Simosaurid fossil from Middle Triassic of Israel + ichthyosaur bone preservation in Jurassic Posidonia Shale of Germany
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Ben Creisler
Mar 25, 2026, 11:50:32 PM (9 days ago) Mar 25
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Ben Creisler
New papers:
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Alberto Cabezuelo-Hernández, Carlos de Miguel Chaves & Adán Pérez-García (2026)
The oldest simosaurids (Anisian of Israel): implications for the paleobiogeographic and stratigraphic distributions of the group
PalZ (advance online publication)
https://doi.org/10.1007/s12542-025-00769-2
https://link.springer.com/article/10.1007/s12542-025-00769-2
The Muschelkalk (Middle Triassic) of Makhtesh Ramon (Israel) has yielded numerous sauropterygian remains, Nothosauria and Placodontia being the most abundant groups. Other Triassic clades of Sauropterygia are also present, such as Pachypleurosauria or Simosauridae. Simosauridae was recognized as a poorly represented clade in Makhtesh Ramon, considering that only four elements were identified and provided limited characters to allow a specific attribution, being identified as Simosaurus sp. The fossil record of Simosauridae spans from the Ladinian (Middle Triassic) to the Carnian (Upper Triassic) in Europe, whereas that of the Middle East has been suggested to be limited to the uppermost Anisian or lowermost Ladinian. In this work, we analyze abundant unpublished material of Simosauridae from Makhtesh Ramon. The unequivocal oldest presence for this lineage is here documented, coming from the Anisian. Their detailed study, along with the revision of the material previously documented from the same area, allows us a justified systematic discussion. The simosaur remains from the Israeli locality are more akin to Simosaurus gaillardoti, from the Ladinian of France and Germany, than to the other defined member of the clade, Paludidraco multidentatus, from the Carnian of Spain. However, the Simosaurus form present in Makhtesh Ramon could represent a taxon different than S. gaillardoti based on some cranial and postcranial differences, as well as its older stratigraphical occurrence. The comparison of the taxon recognized there with the hitherto known fossil record of Simosauridae allows us to propose an update on the paleobiogeographic and stratigraphic distributions of the group.
Alberto Cabezuelo-Hernández, Carlos de Miguel Chaves & Adán Pérez-García (2026)
The oldest simosaurids (Anisian of Israel): implications for the paleobiogeographic and stratigraphic distributions of the group
PalZ (advance online publication)
https://doi.org/10.1007/s12542-025-00769-2
https://link.springer.com/article/10.1007/s12542-025-00769-2
The Muschelkalk (Middle Triassic) of Makhtesh Ramon (Israel) has yielded numerous sauropterygian remains, Nothosauria and Placodontia being the most abundant groups. Other Triassic clades of Sauropterygia are also present, such as Pachypleurosauria or Simosauridae. Simosauridae was recognized as a poorly represented clade in Makhtesh Ramon, considering that only four elements were identified and provided limited characters to allow a specific attribution, being identified as Simosaurus sp. The fossil record of Simosauridae spans from the Ladinian (Middle Triassic) to the Carnian (Upper Triassic) in Europe, whereas that of the Middle East has been suggested to be limited to the uppermost Anisian or lowermost Ladinian. In this work, we analyze abundant unpublished material of Simosauridae from Makhtesh Ramon. The unequivocal oldest presence for this lineage is here documented, coming from the Anisian. Their detailed study, along with the revision of the material previously documented from the same area, allows us a justified systematic discussion. The simosaur remains from the Israeli locality are more akin to Simosaurus gaillardoti, from the Ladinian of France and Germany, than to the other defined member of the clade, Paludidraco multidentatus, from the Carnian of Spain. However, the Simosaurus form present in Makhtesh Ramon could represent a taxon different than S. gaillardoti based on some cranial and postcranial differences, as well as its older stratigraphical occurrence. The comparison of the taxon recognized there with the hitherto known fossil record of Simosauridae allows us to propose an update on the paleobiogeographic and stratigraphic distributions of the group.
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Free pdf:
Andrew Ji Yao Jian, Lorenz Schwark, Stephen Francis Poropat, Alex Ian Holman, Luke Marshall Brosnan, Maria Diaz Mateus, Michael Ernst Böttcher & Kliti Grice (2026)
Microbial oxidation and carbonate cementation led to three-dimensional preservation of ichthyosaur bones
Communications Earth & Environment 7: 268
doi: https://doi.org/10.1038/s43247-026-03366-6
https://www.nature.com/articles/s43247-026-03366-6
Exceptional preservation of ichthyosaur fossils in the Toarcian (~183–180 Ma) Posidonia Shale of southwest Germany was previously attributed to sustained anoxia or euxinic conditions that excluded aerobic scavengers and promoted early diagenetic mineralization. Here we show a partial ichthyosaur specimen within a carbonate concretion that contained three distinct biogeochemical compartments — the host shale, concretion matrix, and fossil bones — reflecting contrasting redox conditions during decomposition and early diagenesis. Under euxinic conditions, sulfate-reducing bacteria in the sediment generated isotopically light bicarbonate, which precipitated as the micritic calcite of the concretion. The bones uniquely preserve highly degraded, heavy carbon-enriched organic matter and heavy sulfur-enriched barite infilling the marrow cavities. We hypothesize this barite was produced by sulfur-oxidizing bacteria that anaerobically metabolized sulfide to sulfate. These results demonstrate that coupled microbial redox processes and carbonate cementation occurred within microenvironments associated with ichthyosaur bodies that enabled their three-dimensional preservation during the Early Jurassic.
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Andrew Ji Yao Jian, Lorenz Schwark, Stephen Francis Poropat, Alex Ian Holman, Luke Marshall Brosnan, Maria Diaz Mateus, Michael Ernst Böttcher & Kliti Grice (2026)
Microbial oxidation and carbonate cementation led to three-dimensional preservation of ichthyosaur bones
Communications Earth & Environment 7: 268
doi: https://doi.org/10.1038/s43247-026-03366-6
https://www.nature.com/articles/s43247-026-03366-6
Exceptional preservation of ichthyosaur fossils in the Toarcian (~183–180 Ma) Posidonia Shale of southwest Germany was previously attributed to sustained anoxia or euxinic conditions that excluded aerobic scavengers and promoted early diagenetic mineralization. Here we show a partial ichthyosaur specimen within a carbonate concretion that contained three distinct biogeochemical compartments — the host shale, concretion matrix, and fossil bones — reflecting contrasting redox conditions during decomposition and early diagenesis. Under euxinic conditions, sulfate-reducing bacteria in the sediment generated isotopically light bicarbonate, which precipitated as the micritic calcite of the concretion. The bones uniquely preserve highly degraded, heavy carbon-enriched organic matter and heavy sulfur-enriched barite infilling the marrow cavities. We hypothesize this barite was produced by sulfur-oxidizing bacteria that anaerobically metabolized sulfide to sulfate. These results demonstrate that coupled microbial redox processes and carbonate cementation occurred within microenvironments associated with ichthyosaur bodies that enabled their three-dimensional preservation during the Early Jurassic.
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