Early Triassic archosauromorph growth strategies + Early Triassic carbon cycle volatility + Permian dryland ecosystem (free pdf)
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Ben Creisler
Jun 5, 2026, 1:50:37 PM (15 hours ago) Jun 5
to DinosaurMa...@googlegroups.com
Ben Creisler
Some recent papers:
Kathleen.N. Dollman, Frederick.B. Tolchard, Jonah.N. Choiniere, John Hancox, Andrew B. Heckert, Chandelé Montgomery, Valentin Buffa & Jennifer Botha (2026)
Synchrotron imaging reveals diversity in archosauromorph growth strategies by the end of the early Triassic
iScience 29(6): 116162
doi: https://doi.org/10.1016/j.isci.2026.116162
https://www.sciencedirect.com/science/article/pii/S2589004226015373
Highlights
Synchrotron micro-CT of Early Triassic archosauromorph bones reveals diverse growth strategies
Results suggest fast growth is not plesiomorphic in Archosauromorpha
Results suggest at least 9 distinct Early Triassic archosauromorph taxa
Driefontein archosauromorph diversity is geographically and temporally localized
Summary
Archosauromorphs are a diverse clade of vertebrates that originated in the Early Triassic and persist today as crown birds (ornithodirans) and crocodilians (pseudosuchians). They exhibit markedly different life-history strategies, with ornithodirans characterized by rapid growth, and more crown-ward pseudosuchians with slower growth rates. Understanding how these patterns emerged requires further insight into growth dynamics among early archosauromorphs. We use synchrotron X-ray micro-computed tomography to investigate the bone microstructure in an assemblage of archosauromorphs from the Early Triassic locality Driefontein Farm 11 in the Olenekian-Anisian Langbergia-Garjainia subzone of the Cynognathus zone in the main Karoo Basin of South Africa. Our findings reveal that growth strategies among Early Triassic archosauromorphs already encompass both rapid and slow growth rates. We further deduce that the diversity in growth strategies observed in crown-ward archosaur lineages were not lineage-specific derived characteristics but rather inherited growth traits already present among their Early Triassic members.
James A. Craig, Neil S. Davies & Lorenzo Marchetti (2026)
Life in a Permian dryland: Evidence from plant and trace fossils of the fluvio-aeolian Cap-aux-Meules Formation (Îles-de-la-Madeleine, Québec)
Palaeogeography, Palaeoclimatology, Palaeoecology 113961
doi: https://doi.org/10.1016/j.palaeo.2026.113961
https://www.sciencedirect.com/science/article/pii/S0031018226004244
Highlights
Rare in situ fossil records of woody seed plants from a Permian dryland.
Earliest vertebrate burrows from aeolian strata.
Earliest record of desert tetrapods outside of western Pangaea.
Insights into dryland ecosystems following Carboniferous-Permian aridification.
Abstract
The Maritimes Basin contains some of Earth's best-studied records of late Palaeozoic terrestrial environments, which have informed much understanding of ichnology and plant and tetrapod evolution during this interval. However, less attention has been paid to the basin's only fluvio-aeolian constituent – the Cap-aux-Meules Formation (Îles-de-la-Madeleine, Québec, Canada) - which has previously been considered unfossiliferous and of uncertain age. In this paper, we report plants and diverse trace fossils from the Cap-aux-Meules Formation and describe their sedimentological context. Fluvial facies record deposition in a dryland river system with ephemeral floodplain lakes. The fluvial fossil assemblage includes 9 invertebrate ichnogenera characteristic of the Scoyenia ichnofacies and a fossil stump of a probable woody seed plant, which expands globally sparse records of upright fossil trees in dryland fluvial facies. The presence of dryland vegetation is further evidenced by rhizoliths and vegetation-induced sedimentary structures, comprising accretionary mounds and decay-related forms. In aeolian facies, interdune deposits contain 8 invertebrate ichnogenera of the Scoyenia ichnofacies, in addition to three forms of tetrapod aestivation burrow which constitute the earliest examples of vertebrate burrows from aeolian strata. Dune facies host abundant tetrapod trackways, resembling Erpetopus and Varanopus curvidactylus, that are characteristic of the late Artinskian-Kungurian (late early Permian) Erpetopus biochron and provide the first direct biostratigraphic age constraint for the Cap-aux-Meules Formation. The formation represents the culmination of long-term aridification in Euramerica, which began in the late Carboniferous, and witnessed the expansion of dryland habitats, the rise to dominance of coniferous seed plants, and the infaunalization of vertebrates and invertebrates. The trace fossils are archetypal of lower Permian aeolian strata, where the earliest widespread evidence for faunal colonisation of desert dune-fields appears globally.
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Free pdf:
Kathleen.N. Dollman, Frederick.B. Tolchard, Jonah.N. Choiniere, John Hancox, Andrew B. Heckert, Chandelé Montgomery, Valentin Buffa & Jennifer Botha (2026)
Synchrotron imaging reveals diversity in archosauromorph growth strategies by the end of the early Triassic
iScience 29(6): 116162
doi: https://doi.org/10.1016/j.isci.2026.116162
https://www.sciencedirect.com/science/article/pii/S2589004226015373
Highlights
Synchrotron micro-CT of Early Triassic archosauromorph bones reveals diverse growth strategies
Results suggest fast growth is not plesiomorphic in Archosauromorpha
Results suggest at least 9 distinct Early Triassic archosauromorph taxa
Driefontein archosauromorph diversity is geographically and temporally localized
Summary
Archosauromorphs are a diverse clade of vertebrates that originated in the Early Triassic and persist today as crown birds (ornithodirans) and crocodilians (pseudosuchians). They exhibit markedly different life-history strategies, with ornithodirans characterized by rapid growth, and more crown-ward pseudosuchians with slower growth rates. Understanding how these patterns emerged requires further insight into growth dynamics among early archosauromorphs. We use synchrotron X-ray micro-computed tomography to investigate the bone microstructure in an assemblage of archosauromorphs from the Early Triassic locality Driefontein Farm 11 in the Olenekian-Anisian Langbergia-Garjainia subzone of the Cynognathus zone in the main Karoo Basin of South Africa. Our findings reveal that growth strategies among Early Triassic archosauromorphs already encompass both rapid and slow growth rates. We further deduce that the diversity in growth strategies observed in crown-ward archosaur lineages were not lineage-specific derived characteristics but rather inherited growth traits already present among their Early Triassic members.
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Free pdf:
Yadong Sun, Linlin Ma, Michael M. Joachimski, Sylvain Richoz, Zaitian Zhang, Erdan Huang, Tian Wang, Leopold Krystyn & Xulong Lai (2026)
The Triassic carbon cycle in turmoil: A 50-m.y. journey from extinction to renewal
Geology (advance online publication)
DOI: https://doi.org/10.1130/G54560.1
https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G54560.1/731634/The-Triassic-carbon-cycle-in-turmoil-A-50-m-y
We present a new, comprehensive carbon isotope (δ13C) compilation for the Triassic that demonstrates a strong coupling between volcanic forcing, carbon cycle stability, and the evolution of ecosystems. The first ∼25 m.y. of the Triassic were characterized by profound δ13C volatility, initiated by the Siberian Traps eruptions and concluding with perturbation linked to the Wrangellia large igneous province. Such volatility is manifested by major negative δ13C excursions as large as ∼8‰−10‰, followed by positive shifts largely reflecting enhanced carbon burial during ecosystem recovery. During the final ∼25 m.y. of the Triassic (Norian−Rhaetian), δ13C variability declined to ∼2‰, indicating a transition to long-term carbon-cycle stability. This stabilization coincided with a reduction in major environmental crises as resilient, modern-style ecosystems became firmly established.
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Yadong Sun, Linlin Ma, Michael M. Joachimski, Sylvain Richoz, Zaitian Zhang, Erdan Huang, Tian Wang, Leopold Krystyn & Xulong Lai (2026)
The Triassic carbon cycle in turmoil: A 50-m.y. journey from extinction to renewal
Geology (advance online publication)
DOI: https://doi.org/10.1130/G54560.1
https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G54560.1/731634/The-Triassic-carbon-cycle-in-turmoil-A-50-m-y
We present a new, comprehensive carbon isotope (δ13C) compilation for the Triassic that demonstrates a strong coupling between volcanic forcing, carbon cycle stability, and the evolution of ecosystems. The first ∼25 m.y. of the Triassic were characterized by profound δ13C volatility, initiated by the Siberian Traps eruptions and concluding with perturbation linked to the Wrangellia large igneous province. Such volatility is manifested by major negative δ13C excursions as large as ∼8‰−10‰, followed by positive shifts largely reflecting enhanced carbon burial during ecosystem recovery. During the final ∼25 m.y. of the Triassic (Norian−Rhaetian), δ13C variability declined to ∼2‰, indicating a transition to long-term carbon-cycle stability. This stabilization coincided with a reduction in major environmental crises as resilient, modern-style ecosystems became firmly established.
======
Free pdf:
James A. Craig, Neil S. Davies & Lorenzo Marchetti (2026)
Life in a Permian dryland: Evidence from plant and trace fossils of the fluvio-aeolian Cap-aux-Meules Formation (Îles-de-la-Madeleine, Québec)
Palaeogeography, Palaeoclimatology, Palaeoecology 113961
doi: https://doi.org/10.1016/j.palaeo.2026.113961
https://www.sciencedirect.com/science/article/pii/S0031018226004244
Highlights
Rare in situ fossil records of woody seed plants from a Permian dryland.
Earliest vertebrate burrows from aeolian strata.
Earliest record of desert tetrapods outside of western Pangaea.
Insights into dryland ecosystems following Carboniferous-Permian aridification.
Abstract
The Maritimes Basin contains some of Earth's best-studied records of late Palaeozoic terrestrial environments, which have informed much understanding of ichnology and plant and tetrapod evolution during this interval. However, less attention has been paid to the basin's only fluvio-aeolian constituent – the Cap-aux-Meules Formation (Îles-de-la-Madeleine, Québec, Canada) - which has previously been considered unfossiliferous and of uncertain age. In this paper, we report plants and diverse trace fossils from the Cap-aux-Meules Formation and describe their sedimentological context. Fluvial facies record deposition in a dryland river system with ephemeral floodplain lakes. The fluvial fossil assemblage includes 9 invertebrate ichnogenera characteristic of the Scoyenia ichnofacies and a fossil stump of a probable woody seed plant, which expands globally sparse records of upright fossil trees in dryland fluvial facies. The presence of dryland vegetation is further evidenced by rhizoliths and vegetation-induced sedimentary structures, comprising accretionary mounds and decay-related forms. In aeolian facies, interdune deposits contain 8 invertebrate ichnogenera of the Scoyenia ichnofacies, in addition to three forms of tetrapod aestivation burrow which constitute the earliest examples of vertebrate burrows from aeolian strata. Dune facies host abundant tetrapod trackways, resembling Erpetopus and Varanopus curvidactylus, that are characteristic of the late Artinskian-Kungurian (late early Permian) Erpetopus biochron and provide the first direct biostratigraphic age constraint for the Cap-aux-Meules Formation. The formation represents the culmination of long-term aridification in Euramerica, which began in the late Carboniferous, and witnessed the expansion of dryland habitats, the rise to dominance of coniferous seed plants, and the infaunalization of vertebrates and invertebrates. The trace fossils are archetypal of lower Permian aeolian strata, where the earliest widespread evidence for faunal colonisation of desert dune-fields appears globally.
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