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Go to: Area of interest – Study area – Methods: cuticular analysis and documentation – Links
Area of interest
My current and ongoing research will investigate the reproductive and vegetative architecture of the
enigmatic Bennettitales — an extinct group of seed plants that is intimately linked to understanding
the relationships between flowering plants and gymnosperms.
The Bennettitales are a lineage of extinct seed plants with cycad-like foliage but flower-like reproductive
organs. The group ranged from the Late Triassic to the Late Cretaceous. Within the last two decades,
Bennettitales have received renewed attention following inferences of their possible close affinity to
angiosperms. In some phylogenetic analyses, they are placed with Gnetales and angiosperms in the so-called
anthophyte clade. The anthophyte concept is, however, not universally accepted and there is currently no
consensus regarding interrelationships among the various groups of extant and extinct seed plants.
Main aims are to understand bennettitalean evolution and clarify the relationships of Bennettitales with
other enigmatic seed plant groups (e.g. the Caytoniales) and angiosperms. Microanatomical analyses will
also evaluate the potential of Bennettitales as palaeoenvironmental/palaeoclimatic indices for the
Mesozoic. Morphological re-evaluation of this group will involve:
(a) Reconstruction of whole-plant-taxa that will serve as natural units to distinctly improve
phylogenetic analyses;
(b) Evaluation of the diversification of Bennettitales temporally and spatially to reveal
evolutionary patterns in bennettitalean fertile and sterile structures (seed cones, "flowers", foliage);
(c) Assessment of cuticular and anatomical adaptations that may be useful for interpreting local
environmental to regional climatic conditions experienced by these plants in the Mesozoic.
Study area
The study area was recently expanded to almost the whole world. Bennettitales are reported from North, Central
and South America, Greenland, Svalbard, Europe, Russia, China, Central and Eastern Asia, Australia, South
Africa and Antarctica.
My recent studies cover floras from Austria, southern Sweden, China, Western and north-eastern Australia,
and I am involved in studies of bennettitaleans from Central Asia (Kyrgyzstan) and Antarctica (North
Victoria Land).
Methods: cuticular analysis and documentation
Usually, the plant fossils occur as impressions and compressions, the latter often with excellently preserved cuticles.
Rock samples with plant remains were dissolved in hydrofluoric acid (HF) in order to remove the sediment, or the plant remains were picked from the rock surface.
Cuticles were macerated according to the standard procedure using Schulze’s reagent (35% HNO3 with a few crystals of KClO3) and 5-10% potassium hydroxide (KOH).
Macerated cuticles were washed in distilled water, gently dehydrated in pure glycerine, and finally mounted in permanent glycerine-jelly microscope slides.
Hand specimens were photographed with a Nikon D80 digital camera; in order to increase contrast, cross-polarisation (i.e. polarised light sources together with a polarising filter over the camera lens) was used.
Cuticles are analysed with a Leitz Diaplan microscope with Nomarski interference contrast and photographed with a Nikon DS-5M digital camera.
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