Edmontosaurus bonebed pseudopathologies + sauropod undertracks from Late Cretaceous of Brazil
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Ben Creisler
Jan 16, 2026, 2:21:42 PM (2 days ago) Jan 16
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Ben Creisler
New papers:
Bethania C. T. Siviero, Elizabeth Rega, Kevin E. Nick & Art V. Chadwick (2026)
Analysis of pseudopathologies in Edmontosaurus annectens bones: taphonomic implications from biogenetic and diagenetic bone alterations from a Cretaceous bonebed in the Lance Formation, Wyoming
Journal of Vertebrate Paleontology e2600392
https://doi.org/10.1080/02724634.2025.2600392
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2600392
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2025.2600392
Pseudopathology in paleontology refers to postmortem bone alteration mimicking osseous features of disease. Differentiating pathologies from pseudopathologies is critical in the investigation of paleopathology, as misattribution can produce erroneous conclusions regarding diseases and life history. In this paper, we describe several examples of pseudopathologies from a Cretaceous commingled monospecific bonebed of Edmontosaurus annectens (Lance Formation, WY). In addition to 96 documented real pathologies or injuries uncovered in examination of over 3000 fossil bone specimens, multiple pseudopathologies were observed. Most of these were bone fractures or patterned erosions of bone material resulting from most likely taphonomic processes. Bone proliferation characterizing the living response to premortem injuries is one clue. Absent this response, perimortem injuries and postmortem changes due to scavenging, weathering, and other factors should be considered. CT imaging of one astragalus showed intense focal radiodensity surrounding the two large lesions, sharply distinct from the surrounding bone. When compared against histological thin sections and SEM-EDS scanning, what appeared in CT as dense sclerotic reactive bone suggested postmortem migration of minerals subsequent to erosive insect boring, a gradient potentially related to the unique microenvironment thereby created affecting subsequent permineralization. Evidence from our analysis of this assemblage supports that even diagnoses supported by non-invasive imaging such as CT scans should, when possible, be tested by histological analysis. Otherwise, a distinctly and disturbingly non-zero number of erroneous conclusions are to be expected from any survey of paleopathology, particularly given the numbers of intervening processes separating a fresh carcass from permineralized bone.
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Free pdf:
Bethania C. T. Siviero, Elizabeth Rega, Kevin E. Nick & Art V. Chadwick (2026)
Analysis of pseudopathologies in Edmontosaurus annectens bones: taphonomic implications from biogenetic and diagenetic bone alterations from a Cretaceous bonebed in the Lance Formation, Wyoming
Journal of Vertebrate Paleontology e2600392
https://doi.org/10.1080/02724634.2025.2600392
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2600392
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2025.2600392
Pseudopathology in paleontology refers to postmortem bone alteration mimicking osseous features of disease. Differentiating pathologies from pseudopathologies is critical in the investigation of paleopathology, as misattribution can produce erroneous conclusions regarding diseases and life history. In this paper, we describe several examples of pseudopathologies from a Cretaceous commingled monospecific bonebed of Edmontosaurus annectens (Lance Formation, WY). In addition to 96 documented real pathologies or injuries uncovered in examination of over 3000 fossil bone specimens, multiple pseudopathologies were observed. Most of these were bone fractures or patterned erosions of bone material resulting from most likely taphonomic processes. Bone proliferation characterizing the living response to premortem injuries is one clue. Absent this response, perimortem injuries and postmortem changes due to scavenging, weathering, and other factors should be considered. CT imaging of one astragalus showed intense focal radiodensity surrounding the two large lesions, sharply distinct from the surrounding bone. When compared against histological thin sections and SEM-EDS scanning, what appeared in CT as dense sclerotic reactive bone suggested postmortem migration of minerals subsequent to erosive insect boring, a gradient potentially related to the unique microenvironment thereby created affecting subsequent permineralization. Evidence from our analysis of this assemblage supports that even diagnoses supported by non-invasive imaging such as CT scans should, when possible, be tested by histological analysis. Otherwise, a distinctly and disturbingly non-zero number of erroneous conclusions are to be expected from any survey of paleopathology, particularly given the numbers of intervening processes separating a fresh carcass from permineralized bone.
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Luciano Alessandretti, Lucas Veríssimo Warren, Heitor Francischini, Caio César Rangel, Beatriz Christofoletti, Leandro Gustavo da Silva Albino, Leonardo Cardoso Moura & Daniel Sedorko (2026)
Late Cretaceous sauropod dinosaur undertracks in floodplain deposits of Sanfranciscana Basin, Brazil, and their paleoecological significance
Palaeoworld 201078
doi: https://doi.org/10.1016/j.palwor.2026.201078
https://www.sciencedirect.com/science/article/abs/pii/S1871174X26000132
Dinosaur undertracks are described in the Upper Cretaceous Capacete Formation of the Sanfranciscana Basin, southeastern Brazil. These vertebrate traces are preserved in fine-grained deposits deposited in muddy and vegetated floodplain settings associated with a meandering river system active during the Campanian–Maastrichtian. Based on sedimentologic data, morphostructural analysis, and comparisons with analogous Cretaceous ichnofossils, we interpret these structures as undertracks produced by sauropods. Notably, although other occurrences of footprints and undertracks are known in younger units, no dinosaur fossils have yet been recovered in the Upper Cretaceous of the Sanfranciscana Basin. However, they are widespread in chronocorrelated units from the Bauru Basin, deposited by fluvial distributary and lacustrine systems under arid to semi-arid climatic conditions. During the Late Cretaceous, these two basins were putatively separated due to the uplift of the Alto Paranaíba High (APH) in the central part of the South American Platform. Our new sedimentologic and paleontologic data from the Sanfranciscana Basin, combined with regional paleogeography and paleoclimate reconstructions, suggest that a rain shadow effect played a key role in influencing precipitation patterns in the northern side of the APH. In this scenario of orographic rainfall, sauropod populations likely migrated from the Bauru Basin in the Southern Hot Arid Belt to the Sanfranciscana Basin in the Equatorial Humid Belt, possibly driven by droughts and shortages of food and water. This inferred migratory pathway likely involved a lowland-upland-lowland journey of dinosaur herds through the APH, eventually leading them to the humid floodplains of the Sanfranciscana Basin, where resources such as food and water were more abundant.
Late Cretaceous sauropod dinosaur undertracks in floodplain deposits of Sanfranciscana Basin, Brazil, and their paleoecological significance
Palaeoworld 201078
doi: https://doi.org/10.1016/j.palwor.2026.201078
https://www.sciencedirect.com/science/article/abs/pii/S1871174X26000132
Dinosaur undertracks are described in the Upper Cretaceous Capacete Formation of the Sanfranciscana Basin, southeastern Brazil. These vertebrate traces are preserved in fine-grained deposits deposited in muddy and vegetated floodplain settings associated with a meandering river system active during the Campanian–Maastrichtian. Based on sedimentologic data, morphostructural analysis, and comparisons with analogous Cretaceous ichnofossils, we interpret these structures as undertracks produced by sauropods. Notably, although other occurrences of footprints and undertracks are known in younger units, no dinosaur fossils have yet been recovered in the Upper Cretaceous of the Sanfranciscana Basin. However, they are widespread in chronocorrelated units from the Bauru Basin, deposited by fluvial distributary and lacustrine systems under arid to semi-arid climatic conditions. During the Late Cretaceous, these two basins were putatively separated due to the uplift of the Alto Paranaíba High (APH) in the central part of the South American Platform. Our new sedimentologic and paleontologic data from the Sanfranciscana Basin, combined with regional paleogeography and paleoclimate reconstructions, suggest that a rain shadow effect played a key role in influencing precipitation patterns in the northern side of the APH. In this scenario of orographic rainfall, sauropod populations likely migrated from the Bauru Basin in the Southern Hot Arid Belt to the Sanfranciscana Basin in the Equatorial Humid Belt, possibly driven by droughts and shortages of food and water. This inferred migratory pathway likely involved a lowland-upland-lowland journey of dinosaur herds through the APH, eventually leading them to the humid floodplains of the Sanfranciscana Basin, where resources such as food and water were more abundant.
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