Erythrobatrachus (marine temnospondyl, Triassic of Australia) revised + Middle Triassic Xingyi Fauna marine fauna (Keichousaurus) lasted ~140 kyr.
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Ben Creisler
Feb 23, 2026, 3:16:48 PMFeb 23
to DinosaurMa...@googlegroups.com
Ben Creisler
Recent papers:
Free pdf:
Benjamin P. Kear, Nicolás E. Campione, Mikael Siversson, Mohamad Bazzi & Lachlan J. Hart (2026)
Revision of the trematosaurid Erythrobatrachus noonkanbahensis confirms a cryptic marine temnospondyl community from the Lower Triassic of Western Australia
Journal of Vertebrate Paleontology e2601224
doi: https://doi.org/10.1080/02724634.2025.2601224
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2601224
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2025.2601224
Tetrapods emerged as dominant marine predators during the earliest Triassic, with trematosaurid temnospondyls representing one of the first groups to radiate globally after the cataclysmic end-Permian mass extinction. Trematosaurids were superficially ‘crocodile-like’ amphibians with elongate tapered skulls and dorsolaterally oriented orbits that suggest adaptation for living within the water column. In Australia, marine trematosaurid fossils have only been recovered from the Blina Shale—an upper Induan–lower Olenekian paralic unit that crops out in the Canning Basin of remote northwestern Western Australia. The Blina Shale was deposited along the edge of a brackish seaway that inundated the East Gondwana interior rift-sag system separating what is today the Australian and Indian landmasses. Historically, a single trematosaurid species, Erythrobatrachus noonkanbahensis, was described from the Blina Shale. However, recent survey of the remains reveals a morphological composite combining the broad-skulled holotype of E. noonkanbahensis, with an extremely narrow-skulled referred specimen that closely resembles the cosmopolitan lonchorhynchine genus Aphaneramma. The Blina Shale temnospondyl assemblage therefore integrated multiple marine trematosaurids that were locally, and likely stratigraphically segregated from more benthic-oriented and non-marine rhytidosteids, capitosauroids, and brachyopids. These distinct temnospondyl communities probably occupied a succession of regressive habitats subject to increasing hyposalinity. Finally, although integrating predominantly southern Gondwanan endemics, the Blina Shale temnospondyl assemblage apparently included some widely distributed marine taxa that may have used the contiguous Pangean coastal fringes to facilitate long-distance dispersal.
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Benjamin P. Kear, Nicolás E. Campione, Mikael Siversson, Mohamad Bazzi & Lachlan J. Hart (2026)
Revision of the trematosaurid Erythrobatrachus noonkanbahensis confirms a cryptic marine temnospondyl community from the Lower Triassic of Western Australia
Journal of Vertebrate Paleontology e2601224
doi: https://doi.org/10.1080/02724634.2025.2601224
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2601224
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2025.2601224
Tetrapods emerged as dominant marine predators during the earliest Triassic, with trematosaurid temnospondyls representing one of the first groups to radiate globally after the cataclysmic end-Permian mass extinction. Trematosaurids were superficially ‘crocodile-like’ amphibians with elongate tapered skulls and dorsolaterally oriented orbits that suggest adaptation for living within the water column. In Australia, marine trematosaurid fossils have only been recovered from the Blina Shale—an upper Induan–lower Olenekian paralic unit that crops out in the Canning Basin of remote northwestern Western Australia. The Blina Shale was deposited along the edge of a brackish seaway that inundated the East Gondwana interior rift-sag system separating what is today the Australian and Indian landmasses. Historically, a single trematosaurid species, Erythrobatrachus noonkanbahensis, was described from the Blina Shale. However, recent survey of the remains reveals a morphological composite combining the broad-skulled holotype of E. noonkanbahensis, with an extremely narrow-skulled referred specimen that closely resembles the cosmopolitan lonchorhynchine genus Aphaneramma. The Blina Shale temnospondyl assemblage therefore integrated multiple marine trematosaurids that were locally, and likely stratigraphically segregated from more benthic-oriented and non-marine rhytidosteids, capitosauroids, and brachyopids. These distinct temnospondyl communities probably occupied a succession of regressive habitats subject to increasing hyposalinity. Finally, although integrating predominantly southern Gondwanan endemics, the Blina Shale temnospondyl assemblage apparently included some widely distributed marine taxa that may have used the contiguous Pangean coastal fringes to facilitate long-distance dispersal.
======
Yingao Zhang, Dayong Jiang, Ryosuke Motani, Andrea Tintori, Zuoyu Sun, Min Zhou, Cindy X. Su, Yinuo Wang & Mingtao Yao (2026)
Astronomical age calibration and duration of the Ladinian (Middle Triassic) Xingyi Fauna, southwestern Guizhou Province, China
Palaeogeography, Palaeoclimatology, Palaeoecology 113652
doi: https://doi.org/10.1016/j.palaeo.2026.113652
https://www.sciencedirect.com/science/article/abs/pii/S003101822600115X
Highlights
Milankovitch cycles controlled continental weathering and marine redox conditions.
New Ladinian astrochronology constrains the Xingyi Fauna's duration to ~140 kyr.
Volcanic fertilization, not weathering, fueled productivity and reptile evolution.
Abstract
The Ladinian Xingyi Fauna records a significant biotic radiation and ecological transition in the Middle Triassic after the end-Permian mass extinction. However, the precise duration and palaeoenvironmental background of the Xingyi Fauna remain unclear. To address this, we conducted a cyclostratigraphic analysis of the Falang Formation at the Nimaigu Section using high-resolution XRF elemental proxies. Spectral analysis of Fe/Al revealed Milankovitch cycles (405-kyr eccentricity, ~95-kyr short eccentricity, ~45-kyr obliquity, 21-kyr precession) and sub-Milankovitch cycles (12.5 kyr, 5.4 kyr), indicating that eccentricity maxima amplified precession-driven hydrological cycles and enhanced siliciclastic input. By integrating independent age constraints and sedimentation rate models, these cycles were anchored to a U-Pb zircon age from a volcanic ash layer and tuned to stable 405-kyr eccentricity, yielding an astronomical timescale spanning approximately 1.49 Myr for the Nimaigu Section from bed 17 to 273. This framework constrains the duration of the fossiliferous level of the Xingyi Fauna from bed 21 to 53 to ~169.49 kyr (ca. 240.47–240.3 Ma). Keichousaurus hui, the typical species of the Xingyi Fauna, has a duration of 103.47 kyr constrained by astronomical cycles but a 95% confidence interval of 214.89 kyr, reflecting its brief duration. The palaeoenvironment of the Xingyi Fauna was driven by a combination of orbital forcing and volcanic activity. The volcanically sourced nutrient supply might have promoted the ecological transition of the Xingyi Fauna. Our results highlight the interaction between orbital forcing and volcanism in shaping Middle Triassic marine ecosystems.
Astronomical age calibration and duration of the Ladinian (Middle Triassic) Xingyi Fauna, southwestern Guizhou Province, China
Palaeogeography, Palaeoclimatology, Palaeoecology 113652
doi: https://doi.org/10.1016/j.palaeo.2026.113652
https://www.sciencedirect.com/science/article/abs/pii/S003101822600115X
Highlights
Milankovitch cycles controlled continental weathering and marine redox conditions.
New Ladinian astrochronology constrains the Xingyi Fauna's duration to ~140 kyr.
Volcanic fertilization, not weathering, fueled productivity and reptile evolution.
Abstract
The Ladinian Xingyi Fauna records a significant biotic radiation and ecological transition in the Middle Triassic after the end-Permian mass extinction. However, the precise duration and palaeoenvironmental background of the Xingyi Fauna remain unclear. To address this, we conducted a cyclostratigraphic analysis of the Falang Formation at the Nimaigu Section using high-resolution XRF elemental proxies. Spectral analysis of Fe/Al revealed Milankovitch cycles (405-kyr eccentricity, ~95-kyr short eccentricity, ~45-kyr obliquity, 21-kyr precession) and sub-Milankovitch cycles (12.5 kyr, 5.4 kyr), indicating that eccentricity maxima amplified precession-driven hydrological cycles and enhanced siliciclastic input. By integrating independent age constraints and sedimentation rate models, these cycles were anchored to a U-Pb zircon age from a volcanic ash layer and tuned to stable 405-kyr eccentricity, yielding an astronomical timescale spanning approximately 1.49 Myr for the Nimaigu Section from bed 17 to 273. This framework constrains the duration of the fossiliferous level of the Xingyi Fauna from bed 21 to 53 to ~169.49 kyr (ca. 240.47–240.3 Ma). Keichousaurus hui, the typical species of the Xingyi Fauna, has a duration of 103.47 kyr constrained by astronomical cycles but a 95% confidence interval of 214.89 kyr, reflecting its brief duration. The palaeoenvironment of the Xingyi Fauna was driven by a combination of orbital forcing and volcanic activity. The volcanically sourced nutrient supply might have promoted the ecological transition of the Xingyi Fauna. Our results highlight the interaction between orbital forcing and volcanism in shaping Middle Triassic marine ecosystems.
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