Arthropods are one of the most successful groups in continental ecosystems. Unfortunately, their fossil record is incomplete, due to the low preservation potential of their fragile exoskeletons and collection bias related to their mostly small size. This study elucidates the arthropod diversity and their fossilization pathways in the Pennsylvanian Zwickau Formation (Westphalian D, Zwickau-Oelsnitz Basin, central Germany). For 150 years, these strata have been known to yield well-preserved arachnids, myriapods and pterygote insects, including large-winged blattoids and Kreischeria wiedei, the largest known trigonotarbid. Detailed study of the embedding architectures and the fossils—involving HF maceration as well as combined transmitted-light and epifluorescence microscopic analysis—reveal an unusually diverse community that inhabited an intramontane peat-forming wetland near alluvial fans. The arthropod remains mainly occur in dm-thick distal crevasse-splay deposits. Accumulation and preservation of the arthropods was likely facilitated via rapid, (sub)autochthonous burial in water-logged overbank sediments that faced limited rhizoturbation after deposition and formed repeatedly due to the tropical, humid climate. As a result, the Zwickau strata became an extraordinary archive for delicate arthropod body fossils. Outstanding examples comprise a unique group of five phalangiotarbids. Various trigonotarbids are available in different preservation types and even reveal insights into their detailed three-dimensional cuticle morphology. HF maceration provided a considerable content of arthropod cuticle remains in the deposits, once more highlighting the significance of host rock processing and mesofossil analysis for filling the gaps in the arthropod fossil record.

The formation of the Isthmus of Panama during the Late Pliocene was a pivotal event in shaping continental biodiversity in the Americas. However, our understanding of the resulting Great American Biotic Interchange (GABI) relies heavily on fossil assemblages from Central America, which remain poorly constrained in terms of composition, depositional context and geological age. This study investigates the host strata, taphonomy and paleoecological significance of vertebrate faunas from Pedro Creek near Santa Rita de Limoncito, southeastern Costa Rica, based on ongoing excavations, high-resolution sedimentological profiling, taphonomic assessment, and geochronological analyses. Most vertebrate remains in this locality occur in two thick, massive intraclast conglomerates interbedded with sandstones and mudrocks of the marginal-marine San Gerardo unit (Upper Miocene). The taphocoenoses are poorly sorted, comprising isolated, disarticulated or fragmentary, relatively unweathered fossils. Based on the Voorhies classification for alluvial vertebrate assemblages, most fossils correspond to Group 1 – bones that are most easily transported. A comparative sample of reworked fossils from the streambed reflects 95% Group 1 and 5% Group 2, indicating progressive hydraulic winnowing. The assemblages include elasmobranch teeth, crocodyliforms and testudines remains (jaw fragments and dermal plates), and a mixture of North American (camels, horses including Equus, gomphotherids) and South American taxa (giant armadillos like Scirrotherium, ground sloths). These findings indicate that the terrestrial vertebrate fossils from Santa Rita de Limoncito are allochthonous elements in fan-delta deposits and provide evidence of faunal exchange across Central America prior to full emergence of the isthmian land bridge.

Sea urchins (phylum Echinodermata, class Echinoidea) have an excellent fossil record throughout the Mesozoic and Cenozoic, but their evolutionary history in the Paleozoic is much less understood. A first diversity maximum of Paleozoic (stem-group) echinoids in the Mississippian has long been recognized, and Mississippian forms are taxonomically and morphologically distinct from their Devonian predecessors. Recent work has shown that Famennian echinoids are more similar to Carboniferous forms than to those of the pre-Famennian Devonian, implying faunal turnover around the Frasnian-Famennian boundary. Ongoing research by the author on Devonian and Mississippian echinoids from Germany and Belgium confirms that the family Lepidocentridae, after attaining its maximum diversity in the Frasnian, likely disappeared at the end of the Frasnian, while the Famennian saw the first appearance of the important Late Paleozoic families Lepidesthidae, Proterocidaridae and Archaeocidaridae. New material also confirms an Early Devonian origin of the family Palaechinidae which, after a long ghost lineage spanning most of the Devonian, would become the primary driver of echinoid diversity increase in the Mississippian. Recent research based on large datasets of museum specimens has underscored the impacts of taphonomic and sampling biases as well as the legacy of scientific colonialism on perceived patterns of paleobiodiversity and paleobiogeography in Paleozoic echinoids. To overcome these challenges and identify genuine diversity patterns, detailed and targeted systematic work based on articulated and disarticulated material must be combined with improved understanding of Paleozoic echinoid phylogeny, paleobiology and habitat preferences.

Black shales are often key archives of past life, thanks to the preservation of organogenic tissues in the absence of oxygen. However, various taphonomic constraints and processes can strongly alter the fossil assemblages and may lead to false palaeoecological conclusions. This talk discusses insect preservation in the Lower Jurassic Posidonia Shale of Schandelah (NW Germany), a window into Mesozoic entomofaunas of central Pangaea. For this purpose, we present a cm-scale analysis of lithofacies and fossil content of a c. 2 m thick and 7 m wide excavation section, stretching the siemensi- to borealis-ammonoid subzones. Emphasise is put on dm-sized polished slabs from intercalated early diagenetic calcite concretions. Consistent with previous studies, the marly strata formed in a fully marine setting close to small islands with limited fluvial input. However, water stagnation and depth seem to have increased over time, given the profile-up decrease in grain size, extent in bioturbation and abundance of macrobenthos in the peloidal concretions. This trend improved the preservation of insects sunken to the sea floor, as reflected by their taphonomy and occurrence: insects are absent in the lowermost siemensi concretions, while resistant coleopteran remains rarely occur in the capillatum and elegantulum concretions. In the uppermost borealis concretions, insects are most abundant, diverse and dominated by isolated wings. Increasing annihilation of anatomical detail in the insect fossils towards the concretion margins attest to chitin dissolution during diagenesis. These results call for more bed-by-bed documentations of fossil content and preservation, and disclose ways to reconstruct the Posidonia-Shale environment.

The Permian saw a strong diversification and spread of dryland ecosystems and is therefore a heyday of terrestrialisation. However, as life spread in environments with low preservation potential, fossil evidence of this evolutionary progress is extremely rare. Most knowledge in recent times resulted from studying fossiliferous strata of volcanic settings in the Euramerican tropics, such as the Chemnitz Fossil Forest (Germany) and the Athesian Volcanic Group (Italy). This talk elucidates the stratigraphy, taphonomy and paleoecological significance of silicifications found on fields and in river beds near Gnandstein/central Germany for two centuries. High-resolution sedimentological logging of the strata reveals that the fossils derive from epiclastic and pyroclastic deposits of the basal Kohren Formation (Asselian, lower Permian), representing the initial deposits of the voluminous NW Saxony Volcanic Complex. Anatomical studies and UV spectroscopy of polished samples from three collections identify various taphotypes in the silicifications and yielded anatomically preserved stems of tree ferns, calamitaleans and pycnoxylic gymnosperms. While the varicolored cherts formed in limnic settings, sizeable fossil trunks 1.5 m in diameter from Gnandstein could indicate the presence of an in-situ forest near the base of the Rüdigsdorf Tuff. Based on our results, the basal Kohren Fm. has a strong potential to disclose Permian tropical ecosystems that coped with extensive volcanism and advocate for future excavations in these occurrences. In addition, the Gnandstein fossils underpin the importance of late-to-post-Variscan volcanism in Euramerica to form fossil archives of deep-time life.

The Lochbrunnen Lake Unit (Oberhof Formation, Thuringian-Forest Basin) represents one of the youngest perennial-lake deposits of the European Permian and is key to understanding limnic ecosystem evolution in tropical Pangea. Based on two excavations, 126 temnospindyl specimens were anatomically documented, biometrically analyzed, taxonomically identified, and their embedding pelites lithologically and taphonomically characterized on a millimeter scale.

Most amphibians—mainly the branchiosaurids Apateon flagrifer and Melanerpeton arnhardti (90–95%) and the eryopid larvae of Onchiodon sp. (5–10%)—are preserved as articulated impressions with skin shadows, occurring in profundal and subordinate littoral facies. Five taphotypes reflect different preservation modes, often linked to microbial mats, anoxia, and sediment dynamics. Dorsoventral orientation predominates, while lateral burial is rare. The lake ecosystem comprised a full trophic web: microbial mats and algae (Perissothallus) as producers; bivalves, conchostracans, crustaceans, branchiosaurids, and Onchiodon larvae as consumers; and xenacanthid sharks and adult Onchiodon as top predators. The dominance of small branchiosaurids indicates ecological instability related to increasing aridification. Under these conditions, A. flagrifer appears as a generalist, while M. arnhardti shows possible adaptations (e.g., sclerotic rings, basibranchial morphology) to living in deep or oxygen-poor waters. Exceptional preservation of the amphibians likely resulted from anoxic events, microbial coverage, and rapid burial. The results document the various taphonomic pathways of amphibians in lakes and enlighten the impacts of late-icehouse environmental changes on low-latitude lake ecosystems.