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Review of Palaeobotany and Palynology 162 (2010) 325–340

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Review of Palaeobotany and Palynology

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Research paper Floristic and vegetational changes in the Iberian Peninsula during Jurassic and Cretaceous

Carmen Diéguez a,⁎, Daniel Peyrot b, Eduardo Barrón c a Departamento de Paleobiología. Museo Nacional de Ciencias Naturales-CSIC. José Gutiérrez Abascal 2, 28006 Madrid, Spain b Departamento y UEI de Paleontología UCM-CSIC , José Antonio Novais 2, 28040 Madrid, Spain c Instituto Geológico y Minero de España, Ríos Rosas 23, 28003 Madrid, Spain article info abstract

Article history: The successive vegetations inhabiting the Iberian Peninsula from the Triassic/Jurassic boundary to the Cretaceous/ Received 3 July 2009 Tertiary Boundary is reviewed based on published palynological and macrofloral data, and the vegetational changes Received in revised form 24 May 2010 set in a palaeogeographical and climate context. Xerophytic microphyllous coniferous forests and pteridophyte Accepted 4 June 2010 communities of arid environments dominated the Jurassic and earliest Cretaceous vegetation. This vegetation was Available online 17 June 2010 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 Keywords: – Jurassic Iberian Peninsula during Jurassic Cretaceous, although palaeobotanical and sedimentological evidences suggest that Cretaceous the climate was not uniform through the whole interval and that were two episodes in the Tithonian–Berriasian and palynoflora Aptian–Albian periods of pronounced dry and/or arid environmental conditions. The composition and structure of macroflora the vegetation was not only affected by evolutionary changes but also by successive global geographical and climate vegetation changes. Hence, significant changes in the distribution of continental areas during the Mesozoic resulted in the latitudinal or sublatitudinal extensions of the climatic belts. © 2010 Elsevier B.V. All rights reserved.

1. Introduction regularity that may be observed in the floras of the Jurassic and Cretaceous, involving the invasion of certain subtropical elements that The Iberian Block remained joined to Laurasia after the break-up of benefited from the rising temperatures of the warm belt. However, during Pangea, beginning of the Jurassic a system of shallow platforms (Gómez Uppermost Jurassic–Lowermost Cretaceous interval the subtropical and Goy, 2005). Throughout the Jurassic the Iberian Block was situated vegetation of this climate belt was never fully replaced. between 20° and 30° N paleolatitude, approximately at the level of the From the T/J (Triassic–Jurassic) to the K/T (Cretaceous–Tertiary), there current Tropic of Cancer (Smith et al., 1973). On the exposed landmasses is a successive change in vegetation structure correlated with a change in of these low palaeolatitudes deserts were formed. Later, in the Late systematic composition. Major floristic changes are particularly mani- Jurassic, the Iberian Block was displaced towards higher and more humid fested in two events that revolutionized terrestrial plant ecosystems: (i) a palaeolatitudes where seasonal dry or winterwet conditions prevailed global increased in abundance and systematic diversity of conifers, mainly (Hallam, 1984; Ziegler et al., 1993; Rees et al., 2000; Willis and McElwain, extinct conifers assignable to the Cheirolepidiaceae as well as other 2002). During the entire Jurassic–Cretaceous time interval, the lands that gymnospermssuchasCycadales,Bennettitales and Ginkgoales. This was today constitute the Iberian Peninsula were partially submerged and associated with a decrease in pteridophytes and pteridosperms diversity separated from the Laurasian continent by the Proatlantic and the Tethys (Willis and McElwain, 2002; Kenrick and Davis, 2004); (ii) the emergence Sea. The exposed land areas were islands with low relief. of angiosperms, their rapid diversification and colonisation of almost all The extensive changes in the distribution of exposed landmasses, continental environments (Hughes et al., 1979; Hughes and McDougall, gave rise to changes in the latitudinal or sublatitudinal extension of 1987; Lidgard and Crane, 1988, 1990; Crane and Lidgar, 1989). climatic belts, which induced large-scale climate perturbations that Palaeobotanical data for the Jurassic of NW areas of the Euro-Sinian modified both the composition of floras and the plant cover of vast areas. Region (sensu Vakhrameev, 1991) are much more abundant than for the Global climate changes had more pronounced effects on floras Iberian Peninsula (Batten, 1996; Batten and Koppelhus, 1996; Barale, inhabiting the bordering areas between the tropical and warm-temperate 1981; Thomas and Batten, 2001; Cleal et al., 2001; Cleal and Rees, 2003; climate belts (Krassilov, 1981). Meyen (1987) noted an interesting van Konijnenburg-van Cittert, 2008) due to the scarcity of macro and microfossils in most sediments dated as Early and Middle Jurassic. However, it is also true that the Mesozoic plant fossils of Spain or Portugal ⁎ Corresponding author. have not enjoyed the traditional interest shown in other European E-mail address: [email protected] (C. Diéguez). countries.

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In the Iberian Peninsula the first palynological study about the SC515 and observed with SEM. The specimens were measured Cretaceous was carried out by Groot and Groot (1962) on sediments with a Measuroscope Nikon and with stereoscopic microscope from Estremadura (Portugal) and by Menéndez Amor and Esteras Leica MZ 16A and Nikon DS-FI1 with the program Nikon NIS- (1964) on Aptian–Albian lignites from the Utrillas Basin (Spain). The Elements. Photography and examination of specimens were made first Iberian Jurassic palynomorphs were studied by Riley (1974) from with an Olympus Zeiss stereomicroscope. In addition, some sediments of the Lusitanian Basin (Portugal). material was examined with a Quanta 200 scanning electron The first study of Portuguese Mesozoic macrofloras was performed by microscope at 25 kV. Hand samples were photographed with a Heer (1881). Later these macrofloras were revised and completed by Canon Eos 300D digital camera under low-angle incident light. Saporta (1894) and Teixeira (1948, 1950, 1952), lacking posterior revisions of Cretaceous macrofloras as a whole while Jurassic floras Geological ages and divisions follow the International Commission were revised by Pais (1974, 1998). Although the studies of Teixeira on Stratigraphy (ICS) and International Union of Geological Sciences provided a wide overview on Mesozoic Portuguese floras, the ages of most (IUGS) (Gradstein et al.,2004). The ages proposed by the authors of the Lusitanian outcrops remain uncertain. Early and Late Cretaceous meso- papers consulted were honoured. To facilitate the discussion of the plant floras from Lusitanian Basin has been extensively studied (Eriksson et al., fossils we grouped the fossil microfloras according to their stratigraphic 2000; Friis and Pedersen, 1996; Friis et al., 1992, 1994, 1997, 1999, 2000a, occurrence. Macrofloral data are presented according to their age and 2000b, 2003, 2004, 2009a, 2009b; Mendes et al., 2008a, 2008b; Pedersen, the different outcrops studied. We calculated the taxa richness by et al., 2007; Rydin et al., 2006; Schönenberger et al. 2001; von Balthazar et counting one organ per plant group of every outcrop and present this al., 2005). A thorough synthesis of Cretaceous mesofossils and pollen in variable according to the main suprageneric taxonomic groups. Out- situ from Lusitanian Basin was recently carried out by Friis et al. (2010). crops for which only a single species has been described were omitted. Macrofloras from Jurassic and Cretaceous of Spain are known from the pioneer work by Zeiller (1902) on few compressions from Montsec 3. Jurassic vegetation outcrops (Lérida province). More than fifty years later, Depape and Doubinger (1956–1960) described the first complete floral assemblage 3.1. Palaeogeographical remarks which compares with Wealden floras. From the seventies, studies of Spanish Cretaceous floras have been sparse and most of them focused on During Jurassic (Fig. 1A, B) large proportions of the central and the description of new taxa. Despite these studies, most of Iberia's western Iberian plate formed an emergent massif (the so-called Jurassic and Cretaceous floras are still not fully known, and most of them Iberian Massif), while the surrounding areas were occupied by are not properly dated. So, the history of the vegetation of Iberia from T/J intracratonic basins that formed shallow epicontinental seas charac- to K/T is poorly understood. To date, no synthesis of integrating terized by marine carbonate deposits (Aurell et al., 2002). Today the palaeobotanical and palynological data with the palaeogeographic Iberian Peninsula displays extensive areas with outcrops in the changes in the Iberian Block, considering its insular character and the Jurassic rocks. There are abundant remnants of the Jurassic marine possible existence of the region's own endemic flora existed. Neither has fauna such as ammonoids, brachiopods, bivalves, ostracods, and any previous author examined relationships among the different plant foraminifera (Vera, 2004). In contrast, only few leaf remains and other associations inferred from the climate conditions prevailing in the area plant macrofossils are preserved in these predominantly marine over this time period, nor the type of existing vegetation. sediments. Thus, the data currently available are essentially palynological, although there are some leaf and trunk remains from the Late 2. Materials and methods Jurassic (Fig. 2). During this period, shallow-water developed receiving siliciclastic sediments of continental or transitional origins. In this paper, we exhaustively reviewed the findings of palaeobotanical studies including micro, and macroremains of the Jurassic and 3.2. Plant assemblages and vegetation Cretaceous found in the Iberian Peninsula. Rich mesofossils floras from Portugal have not been considered in this work. Palynological assemblages of the Lower Jurassic are characterized Many of the floral assemblages described in the present work have by a low diversity of taxa and a numerical dominance of specimens of been studied by the authors of this issue (e.g. Diéguez and Meléndez, the genus Classopollis, a typically Mesozoic type of pollen produced by 2000; Barrón and Azêredo, 2003; Barrón et al., 2006; Peyrot et al., 2007a, conifers of the extinct family Cheirolepidiaceae (Taylor and Alvin, 2007c; Diéguez et al., 2007, 2009). The techniques applied to these 1984; Watson, 1988). In general, Cheirolepidiaceae seem to have been materials were as follows: drought resistant, thermophilous shrubs and trees (Francis, 1983; Vakhrameev, 1991). Some species of this family were probably coastal – Palynological samples were prepared following the standard plants (Alvin, 1982; Watson, 1988). techniques (Batten, 1999) based on acid treatment (HCl, HF, and Near the T/J boundary of the Asturias region (N Spain), the xerophytic

HNO3) at high temperature. The palynomorphs concentration was coniferous forests that developed during the Rhaetian became consid- estimated by passing the resulting residues through 500, 250, 75, 50 erably impoverished mainly due to the extinction of Triassic plants and 10 μm sieves. Slides were prepared by mounting in glycerine producing the pollen species Rhaetipollis germanicus Schulz, Granuloper- jelly. Some 500–1000 palynomorphs (on up to four replicates) were culatipollis rudis Venkatachala and Gózcán emend. Morbey, Ovalipollis identiﬁed per sample to determine the species ratios. Microscopic pseudoalatus (Krutzsch) Schuurman and Tsugaepollenites pseudomassulae analysis of residues has been performed by a Leica Laborlux D (Mädler) Morbey. The plant communities were reduced to cheirolepi- microscope. Specimens with obscure morphology and biostrati- diaceous stands interspaced by an undergrowthvegetationofscarce graphic key forms has been later analysed and imaged by a Biorad lycophytes and ferns adapted to dry environments (Barrón et al., 2006). 1024 confocal laser scanning microscope driven by Leica Confocal Climate changes at the T/J transition are characterized by a distinct, Scanware.VGStudioMax1.2 (Volume Graphics GmbH, Heidelberg, mostly Hettangian, humid time interval. In Asturias, this is recorded at Germany) was employed to process the image stacks and generate the beginning of the period by an increased proportion of miospores three-dimensional reconstructions of the whole grains. of hygrophyllous plants such as lycophytes, ferns and Taxodiaceae. – Macroremains were prepared under dissecting microscope by Similarly, this humid period may be inferred from the Association 2 of dégagement with steel needles to fully reveal details of plant “Grès de Silves” (Lusitana basin, Portugal) (Adloff et al., 1974). morphology. Silicone RTV replicas were prepared of epidermal This humid interval was followed in the Asturian Hettangian by a prints. These were coated with 15 μm of gold by a Sputter Bio-Rad cheirolepidiaceous conifer forest associated with Araucariaceae, Author's personal copy

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Fig. 1. Palaeogeographical sketch maps showing the evolution of North-Atlantic region at four time-slices correponding to A: Hettangian, B: Oxfordian, C: Aptian and D: Maastrichtian. Modiﬁed from Smith et al., 1994.

Fig. 2. Selected Jurassic outcrops mentioned in the text: 1) La Camocha mine (Asturias region, N Spain), Rhaetian–Hettangian; 2) Miedes de Atienza (Guadalajara province, northern sector of the Castilian Branch, Iberian Ranges, C Spain), Hettangian; 3) Beira Litoral (Lusitanian Basin, W Portugal), Hettangian–Sinemurian, 4) Sierra Palomera section (Teruel province, central sector of the Aragonese Branch, Iberian Ranges, E Spain), upper Pliensbachian–upper Toarcian; 5) Fuentelsaz section (central sector of the Castilian branch, Iberian Ranges, C Spain), upper Toarcian–lower Aalenian; 6) Lusitanian Basin (Ribatejo, W Portugal), Early–Late Jurassic; 7) Espichel Cap (Setúbal Peninsula, W Portugal), Kimmeridgian– Portlandian; 8) Almansa section, (S Iberian Ranges, Albacete province, E Spain), Kimmeridgian–Portlandian; 9) Villaviciosa and Ribadesella outcrops (Asturias, N Spain), Kimmeridgian; 10) Aguilar Formation (Burgos and Palencia provinces, N Spain), Tithonian–Berriasian. Square: palynomorphs, circle: macroremains. Author's personal copy

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Pinaceae and Ginkgoales/Cycadales/Bennettitales, as inferred from and Botryococcus (Pereira et al., 1998; Barrón and Azêredo, 2003). The palynofloral assemblages (Barrón et al., 2006; Gómez et al., 2007) plants inhabiting these swamps were mainly ferns of the families suggesting a return to drier conditions. Schizaeaceae and Osmundaceae, and conifers of the family Taxodiaceae. These changes have not been observed in the Hettangian of the Better-drained soils, sandy areas and the transition to higher lands were Iberian Range which is a northwest-trending fold and thrust belt located inhabited by tree ferns adapted to dry environments. In uplands, in Eastern Spain where Late Triassic and Early Jurassic deposits are well- conifers of the families Pinaceae and Podocarpaceae thrived. exposed (Gómez et al., 2007). Instead a low diversity vegetation The increase in Late Jurassic of spore and pollen diversity might dominated by Cheirolepidiaceae trees or shrubs and a few other plant reflect a change in climate to more humid conditions maybe without species indicate adaptation to severe aridity. Similar vegetation has also any marked seasonality. So, in the Kimmeridgian of Asturias (Lastres been suggested for the Hettangian–Sinemurian of Portugal (Adloff et al., Fm., Oles), the occurrence of trunks lacking growth rings (Protocupres- 1974) and the Upper Pliensbachian and Upper Toarcian of the Iberian sinoxylon and Agathoxylon) agrees with these new climate conditions Range (Barrón et al., 1999; Peyrot et al., 2007a). (Valenzuela et al., 1998). This is consistent with the suggestion of At the beginning of the Jurassic period, the Iberian plate was situated Chaloner and Creber (1990) who described that in this geological period in a position north of a latitudinal zone characterized by desert between palaeolatitudes 32° N and 32° S, the temperature gradient from environments (Rees et al, 2000). From the late Pliensbachian and equator to poles was much lower than exists today. onwards the genus Spheripollenites becomes increasingly common in The occurrence of Iberian Kimmeridgian leaf-flora with Cupressino- the palynological assemblages (Barrón et al., 1999; Cresta et al., 2001; cladus, Brachyphyllum, Otozamites, Pagiophyllum and Pterophyllum which Veiga de Oliveira et al., 2007) being spores of pteridophytes very scarce show xeromorphyc features in their morphology and leaf anatomy (Pais, (Plate I,Fig.1).AccordingtoCourtinat (2000), this pollen was produced 1974, 1998; Barale and Calzada, 1985; Valenzuela et al., 1998), enjoyed by conifers inhabiting swamp environments comparable to mangroves. the existence of relatively dry environments. However, the scarce Spheripollenites numerically dominate assemblages close to the Lower/ occurrence of this type of macroremains reflects a vague idea of the Middle Jurassic transition of the Iberian Range (Cresta et al., 2001; vegetation prevailing in the Kimmeridgian. Barrón et al., 2010). Callialasporites, a pollen related to the family Macrofloras of the Uppermost Jurassic–Lowermost Cretaceous Araucariaceae, starts to appear relatively frequently in the palynological (Tithonian–Berriasian) are scarce in Western Europe (Vakhrameev, assemblages found beyond the Upper Toarcian (Barrón et al., 2010). 1991; Cleal et al., 2001). Palaeontological and sedimentological data on a Palynological assemblages from the Late Jurassic indicate an increase global scale indicate that, already from the start of this interval, there in species diversity both in pteridophyte taxa and in various groups of was a trend towards more arid conditions throughout all of Europe gymnosperm compared to the Early Jurassic assemblages (Riley, 1974; (Hallam, 1984, 1985; Hallam et al., 1993; Vakhrameev, 1991; Ziegler Boland, 1986; van Erve and Mohr, 1988; van Erve et al., 1988; Mohr and et al., 1993). According to these authors, this trend was related to the Schmidt, 1988; Mohr, 1989; Vink, 1995; Wijlaars, 1995; Castro, 1996, displacement of continental masses northwards which was accompa- 1998; Mohr and Schultka, 2000; Barrón and Azêredo, 2003; Fernández- nied by extensive marine transgressions in Europe, Asia Minor and Marrón et al., 2006; Barrón et al., 2008). Concretely, miospore western Siberia. The aridisation affected landmasses from England to assemblages are characterized by prolific verrucate trilete spores Mongolia and, possibly, western China. ascribed to the genera Converrucosisporites, Lophotriletes and Rubinella The fossil floras indicate marked seasonality, with warm, wet winters (Plate I, Fig. 2); and Classopollis, bisaccate pollen of seed ferns, and dry, muggy summers similar to the present climate of Western Podocarpaceae and Pinaceae, inaperturate grains of Spheripollenites Australia. The components of the vegetation of lower to mid-palaeolati- and Araucariaceae and poroid grains of Exesipollenites (van Erve and tudes was characterized by strongly xeromorphic features, suggesting a dry Mohr, 1988; Barrón and Azêredo, 2003; Barrón et al., 2008). Moreover, climate and partly-forested landscape. These floras were of low diversity during the Kimmeridgian the taeniate trilete spores of the genus and dominated by microphyllous elements (conifers and cycadophytes). Cicatricosisporites, attributable to the family Schizaeaceae, start to be Sedimentological data for Iberia indicate a semi-arid Mediterranean frequently found in palynological assemblages, their percentages rising type climate (Valdes and Sellwood, 1992) under which xerophytic floras towards the Cretaceous (van Erve and Mohr, 1988; van Erve et al., 1988). would have developed such as those found in Villela (Aguilar Fm., Possibly, throughout this whole period, Cheirolepidiaceae communi- Burgos and Palencia provinces, N Spain). The composition of the Villela ties continued to characterize the vegetation of vast regions of the Iberian macroflora (Hernández et al., 1998; Diéguez et al., 2009)comprising Massif. Palynological studies indicate the significant development of 8.2% ferns (Plate II, Fig. 1) and 91.8% Bennettitales (Plate II,Fig.2) coastal communities with Spheripollenites-producing conifers and some indicates dry savannah type vegetation with open forested areas Corystospermales, and a coastal strip represented by Cheirolepidiaceae dominated by medium height drought-resistant plants. The fossil record and Araucariaceae. In the undergrowth of these coastal formations, the only reflects this type of vegetation in the Upper Jurassic Morrison Fm. appearance of Cycadales and Bennettitales is suggested by the presence of (USA) and Tendaguru Fm. of North Africa (Rees et al., 2004). Cycadopites, Eucommiidites and Exesipollenites. In a second strip of vegetation, with no direct influence of the sea, 4. Cretaceous vegetation lowland communities developed. Here, vegetation composed of ferns of the families Cyatheaceae, Dicksoniaceae, Gleicheniaceae and Matonia- 4.1. Palaeogeographical remarks ceae, as well as seed plants of the families Cycadaceae, Ginkgoales, Bennettitales and Cheirolepidiaceae, grew. In several places, swamps or At the beginning of the Cretaceous, Laurasia and Gondwana started flooded areas developed as suggested by the presence of Charophyta to separate into isolated continental masses. The fragmentation of

Plate I. Selected spore and pollen types of the Jurassic and Cretaceous of Spain:

Fig. 1. Tetrade of Kraeuselisporites reissingeri (Harris 1957) Morbey 1975, Upper Toarcian, Fuentelsaz section, Guadalajara province. Fig. 2. Rotverrusporites major (Couper 1958) Norris 1968, Kimmeridgian, Playa de Vega section, Ribadesella, Asturias region. Fig. 3. Concavissimisporites verrucosus (Delcourt and Sprumont 1955) Delcourt, Dettmann and Hughes 1963, Upper Aptian–Lower Albian, Mine Z, Oliete subbasin, Teruel province. Fig. 4. Clavatipollenites tenellis Paden Phillips and Felix 1971, Upper Aptian–Lower Albian, Mine Z, Oliete subbasin, Teruel province. Fig. 5. Atlantopollis verrucosus (Groot and Groot 1962) Krutzsch 1967, Upper Cenomanian, Puentedey section, Burgos province. Fig. 6. Cerebropollenites macroverrucosus (Thiergart 1949) Schulz 1967, Upper Aptian–Lower Albian, Mine Z, Oliete subbasin, Teruel province. Fig. 7. Gabonisporis vigourouxii Boltenhagen, 1967, Campanian–Maastrichtian, Chera outcrop, Valencia province. Bars: 1–2, 4–7=10 μm, 3=20 μm. Author's personal copy

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Gondwana marked the onset of the formation of the south Atlantic. The The vegetation of this interval was quite similar to the vegetation opening of ocean masses between continents (Fig. 2) produced the of the uppermost Jurassic, and included pteridophytes and gymnos- expansion of epicontinental shallow seas in North America, North Africa perms. Classopollis-producers along with Araucariaceae and Taxodia- and Northern Europe along with flooding of most of South Eurasia, ceae–Cupressaceae may account for a significant component of which was converted into an archipelago (Smith et al., 1973, 1981, coastal forests. Pteridophytic communities seem to show a lower 1994). Throughout the entire Cretaceous, variations in the intensity and diversity of lycopsids than ferns. velocity of the drifting sea floor caused sea level fluctuations and this To date, there are no published data describing assemblages of period was therefore characterized by constant marine transgressions macrospores of heterosporous lycopsids and ferns. However, this lack of and regressions. data seems more to reflect a lag in the fossil record than the true absence The Tethys, which originally flooded the south of Europe, rose until of lowland aquatic or semi-aquatic plant communities involving these it covered the British Isles, Central Europe, southern Scandinavia and floras. Fresh-water swamps and lakes are likely to have been colonized European Russia. by these plants in the Iberian Peninsula in a similar way to how this The outcome of all this was the division of the Earth into isolated occurred in the English Weald (Batten et al., 1996)ortheEarly landmasses. This series of palaeogeographic variations, led to an Cretaceous of North America (Nowak and Lupia, 2004). increase in regional differences among floras and to the emergence of There is an almost continuous plant macrofossil record from the Early endemic floras and faunas. The endemic populations, as products of Cretaceous of Spain ranging from the Berriasian–Valanginian to the Albian their isolation on the continents landmasses of the Upper Cretaceous, (Fig. 3). To date, macrofloras have been described in the provinces of Lérida evolved to generate a large part of the current diversity of terrestrial life (Zeiller, 1902; Menéndez Amor, 1951; Barale et al., 1984; Blanc-Louvel, (Meyen, 1987, Vakhrameev, 1991). 1984; Barale, 1991, 1995; Dilcher and Hill, 2003); Teruel (Lemoigne and In this frame of intense palaeographic change (Fig. 1C, D), the Iberian Marin, 1972; Gomez, 2002; Gomez et al., 1999, 2000, 2002; Sender et al., Peninsula that had remained during the Jurassic at a palaeolatitude 2005, 2008; Diéguez et al., 2007); Cuenca (Álvarez-Ramis and Meléndez, between 20° and 30° N, rotated almost 26° in an anticlockwise direction 1971; Diéguez, 1992, 1996; Diéguez and Martín-Closas, 1995; Diéguez and with respect to the current North pole and to Europe, which remained Trincão, 1995; Diéguez and Meléndez, 2000; Martín-Closas and Diéguez, stable, changing in palaeolatitude to 30°N after the Cenomanian (Juárez 1998; Sanz et al., 1988, 1990, 1994, 1999, 2000; Gomez et al., 2001); La et al., 1998; Márton et al., 2004). During the first half of the Cretaceous Rioja (Depape and Doubinger, 1956–1960; Román Gómez, 1986–87; period, temperatures were warm, seasonality was low, and global sea Barale and Viera, 1991; del Nido et al., 1998); Burgos (Álvarez-Ramis, levels were high (there was no polar ice). Towards the end of the 1981a; García Esteban et al., 2006)andAsturias(Álvarez-Ramis and Cretaceous, however, climate changed severely, sea levels fell, and there Lorenzo, 1979). These macrofossil assemblages (Fig. 4) are rich in ferns, was intense volcanic activity in Europe. many with geographically and stratigraphic widely distribution genera, and often with xeromorphic characteristics such as Ruffordia, Onychiopsis, Cladophlebis and Weichselia.Thefloras also contain abundant microphyl- 4.2. Plant assemblages and vegetation of the Lower Cretaceous lous conifers such as Brachyphyllum, Sphenolepis, Pagiophyllum and Cupressinocladus accompanied, although in small amounts, by remains of Palynological studies on the Berriasian–Hauterivian period are scarce macrophyllous conifers attributable to the genus Podozamites.Remainsof in the Iberian Peninsula and mainly referred to Portugal (Pais and Reyre, seed ferns and Ginkgoales are scarce not consistently recorded in all floras. 1980–1981; Taugourdeau-Lantz et al., 1982; Médus, 1983; Berthou et al., Similarly, although in smaller amounts and showing lesser diversity than 1983; Trincão, 1987; Taugourdeau-Lantz, 1988; Trincão, 1990). In Spain the former groups, are remains of Equisetales and Lycopodiales. only three palynological assemblages had been described which are An outstanding feature of most of these floras compared to the older those from Montsec (SE Pyrenees) dated as Berriasian–Valanginian floras is the presence of angiosperms. Macrofossils showing affinity to (Courtinat, 1984), and from Lower Valanginian and Hauterivian of The the Ranunculaceae (Plate II, Fig. 3) have been recorded in the Berriasian– Maestrazgo (NW Spain) (Solé de Porta and Salas, 1994). Valanginian (Barale, 1995) at Montsec. Also, remnants of sapindophy- The overall composition of the palynological assemblages of the lous and platanophylous leaves of primitive angiosperms are a frequent Earliest Cretaceous in Iberian Peninsula differs only slightly to those of constituent of the floras of the Upper Barremian of the Cuenca province the Jurassic. In both cases, the dominant components of the palynofloras (Diéguez et al., 1995a) and of the Albian of Teruel Province (Sender et al., are trilete spores referred to Schizaeaceae, Osmundaceae, Gleichenia- 2005). The Lusitanian floras of the Barremian–Aptian (Cercal, Vale de ceae, Matoniaceae and Cyatheaceae–Dicksoniaceae (Berthou et al., 1983; Agua, Buarcos, Torres Vedras and Famalicão) document the presence of Trincão, 1987; Taugourdeau-Lantz, 1988) and bisaccate conifer grains over 150 angiosperm taxa represented by leaves, flowers, fruits and such as Podocarpidites and Pytiosporites (Taugourdeau-Lantz et al., 1982). seeds, both of magnoliids and monocotyledons (Teixeira, 1948, 1950; The first description of angiosperm pollen grains in the Iberian record Eriksson et al., 2000; Friis et al., 2001, 2004), and other angiosperm corresponds to specimens attributed to Clavatipollenites hughesii,fromthe groups have been identified in the Late Aptian–Albian of Portugal (von Valanginian of Porto da Calada, western Portugal (Trincão, 1990). Balthazar et al., 2005; Heimhofer et al., 2007).

Plate II. Selected plants megaremains from Jurassic and Cretaceous sediments in Spain. All specimens are housed at the Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain.

Fig. 1. Cladophlebis denticulata (Brongniart) Fontaine. MNCNV-7991. Incomplete pinna of penultimate order. Tithonian–Berriasian, Aguilar Formation (Burgos-Palencia provinces). Fig. 2. Ptilophyllum acutifolium Morris. MNCNV-7946. Leaf fragment showing falcate leaﬂets. Tithonian–Berriasian, Aguilar Formation (Burgos-Palencia provinces). Fig. 3. Ranunculus ferreri (Teixeira) Blanc-Louvel. MNCNV-125. Axe showing three fruits? Berriasian–Valanginian, Montsec (Lérida province). Fig. 4. Montsechia vidali (Zeiller) Teixeira. MNCNV-122. Shoot with verticillate leaves. Berriasian-Valanginian, Montsech (Lérida province). Fig. 5. Drewria sp. LH-13.311. Fragment of stem with opposite leaves. Upper Barremian, Las Hoyas (Cuenca province). Fig. 6. Coniopteris laciniata Diéguez and Meléndez. ADR-0119P. Pinna with pinnules at different fertilization stages. Upper Barremian, Las Hoyas (Cuenca province). Fig. 7. Ctenozamites insignis (Fontaine) Harris. MNCNV-3210. Fragment of an stem showing pinnate shoots and leaﬂets. MNCNV-3210. Turonian, Guadalix de la Sierra (Madrid province). Fig. 8. Portion of a Marchantiopsid colonization mat. MNCNV-10102. Lower Albian, Oliete subbasin (Teruel province). Fig. 9. Sapindopsis angusta (Heer) Seward. MNCNV-7535. Pinnate leaf. Turonian, Guadalix de la Sierra (Madrid province). Fig. 10. Laurophyllum palaeocretacica (Saporta) Teixeira. MNCNV-3203. Notophyllous leaf. Turonian, Soto del Real (Madrid province). All bars: 5 mm. Author's personal copy

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The material from the sites of Las Hoyas (Upper Barremian) and and Meléndez, 2000) shows a higher abundance (19%) and greater Oliete (Aptian–Albian) has generated particular interest owing to the diversity (18 taxa) of ferns (Figs. 5 and 6; Plate II,Fig.6)thananyother presence of rare elements with a scarce fossil record or to the relative Iberian flora of the Lower Cretaceous and resembles more those described proportions of these elements at these sites. for the Wealden deposits of south-east England. The Las Hoyas flora TheLasHoyassite(Cuenca)(Sanz et al., 1988; Diéguez et al., 1995a, composition also reveals a lesser diversity of conifers than those exhibited 1995b; Martín-Closas and Diéguez, 1998; Sanz et al., 1999, 2000; Diéguez by other Iberian floras, (Teixeira, 1948, 1950). In addition, the intriguing Author's personal copy

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Fig. 3. Selected Cretaceous outcrops mentioned in the text: 1) Lusitanian Basin (N Lisbon area, W Portugal), Berriasian–Albian; 2) Espichel Cap (Setúbal Peninsula, W Portugal), Berriasian–Hauterivian; 3) Algarve region (S Portugal), Aptian–Albian; 4) Montsec (Pyrenees, Lérida province, NE Spain), Berriasian–Valanginian; 5) The Maestrazgo region (Teruel and Castellón provinces, eastern sector of the Aragonese Branch, Iberian Ranges, E Spain), Valanginian–Albian; 6) Buarcos outcrops (Lusitanian Basin, Beira Litoral, W Portugal), Barremian–Aptian; 7) Las Hoyas-Uña-La Cierva (Cuenca province), the two ﬁrst localities are upper Barremian, La Cierva is Albian in age; 8) Escucha Formation (Teruel province, central sector of the Aragonese Branch, Iberian Ranges, E Spain), Aptian–Albian; 9) Peñacerrada ambarigenous outcrop (Basque–Cantabrian Basin, Álava province, N Spain), Aptian– Albian; 10) Puentedey outcrop (Basque–Cantabrian Basin, Burgos province, N Spain), Cenomanian–Turonian; 11) Southern margin of the Sierra de Guadarrama outcrops (Madrid province, C Spain), Upper Turonian; 12) Chera outcrops (S Iberian Ranges, Valencia province, E Spain), Campanian–Maastrichtian; 13) Tremp Formation (Pyrenees, NE Spain), Maastrichtian; 14) Pola de Siero outcrop (Asturias region, N Spain), Aptian–Albian; 15) Villadiego outcrop (Basque–Cantabrian Basin, Burgos province, N Spain), Aptian–Albian; 16) Ortigosa de Cameros outcrop (N Iberian Ranges, La Rioja, N Spain), Aptian; 17) Préjano outcrop (N Iberian Ranges, La Rioja, N Spain), Aptian–Albian. Square: palynomorphs, circle: macroremains, star: amber.

Fig. 4. Species richness indices for macroﬂoras of the Lower Cretaceous discovered at Spanish sites (B–V: Berriasian–Valanginian; B: Upper Barremian; Ap: Aptian; Ap–Al: Aptian–Albian; Al: Albian). Author's personal copy

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Fig. 5. Comparative species richness of Filicales and Coniferales in Lower Cretaceous Spanish macrofloras. plant Montsechia vidali (Zeiller) Teixeira (Plate II, Fig. 4) is only recorded in close to the lake shore. It may be characterized as a microphyllous the floras of Las Hoyas and Montsec where it occurs abundantly. Las Hoyas evergreen forest vegetation of a marked xeric nature similar to those flora also comprises leaf and inflorescence remains attributable to the developing throughout the Cretaceous below palaeolatitudes of 40° Gnetales (Diéguez, 1996; Crane, 1996)(Plate II,Fig.5)notobservedin (Spicer et al., 1993). The forest was dominated by microphyllous other macrofloras in Spain. This would be the most ancient record of this conifer trees with an understory vegetation of shrubby Bennettitales, Order and the single record for the European sites with the exception of seed ferns and Gnetales, and an herbaceous stratum of many ferns and seeds of ephedraceas found at the Barremian–Aptian boundary of Torres some Equisetales, Lycopodiales and bryophytes. Vedras (Portugal) (Rydin et al., 2006). The vegetation inferred from palynomorphs available for the Spanish The composition and the xeromorphic characteristics of Las Hoyas Barremian is consistent with the arid climate determined by Ruffell and flora indicate stressful environment with warm to torrid conditions in Batten (1990) for the Barremian–Lower Aptian period in Europe. a winterwet biome (Diéguez and Meléndez, 2000; Fig. 7). Barremian associations show high percentages of Classopollis (Leereveld The Las Hoyas flora was deposited in a lacustrine environment, and et al., 1989; Gomez et al., 2001) indicating forests and scrubs of conifers, comprises a mixture of aquatic plants and plants that probably grew surely linked to warm, arid environments. Solé de Porta and Salas (1994)

Fig. 6. Proportions of macroremains referred to the main plant groups detected in the macrofossil assemblage of Las Hoyas (Cuenca province, Spain). Author's personal copy

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Fig. 7. Palaeogeographical reconstruction and biome map for the Late Cretaceous. Modified from Willis and McElwain, 2002. described for the Upper Barremian of the Maestrazgo an increase in pollen Its understory was diverse and characterized by lycopsids and of the Gnetales, which account for up to 8% of the total spore/pollen Schizaeaceae. The second one grew on coastal environments and contents, confirming the existence of this arid stage. Vascular cryptogams corresponded to xeromorphic vegetation comprised of Cheirolepidia- are characterized by spores of the genera Appendicisporites, Cicatricosis- ceae, Cycadophyta, Gnetophyta and some arborescent ferns adapted porites, Deltoidospora, Matonisporites and Trilobosporites (Doubinger and to dry conditions of the families Matoniaceae and Cyatheaceae/ Mas, 1981; Solé de Porta and Salas, 1994; Gomez et al., 2001), that were Dicksoniaceae/Dipteridaceae. probably related as much to swamp, lagoon or fluvial environments as to During the mentioned interval in the Iberian Range palynological savannah ecosystems. assemblages showed a great diversity and indicate three different types The Oliete macroflora (Escucha Fm, Teruel, Spain) (Diéguez et al. of vegetation depending on the environment under the pollen plants- 2007) developed during an arid period at the margin of a restricted producers had grown. There existed vegetation linked to back swamps, lagoon and consists of a bryophyte-rich horizon. This horizon includes riverbanks and other freshwater-related environments comprising: “in situ” specimens (Plate II, Fig. 8) of liverworts that except for the lack Bryophyta, Lycophyta, Shizaeaceae, Osmundaceae, Cerebropollenites of costa are closely similar to the gametophytes of extant Marchantia- (Plate I,Fig.6), Cycadales/Ginkgoales/Bennettitales and angiosperms ceae in all over morphology. In addition the studied specimens present (Plate I, Fig. 4); conifer vegetation determined by the abundance of the air chambers in the thallus and the characteristic scyphulae. For these pollen of Taxodiaceae–Cupressaceae that would correspond to forests features altogether the specimens were referred to Family Marchantia- occupying riverbanks or mangroves; and forests dominated by ceae (Diéguez et al., 2007). The fossil liverworts occur abundantly over a Cheirolepidiaceae and tree ferns of the group Cyatheaceae/Dicksonia- considerable area and evidently reproduced asexually. This together ceae/Dipteridaceae (Plate I, Fig. 3) which grew in more stressed with the complete absence of other plant or animal remains has conditions (Solé de Porta et al., 1994; Peyrot et al., 2007b, 2007c). attributed this macroflora to an “in situ” clonal colonisation mat. No Macrospores have been recorded in the Iberian Peninsula during this fossil record of liverwort-rich horizons exists in the palaeogeographic interval. Their presence may support the dwelling of heterosporous ferns low-latitude zones located in arid climatic belts. and lycopsids in shallow, calm and fresh-water environments at least From a palaeoecological standpoint, the xerophytic features of the during the Albian (Busnardo and Taugourdeau, 1964). This environment specimens and their exclusively asexual reproduction mode confirm must also have been populated with Charophytes and primitive this colonization mat formed under environmental conditions that angiosperms (Martín-Closas, 2003). Over this period, it also seems that were extremely hot and dry. Moreover, the production of gemmae is angiosperms were capable of frequently colonizing disturbed environ- an adaptive strategy to extreme conditions (Callaghan et al., 1997). ments including riverbanks, temporary ponds and periodically flooded In terms of vegetation, this macroflora represents a xerothermo- plains (Retallack and Dilcher, 1981; Feild et al., 2004; Coiffard et al., 2006). philous bryophyte community well adapted to conditions of extreme According to Taugourdeau-Lantz et al. (1982), Albian assemblages dryness and warmth. The loose arrangement of specimens indicates are dominated by bisaccate pollen grains, Classopollis and, to a lesser an initial stage of colonization of the environment. extent, Araucariacites. However, the frequent occurrence of angio- The significance and singularity of this vegetation is determined by sperm pollen grains in Lower Albian assemblages suggests that this the scarcity of records of marchantiacean representatives and the fact group represented yet a significant part of the vegetation of the that it is the only description of a colonization mat comprised of Iberian Peninsule at that time. This is well-reflected in Foz de Folcão bryophytes in zones of low latitude in arid climate belts. (Portugal) by the high numeric percentages detected of up to 25%, and During the Upper Aptian–Lower Albian, a conifer forests occupied the abundance of tricolpate forms (Médus and Berthou, 1980). a curved land strip from the North to the East of the Iberian Peninsula following the Early Cretaceous coastal line (Fig. 3), and gave rise to 4.3. Plant assemblages and vegetation of the Upper Cretaceous large amounts of resin that is now preserved as amber with important biological inclusions (Delclòs et al., 2007; Najarro et al., 2009). This Few palynological studies have focused on the Upper Cenomanian– amber could have been produced by conifer trees of families Turonian interval in the Iberian Peninsula (Fig. 3). The most recent Araucariaceae and Cheirolepidiaceae (Alonso et al., 2000; Menor- palynological study addresses a section of the Cenomanian–Turonian Salván et al., 2009). boundary at Puentedey (Burgos Province, Spain) (Peyrot et al., 2008). In the Basque–Cantabrian basin, two vegetation strips may be Assemblages include abundant angiosperm pollen grains as well as a distinguished (Barrón et al., 2001). One of these developed on alluvial small proportion of conifer pollen grains and spores. Angiospermid grains plains and showed evidence of a mixed conifer forest, essentially of are characterized by Normapolles, mainly represented by the genera Araucariaceae and Taxodiaceae–Cupressaceae, sometimes accompa- Atlantopollis (Plate I,Fig.5)andComplexiopollis. These palynological data nied by different species of Pinaceae, Podocarpaceae and Ginkgoaceae. suggest the presence of open forest communities dominated by Author's personal copy

C. Diéguez et al. / Review of Palaeobotany and Palynology 162 (2010) 325–340 335 angiosperms, since the producers of Normapolles could form a significant remains of Filicales and a low diversity. Gymnosperms are abundant part of open arboreal communities (Batten, 1984, Friis et al., 2006). The with the marked presence of macroremains of Cycadales, specifically gymnosperm component was dominated by Classopollis and, to a lesser Ctenozamites insignis (Fontaine) Harris (Plate II, Fig. 7), and of extent, by bisaccate and inaperturate pollen grains of conifers such as Taxodiaceae. However, while Frenelopsis are still abundant, they appear Taxodiaceae–Cupressaceae, Pinaceae and Araucariaceae. in lower amounts than in the other sites of the area. In addition, cone- As a whole, gymnosperm pollen grains have remained abundant and bracts of Araucariaceae are frequently observed. The abundant macro- their plant producers constituted a significant component of the Iberian remains of angiosperms reveal a high diversity with 22 different taxa, vegetation of this time interval (Sole de Porta, 1978). The Cheirolepi- among which we should mention Sapindopsis angusta (Heer) Seward diaceous genus Classopollis is typically the most abundant form, but the (Plate II, Fig. 9), owing to its high representation and good preservation. conifer genera Pityosporites and Abietineaepollenites are also well In the floristic composition of Soto del Real (Diéguez, 1986; represented. Gnetales are generally rare to occasional in pollen records Diéguez et al., 1993, 2000), dated as Upper Turonian, ferns and (Van Amerom, 1965; Peyrot et al., 2008) but can locally amount to close angiosperms occurs in low number, (Plate II,Fig.10),while to 8% of the gymnosperm content (Sole de Porta, 1978). gymnosperms are represented, essentially by major groups such as Pteridophytes seem to have played a less significant role in the Cycadales and the Coniferales, the latter comprising several families: plant communities of this interval than during the earliest Cretaceous Taxodiaceae, Podocarpaceae and Cheirolepidiaceae. when Schizeaceae was the most diverse family. From sedimentological and palaeobotanical data we can infer that The scarce macrofloral sites of the Upper Cretaceous, dated as Upper the prevailing palaeoenvironment in the area during Upper Turonian, Turonian (Diéguez et al., 2000), are concentrated at the southern margin was marked by the aridity and/or a high salinity. of the Sierra de Guadarrama (Torrelaguna, Guadalix de la Sierra and Soto Both in Guadalix de la Sierra and in Soto del Real, the herbaceous del Real in the Madrid province). The plant assemblages found indicate stratum consisted of Filicales, Lycopodiales and, in smaller propor- the existence of, at least, three different well established floras (Fig. 8), tions, monocotyledonous angiosperms (Phyllotaenia). This stratum with different types of vegetation and a high diversity (macroremains of does not seem too extended given the low number of preserved 53 taxa attributed to 5 main groups) that developed under a markedly remains, although the reason for this could lie in taphonomic seasonal climate of warm wet winters and dry hot summers in an area circumstances. The shrub or semiarborescent stratum, which judging close to the sea. Geological data (Diéguez et al., 2000) have established from its high percentage of macroremains of Ctenozamites insignis the existence of a coastal–littoral zone, corresponding to one of the (Fontaine) Harris was well-developed, was represented by different marine regression episodes that took place during the Upper Cretaceous. taxa of Cycadales, some taxa of Cheirolepidiaceae and by angiosperms. The Upper Turonian macroremains of Torrelaguna (Menéndez The arboreal stratum consisted of several taxa of microphyllous Amor, 1952; Álvarez-Ramis, 1980, 1981b; Álvarez-Ramis et al., 1984; conifers such as Pseudofrenelopsis parceramosa (Fontaine) Watson and Diéguez et al., 1993, 2000)indicateaflora comprised mainly of remains numerous species of Brachiphyllum, Sequoiites and Pagiophyllum. attributable to Cheirolepidiaceae, which represent, depending on the These observations all point to an open vegetation structure of forests sampling point, 80 to 100% of the fossils found. When present, of xerophytic conifers interspersed with angiosperms. angiosperms that represent the remaining 20% show a greater diversity Despite these rich, diverse macrofloras, the Upper Cretaceous including five different taxa. These data reveal the vegetation was a material from Madrid has so far not yielded any independently dated closed forest of xerophytic conifers. palynofloral assemblages. According to Kedves et al. (1999), these The Guadalix de la Sierra site (Upper Turonian) (Álvarez-Ramis, associations could show reworked palynomorphs from several 1980; Gómez-Porter, 1984; Diéguez et al., 1993, 2000) shows scarce periods of the Upper Cretaceous and Palaeogene, so based on these

Fig. 8. Species richness indices for macroﬂoras of the Upper Cretaceous in Spanish outcrops (UT: Upper Turonian; uM: uppermost Maastrichtian). Author's personal copy

336 C. Diéguez et al. / Review of Palaeobotany and Palynology 162 (2010) 325–340 data have not been attempted inferences on the type of palaeoenvi- 5. Conclusions ronment. The same conclusion has been recently drawn by Nichols and Johnson (2008), who pointed out the weakness of the This review of existing data on palaeobotanical and palynological biostratigraphical frame of other Iberian palynofloral studies. assemblages of the Jurassic and Cretaceous of the Iberian Peninsula Palynological studies performed on Spanish uppermost Cretaceous shows an almost uninterrupted record from the Oxfordian to the K/T material are scarce and often lack a robust biostratigraphical frame boundary. However, most of these fossil floras needed revision by means (Ashraf and Erben, 1986; Nichols and Johnson, 2008). In this context, of using more modern techniques that allow an accurate identification. the Campanian–Maastrichtian material from Chera (Valencia, Spain), In addition a thorough study is required in order to elucidate their overall cross-dated by evidence of Charophytes (Company Rodríguez et al., composition since, in many cases; they have been studied partially and 2005), may provide valuable palynological evidences of the Iberian only descriptions of one or several of the found species are available. palaeovegetation. This palynoflora was characterized by a great The palynological and macrofloral assemblages examined for each abundance of Normapolles, triporate angiosperm pollen species and time period are not fully comparable. One reason for this could be the a 50% of fern spores (Plate I, Fig. 7). Gymnosperm pollen grains were different pollination modes of their components i.e., Cheirolepidiaceae rare. These palynological results suggest a palaeovegetation domi- (anemophilous) and Bennettitales (probably entomophilous) respec- nated by Fagales, conifers, Bennetitales, Cycadales and angiosperm tively that comprise the predominating elements of the different producers. The vegetation may also have included some conifers associations of the Jurassic and Lower Cretaceous. An alternative (mainly Taxodiaceae–Cupressaceae and Cheirolepidiaceae) and an- explanation could be the environment in which the assemblages giosperm producers of triporate grains being the undergrowth developed, since the different depositional settings inferred from consisting of herbaceous monocotyledons, and ferns. Spores of sedimentological data correspond to lakes, lagoons and coastal environ- Filicales are typically poorly represented in the assemblages but ments featuring a highly diverse ecology. may locally display high diversity since Ashraf and Erben (1986) Macrofossil remains of the Jurassic floras of the Iberian Peninsula described more than 50 different forms. are generally lacking. This is due to the insular position of the Iberian In the uppermost Maastrichtian, the macroflora of Isona (Lérida, Block in the desert climate belt and sediments, many carbonate, were Spain) (Vicente i Castells, 2002) already reveals a broad dominance of deposited on the marine platforms surrounding the block. Hence, angiosperms, which were mostly deciduous, accompanied by pter- from the Hettangian to the Oxfordian there is only record of few idophytes, Cycadales, Ginkgoales and conifers (Fig. 8). The overall palynological assemblages of low diversity showing a great taxonomic picture reflects widely represented palmaceous plants and lauraceous bias towards the pollen grains of anemophilous gymnosperms elements. The different sites record floras consistent with the coastal (Classopollis and Spheripollenites as from the Toarcian). and lacustrine environments as well as marshlands characterizing the To date, no macrofloras of the Lower and Middle Jurassic have been Tremp Fm. (Díaz Molina, 1987). discovered. The macrofloral assemblage of Villela (Tithonian–Berria- Sediments are those of a lagoon of varying salinity that allowed the sian) is the only resource providing information on a period of preservation of algae (Characeae, Corallinaceae and Codiaceae) and extreme aridity in the area reflecting global aridisation. diverse aquatic angiosperms (Ranunculaceae and Potamogetonaceae). For the Lower Cretaceous, macroremain assemblages displayed a Palynological assemblages (de Porta et al., 1985) are consistent with dominance of microphyllous conifers, mainly Cheirolepidiaceae, the macroflora and show a conspicuous dominance of angiosperms which suggest they developed in a more arid climate than that amounting to 60%, and a lower abundance of pollens that showed prevailing in other areas of the European phytogeographical province botanical affinity to Cycadaceae and Cupressaceae. The vegetation to which they belonged. This is also confirmed by the presence of inferred is one of a mixed-deciduous evergreen tropical forest. Gnetales and Marchantiales. A few sections encompass the K/T boundary in the Pyrenees The first macroremains attributed to the angiosperms (Ranuncu- (Médus et al., 1992; López-Martínez et al., 1999, Fernández-Marrón laceae) appear in the Berriasian–Valanginian of Spain while it is not et al., 2004). They are characterized by pteridophyte spores and until the Barremian–Aptian that other groups of angiosperms appear Normapolles which indicated evergreen tropical–subtropical vegeta- in Portugal. The first angiosperm pollen record occurs in the tion. A noteworthy characteristic of the European sections is the low Valanginian of Portugal, and in Spain this evidence does not emerge response, if any, to the K/T by the vegetation as reflected by their until the Upper Barremian. Although the diachronous appearance of palynofloral assemblages (Knobloch et al. 1993; Nichols and Johnson, angiosperms at the different sites of the Peninsula seems certain, their 2008). record only becomes significant (Fig. 9) from the Barremian onwards.

Fig. 9. Evolution of percentages of the main groups of miospores throughout the Jurassic and the Cretaceous taking into account the number of taxa presented in each period. Author's personal copy

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In the Upper Cretaceous, both macrofloras and palynofloras Aurell, M., Meléndez, G., Olóriz, F., Bádenas, B., Caracuel, J.E., García-Ramos, J.C., Goy, A., – Linares, A., Quesada, S., Robles, S., Rodríguez-Tovar, F.J., Rosales, I., Sandoval, J., occurred in sediments dated as Upper Cenomanian Turonian and as Suárez de Centi, C., Tavera, J.M., Valenzuela, M., 2002. Jurassic. In: Gibbons, W., Turonian, lacking macrofloras from sediments of the Upper Turonian– Moreno, T. (Eds.), The Geology of Spain. Geological Society, London, pp. 213–253. Upper Maastrichtian interval. Barale, G., 1981. La paléoflore jurassique du Jura français: Étude systématique, aspects stratigraphiques et paléoécologiques. Documents des Laboratoires de Géologie. Lyon Among the most outstanding features of comparison between 81, 1–467. Turonian macro and microfloras is the lack of agreement in terms of Barale, G., 1991. The fossil flora of the Lower Cretaceous (Berriasian–Valanginian) their composition and relative abundance of groups, especially lithographic limestones of Montsec (Lleida Province, Spain). In: Martínez-Delclòs, angiosperms. Most macrofloral sites of this age show a dominance X. (Ed.), The Lower Cretaceous Lithographic Limestones of Montsec: Ten Years of Paleontological Expeditions. Instituto de Estudios Ilerdenses, Lleida, pp. 39–47. of gymnosperms. Thus, there exists a clear compositional difference Barale, G., 1995. The fossil flora megarests and microrests. In: Martínez-Delclós, X. (Ed.), among the sites of this age as well as a difference in the interpreted Montsec and Montral-Alcover, two Konservat-Lagerstätten, Catalonia. Spain. – vegetation. This could be the outcome of incorrect dating of any of Instituto de Estudios Ilerdenses, Lleida, pp. 31 38. Barale, G., Calzada, S., 1985. Primera demostración paleontológica del Kimmeridgiense these sites or perhaps the entire set of sites. en Garraf (Barcelona). Acta Geológica Hispánica 20, 227–231. In the uppermost Cretaceous, the dominance of angiosperms in plant Barale, G., Viera, L.I., 1991. Description d'une nouvelle paléoflore dans le Crétacé communities is appreciable both in its palynofloras and macrofloras. inférieur du Nord de l'Espagne. Munibe 43, 21–35. Barale, G., Blanc-Louvel, C., Buffetaut, E., Courtinat, B., Peybernes, B., Vía Boada, L., Wenz, S., The present reconstruction reveals that the different vegetation types 1984. Les gisements de calcaires lithographiques du Crétacé inférieur du Montsech that successively configured the landscape of the time period considered (Province de Lérida, Espagne). Considerations paléoécologiques. Geobios Mém. Spéc. were: xerophilous forests of microphyllous conifers (Lower and Middle 8, 275–283. Barrón, E., Azêredo, A.C., 2003. Palynology of the Jurassic (Callovian–Oxfordian) Jurassic); swamp vegetation comprised of vascular cryptogams (Late succession from Pedrogao (Lusitanian Basin, Portugal). Palaeoecological and Jurassic); dry savannas of ferns and Bennettitales (Tithonian–Berria- palaeobiogeographical aspects. Neues Jarbuch fur Geologie und Paläontologie sian); forests of xerophytic conifers interspersed with aquatic angios- Abhandlungen 227 (2), 259–286. – Barrón, E., Comas-Rengifo, M.J., Trincão, P., 1999. Estudio palinológico del tránsito perms (Berriasian Valanginian); xerophytic conifer forests featuring Pliensbachiense/Toarciense en la Rambla del Salto (Sierra Palomera, Teruel, Gnetales and scarce possibly aquatic angiosperms (upper Barremian); España). Cuadernos de Geología Ibérica 25, 171–187. bryophyte mats colonizing coastal dunes (Aptian–Albian); xerophytic Barrón, E., Comas-Rengifo, M.J., Elorza, L., 2001. Contribuciones al estudio palinológico fl conifer forests containing woody angiosperms (upper Cenomanian– del Cretácico Inferior de la Cuenca Vasco-Cantábrica: los a oramientos ambar- ígenos de Peñacerrada (España). Coloquios de Paleontología 52, 135–156. Turonian); and broad-leaved angiosperm forests (Maastrichtian). From Barrón, E., Gómez, J.J., Goy, A., Pieren, A.P., 2006. The Triassic-Jurassic boundary in these vegetation types, we can infer a semi-arid subtropical climate with Asturias (northern Spain): palynological characterisation and facies. Review of – two clear episodes of rising temperatures and/or increased aridity at Palaeobotany and Palynology 138, 187 208. – Barrón, E., García-Ramos, J.C., Piñuela, L., Ruiz-Omeñaca, J.I., 2008. Aspectos palinoló- least at the local level: one in the Tithonian Berriasian that gave rise to gicos de la Formación Vega (Ribadesella). Jurásico Superior de Asturias. 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