The continental Lower Permian Słupiec Formation (the Sudetes Mountains, southwestern Poland) is well known for the occurrence of fossilized tracks of Early Permian tetrapods. Previous reports have focused on the taxonomy of tracks and their producers. The track assemblage was apparently missing the footprints of amphibians and thus such tetrapods were thought to be truly absent in the Słupiec Early Permian paleohabitat. The present paper utilizes the results of experiments and field surveys in order to test a possibility that tracks of tiny tetrapods (e.g., with body mass < 9 g), including amphibians, could be missing due to taphonomic filtration. The experimental tests were performed to investigate the following: (1) the interplay between the sizes of the penetrator (representation of trackmaker's pes and manus) and the particles within the substrate, with emphasis on how the size interplay affects the lamina-modification mechanism, e.g., lamina-piercing by sand versus lamina compaction/displacement by sand or clay; (2) undertrack production in laminated sandy substrates by tiny tetrapods; and (3) the taphonomic impact that biofilm may have on the occurrence of tiny tetrapod tracks in clay. The results of experimental tests and the field survey suggest that tiny tetrapod tracks (e.g., amphibians) may be underrepresented in the Słupiec Formation track assemblage due to negative taphonomic filtration.

In-situ fossil forests are valuable biogenic archives for the structure and setting of paleocommunities and the ecology of their organisms. Here, we present the first trees preserved in growth position in their embedding strata from the Kungurian (lower Permian) Athesian Volcanic Group, Northern Italy—one of the most extensive volcanic successions of post-Variscan Euramerica. We reconstruct the structure, rise and demise, and paleoecology of the forest based on high-resolution documentation of facies architectures and petrography, and the paleontological and taphonomic characters of the fossil content. Generally, the fossiliferous strata record a volcanotectonically controlled base-level rise in a limnic, possibly endorheic wetland basin from a low-relief volcanic landscape. The forest, preserved as calcified stem bases with roots, grew during a short interval of lake-level stasis on a small deltaic sheetflood fan. The forest comprised trees less than 5 m tall with tabular root systems adapted to the waterlogged substrate, and was buried and destroyed by mass flows following rapid submergence. These mass-flow deposits yield parautochthonous woody debris providing anatomical evidence of conifers as the major arborescent plants of the fossil forest. Our results not only elucidate the root architecture of Paleozoic conifers, but also document the ecomorphological plasticity of these plants and substantiate the presence of coniferopsids in wetlands around the Carboniferous/Permian boundary. Further, the evidence of lake perenniality in the studied succession is among the youngest known from the Permian of Europe, pointing to the highly differentiated late-icehouse impacts on continental environments in the Euramerican tropics.

Long-term global warming during the early Paleogene was punctuated by several short-term ‘hyperthermal’ events, the most pronounced being the Paleocene–Eocene Thermal Maximum (PETM). During this long-term warming, tropical climates expanded into extra-tropical areas, creating a widespread band of thermophilic flora that reached into the paratropics, possibly as far north as mid-latitude North America in some regions. Relatively little is known about these paratropical floras, despite distribution across the North American Gulf Coastal Plain. We assess floras from the Gulf Coastal Plain in Central Texas before and after the Paleocene–Eocene boundary to define plant ecosystem changes associated with rapid global warming in this region. After the Paleocene–Eocene boundary, these floras suggest uniform plant communities across the Gulf Coastal Plain, but with high turnover rate and changes in community composition. Paleoecology and paleoclimate assessments from Central Texas Paleocene and Eocene floras suggest a warm and wet environment, indicative of tropical seasonal forest to tropical rainforest biomes. Fossil evidence from the Gulf Coastal Plain combined with the Bighorn Basin, Wyoming data suggest that early Paleogene warming helped create a paratropical belt that extended into mid-latitudes. Evaluating the response of fossil plant communities to rapid global warming has important implications for understanding and preparing for current global warming and climate change.