Publications
Recalibration of the insect evolutionary time scale using Monte San Giorgio fossils suggests survival of key lineages through the End-Permian Extinction
A groundbreaking recalibration of the insect evolutionary time scale, using exceptionally preserved 240-million-year-old fossils from Monte San Giorgio, reveals that key insect lineages survived the catastrophic End-Permian Extinction. These findings, derived from phylogenomic dating analysis, push back the origins of major groups like Lepidoptera (moths and butterflies), Hemiptera: Heteroptera (true bugs), and Diptera (flies) by up to 200 million years. The study suggests that critical evolutionary innovations, such as flight and metamorphosis, emerged much earlier than previously thought, challenging long-held assumptions about insect resilience during mass extinction events.
New holostean fishes (Actinopterygii: Neopterygii) from the Middle Triassic of the Monte San Giorgio (Canton Ticino, Switzerland)
Paleontologists have uncovered two new species of holostean fish, Ticinolepis longaeva and T. crassidens, from the Middle Triassic carbonate platform deposits of Monte San Giorgio in Switzerland. These findings provide critical insights into the evolutionary history of neopterygian fishes, revealing a mosaic of halecomorph and ginglymodian traits that suggest these species represent basal holosteans. The study highlights distinct habitat partitioning between the two species, with T. longaeva adapting to more restricted environments while T. crassidens exhibited anatomical adaptations indicative of a durophagous diet. Additionally, the research documents intraspecific variation and ontogenetic changes in T. longaeva, offering a nuanced understanding of its ecological adaptability over time.
A New Early Semionotidae (Semionotiformes, Actinopterygii) from the Upper Ladinian of Monte San Giorgio Area Southern Switzerland and Northern Italy)
A new genus of early Semionotidae, Sangiorgioichthys aldae, was discovered from the Upper Ladinian Kalkschieferzone of Monte San Giorgio, a UNESCO World Heritage Site spanning southern Switzerland and northern Italy. This fossil provides critical insights into the poorly understood early history of Semionotiformes, with distinct morphological features such as ganoine-covered dermal skull bones, an unusually large ventral infraorbital, and specialized dentition. The study employed detailed anatomical analysis to classify the specimen within the Semionotidae family, noting shared diagnostic traits while highlighting unique characteristics that differentiate it from other known taxa. This discovery contributes significantly to understanding the evolutionary trajectory of this ancient fish group during the Triassic period.
Early Ladinian Radiolarian Fauna from the Monte San Giorgio (Southern Alps, Switzerland): Systematics, Biostratigraphy and Paleo(Bio)Geographic Implications
A pioneering study of radiolarian fauna from the UNESCO-listed Monte San Giorgio reveals a unique early Ladinian assemblage, characterized by low diversity and restricted circulation. The research identifies 73 species, including seven new ones, and introduces four novel genera, providing critical insights into the paleo(bio)geography of the Tethys. This first-ever description of radiolarians from Monte San Giorgio supplements knowledge of the uppermost Ladinocampe multiperforata Radiolarian Zone, confirming stability in radiolarian fauna across the Anisian/Ladinian boundary. The findings suggest open-marine connections between the Monte San Giorgio basin and broader Tethyan regions during early Ladinian times.
Two new species ofSaurichthys(Actinopterygii: Saurichthyidae) from the Middle Triassic of Monte San Giorgio, Switzerland, with implications for character evolution in the genus
Two new species of the iconic Triassic fish genus Saurichthys have been identified from the Middle Triassic Besano Formation at Monte San Giorgio, Switzerland: S. breviabdominalis, distinguished by its elongated operculum and reduced abdominal region, and S. rieppeli, notable for its block-like haemal arches and unique fin structures. Phylogenetic analysis reveals that S. rieppeli occupies a basal position among Alpine Triassic saurichthyids, supporting hypotheses of convergent evolution in scale reduction within the genus. Meanwhile, S. breviabdominalis forms a monophyletic group with local congeners, suggesting sympatric divergence—a finding that sheds light on ecomorphological divergence and resource partitioning in Triassic marine ecosystems. The study leverages detailed morphological analysis to elucidate character evolution and ecological adaptations in saurichthyid fishes.
Palaeoenvironmental significance of organic facies and stable isotope signatures: the Ladinian San Giorgio Dolomite and Meride Limestone of Monte San Giorgio (Switzerland, WHL UNESCO)
Monte San Giorgio reveals that its Ladinian carbonate section contains immature organic matter primarily of marine bacterial origin, with increasing land plant-derived contributions upsection. This study links organic-matter accumulation to sea-level changes, productivity, and volcanic activity-induced rainfall. Enhanced productivity during high sea levels contributed to black-shale formation under anoxic-sulphidic conditions, while low sea levels intensified runoff, leading to basin restriction and laminated limestone deposition under dysoxic to anoxic conditions. Benthic microbial activity played a significant role in hydrogen-rich organic matter production, carbonate precipitation, and vertebrate fossil preservation. The research integrates sedimentology, geochemistry, and microscopy to provide insights into palaeoenvironmental dynamics.
Ossification sequences and associated ontogenetic changes in the bone histology of pachypleurosaurids from Monte San Giorgio (Switzerland/Italy)
Pachypleurosaurids from Monte San Giorgio exhibit a transition from 'terrestrial' to more 'aquatic' osteogenetic sequences, as evidenced by increasing heterochronic shifts with decreasing stratigraphic age. This study reveals that forelimb ossification precedes hind limb elements in all stages except initiation, while early phase compaction processes align with the hypothesized plesiomorphic eureptilian condition. The research analyzed bone histology and taphonomic patterns in four pachypleurosaurid species, comparing them to extant terrestrial lizards and secondarily aquatic reptiles to determine evolutionary trends in osteogenesis.
Long bone microstructure gives new insights into the life of pachypleurosaurids from the Middle Triassic of Monte San Giorgio, Switzerland/Italy
A detailed analysis of long bone microstructure in four pachypleurosaurid taxa from Monte San Giorgio reveals distinct adaptations to secondary aquatic lifestyles, supporting earlier findings on habitat diversity and reproductive strategies. The study highlights high compactness values in their bones, characterized by a thick cortex and persistent calcified cartilaginous core, with variations in remodeling processes, growth cycle spacing, and vascularization. These differences suggest varying longevities, ages at sexual maturity, and potential climate-dependent reproductive seasons akin to modern squamates. The research combines histological data with morphological and facies distribution studies, offering new insights into the life history of these Middle Triassic reptiles.
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