Luis Miguel Sender

A new uppermost Albian flora from Teruel province, northeastern Spain

ABSTRACT This paper reports a new Early Cretaceous flora discovered recently near the village of Estercuel (Teruel province, northeastern Spain). The plant bearing beds belong to the uppermost part of the Early Cretaceous succession, at the top of the fluvial deposits of the Utrillas Formation. The site has yielded a diverse assemblage of plant compressions including lycopods and ferns, various gymnosperms as well as terrestrial and aquatic angiosperms. Leaves of aquatic lycopods (Isoetites sp.) constitute a minor component of the palaeobotanical assemblage. Filicales are not very common, with Dicksoniales (Onychiopsis sp.) and a few specimens of Cladophlebis type fronds. The gymnosperms are represented by fragmented remains of long parallel veined Desmiophyllum leaves as well as a great abundance of conifer axis corresponding to the form-genus Pagiophyllum and female cones. Terrestrial angiosperms include pinnately lobed leaves of the genus Myricompia, simple leaves with spatulate lamina and some petiolate leaves both corresponding to angiosperms of uncertain affinity. Aquatic angiosperms consist of Nelumbo-like floral receptacles (Nelumbonaceae, Proteales) and Aquatifolia cf. fluitans (Nympheales). The palynological assemblage is dominated by pollen of gymnosperms (mainly Taxodiaceaepollenites hiatus, Classopollis major and Araucariacites australis). It also includes many angiosperm grains (Afropollis jardinus, Clavatipollenites spp., Dichastopollenites spp., Liliacidites doylei, Monosulcites chaloneri, Penetetrapites mollis, Pennipollis spp., Phimopollenites augathellaensis, Retimonocolpites textus, Rousea spp., Senectotetradites varireticulatus, Stellatopollis barghoornii, Striatopollis spp., Transitoripollis sp. cf. T. similis, Tricolpites spp., Tricolporoidites sp.) and records the first occurrence of tricolporate forms in the uppermost part of the Utrillas Formation. Both macroflora and microflora assemblages present taxa similar to those of the uppermost Albian Shaftesbury Formation in northwestern Alberta in Canada, the uppermost Albian Denton Shale Member of Bokchito Formation in southern Oklahoma, the lower part of the Upper Albian Dakota Formation from the mid-west of North America, and Subzone II C of the Potomac Group, eastern United States. Both macro- and microflora assemblages display boreal influence with some similar taxa to those of the Upper Albian Kome Formation in western Greenland and some taxa as Afropollis jardinus and Stellatopollis barghoornii more frequently found in the tethyan and gondwanan realms. A gondwanan affinity is also indicated by the presence of Klitzschophyllites leaves.

Klitzschophyllites, Aquatic Basal Eudicots (Ranunculales?) from the Upper Albian (Lower Cretaceous) of Northeastern Spain

Klitzschophyllites choffatii (Saporta sensu Teixeira) emend. is reported from the upper Albian of the Utrillas Formation at the Plou locality, Teruel Province, northeastern Spain. The species shows obovate microphylls; dense, flabellate primary and secondary veins interconnected by fine, reticulate tertiary veins and intersecting with an intramarginal vein; and small glands in sinuses between triangular teeth. It exhibits more affinities with basal eudicots (especially some Ranunculales) than with monocots. Sedimentological and taphonomic evidence, along with morphofunctional features, supports a freshwater hydrophytic habit for K. choffatii.

Focused ion beam nano-sectioning and imaging: a new method in characterisation of palaeopalynological remains

Abstract Dual-beam focused ion beam scanning electron microscopy (FIB-SEM) is here applied to palaeopalynology in order to slice spores and pollen grains for reconstructing their ornamentation and wall-ultrastructure. Characteristics of spore and pollen wall structure are important for understanding botanical affinities and phylogeny and are of particular interest for establishing ancestral states in pollen of early flowering plants. While ultramicrotomy is the most commonly used method for ultrathin sections for studying ultrastructural details of spores and pollen under transmission electron microscopy (TEM), the FIB-SEM technique allows three-dimensional imaging. Furthermore, the region of interest may be selected with nanometric precision when using FIB-SEM. Initial studies of palaeopalynological remains using FIB slicing for SEM imaging have revealed very promising results. Moreover, this technique can be similarly easy applied to many other palaeontological remains.

Palynological studies of the boundary marls unit (Albian-Cenomanian) from northeastern Spain. Paleophytogeographical implications

ABSTRACT Detailed records of spore-pollen assemblages from four sites located in the Aliaga and Oliete Sub-basins provide new insights into the palaeoclimatic and palaeogeographic settings during the Albian-Cenomanian transition in the Maestrazgo Basin (northeastern Spain). Palynological taxa such as Afropollis jardinus Doyle, Jardiné & Doerenkamp, 1982, Elaterosporites klaszii (Jardiné & Magloire) Jardiné, 1967, Equisetosporites ambiguus (Hedlund 1966) Singh, 1983, Gabonisporis pseudoreticulatus Boltenhagen, 1967, Senectotetradites varireticulatus Dettmann, 1973, Stellatopollis barghoornii Doyle, 1975, and the dinoflagellate cyst Cyclonephelium chabaca Below, 1981 indicate a latest Albian age for this unit. Abundance of Gondwanan elements such as Afropollis Doyle, Jardiné & Doerenkamp, 1982, Elaterosporites Jardiné, 1967 and Stellatopollis Doyle, 1975 indicates a northward extension of the paleogeographic distributions of those taxa during this time. Comparison between the studied microflora of the Iberian Range and microfloras from Tethyan and Gondwanan realms allows better understanding of the Tethyan paleogeographic setting.

Singular taphonomic record of a wildfire event from middle Albian deposits of Escucha Formation in northeastern of Spain

A fossil plant assemblage composed of a great amount of macro, meso and microscopical charcoalifed remains occur in a single layer in Albian deposits of the Escucha Formation in northeastern Spain. This assemblage consists fundamentally of fragments of pinnae and pinnules corresponding to the Matoniaceous ferns Weichselia reticulata and Phlebopteris dunkeri also with some gymnosperm wood remains. The features of both the fossil plants and the deposit itself indicate accurate paleoenvironmental conditions related to the action of wildfires over the vegetation growing in freshwater swamp plains during Albian in Southwestern Eurasia.

Paleoenvironmental reconstruction of an Albian plant community from the Ariño bonebed layer (Iberian Chain, NE Spain)

The AR-1 layer, corresponding to the Escucha Formation (Lower Cretaceous) in the Santa Maria Mine of Ariño, has supplied rich and well-preserved macrofloral and palynological assemblages showing interesting data about both taphonomic and environmental conditions. This single layer is located in the Oliete Sub-Basin from the Maestrazgo Basin in northeastern Spain, and it represents one of the most outstanding single layer fossil sites in the world. This site shows abundant and diverse fauna containing exquisitely preserved vertebrate and invertebrate fossils (dinosaur bones, turtles, crocodiles, fishes, molluscs and ostracods) and also plant remains of Albian age. The assemblage is especially significant for dinosaur phylogenetic analysis. The sedimentary environment corresponds to a freshwater swamp plain with sporadic marine inputs within a deltaic–estuarine system under subtropical–tropical climate.

Palaeobotanical remains associated with dinosaur fossils from the Camarillas Formation (Barremian) of Galve (Teruel, Spain)

A well-preserved macroflora and rich palynological assemblages corresponding to the Camarillas Formation (early-middle Barremian) in the San Cristóbal and Galve Mine sites from the Galve sub-basin in northeastern Spain are presented here. These remains represent the first fossil plant evidence from these deposits. Within plant macroremains, the cheirolepidiacean Pseudofrenelopsis aff. varians (Fontaine) Watson has been found. The palynological assemblage yielded well-preserved spores and pollen grains, mainly dominated by the genus Classopollis. Spores are also abundantly represented by schizaeacean spores (Cicatricosisporites and Plicatella). This spore assemblage supports an early-middle Barremian age for these localities. It is noteworthy that small basal angiosperm pollen grains of the genera Crassipollis and Retimonocolpites, together with other indeterminate grains, have been reported here. This flora constitutes the primary food producer for dinosaur at that time, and thus the information of the flora is important for the understanding of the ecological background for the dinosaur evolution during the Early Cretaceous.

A New Isoetalean Microsporophyll from the Latest Albian of Northeastern Spain: Diversity in the Development and Dispersal Strategies of Microspores

In this paper well-preserved isoetalean microsporophyll, containing in situ microspores, is described from the uppermost part of the Utrillas Formation (latest Albian) in Teruel Province, northeastern Spain. Similar but dispersed microspores were described previously as Peromonolites. Fossil plant impressions and compressions including the sporophyll lamina and microsporangium are referred to the fossil genus Isoetites. Although Isoetes-like megafossil remains, often with in situ or associated megaspores, are known from quite a few Cretaceous sites, and dispersed microspores are known, the presence of intact microsporangia is rare. Herein we suggest that microsporangia may have dispersed in masses, possibly representing a new unknown strategy in microspore dispersal in this group of plants.

New palaeobotanical data from the Lower Devonian of Mezquita de Loscos (Teruel Province, Spain)

Recent fieldwork has uncovered three new localities from the Lower Devonian of Mezquita de Loscos (Teruel Province, Spain) with further plant mega-fossils and the first record of micro-fossils. Such plant remains have been interpreted as belonging to a basal euphyllophyte, Taeniocrada-like stems, Hostinella genus and paired sporangia. Fourteen spore taxa were recovered, including Ambitisporites, Aneurospora, Brochotriletes, Chelinospora, Emphanisporites, Gneudnaspora and Retusotriletres, among others. New evidence confirms a Lochkovian age for this outcrop and suggests that the plant diversity was more complex than originally documented.

New reconstruction of Weichselia reticulata (Stokes et Webb) Fontaine in Ward emend. Alvin, 1971 based on fertile remains from the middle Albian of Spain

Exceptionally well-preserved specimens from the middle Albian of Spain corresponding to a nearly complete fertile frond and fragments of pinnae containing soral clusters of the tree fern Weichselia reticulata have provided new data about the structure and arrangement of pinnae and their associated fertile reproductive structure. This new material has been compared with the previous studies, and recostructions of this fern and the new data indicate the segregation of vegetative and fertile fronds within the main stipe of this fern.