ptilophyllum cf. pectiniformis and cf. Ptilophyllum sp., and the occasional presence of ferns (1.5%) represented by the taxon Cladophlebis cf. denticulata. The presence of the Anisoptera Cymatophlebia cf. longialata suggests a higher affinity for a Tithonian age of the studied site, and the anatomy and palaeogeographical distribution of this species suggest capacity to migrate for rather long distances. The floristic composition of the site differs remarkably from other Tithonian-Berriasian floras of the Iberian Peninsula. The presence of Odonata and the distinctive flora in (semi)arid conditions could be due to the hot-spring providing an environmental niche with constant conditions of warmth and humidity forming an ‘ecological oasis’.
... In the context of the anthophyte debate, we place special emphasis on the morphology and anatomy of seeds and the associated structures borne on bennettitalean ovulate receptacles. We use the resulting information to execute detailed comparisons of bennettitalean cones and seeds to similar organs and tissues of Gnetales and to an array of dispersed charcoalifi ed fossil seeds (hereafter referred to in this paper as " charcoalifi ed seeds " ) described by Friis and Pedersen (1996) , Rydin (2005) , Friis et al. (2007) , and Mendes et al. (2008) . ...
Article
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Bennettitales is an extinct group of seed plants with reproductive structures that are similar in some respects to both Gnetales and angiosperms, but systematic relationships among the three clades remain controversial. This study summarizes characters of bennettitalean plants and presents new evidence for the structure of cones and seeds that help clarify relationships of Bennettitales to flowering plants, Gnetales, and other potential angiosperm sister groups. Bennettitales have simple mono- or bisporangiate cones. Seeds are borne terminally on sporophylls. They have a unique structure that includes a nucellus with a solid apex, no pollen chamber, and a single integument, and they are clearly not enclosed by a cupule or other specialized structures. Such features differ substantially from Gnetales, flowering plants, and the seed fern Caytonia, providing no compelling evidence for the origin of the angiospermous carpel. Cladistic tests were performed to assess the strength of the "anthophyte hypothesis" and possible relationships of Bennettitales, Gnetales, and Caytonia to flowering plants. Our results do not support the anthophyte hypothesis for the origin of angiosperms by a transformation of fertile organs that were already aggregated into a cone or flower-like structure. However, the anthophyte topology of the seed plant tree continues to be supported by morphological analyses of living and extinct taxa.
... Although the studies of Teixeira provided a wide overview on Mesozoic Portuguese floras, the ages of most Lusitanian outcrops remain uncertain. Early and Late Cretaceous mesofloras from Lusitanian Basin has been extensively studied (Eriksson et al., 2000; Friis and Pedersen, 1996; Friis et al., 1992 Friis et al., , 1994 Friis et al., , 1997 Friis et al., , 1999 Friis et al., , 2000a Friis et al., , 2000b Friis et al., , 2003 Friis et al., , 2004 Friis et al., , 2009a Friis et al., , 2009b Mendes et al., 2008a Mendes et al., , 2008b Pedersen, et al., 2007; Rydin et al., 2006; Schönenberger et al. 2001; von Balthazar et al., 2005). A thorough synthesis of Cretaceous mesofossils and pollen in situ from Lusitanian Basin was recently carried out by Friis et al. (2010). ...
Article
The successive vegetations inhabiting the Iberian Peninsula from the Triassic/Jurassic boundary to the Cretaceous/Tertiary Boundary is reviewed based on published palynological and macrofloral data, and the vegetational changes set in a palaeogeographical and climate context. Xerophytic microphyllous coniferous forests and pteridophyte communities of arid environments dominated the Jurassic and earliest Cretaceous vegetation. This vegetation was replaced in the mid Early Cretaceous by mixed forests of pteridophytes, gymnosperms and angiosperms. The composition of the successive plant assemblages suggests that a subtropical arid climate generally prevailed in the Iberian Peninsula during Jurassic-Cretaceous, although palaeobotanical and sedimentological evidences suggest that the climate was not uniform through the whole interval and that were two episodes in the Tithonian-Berriasian and Aptian-Albian periods of pronounced dry and/or arid environmental conditions. The composition and structure of the vegetation was not only affected by evolutionary changes but also by successive global geographical and climate changes. Hence, significant changes in the distribution of continental areas during the Mesozoic resulted in the latitudinal or sublatitudinal extensions of the climatic belts.
... Over the past twenty-five years studies of a series of mesofossil floras containing well-preserved angiosperm and non-angiosperm reproductive structures have provided important information on the biology, systematic composition and diversity of Early Cretaceous floras (e.g. Friis et al., 2006; Mendes et al., 2008a,b; Friis et al., 2009). ...
... A new element in this discussion is the description by of Early Cretaceous dispersed seeds with a micropylar tube, as in both Bennettitales and Gnetales, and a four-part outer envelope, which they compared with the bipartite envelope in Gnetales and the tripartite envelope in the less completely reconstructed fossil order Erdtmanithecales (producers of Eucommiidites pollen; Friis and Pedersen 1996;Mendes et al. 2008). In a cladistic analysis building on the seed plant data set of Hilton and Bateman (2006), in which rescored Bennettitales as having a ''partite (valvate) outer envelope,'' the dispersed seeds were sister to Gnetales in a clade including Bennettitales, Erdtmanithecales, and Gnetales, whereas previously Bennettitales and Gnetales were separated. ...
Article
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Inferences on the origin of the angiosperm flower require consideration of other seed plants, especially fossils. Molecular data favor a relationship of Gnetales to conifers rather than to angiosperms, and both alternatives are equally parsimonious in terms of the morphological data set presented here. However, if molecular relationships among extant taxa are accepted, morphology still associates glossopterids, Pentoxylon, Bennettitales, and Caytonia with angiosperms. Bennettitales had flowerlike structures, but if Caytonia is sister to angiosperms, aggregation of fertile parts probably occurred independently in Bennettitales and angiosperms. These results and developmental genetic data are consistent with homology of the angiosperm bitegmic ovule with the cupule of glossopterids and Caytonia, while the carpel could represent a leaf and a cupule-bearing axillary branch. Origin of an adaxial cross zone could produce a uniovulate, ascidiate carpel, as in living basal angiosperms. Stamens may represent similar units bearing two microsynangia. However, ovulate structures of Pentoxylon and Bennettitales are more difficult to interpret, and any homologue of the carpel wall in Caytonia is unclear. Further progress may require better understanding of homologies in known fossils and/or recognition of closer stem relatives of angiosperms. A proposed Cretaceous stem relative, Archaefructus, is more likely a crown-group angiosperm related to Hydatellaceae (Nymphaeales).
... In this preliminary approach, we compare the environmental interpretation of clay minerals with key palaeobotanical studies by the authors, namely Heimhofer et al. (2007Heimhofer et al. ( , 2012 and Mendes et al. (2008Mendes et al. ( , 2010Mendes et al. ( , 2011, as presented in Fig. 1. Thus, climatic indications in the figure are tentative and represent an initial approach that will lead to subsequent studies based on larger numbers of clay data (of contrasting palaeoenvironments), integration of other plant records, and other environmental proxies, and aimed at understanding the role of climate versus the role of sedimentary conditions. ...
... The detailed preservation of reproductive structures enabled comparisons to be made with the modern flora, as well as a systematic analysis and establishment of phylogenetic systematic relationships, improving our understanding of the reproductive biology of angiosperms during the Cretaceous. The coeval Early Cretaceous mesofossil pollen-producing structures and seeds ascribed to the Bennettitales–Erdtmanithecales–Gnetales (BEG) group occur in the same ecosystems and are also very well represented (e.g., Pedersen et al. 1989; Friis et al. 2009; Mendes et al. 2008 Mendes et al. , 2010). ...
Conference Paper
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The Lower Cretaceous of the Lusitanian Basin (western Portugal) contains rich assemblages of plant remains. The study of the palynological and mesofossil flora of the Berriasian Bombarral Formation in Vale Painho, near Juncal, contributes to ascertaining the environmental conditions during deposition, the vegetation diversity, and the unit’s age. The fossil site is just below the base of the Figueira da Foz Formation, a basin-wide breakup paraconformity. Regional correlation with biostratigraphically dated units (Lourinhã p.p., Farta Pão, Porto da Calada, and Serreira) points to a Berriasian age for the top of the Bombarral Formation. The Vale Painho palynological assemblage is clearly dominated by fern spores and gymnosperm pollen. The mesofossil flora is characterized by seeds of conifers or taxa related to the Bennettitales– Erdtmanithecales–Gnetales (BEG) group, in agreement with palynomorphs. No angiosperm remains were recognized. The assemblage is very similar to the Berriasian to Valanginian Bornholm flora (Denmark). Plant features and sedimentary proxies indicate a hot climate with marked seasonality in precipitation.
... In this preliminary approach, we compare the environmental interpretation of clay minerals with key palaeobotanical studies by the authors, namely Heimhofer et al. (2007Heimhofer et al. ( , 2012 and Mendes et al. (2008Mendes et al. ( , 2010Mendes et al. ( , 2011, as presented in Fig. 1. Thus, climatic indications in the figure are tentative and represent an initial approach that will lead to subsequent studies based on larger numbers of clay data (of contrasting palaeoenvironments), integration of other plant records, and other environmental proxies, and aimed at understanding the role of climate versus the role of sedimentary conditions. ...
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We collected a set of 120 clay samples with precise stratigraphic locations from the Lower Cretaceous coastal outcrops of the Ericeira area (western Portugal). The kaolinite versus illite dominance can be considered as revealing wet or dry climates, respectively, prevailing in the watershed. Swelling clays are associated with seasonally dry climates. However, since hydrodynamics and rejuvenation events also control clay associations, the relative role of climate versus depositional setting is still to be fully deciphered. As the onshore Lower Cretaceous of western Portugal is a key area for studying the Early Cretaceous initial diversification of angiosperms, several well-studied floras are summarized and their environmental interpretations presented.
... Despite Erdtman's ambivalence over pollen analysis, he did continue to publish on fossil pollen, writing excitedly, for example, about his finding of pollen with three colpi in samples from the Lower Jurassic (Erdtman, 1948). The family Erdtmanithecaceae and two genera, Erdtmanitheca and Erdtmanispermum, were later named to honour Erdtman's first report of these unusual gymnosperms with close relationship to the Gnetales (Pedersen et al., 1989;Friis & Pedersen, 1996;Mendes et al., 2008;2010). ...
Article
Gunnar Erdtman is known for his founding contributions to pollen analysis and morphology, and for his richly illustrated books. The palynogram illustrations he devised, which include multiple perspectives and transects of pollen’s surface and internal structures, helped to bring order to a subject of overflowing complexity. This article explores Erdtman’s visual skills and the influences of both nature and nurture on his work – investigating his development as an articulate observer, his eventual focus on pollen structure and his sustained career outside of Swedish academia.
... The Mesozoic fossil family ERDTMANITHECACEAE Friis & Pedersen is established for Eucommiidites-producing plants and the order ERDTMANITHECALES Friis & Pedersen to accommodate this family (Friis and Pedersen, 1996). It proliferated during the Jurassic and Early Cretaceous and became extinct during the early part of the Late Cretaceous (Mendes et al., 2008). Their seeds are organized in the same way as BENNETTITALES Engler and EPHEDRACEAE Dumortier, and may reflect similar ecological preferences. ...
Article
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The ecogroup classification based on the growth-form of plants (Eco-Plant model) is widely used for extant, Cenozoic, Mesozoic, and Paleozoic paleoenvironmental reconstructions. However, for most Mesozoic dispersed sporomorphs, the application of the Eco-Plant model is limited because either their assignment to a specific ecogroup remains uncertain or the botanical affinities to plant taxa are unclear. By comparing the unique outline and structure/sculpture of the wall of dispersed sporomorph to the sporomorph wall of modern plants and fossil plants, 861 dispersed Mesozoic sporomorph genera of Bryophytes, Pteridophytes, and Gymnosperms are reviewed. Finally, 474 of them can be linked to their closest parent plants and Eco-Plant model at family or order level. Based on the demands of the parent plants to different humidity conditions, the Eco-Plant model separates between hydrophytes, hygrophytes, mesophytes, xerophytes, and euryphytes. Additionally, due to different temperature demands a separation in megathermic, mesothermic, microthermic, and eurythermic plants is possible. In the Mesozoic, both spore-producing and pollen-producing plants are adapted to different kinds of humidity. The concept to use the spore/pollen ratio to reflect the hygrophytes/xerophytes ratio is therefore questionable. The presented ecogroups for dispersed Mesozoic sporomorphs now allow identifying at least relative plant, paleoenvironmental and paleoclimate changes in Mesozoic sedimentary records.
... Currently, about 30 species have been identified. Of these, 17 species have been formally named and assigned to eleven extinct genera (Acanthocatia, Buarcospermum, Cattomia, Ephedrispermum, Erdtmanispermum, Lignierispermum, Lobospermum, Quadrispermum, Raunsgaardispermum, Rugonella, Tomcatia) or to the extant genus Ephedra (Pedersen et al. 1989;Rydin et al. 2006a;Mendes et al. 2008aMendes et al. , 2008bFriis et al. 2009Friis et al. , 2013. Several of these seeds have a rugulate surface formed by the uneven distribution of sclerenchyma cells in the seed envelope as occurs in Bicatia, but none of them have the combination of features seen in the three new Bicatia species and none have so far been associated with Welwitschia type pollen. ...
Article
Bicatia gen. et sp. nov. from the Early Cretaceous of the Northern Hemisphere is described based on three species of dispersed seeds: Bicatia costata from the Juncal and Famalicão localities (western Portugal) and the Kenilworth locality (eastern North America), B. juncalensis from the Juncal locality, and B. rugosa from the Puddledock locality (eastern North America). Seeds of B. costata and B. rugosa are known from both lignitised (Juncal, Kenilworth, Puddledock) and charcoalified specimens (Famalicão, Puddledock), whereas seeds of B. juncalensis are known only from lignitised material (Juncal). All three species have the same characteristic chlamydospermous organisation seen in the wide range of other Early Cretaceous seeds that have been assigned to the Bennettitales-Erdtmanithecales-Gnetales (BEG) group. However, the species of Bicatia differ from all previously described BEG seeds in having a disymmetrical and flattened seed envelope with more or less distinct lateral wings. All three species are also closely associated with polyplicate pollen grains that have a prominent distal colpus. Pollen grains of this kind are very similar to those of extant Welwitschia. The combination of seed and pollen features seen in Bicatia provides the strongest documentation so far of Welwitschia-like plants in the Northern Hemisphere during the Early Cretaceous.
... Combined palynological-mesofossil studies were carried out for two other Early Cretaceous floras from Portugal: the Vale Painho flora (Mendes et al. 2008a(Mendes et al. , b, 2011 and Chicalhão flora (Mendes et al. 2014), both collected in the Juncal area close to where the Nossa Senhora da Luz flora was collected. ...
Article
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A new fossil flora is described from the Early Cretaceous of the western Portuguese Basin, based on a combined palynological-mesofossil study. The fossil specimens were extracted from samples collected in the Nossa Senhora da Luz opencast clay pit complex near the village of Juncal in the Estremadura region. The plant-bearing sediments belong to the Famalicão Member of the Figueira da Foz Formation, considered late Aptianearly Albian in age. The palynological assemblage is diverse, including 588 spores and pollen grains assigned to 30 genera and 48 species. The palynoflora is dominated by fern spores and conifer pollen. Angiosperm pollen is also present, but subordinate. The mesofossil flora is less diverse, including 175 specimens ascribed to 17 species, and is dominated by angiosperm fruits and seeds. The mesofossil flora also contains conifer seeds and twigs as well as fossils with selaginellaceous affinity. The fossil assemblage indicates a warm and seasonally dry climate for the Nossa Senhora da Luz flora.
... Electromagnetic radiation provides a range of noninvasive technologies (Becraft, 2013;Fiorani et al., 2013), although only few of these have as yet been adapted to study seed. Computed tomography (CT), based on X-rays, can be used to derive both elemental composition (Lombi et al., 2011) and high-resolution structure (Friis et al., 2007;Mendes et al., 2008;Verboven et al., 2013). Optical methods reliant on visible light can capture seed shape, size and colour (Dell'Aquila, 2007;Wagner et al., 2011). ...
Article
The large numbers of samples processed in breeding and biodiversity programmes require the development of efficient methods for the nondestructive evaluation of basic seed properties. Near-infrared spectroscopy is the state-of-the-art solution for this analytical demand, but it also has some limitations. Here, we present a novel, rapid, accurate procedure based on time domain-nuclear magnetic resonance (TD-NMR), designed to simultaneously quantify a number of basic seed traits without any seed destruction. Using a low-field, benchtop 1H-NMR instrument, the procedure gives a high-accuracy measurement of oil content (R2 = 0.98), carbohydrate content (R2 = 0.99), water content (R2 = 0.98) and both fresh and dry weight of seeds/grains (R2 = 0.99). The method requires a minimum of ~20 mg biomass per sample and thus enables to screen individual, intact seeds. When combined with an automated sample delivery system, a throughput of ~1400 samples per day is achievable. The procedure has been trialled as a proof of concept on cereal grains (collection of ~3000 accessions of Avena spp. curated at the IPK genebank). A mathematical multitrait selection approach has been designed to simplify the selection of outlying (most contrasting) accessions. To provide deeper insights into storage oil topology, some oat accessions were further analysed by three-dimensional seed modelling and lipid imaging. We conclude that the novel TD-NMR-based screening tool opens perspectives for breeding and plant biology in general.
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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.
Chapter
In addition to those fossil plants that can be put in angiosperms with confidence, there are more fossil plants that are more or less related to angiosperms, but the current knowledge on them does not allow the author to put them in angiosperms according to the criterion presented in Chap. 3. In this chapter, four of these plants are briefly documented. These fossils show combinations of characters that are never seen in typical gymnosperms but are frequently seen in angiosperms. Their trans-angiosperm-gymnosperm traits prompt the author to share their information with the readers. It is hoped that future study will elucidate on their position in the evolutionary map of angiosperms and seed plants.
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This book provides up-to-date coverage of fossil plants from Precambrian life to flowering plants, including fungi and algae. It begins with a discussion of geologic time, how organisms are preserved in the rock record, and how organisms are studied and interpreted and takes the student through all the relevant uses and interpretations of fossil plant. With new chapters on additional flowering plant families, paleoecology and the structure of ancient plant communities, fossil plants as proxy records for paleoclimate, new methodologies used in phylogenetic reconstruction and the addition of new fossil plant discoveries since 1993, this book provides the most comprehensive account of the geologic history and evolution of microbes, algae, fungi, and plants through time. * Major revision of a 1993 classic reference * Lavishly illustrated with 1800 images and user friendly for use by paleobotanists, biologists, geologists and other related scientists * Includes an expanded glossary with an extensive up-to-date bibliography and a comprehensive index * Provides extensive coverage of fungi and other microbes, and major groups of land plants both living and extinct.
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Cambridge Core - Palaeontology and Life History - Early Flowers and Angiosperm Evolution - by Else Marie Friis
Article
A new Early Cretaceous flora is described from the Lusitanian Basin in the Estremadura region (western Portugal) based on a combined study of mesofossils and palynomorphs. The fossil specimens were extracted from samples collected in the Chicalhão clay pit complex, near the village of Juncal from sediments belonging to the Figueira da Foz Formation. The plant bearing sequence is considered to be of Late Aptian–Early Albian age. Palynomorphs and mesofossils are generally well-preserved and include about 63 taxa. The palynoflora is dominated by conifer pollen and fern spores. Angiosperm pollen is also present, but subordinate among the palynomorphs. In contrast, angiosperms completely dominate the mesofossil flora and are mainly represented by fruits and seeds. Four taxa of angiosperm flowers were also identified. The combined palaeobotanical and sedimentological evidence indicates seasonally dry climate and an open vegetation consisting of a mixed conifer forest with an understorey and ground cover of ferns and angiosperms and with patchy occurrences of lycophytes and plants of the Bennettitales–Erdtmanithecales–Gnetales (BEG) group. Angiosperms probably inhabited moister areas bordering rivers and lakes.
Conference Paper
As we continue to push the limits of technology further, our power grid is struggling to keep up with these technological advances. This project outlines the design of home microgrid with load management, smart metering, and distributed generation, which is the future of smart grid technology. In order to properly stabilize itself, a microgrid will require load management and smart metering to balance the loads to the generator. This system will be introduced to an existing home to convert the home into a smart home microgrid. The load management and smart metering will help the homeowner identify large drains of power in the home and control these electrical loads to lower energy costs and waste. The distributed generation will allow the homeowner to further reduce their electrical load on the power grid by taking the load up itself and it will also be able to push power back out onto the distribution lines. When the value placed on a microgrid by local distribution and PJM is considered, the financial benefits will produce a low risk investment with other physical benefits. Finally, when the microgrid is islanded in a power outage, the generator will produce electric power increasing the reliability of the home's electricity and allowing power inverters to remain active so PV can still be utilized.
Article
Five species of seeds are described in four new genera that are broadly similar to seeds of the Bennettitales, Erdtmanithecales, and Gnetales (Tomcatia taylorii, Tomcatia sp., Cattomia trapezoides, Acanthocatia virginiensis, Quadrispermum parvum). The material is based on numerous charcoalified and lignitic specimens recovered from Early Cretaceous mesofossil floras in Portugal (Arazede, Buarcos, Catefica, Famalicão, Torres Vedras, Vale de Agua) and eastern North America (Puddledock). The seeds all have a prominent seed envelope that encloses a thin integument and the lower part of the long, slender micropylar tube. Seeds of all four genera are distinguished from previously described seeds of this kind in having a strongly four-angled seed envelope with distinct transverse ridges that create a rugulate seed surface. The seed envelope is composed of sclerenchyma cells toward the inside and an outer zone of nonlignified cells toward the outside. The outer zone is often composed of distinctive and prominent elongated cells that are very similar in position and form to the tubular cells reported in seeds of Bennettitales. In Cattomia the tubular cells are especially well-developed at the apex and base of the seeds, as well as along the angles of the seed envelope. In Tomcatia and Acanthocatia they form pronounced apical projections and are also present over the angles of the seed envelope and at the base. In Quadrispermum, where the seeds are borne in the axils of opposite bracts, the tubular cells are less well developed but are nevertheless present at the base of the seed. It is unknown how the seeds of the other taxa were borne, but in Cattomia the strongly developed sheet of tubular cells at the base of the seeds suggests that they were not borne in the same way as seeds of Quadrispermum. The distinctive organization of the seeds seen in Tomcatia, Cattomia, Acanthocatia, and Quadrispermum links them to previously described seeds of Erdtmanithecales and Gnetales. Similarities in seed organization, combined with the presence of the tubular cells, as seen especially clearly in Cattomia, provide further evidence of a close relationship of some of the dispersed seeds to Bennettitales.
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Premise of study: Anatomically preserved evidence for a novel clade of gymnosperms emphasizes diversity of seed plants immediately prior to the appearance of angiosperm fossils in the paleontological record. Methods: Cupulate seeds from the Early Cretaceous Apple Bay locality (Vancouver Island) are described from serial cellulose acetate peels and 3D reconstruction. Phylogenetic context is assessed through the comparative analysis of gymnosperm seed producing fructifications and maximum parsimony analysis of a revised morphological dataset for seed plant phylogeny. Key results: Xadzigacalix quatsinoensis gen. et sp. nov. is characterized by an orthotropous ovule with an elongated micropyle and complex integument, enclosed within a radial cupule. The micropylar canal is elongated; and the nucellus extends into the micropyle to seal the post pollination ovule. Except at the apex of the micropyle, the seed is completely enclosed by a parenchymatous cupule with ca. 20 axially elongated secretory ducts. The cupulate seed is produced upon a triangular woody stele, consisting of a parenchymatous pith surrounded by radially-aligned tracheids. The stele produces three short terete traces that terminate within the base of the cupule as transfusion tissue at the seed chalaza. Conclusions: Organography, vascularization, nature of the integument and nucellus, and configuration of the micropylar canal distinguish Xadzigacalix quatsinoensis from all other gymnosperm clades. Cladistic analyses suggest the new plant may have affinities with gnetophytes or angiosperms. These results are complemented with a critical re-evaluation of ovulate structures for Mesozoic gymnosperms, providing new insight into plant diversity immediately antecedent to the explosive diversification of flowering plants. This article is protected by copyright. All rights reserved.
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Em Portugal, são conhecidos depósitos do Cretácico em ambas as margens atlânticas do território nacional, quer no Algarve (Bacia Algarvia) quer na ocidental (incluindo a Bacia Lusitânica) Tratam-se de sedimentos carbonatados e siliciclásticos altemantes no tempo e misturando-se no espaço, testemunhado ambientes marinhos pouco profundos, lagunares, litorais e fluviais. Durante o Cretácico Inferior a máxima influência marinha da zona ctualmente emersa da Bacia Lusitânica situava-se nas proximidades de Cascais, e a transgressão máxima não ultrapassou muito o paralelo de Torres Vedras. O elevado nível eustático do Albiano ao Turoniano, com máximo no Cenomaniano superior, exprimiu-se por uma plataforma carbonatada epicontinental de afinidades tetianas, que se estendeu para norte, uniformizando a topografia e atingindo o pleno enchimento da Bacia Lusitânica. Os depósitos mais recentes, do Turoniano ao Campaniano estão preservados exclusivamente a norte do paralelo de Caldas da Rainha e apresentam uma clara tendência progradante. Na área atualmente emersa, estão registados episódios transgressivos circunscritos no Coniaciano e no Campaniano médio, até à emersão e paragem de sedimentação, expressa por um silcreto muito evoluído. No Algarve, a sedimentação cretácica deu-se numa plataforma costeira com topografia geral de rampa, com polaridade marinha para sul. A composição das unidades litostratigráficas, as atribuições cronológicas, as evoluções paleogeográficas e as organizações sequenciais demonstram que a deposição esteve sujeita, em ambas as margens, a um duplo controlo: o controlo global eustático de longo-temo que se exprimiu no baixo nível do Cretácico Inferior, pela subida e alto nível no Albiano e Turoniano, e a subsequente relativa estabilidade até ao Campaniano. A influência do eustatismo está também demonstrada pela identificação de todas as sequências deposicionais de 3a ordem descritas em diversas bacias sedimentares europeias entre o Valanginiano e o Albiano. O controlo regional, de natureza tectónica manifesta-se particularmente na Bacia Lusitânica, entre o Berriasiano e o Albiano, com a deposição a ser marcada pela abertura do Atlântico Norte. Com efeito, os ciclos transgressivos-regressivos de 2a ordem podem ser relacionados com as várias etapas conducentes à implantação de crosta oceânica e sua propagação para norte, sucessivamente nos sectores do Tejo, Ibérico e da Galiza. A transição entre a fase de rotura continental e a fase de margem passiva deu-se no Aptiano superior. Os principais eventos que assinalam tal evolução são também percetíveis no Algarve. No Cretácico Superior a subsidência diminui fortemente na margem oeste, onde as descontinuidades sedimentares refletem a rotação anti-horária da Placa Ibérica e as tensões transpressivas e, depois, compressivas nos limites setentrional, meridional e oriental desta placa, acompanhadas de intrusões magmáticas e vulcanismo no final do Campaniano. No Algarve, os depósitos albo-aptianos e cenomanianos testemunham uma forte aceleração de subsidência por detumescência térmica, sob regime transtensivo entre a África e a Ibéria; a ausência de depósitos mais recentes deve-se a um evento geodinâmico maior no Campaniano, resultante do inicio da compressão entre a Africa, a Ibéria e a Eurásia.
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Seven species of sporomorphs are described occuring in large quantities in Keuper sediments of Western, Central and Southern Poland. Among these species three are new: Triadispora keuperiana, Triadispora undulata and Eucommiidites sulechoviensis; one species is a newly established combination of the species Todisporites cinctus (Mai.) nov. comb. The descriptions of the remaining three already given in foreign literature are supplemented by new observations made on the material investigated.
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A Middle Oxfordian to Tithonian transgressive/regressive 2nd-order sequence is recognized over most of the Lusitanian Basin of Portugal. This paper describes the nature of this sequence and its constituent 3rd-order sequences in the Arruda subbasin situated 30 km north of Lisbon. Lack of good outcrops precludes the identification of 3rd-order sequences in the transgressive part of the 2nd-order sequence, but they are easily identified in the regressive part in four different tectonic settings. The transgressive part of the 2nd-order sequence is related to rift movements that created the subbasin. During rift initiation, carbonate depositional systems dominated. These were drowned during the rift climax phase when footwall uplift caused local erosion and karstification, and the influx of coarse siliciclastic sediments near active faults. 2nd-order maximum flooding occurred during the Late Oxfordian bimammatum zone at which time the subbasin was relatively starved of sediment and was a deep depression. Third-order sequences deposited during the immediate postrift phase (i.e., at the beginning of the 2nd-order regression) are aggradational lowstand arkosic submarine fan deposits. As accommodation was reduced by sedimentation, localized transgressive to highstand reefal carbonates formed on the shallow proximal part of the fan. The late postrift phase was heralded by progradational sequences consisting of lowstand finegrained slope deposits capped by transgressive/highstand coral boundstones and oolites. These filled the basin virtually to sea level, so that succeeding 3rd-order sequences lacking lowstands developed in shallow, low-energy carbonate and siliciclastic fluvial facies. Limited biostratigraphic control suggests that the 11 3rd-order sequences may be co-eval with those recognized elsewhere in Europe. If this is correct, the ages of these European sequences suggest that the rift climax event in the Arruda subbasin lasted only 1–2 my, and that subsidence rates approached 2m/ky in the center of the subbasin.
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Late Upper Kimmeridgian to final Portlandian sediments in the environs of Arruda dos Vinhos, Portugal, consist of deltaic siliciclastics, the Sobral formation, and lagoonal deposits, the limestone —marl sequence of the “Pteroceriano” formation and the limestone—marl—sandstone sequence of the Freixial formation. The lagoonal sediments grade into coastal and terrestrial clastics in northward and westward direction. Formal definition according to the ISSC norms is suggestively given for all lithological units and tentatively applied to further regions by basing on published studies in order to give a lithostratigraphic framework for the highly intertonguing sequence of the study area and the entire Lusitanian Basin. This approach is of special importance, since available stratigraphic data are scarce and sometimes even contradictory. The examined sequence lies within the Virguliana biozone and the Lusitanica biozone, based on benthic foraminifers. A further subdivision of the first is possible by the appearance of the alga Permocalculus n.sp. which is preliminarily described. The lack of a refined biostratigraphic classification can be partly balanced by considerations on subsidence and depositional rates, global sea level changes, diachronism, sedimentary processes and depositional models, so that a sketch-like paleageographic reconstruction can be concluded. The Upper to late Upper Kimmeridgian Sobral formation consists of three main sediment types: Sandstones exhibiting the brackish water bivalve Eomiodon securiformis are attributed to delta front environments, thin oolitic horizons are interpreted as distal/tidal bars, and silty-marly sediments, often with bivalve meadows of Gervillia sobralensis or bivalve banks of Isognomon lusitanicum, represent prodelta and interdistributary bay deposits. Soft bottom substrata were also inhabited by the specialized regular sea—urchin Pseudocidaris lusitanicus and occasionally by adapted corals which are interpreted in respect of functional morphology. The delta complex was prograding from west and north. It was biparted in N-S direction by a morphological and structural ridge, possibly caused by uprising salt diapirs. The delta not only outwedges towards south but also towards southeast due to another structural high along the Vila Franca fault system. This resulted in lowered subsidence rates, so that distribution of the eastern part of the delta was mainly determined by the heavily subsiding Arruda depocenter. The superimposed, uppermost Kimmeridgian to early Lower Portlandian “Pteroceriano” formation is mainly restricted to this Arruda depo-center, only extending further north and west at its base, probably coinciding with the peak in global eustatic sea level highstand. The formation’s lower part is mainly composed of low energetic marls and limestones, among which the nodular Arcomytilus limestones deserve special interest, since they indicate occasional very rapid deposition of lime mud followed by morphological adaptions of the bivalve Arcomytilus morrisi. Macrofaunal shell coquinas interpreted as storm layers are another important facies type. Intensive subsidence in the Arruda depo-center caused large thicknesses and pronounced channelling of terrigenous clay, in contrast to the structurally higher block further east where low depositional rates led to oncoid formatian and occasional establishment of coral facies. Heavy, though intermittent, subsidence in a wrench block directly bordering the Vila Franca fault system further east resulted in considerable thicknesses in this area. Contemporaneously, marginal marine siliciclastics (Santa Cruz member of the Bombarral formation, upper sandstone group) were deposited further west and north which only cccasionally affected the area of “Pteroceriano” facies around its western and northern borders. This indicates the establishment of a clastic trap in the north and the continuing activity of the mentioned morphological elevations, now acting as clastic fences in the west and east. General shallowing in the upper part of the “Pteroceriano” formation led to a vast establishment of mud-rich coral patch reefs and associated high and low energy facies lypes. Particularly discussed here are the adaption of corals to fairly high background sedimentation and the systematic position of some algae (Marinella lugeoni, Solenopora cayeuxiformis n.sp., Lithocodium sp.). This development was restricted to the Arruda depo-center. Perfect sheltering from terrestrial clastics in the west, north and, probably, east (Bombarral formation) indicates once more highly potent clastic fences in form of now emerging elevations. High subsidence rates in the north resulted in trapping coarse clastics, only allowing terrigenous clay to pass which settled down in tranquil water settings between individual patch reets. During deposition of the late Lower to final Portlandian Freixial formation, no clastic traps or fences were obvious, so that episodic hinterland uplift and minor sea level fluctuations resulted in rapid spreading and withdrawal of sand facies from and to the west, north and east. More basinwards, typical lagoonal limestones were deposited, dominated by foraminifers during times of slightly elevated salinities or by algae during more normal periods. The study area silted and sanded up completely towards the Cretaceous boundary. The late Upper Jurassic Lusitanian Basin displays the typical character of a protoocean marginal basin, characterized by calcareous facies into which clastic wedges were prograding. Yet, basin configuration and symmetry of sediment arrangement differs from other Jurassic marginal basins of the young Northern Atlantic, thus pointing out the control of basin development by local parameters.
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Detailed investigations on Lower Cretaceous Ephedra L. fossils (Gnetopsida) reveal morphological characters similar to those of extant Ephedra rhytidosperma Pachomova, including articulate branches with many fine longitudinal striations, a dichasial branching pattern, uni- or bi-ovulate cones with paired bracts, cones terminal on branchlets, and seeds with a short, straight micropylar tubes, covered by numerous regular and prominent transverse laminar protuberances. Fossils are similar to extant E. rhytidosperma reproductive organs but differ in some vegetative structures and are described and discussed here as Ephedra archaeorhytidosperma Y. Yang et al. Because E. rhytidosperma is currently considered one of the most specialized members in Ephedra L. section Pseudobaccatae Stapf, the occurrence of E. archaeorhytidosperma in the Yixian Formation suggests that Ephedra L. was perhaps a more diverse genus in the Lower Cretaceous. Perhaps the evolution and diversity of Ephedra L. was already in place by the Lower Cretaceous and certainly before the end of the Mesozoic.
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Pollen grains of Eucommiidites type were produced by Mesozoic gymnosperms of supposedly gnetophytic affinities. Microsporangiate organs and seeds with Eucommiidites pollen in situ were recently assigned to an extinct family Erdtmanithecaceae of the order Erdtmanithecales. We studied micromorphology and ultrastructure (SEM, TEM) of in situ Eucommiidites-type pollen grains from pollen cones Bayeritheca hughesii, recently described from the Late Cretaceous of Bohemia, a putative member of the Erdtmanithecales, and Hastystrobus muirii from the Middle Jurassic of Yorkshire), which perhaps has a more conventional cycadophytic microsporophyll morphology. Pollen from both taxa show differences in configuration of lateral furrows and arrangement of infratectal granules. The pollen cones of Aegianthus (mid-Jurassic of Siberia) and Loricanthus (Early Cretaceous of Transbaikalia), macromorphologically similar to Erdtmanitheca, produced monosulcate pollen grains ultrastructurally similar to Eucommiidites, but lacking additional furrows, whereas in the trisulcate Cryptosacciferites and Zolerella, the ultrastructures are alveolate rather than granular, attesting to parallel development of Eucommiidites morphology in different groups of Mesozoic gymnosperms.
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The extant species of the seed plant group Gnetales (Ephedra, Gnetum and Welwitschia) have been considered a remnant of a much greater, now extinct, diversity due to the pronounced differences in form and ecology among the genera. Until recently, this hypothesis has not been supported by evidence from the fossil record. This paper adds to the expanding information on Gnetales from the Early Cretaceous and describes coalified seeds from Barremian-Albian localities in Portugal and USA. The fossils were extracted from sediment samples by sieving in water. Adhering mineral matrix was removed by chemical treatment. Seeds were investigated using light and scanning electron microscopy. Morphology and anatomy of the seeds were documented and compared with those of extant species. The fossils share characters with extant Ephedra, for example papillae on the inner surface of the seed envelope and in situ polyplicate pollen grains that shed the exine during germination. They differ from extant Ephedra seeds in morphological and anatomical details as well as in their smaller size. Two new species of Ephedra are described together with one species assigned to a new genus of Gnetales. Other Ephedra-like seeds, for which pollen and critical morphological details are currently unknown, are also present in the samples. These Cretaceous seeds document that key reproductive characters and pollen germination processes have remained unchanged within Ephedra for about 120 million years or more. There is sufficient variety in details of morphology to suggest that a diversity of Ephedra and Ephedra-like species were present in the Early Cretaceous flora. Their presence in Portugal and eastern North America indicates that they were widespread on the Laurasian continent. The fossil seeds are similar to seeds of Erdtmanithecales and this supports the previously suggested relationship between Erdtmanithecales and Gnetales.
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Rich fossil floras including structurally preserved flowers, fruits, seeds and dispersed stamens have recently been extracted from mid-Early Cretaceous sediments from Portugal. The material illustrates considerable morphological variability in number and arrangement of floral parts, with the most diversity among magnoliid taxa; relatively few eudicots have been identified. Generally the flowers are small with undifferentiated perianth and massive androecium, and include both bisexual and unisexual forms. The most unexpected result of this study of Early Cretaceous flowers from Portugal is the presence of several epigynous forms at this early stage of angiosperm evolution.
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A study of spores and pollen in nonmarine sediments of Cretaceous age from Maryland and Delaware indicates that these deposits range from Lower Cretaceous to lowermost Upper Cretaceous. Twenty-two species of spores and pollen are described, eleven of which are new.
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The characteristic Mesozoic pollen genus Eucommiidites is described from pollen organs and seeds recovered in Cretaceous strata of North America and Europe. The pollen organs are from the Cenomanian of Texas and are referred to Erdtmanitheca texensis gen. et sp. nov. Small seeds from the Lower Cretaceous (upper Berriasian to Valanginian) of Bornholm, Denmark contain abundant Eucommiidites pollen in their micropyles. The seeds are referred to Erdtmanispermum balticum gen. et sp. nov. Reevaluation of other seeds known to contain Eucommiidites pollen indicates that they share significant similarities with Erdtmanispermum and that they may have been produced by closely related plants. Comparison of "Eucommiidites plants' with other seed plants suggests that they are probably most closely related to the anthophytes comprising Bennettitales, Pentoxylales, Gnetales and angiosperms. -from Authors
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Accounts of the occurrence of angiosperms in pre-Albian (often Jurassic) beds are found in paleobotanical literature. These early finds are frequently based on a very interesting sporomorph Eucommiidites. In 1961, Hughes found Eucommiidites in the micropylar canals of gymnospermous seeds from the Wealden of England.In a sample from the Patuxent Formation (Neocomian-Aptian) from Virginia, hundreds of well preserved specimens of a seed species have been found. The well defined micropyle and pollen chamber leave no doubt of its gymnospermous affinity. In over 50% of the specimens, grains of Eucommiidites are found either in the micropylar canal or in the pollen chamber to the exclusion of other pollen types. The similarity of N.F. Hughes' findings from the Wealden of England and the Patuxent material leaves no doubt that EucommiiditesErdtman should not be considered as evidence for the existence of pre-Albian angiosperms.
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A new pollen organ, Eucommiitheca hirsuta, containing Eucommiidites pollen grains is described from the Early Cretaceous of Portugal. The material comprises dispersed microsporangiate units and fragments of axes bearing microsporangiate units in an opposite and decussate arrangement. Each microsporangiate unit consists of a slightly angular to rounded peltate scale attached centrally to a short stalk, and with whorls of sporangia around the distal part of the stalk. Sporangia are stalked and free, with longitudinal dehiscence, and contain pollen grains similar to the characteristic dispersed pollen genus Eucommiidites. Eucommiitheca is comparable to Erdtmanitheca, another Cretaceous pollen organ containing Eucommiidites pollen, in the peltate nature of the microsporangiate units, but microsporangiate units in Erdtmanitheca are arranged in dense heads and sporangia are elongate. The opposite and decussate arrangement of the microsporangiate units in Eucommiitheca is in accordance with the possible affinity to the Gnetales suggested earlier for Eucommiidites-producing plants based on structure of their pollen grains and seeds, but peltate microsporophylls similar to those of Eucommiitheca do not occur in the Gnetales. Eucommiitheca is compared to other fossil reproductive organs, and the bennettitalean affinity of the fossil Sturiella langeri is questioned in light of our new findings. A new family Erdtmanithecaceae is established to accomodate Eucommiidites and the Eucommiidites-producing plants Eucommiitheca, Erdtmanitheca, Erdtmanispermum, Spermatites pettensis, S. putuxensis, and Allicospermum retemirum. This family is based on a unique suite of reproductive characters, including peltate microsporangiate units aggregated in heads or spikes, each bearing numerous sporangia in a radial arrangement; pollen grains with two lateral colpi or a ring colpus flanking a distal main colpus; and seeds with a distinct megaspore membrane, several envelopes surrounding the nucellus, and a long, narrow micropylar tube.
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Together with other plant remains of Upper Liassic-Aalenian age there were found in Grojec near Krakow, Poland, seeds known from the Yorkshire Gristhorpe Bed as Allicospermum relemirum Harris. On maceration these seeds showed in their pollen chamber and mieropyle, pollen of Eucommiidites troedssonii Erdtman which adds to similar evidence provided already by Hughes (1961) and Brenner (1966). The structure of the seed is described, discussed and compared with that of Spermatites pettensis Hughes which contained pollen of Eucommiidites delcourtii Hughes. S. pettensis is shown to agree in structure with the macerated A. retemirum, but it is of a different size. A. retemirum is considered to be related to either the Ginkgoales, Cycadales or Pteridosperms, or else to a new, not yet known group of plants. Its affinity with the Chlamydospermales is considered less likely.
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A new pollen organ, Bayeritheca hughesii gen. et sp. nov. with in situ Eucommiidites pollen grains, is described from the Cenomanian of Bohemia in Central Europe. It is based on a single lignified specimen which is the largest Eucommiidites -producing pollen structure described so far. It shows whorls of microsporangiate units attached to a massive main axis forming a cone-like structure. Each microsporangiate unit forms distally an angular head bearing trichomes and centrally arranged mucronate tubercles. The head is attached to a short stalk. Proximal sides of heads display radially arranged synangia. Each synangium contains an unknown number of pollen sacs with numerous Eucommiidites pollen grains.Bayeritheca is the only genus of Erdtmanithecales in which synangia instead of sporangia are found. Bayeritheca differs from Eucommiiditheca Friis & Pedersen in the whorled arrangement of microsporangiate units, which are densely spaced forming a cone-like structure. It differs from Erdtmanitheca Pedersen, Crane & Friis in the elongate shape of the whole organ, slender main axis, shorter pollen sacs, and different Eucommiidites pollen.
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One section in the Algarve Basin (southern Portugal) and several sections in the Western Portuguese Basin (Lisbon region) have been investigated palynologically with emphasis on the use of dinoflagellate cysts in stratigraphy. As a result, the stratigraphy of both basins can be defined more accurately. In the Western Portuguese Basin the existence of Jurassic and Late Valanginian-Early Hauterivian strata could not be established from dinoflagellate cyst associations. The existence of a hiatus comprising at least the Upper Barremian was confirmed but a continuous Late Aptian-Early Albian sequence in the basin could not be unambiguously identified. In the Algarve Basin the Upper Aptian is well-developed.
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New data on the evolution of rift basins is presented after analysing the Late Jurassic stratigraphy of the Central Lusitanian Basin (west Iberia). Well, outcrop and regional 2D seismic reflection profiles are used to investigate the differences in stratigraphic signature between diapir- and fault-bounded sub-basins. During the Late Jurassic syn-rift phase, surface rupturing in fault-bounded sub-basins resulted in the formation of tectonic scarps from which footwall-derived gravity flows were sourced. In contrast, the diapir-bounded Bombarral-Alcobaça sub-basin evolved as a distal bowl-shaped depocentre with an axis located up to 10 km away from its basin margins. Low-gradient marginal slopes developed in the Bombarral-Alcobaça sub-basin during the Late Jurassic rifting, while growing salt pillows limited the vertical propagation of basement normal faults. Differences in tectonic evolution, basin physiography and sediment input are the main factors responsible for the distinct sedimentary evolutions recorded in the study area: (1) transverse footwall-derived sediment fans, predominant in fault-bounded regions, give place to axial southwards-prograding fluvial to shallow-marine units in the diapir-bounded sub-basins; (2) growing salt pillows, absent in the fault-bounded sub-basins, formed barriers to and limited the development of transverse drainage systems.
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Vita. Thesis (Ph. D.)--Pennsylvania State University. Includes bibliographical references (leaves 258-263).
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Based on the author's thesis, Université Paul Sabatier, Toulouse, 1972. Includes bibliographical references (p. [466]-471).
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Gnetales comprise three unusual genera of seed plants, Ephedra, Gnetum, and Welwitschia. Their extraordinary morphological diversity suggests that they are survivors of an ancient, more diverse group. Gnetalean antiquity is also supported by fossil data. Dispersed “ephedroid” (polyplicate) pollen first appeared in the Permian >250 million years ago (Myr), and a few megafossils document the presence of gnetalean features in the early Cretaceous. The Cretaceous welwitschioid seedling Cratonia cotyledon dates the split between Gnetum and Welwitschia to before 110 Myr. Ages and character evolution of modern diversity are, however, controversial, and, based on molecular data, it has recently been suggested that Ephedra is very young, only 8–32 Myr. Here, we present data on the evolutionary history of Ephedra. Fossil seeds from Buarcos, Portugal, unequivocally link one type of Cretaceous polyplicate pollen to Ephedra and document that plants with unique characters, including the peculiar naked male gametophyte, were established already in the Early Cretaceous. Clades in our molecular phylogeny of extant species correspond to geographical regions, with African species in a basal grade/clade. The study demonstrates extremely low divergence in both molecular and morphological characters in Ephedra. Features observed in the fossils are present in all major extant clades, showing that modern species have retained unique reproductive characters for >110 million years. A recent origin of modern species of Ephedra would imply that the Cretaceous Ephedra fossils discussed here were members of widespread, now extinct sister lineage(s), and that no morphological innovations characterized the second diversification. • molecular phylogeny • fossil record • Gnetales • molecular dating
50–56 Plate I. Erdtmanispermum juncalense Mendes, Friis & Pais sp. nov. from the Early Cretaceous of Portugal (Juncal village). SEM-micrographs of seeds
  • M M Mendes
M.M. Mendes et al. / Review of Palaeobotany and Palynology 149 (2008) 50–56 Plate I. Erdtmanispermum juncalense Mendes, Friis & Pais sp. nov. from the Early Cretaceous of Portugal (Juncal village). SEM-micrographs of seeds. (1).