Christa-Charlotte Hofmann

Pollen distribution in sub-Recent sedimentary environments of the Orinoco Delta (Venezuela) – an actuo-palaeobotanical study

Abstract A reinvestigation of the palynology of Recent and sub-Recent Orinoco Delta sediments complements the work by Jan Muller concerning the taxonomy and diversity of pollen grains. Surficial sediment samples and samples from shallow drill cores taken from three different deltaic environments (Cano Guaneira, mangrove forest, and palm-swamp) were studied with light microscopy and SEM. The standing vegetational types of the sampling sites were reflected to different degrees (42–71%) by the palynomorph assemblages. Generally, the pollen taxa preserved in all sediment samples reflected (a) the most abundant and most pollen producing taxa of the local and the surrounding vegetation, and (b) the taxa common along the distributaries in the delta. In each palynomorph assemblage, 77–80% of taxa are allochthonous or parautochthonous and represent 36–78% of the pollen sum. In more open fluvial localities, these elements originated upstream and were transported by the river. Input of allochthonous palynomorphs into a more closed sedimentary system, such as a flood basin, is more restricted (36% of the pollen sum) and occurred mostly during floods. Floral composition also has an influence on the amount of autochthonous palynomorphs. The palynomorph assemblages from less diverse vegetational types (21–22 taxa) that are dominated by one or few taxa contain less allochthonous palynomorphs (39–36% of the pollen sum) than the assemblage of a diverse (>45 taxa) vegetation type that contains 78% of allochthonous palynomorphs.

Advances in our knowledge of the Miocene plant assemblage from Kreuzau, Germany

Abstract The history of palaeobotanical research on Kreuzau is outlined. The sedimentary succession is interpreted and the age of the site discussed. Based on a compilation of the different plant parts, the florisitic composition of the assemblage is analysed. Some new and interesting discoveries are described and inferences made with regard to the habitats of these and other elements. Different techniques are used in an evaluation of the palaeoclimate and signs of faunal interaction mentioned.

Lythrum and Peplis from the Late Cretaceous and Cenozoic of North America and Eurasia: new evidence suggesting early diversification within the Lythraceae.

PREMISE OF THE STUDY To fully understand the evolution of todays angiosperms, the fossil record of plant families and genera must be used to determine their time of origin and phytogeographic history. As within many angiosperm families, the interrelationships of extant Lythraceae are hard to resolve without sufficient data from the geological past. Here we establish the earliest fossil occurrences of Lythraceae and start resolving the interrelationships and evolution of two of its genera, Lythrum and Peplis. METHODS We studied several Cretaceous and Cenozoic palynofloras from the northern and southern hemispheres. Using the single-grain technique, we screened the treated samples for Lythrum- and Peplis-type pollen. The same individual pollen grains were observed under both the light- and scanning electron microscope, allowing a high taxonomic resolution to be achieved. KEY RESULTS Fossil Lythraceae pollen grains are rare in palynological samples. Nevertheless, we were able to identify Lythrum and Peplis pollen from Late Cretaceous sediments and thereby extend the fossil record of the two genera by ca 70 million years. CONCLUSIONS The appearance of Lythrum and Peplis in North America and Peplis in Asia at approximately the same interval in the mid Late Cretaceous points to an already wide geographical distribution by then. These findings add vital information for the time of origin of the Lythraceae and suggest a higher diversity within the family. They also indicate that the distribution of particular genera during the Cretaceous was wider than previously thought.

Upper Cretaceous sulcate pollen from the Timerdyakh Formation, Vilui Basin (Siberia)

Abstract One inaperturate and 16 monosulcate pollen types are described from the latest Campanian to earliest Maastrichtian sediments of the Vilui basin, Siberia, using both light and scanning electron microscopy, and assigned systematically when possible to modern families or subfamilies. Despite their scant occurrence, the pollen grains show considerable diversity. Two new genera have been erected. Lasioideaecidites with two species, Lasioideaecidites hessei and Lasioideaecidites bogneri, represents the earliest record of the subfamily Lasioideae (Araceae). Aristolochiacidites with one species, Aristolochiacidites viluiensis, is assigned to the subfamily Aristolochioideae (Aristolochiaceae) and represents the first fossil pollen record of the family. A new species of Liliacidites, Liliacidites goldblattii, is closely similar to pollen of Isophysioideae (Iridaceae) and/or Doryanthaceae and is the first fossil evidence of the clade that includes these closely related families. A further nine new fossil species are described (Clavatipollenites timerdyakhensis, Liliacidites palaeofritillaria, Retimonocolpites longosucatus, R. microreticulatus, R. microrugulatus, R. lysichitonoides, R. chapmaniae, Monosulcites parvus and Arecipites tyungensis) and assigned to Chloranthaceae, Araceae (Orontioideae, ?Pothoideae), Liliaceae, ?Hypoxidaceae and Arecaceae. The Hydatellaceae (Nymphaeales) may also be present in the palynoflora of the Vilui Basin, represented by pollen similar to M. rivularis Braman from the Santonian to Campanian (Upper Cretaceous) Milk River Formation, Canada.

Reconstruction of Different Wetland Plant Habitats of the Pannonian Basin System (Neogene, Eastern Austria)

Abstract Sedimentary and palynofacies analysis, total organic carbon content (TOC), and palynology from a densely sampled, small, lignite-bearing succession of Late Miocene age at Badersdorf, SE Austria, were compared with modern wetland ecologies. From this, six hydrologically controlled palynofacies types and six associated paleo-plant habitats in an ancient wetland system were differentiated. The associated woody and herbaceous hinterland flora also were distinguished. At least four horizons with relatively high fusinite content have been preserved, indicating occurrence of paleo-wildfires in either the wetland or the hinterland. The palynofacies types were used to determine the taphonomic bias of the associated palynomorph assemblages, which, together with a comparison with modern wetland vegetation, led to differentiation of the paleo-plant habitats. The paleo-wetland was dominated mainly by Glyptostrobus-containing vegetation, and comprised clastic swamp forests with woody angiosperms, natural levee forests, fern- and Glyptostrobus-dominated organic swamps, freshwater marshes, and wet prairies. The occurrence of more than 40 herbaceous taxa at this locality indicates that the lowland vegetation was not composed of only different closed-forest types, but also of areas with herbaceous vegetation. The more zonal vegetation of the adjacent hinterland has been interpreted as a mix of Pinaceae and woody angiosperms with patches of more herbaceous xeric layers.

Upper Cretaceous pollen flora from the Vilui Basin, Siberia: Circumpolar and endemic Aquilapollenites, Manicorpus, and Azonia species

A detailed LM and SEM examination of the Upper Cretaceous Timerdyakh Formation microflora from the Vilui Basin yielded 13 Aquilapollenites, two Manicorpus, and three Azonia species. Comparisons with existing taxa from the Russian Federation and North America are impeded by the fact that many previously described forms were investigated using LM only, while SEM was very rarely used. Consequently, some of the pollen types reported in this study could not be ascribed to any previously documented taxa and have been described as nine new species. Further one previously described variety has been renamed. Except for two Azonia species and four Aquilapollenites species that also occur in Alaska, Canada and the Rocky Mountains in USA, the remaining taxa described here are restricted to the Late Cretaceous Khatanga‐Lena‐Subprovince. The several species unique to the Vilui Basin might indicate separate evolutionary paths for the genera Aquilapollenites and Manicorpus in North America and both northern and southern Asia during the Upper Maastrichtian.

An Early Miocene Plant Assemblage Severely Influenced By A Volcanic Eruption, Styria, Austria

Sediment and organic facies as well as leaves, pollen, and diaspores co-occurring in a tuffite exposed in Oberdorf (Ko¨flach/Voitsberg lignite area, Styria, Austria) were investigated. The tuffite is distinguishable from the under- and overlying clastic sediments and shows locally normally-graded lapilli, which is assumed to be a sign of direct airfall. The plant assemblage partly resulted from a volcanic eruption that coincided with the season in which many woody plants were flowering; deciduous ones were leafless or in the state of opening their buds; diaspores were not yet developed. Leaves of evergreen woody species, buds/bud scales, and clusters of immature pollen partly with adhering anther material were stripped off their parent plants and quickly embedded in the tuffite. The leaves of deciduous taxa and herbaceous monocotyledons, diaspores, partly also pollen, and organic facies components indicate progressive degradation. Such degraded plant debris probably accumulated in the backswamp sediments prior to the volcanic eruption. The tephra can only be correlated to the ‘Lower Rhyolite Tuffs’ in the Pannonian Basin (Hungary), indicating a (Late) Eggenburgian/Early Ottnangian age. The new species Ternstroemites waltheri is described. Distylium fergusonii Knobloch and Kvacek and Laurophyllum rugatum Kvacek and Bůžek are first reports from Austria.

Eocene Loranthaceae pollen pushes back divergence ages for major splits in the family

Background We revisit the palaeopalynological record of Loranthaceae, using pollen ornamentation to discriminate lineages and to test molecular dating estimates for the diversification of major lineages. Methods Fossil Loranthaceae pollen from the Eocene and Oligocene are analysed and documented using scanning-electron microscopy. These fossils were associated with molecular-defined clades and used as minimum age constraints for Bayesian node dating using different topological scenarios. Results The fossil Loranthaceae pollen document the presence of at least one extant root-parasitic lineage (Nuytsieae) and two currently aerial parasitic lineages (Psittacanthinae and Loranthinae) by the end of the Eocene in the Northern Hemisphere. Phases of increased lineage diversification (late Eocene, middle Miocene) coincide with global warm phases. Discussion With the generation of molecular data becoming easier and less expensive every day, neontological research should re-focus on conserved morphologies that can be traced through the fossil record. The pollen, representing the male gametophytic generation of plants and often a taxonomic indicator, can be such a tracer. Analogously, palaeontological research should put more effort into diagnosing Cenozoic fossils with the aim of including them into modern systematic frameworks.

LM and SEM investigations of pollen from PETM and EECO localities of Austria and Great Britain: new findings of Atherospermataceae, Annonaceae, Araceae and Arecaceae from the Lower Eocene

Fossil pollen from three Lower Eocene localities was investigated by LM and SEM: The Palaeocene–Eocene Thermal Maximum (PETM) section at St Pankraz (Salzburg), three Brixton drill cores covering the PETM and the Early Eocene Climate Optimum locality at Krappfeld. Some pollen taxa found have been affiliated to Laurelia, today a southern hemispheric Atherospermataceae unknown from Europe, to two Annonaceae lineages, such as the African Monodora clade and a probable precursor of the old world Fenerivia/Maasia clades, thus representing two taxa not previously reported from the fossil record. Further two wetland associated Araceae (Limnobiophyllum and Lysichiton) are present as well as various Arecaceae, including not only previously described Salaccinae and Calaminae/Plectocomiinae, but also undocumented Bactridinae, Elaeidinae (both Cocoseae), and Coryphoideae and Arecoideae, although pollen from the latter two subfamilies could not be assigned in more detail.

SEM investigation of pollen from the lower Eocene (Carinthia and Salzburg in Austria and Brixton, London area, in England): new findings of Vitaceae, Euphorbiaceae, Phyllanthaceae, Fabaceae, Anacardiaceae, Araliaceae and Apiaceae

Three European lower Eocene localities comprising sediments from the Paleocene-Eocene Temperature Maximum (PETM, St Pankraz, Austria and Brixton, England) and the Early Eocene Climate Optimum (EECO, Krappfeld, Austria) have been investigated palynologically with light microscopy and scanning electron microscopy. The pollen taxa systematically investigated here have been affiliated to the following families and genera: Vitaceae gen. indet. and Parthenocissus, Euphorbiaceae s.s. (two “Bernardieae clade” types, Cephalocroton), Phyllanthaceae (two Flueggea types, Bischofia), one taxon of Euphobiaceae/Phyllanthaceae fam. indet., Fabaceae (“Millettioid clade” type), Anacardiaceae (two Anacardium types, Gluta, and Lannea), Araliaceae (A. gen. indet., two Aralia types, Panax, and Hydrocotyle) and one Apiaceae gen. indet. Further, we present here the earliest known occurrences of pollen of “Bernardieae clade” type, Cephalocroton, unknown Euphorbiaceae/Phyllanthaceae taxon, Flueggea, Bischofia, “Millettioid clade” type, Anacardium, Gluta, Aralia and Panax types in the fossil record.