Sprecher
Beschreibung
The lower Aptian flora of the Crato Fossil Lagerstätte in the Araripe Basin in NE Brazil opens a unique window to a late Mesozoic low latitude paleo-ecosystem in northern Gondwana. The investigation of the floristic composition of the Crato Formation flora and the combined analysis of its floristic composition and geological background data provide an important opportunity to explore the environmental and climatic conditions under which gymnosperms were still the predominant group of vascular plants in the paleovegetation while flowering plants were already diversified. Gymnospermous plants were identified from foliage, reproductive structures, wood and pollen records. Some whole-plant species could be reconstructed so far but a considerable number of fossils belongs to incompletely known plants. Generally, gnetalean plants have had the highest diversity in Earth’s history during the Early Cretaceous, which is also supported by the phytotaphocoenosis of the Crato Formation flora. Besides members and relatives of extant families and genera of Gnetales several extinct taxa with gnetalean affinity were described. The conifers include representatives of Araucariaceae, Cupressaceae, Pinaceae, Podocarpaceae and the extinct Cheirolepidiaceae and „Podozamitaceae“. Other extinct gymnosperm orders such as Caytoniales and Erdtmanithecales were present as well. Not all taxonomic groups recognized from the pollen assemblage were also evidenced in the macrofossil component so far, and vice versa. The habit of gymnospermous plants was considered large trees (araucarias), shrubs (likely frenelopsids; gnetaleans), and herbaceous plants (gnetalean-like taxa). Their morphological and anatomical characteristics indicate various adaptations to specific environmental and climatic conditions.