Sprecher
Beschreibung
The historical locality of Bjørnøya (Bear Island, Svalbard) yields one of the few known uppermost Famennian (~360 Ma) terrestrial floras, originally documented by pioneering paleobotanists A.G. Nathorst and H.J. Schweitzer. A forthcoming summer 2026 expedition aims to provide a comprehensive geological context for these plant-bearing strata, integrating high-resolution sedimentology and paleoecological analyses to reconstruct the architecture of these latest Devonian communities. Based on historical collections and new material, rhacophytalean ferns from Bjørnøya are re-evaluated using modern morphological insights to clarify the complex morphology and architectural development of Cephalopteris mirabilis. Initial co-occurrence and quadrat-based analyses suggest an ecological partitioning similar to the Catskill Formation (USA), where distinct lineages dominated specific microhabitats. The latest Famennian landscapes comprised lycopsid forests surrounding oxbow lakes and stands of arborescent sphenopsids assigned to Pseudobornia ursina. Understory vegetation was specialized on these water-saturated soils, consisting primarily of an undescribed seed plant morphotype. Concurrently, alluvial floodplains adjacent to these mires were heavily dominated by the scrambling, spiny rhacophytalean C. keilhaui. This fieldwork provides critical macrofossil compression material to propose comprehensive whole-plant concepts. Ultimately, this research offers a detailed reconstruction of the paleotropical vegetational shifts that occurred during a pivotal evolutionary window. This key period saw the rapid radiation of ferns, early seed plants, and arborescent lycopsids, providing a crucial evolutionary bridge toward the iconic Carboniferous coal swamp ecosystems.