The Carnian Pluvial Episode (CPE), dated to 234-232 Ma, marks a major climatic disruption during the Late Triassic, interrupting the prevailing arid conditions in the paleotropics with increased humidity. The CPE coincided with key evolutionary events in the marine and terrestrial realms. In the Central European Basin, this shift is recorded by a rise in siliciclastic sedimentation, notably in the Ergolz Member (‘Schilfsandstein’) of the Klettgau Formation. We present palynological and bulk organic carbon isotope data from the Bözberg core, in northern Switzerland. Palynological data indicate an organic matter input predominantly of terrestrial origin, with well-preserved assemblages. Althought spore diversity is low, sporomorphs offer valuable insights into regional paleoenvironmental changes. Qualitative and quantitative analyses reveal a shift from xerophytic to hygrophytic assembalges, accompanied by an increase in spore abundance, suppporting evidence for changing climatic conditions during the CPE in this region. A notable feature is the occurence of Aulisporites astigmosus, a taxon associated with humid intervals during the CPE in Tethyan records (Baranyi et al., 2018).

References :

Baranyi, V., Miller, S. V., Ruffell, A., Hounslow, W., M. & Kürschner, M. W. 2018: A continental record of the Carnian Pluvial Episode (CPE) from the Mercia Mudstone Group (UK): palynology and climatic implications, Journal of the Geological Society, 176, 149-166.  

The Carnian Pluvial Episode (CPE) is marked by a major climate shift with prevailing humid conditions in the paleotropics during the Late Triassic. It coincided with the key origination and/or radiation of several major groups (e.g., ammonoids, conodonts) as well as the diversification of terrestrial tetrapods and plants such as several modern fern and conifer families, and the Bennettitales. Despite extensive research carried out in the last years, particularly in the Tethys Realm, questions remain regarding the origin and impact of this climatic episode.

The Natural Science Museum “Enrico Caffi” of Bergamo, houses an extensive collection (more than 1,000 specimens) of plant fossils from the Carnian of Mount Pora. The plant fossil assemblage has been described partly by Passoni & van Konijnenburg-van Cittert (2003), who documented a diverse assemblage including Pseudodanaeopsis aberi, Sphenozamites spp., and Elatocladus porensis. It includes, however also several horsetail stem fragments of the species Equisetites arenaceus, broad-leaved conifers belonging to the species Pelourdea vogesiaca and several taxa of Brachyphyllum type conifers. Rare are fern frond fragments and smal droplets of amber. The latter were identified using a Dino-Lite digital microscope, equipped with 465 nm blue excitation LEDs and a 510–545 nm emission filter. Also Coprolites were detected together with the plants on the slabs.

The Carnian Pluvial Episode (CPE) has been identified as a time of plant radiation and origination of new lineages, likely related to rapid changes from xerophytic to more hygrophytic floras. Increasing humidity, causally resulting from large igneous province volcanism, is considered the likely trigger for the observed changes in terrestrial ecosystems. Understanding the cause and effects of the CPE on the plant realm requires the study of well-preserved floras that are precisely aligned with the CPE. Some of the most iconic Carnian floras are located in the Alps, laying during the CPE in the northwestern margin of the Tethys. This includes the famous Lunz locality (Northern Calcareous Alps) with the so far most diverse and rich plant fossil assemblages, as well as the Raibl plant fossil assemblages (Carnic Alps) and Dibona and Monte Pora (Southern Alps). These successions did not only yield the oldest fossiliferous amber worldwide. Integrated studies of palynomorphs and macro-remains reveal a variety of different plant fossil assemblages from highly diverse ones dominated by ferns and cycadophytes to plant fossil assemblages almost exclusively composed of conifers that show a mixture of predominantly late Palaeozoic (Majonicaceae, Voltziaceae), Mesozoic (Cheirolepidiaceae), and extant (Araucariaceae, Pinaceae, and Podocarpaceae) conifer families.

The author presents a detailed description and depiction of 13 tooth morphotypes, based on isolated marine reptile teeth from the Lower Toarcian Posidonia Shale Formation (PSF) of Schandelah, Lower Saxony, northern Germany. These morphotypes are compared to selected reference specimens from the collections of the Staatliches Museum für Naturkunde, Stuttgart, Germany, as well as the Staatliches Naturhistorisches Museum, Braunschweig, Germany, with the purpose of systematic assignment. This comparison process shows that most of the isolated teeth belong to thalattosuchian crocodylomorphs, which is surprising, as most non-tooth marine reptile fossils from the Schandelah quarry belong to ichthyosaurians. Even with this disparity in tooth distribution between morphotypes, the isolated teeth can be assigned to all five ichthyosaur genera (Stenopterygius, Hauffiopteryx, Eurhinosaurus, Temnodontosaurus, and Suevoleviathan) known from the PSF, three thalattosuchians (Macrospondylus bollensis, Pelagosaurus typus, and Mystriosaurus laurillardi), and tentatively one pliosauroid (Rhomaleosaurus zetlandicus). Stratigraphic distribution of the isolated teeth points to all groups of marine reptiles having been present throughout the entire section of the PSF exposed at the Schandelah quarry. The thalattosuchian teeth yield the most reliable data on stratigraphic range, as they make up the bulk of all isolated teeth. Finally, new additions to the north German PSF faunal assemblage can be made, as certain tooth morphotypes are the first evidence for the presence of the ichthyosaurian genus Suevoleviathan, the thalattosuchian M. laurillardi, and the pliosauroid R. zetlandicus.

The world’s largest ammonite, Parapuzosia (P.) seppenradensis (Landois, 1895), has fascinated the world ever since the discovery in 1895 of a specimen measuring 1.74 metres (m) in diameter near Seppenrade in Westfalia, Germany. Its co-fauna was describedin detail The species was also found in sections in Mexico and southern England. The high-resolution integrated stratigraphy allows for precise trans-Atlantic correlation of these occurrences, and the Tepeyac section in Mexico has become Associated Stratotype Section and Point for the base of the Campanian (Gale et al. 2023). It yields giant ammonites in original deposition context (Ifrim et al., 2021) together with a rich macrofossil assemblage (Ifrim and Stinnesbeck, 2021) which is correlated to other parts of the world by ammonoid and inoceramid stratigraphy and the stable carbon isotope curve. The ammonoids in the co-fauna of P.(P.) seppenradensis in Germany and Mexico show common and endemic species. They allow for the interpretation of partially unexpected paleobiogeographic relations.

References

Gale, A., Batenburg, S et al. 2023. The Global Boundary Stratotype Section and Point (GSSP) of the Campanian Stage at Bottaccione (Gubbio, Italy) and its Auxiliary Sections: Seaford Head (UK), Bocieniec (Poland), Postalm (Austria), Smoky Hill, Kansas (U.S.A), Tepayac (Mexico). Episodes. doi: 10.18814/epiiugs/2022/022048.

Ifrim, C., Gale, A.S. et al. 2021. Ontogeny, Evolution and palaeobiogeographic distribution of Parapuzosia (P.) seppenradensis, the world's largest ammonite. PLoS ONE 16, e0258510. doi: 10.1371/journal.pone.0258510.

Ifrim, C., Stinnesbeck, W., 2021. Ammonoids and their biozonation across the Santonian-Campanian boundary in north-eastern Coahuila, Mexico. Paleontologia Electronica 24.3.a34. doi: https://doi.org/10.26879/1046.

Areas of high biodiversity have shifted from the Mediterranean Tethys to the Coral Triangle in the western Pacific throughout the Cenozoic—a phenomenon often linked to plate tectonics shaping habitat heterogeneity. We use assemblage-level data from the Paleobiology Database to document spatiotemporal changes in alpha diversity of marine benthic communities, analyzing over 10,000 collections with at least 30 counted individuals.

Applying both traditional diversity metrics and rank-abundance distribution models, we observe a consistent trend of increasing alpha diversity toward the present and a growing proportion of complex benthic communities over time. Strong correlations between local and regional diversity measures suggest that regional species pools fundamentally structure local community diversity.

Despite potential lithification biases, environmental setting—particularly clastic-influenced reef environments—best explains the preserved spatial distribution of hotspots. Within the Tethys Ocean, biodiversity hotspots consistently occurred away from the equator, primarily along its northwestern margin near the modern Mediterranean, with occasional additional centers in South China, India, and Sinai.

Remarkably, the last time an area corresponding to today’s Indo-Australian Archipelago was a hotspot of local richness was during the Middle Triassic, approximately 245 million years ago. This implies that the modern Coral Triangle is at a truly exceptional place, whereas the western Tethys region served as a stable marine biodiversity hotspot for nearly 200 million years.