Dinosaur bone structure and gigantism + dinosaur tail traces + Patagonichornis holotype + lichens to detect dinosaur bones + Mark Norell
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Ben Creisler
Nov 3, 2025, 1:51:50 PM (3 days ago) Nov 3
to DinosaurMa...@googlegroups.com
Ben Creisler
Some recent papers:
Dinosaurs exhibit conservative patterns of high cortical thickness across diverse taxa, reflecting phylogenetic constraints linked to archosaurian joint morphology and pneumaticity
Cenozoic megamammals display greater variability in cortical architecture, with xenarthrans showing extremely thin cortices and expanded trabecular networks
Bone compactness does not scale predictably with body mass, reflecting complex interplay of phylogenetic, biomechanical, and ecological factors
Trabecular bone coverage shows fundamental differences between clades, with dinosaurs at 23-40% and megamammals ranging from 0-53% of cross-sectional area
Terrestrial gigantism evolved through divergent pathways, with dinosaurs favoring cortical reinforcement while mammals adopted flexible trabecular expansion strategies
ABSTRACT
Bone microanatomy provides critical information about the biomechanical strategies employed by vertebrates to sustain large body sizes. Yet, direct comparisons between bone microstructure in extinct megamammals and quadrupedal dinosaurs remain rare, despite their convergent evolution of gigantism. This study addresses that gap. We analyze the proportions of cortical and trabecular tissue in appendicular bones from 22 specimens (9 quadrupedal dinosaurs, 13 megamammals) using specimen-level phylogenetic comparative methods. Specimen-level analysis reveals that dinosaurs exhibit a conservative pattern (cortical coverage 60-77%) with low morphological disparity, while megamammals display 88% greater morphospace variation (47-87%). Principal component analysis of individual specimens demonstrates complete phylogenetic separation in bone microstructure space (98% variance), with dinosaurian patterns likely reflecting phylogenetic constraints associated with archosaurian joint morphology, pneumaticity, and soft tissue load transmission. In contrast, megamammals display greater variability in cortical architecture. Xenarthrans are characterized by extremely thin cortices and expanded trabecular networks, while ungulates and proboscideans employ diverse strategies that balance cortical thickness with trabecular reinforcement. Individual specimen analysis reveals trabecular coverage ranging from 0% (some Glyptotherium elements) to 53% (Eremotherium), compared to the narrower dinosaurian range (23-40%). Allometric analyses show no significant scaling relationship between body mass and bone structure in either group (p > 0.5), suggesting that bone architecture reflects phylogenetic constraints and biomechanical strategies rather than simple size effects. This study illustrates the divergent evolutionary pathways by which mammals and dinosaurs achieved gigantism, highlighting the importance of integrating microanatomical, biomechanical, and functional data in interpreting the paleobiology of extinct vertebrates.
Ignacio Díaz-Martínez, Sofía Urzagasti-Torres, Paolo Citton, Matteo Belvedere & Silvina de Valais (2025)
The Holotypes of Patagonichornis venetiorum Casamiquela 1996 and Tridigitichnus inopinatus Casamiquela 1996 Vertebrate Ichnotaxa (Late Cretaceous, Patagonia): History and Patrimonial Significance
Geoheritage 17: 161
doi: https://doi.org/10.1007/s12371-025-01211-4
https://link.springer.com/article/10.1007/s12371-025-01211-4
The Late Cretaceous (Campanian–Maastrichtian) vertebrate ichnotaxa Patagonichornis venetiorum Casamiquela 1996 and Tridigitichnus inopinatus Casamiquela 1996 were established based on material preserved on a sandstone slab from the Angostura Colorada Formation, Montón Iló quarry, Río Negro Province, Patagonia, Argentina. This slab, along with others from the same locality, was used for constructions near Ingeniero Jacobacci town. The holotype-bearing slab is currently housed at the Museo di Storia Naturale di Venezia Giancarlo Ligabue (Venice, Italy). This study aims to reconstruct the circumstances surrounding these holotypes. Through visits to the Museo Antropológico e Histórico Jorge H. Gerhold (Ingeniero Jacobacci, Argentina), the original sidewalk from which the slab was removed, was identified. Moreover, nine track-bearing slabs with avian footprints and invertebrate traces were identified on the same sidewalk. Due to limited accessibility of the original descriptions, these ichnotaxa have received little scientific attention. Although P. venetiorum and T. inopinatus remain available names under ICZN regulations, their ichnotaxonomical validity requires further assessment. To highlight their importance as movable paleontological heritage, a detailed report —including descriptions, photographs, and 3D model— was prepared for the Ingeniero Jacobacci and Venice museums. The compiled data serve as a crucial reference for future research and conservation initiatives, promoting their patrimonial, educational, and touristic value. This work underscores the importance of interdisciplinary collaboration for the study and preservation of paleontological heritage.
=====
Brian J. Pickles, Caleb M. Brown, Sean Herridge-Berry, Cameron R. Martin, Melissa Dergousoff, Teri Gilmar, Phil R. Bell & Derek R. Peddle (2025)
Remote sensing of lichens with drones for detecting dinosaur bones
Current Biology 35(21): R1044-R1045
doi: https://doi.org/10.1016/j.cub.2025.09.036
https://www.sciencedirect.com/science/article/pii/S0960982225012060
Free pdf:
https://www.cell.com/action/showPdf?pii=S0960-9822%2825%2901206-0
Advances in palaeontology and evolutionary biology are often linked to the discovery of new fossils, yet these discoveries are typically serendipitous. Here, we report that lichens can serve as biological indicators of vertebrate fossils in western North America and can be identified using remote sensing. Lichens are symbioses between fungi and algae (and/or cyanobacteria) that play important ecological roles and colonise many substrates, including fossils. Preferential colonisation of dinosaur bones by lichen with vibrant orange pigmentation (Figure 1A,B) has been recognised anecdotally for decades (Darren H. Tanke, personal communication). We found that the spectral reflectance profiles of these lichen pigments and the preferential association between modern lichens and ancient bones can be used to detect dinosaur fossils by remote sensing, for which we propose new spectral indices.
====
Tito Aureliano, Virgínia Maciel, Vitor P.G. Costa, Ana Clara F. de Paiva, Claude Luiz de Aguilar Santos & Aline M. Ghilardi (2025)
Bone structure and the evolution of different pathways to gigantism in dinosaurs and megamammals
Journal of South American Earth Sciences 105855
doi: https://doi.org/10.1016/j.jsames.2025.105855
https://www.sciencedirect.com/science/article/abs/pii/S0895981125005176
Highlights
Tito Aureliano, Virgínia Maciel, Vitor P.G. Costa, Ana Clara F. de Paiva, Claude Luiz de Aguilar Santos & Aline M. Ghilardi (2025)
Bone structure and the evolution of different pathways to gigantism in dinosaurs and megamammals
Journal of South American Earth Sciences 105855
doi: https://doi.org/10.1016/j.jsames.2025.105855
https://www.sciencedirect.com/science/article/abs/pii/S0895981125005176
Highlights
Dinosaurs exhibit conservative patterns of high cortical thickness across diverse taxa, reflecting phylogenetic constraints linked to archosaurian joint morphology and pneumaticity
Cenozoic megamammals display greater variability in cortical architecture, with xenarthrans showing extremely thin cortices and expanded trabecular networks
Bone compactness does not scale predictably with body mass, reflecting complex interplay of phylogenetic, biomechanical, and ecological factors
Trabecular bone coverage shows fundamental differences between clades, with dinosaurs at 23-40% and megamammals ranging from 0-53% of cross-sectional area
Terrestrial gigantism evolved through divergent pathways, with dinosaurs favoring cortical reinforcement while mammals adopted flexible trabecular expansion strategies
ABSTRACT
Bone microanatomy provides critical information about the biomechanical strategies employed by vertebrates to sustain large body sizes. Yet, direct comparisons between bone microstructure in extinct megamammals and quadrupedal dinosaurs remain rare, despite their convergent evolution of gigantism. This study addresses that gap. We analyze the proportions of cortical and trabecular tissue in appendicular bones from 22 specimens (9 quadrupedal dinosaurs, 13 megamammals) using specimen-level phylogenetic comparative methods. Specimen-level analysis reveals that dinosaurs exhibit a conservative pattern (cortical coverage 60-77%) with low morphological disparity, while megamammals display 88% greater morphospace variation (47-87%). Principal component analysis of individual specimens demonstrates complete phylogenetic separation in bone microstructure space (98% variance), with dinosaurian patterns likely reflecting phylogenetic constraints associated with archosaurian joint morphology, pneumaticity, and soft tissue load transmission. In contrast, megamammals display greater variability in cortical architecture. Xenarthrans are characterized by extremely thin cortices and expanded trabecular networks, while ungulates and proboscideans employ diverse strategies that balance cortical thickness with trabecular reinforcement. Individual specimen analysis reveals trabecular coverage ranging from 0% (some Glyptotherium elements) to 53% (Eremotherium), compared to the narrower dinosaurian range (23-40%). Allometric analyses show no significant scaling relationship between body mass and bone structure in either group (p > 0.5), suggesting that bone architecture reflects phylogenetic constraints and biomechanical strategies rather than simple size effects. This study illustrates the divergent evolutionary pathways by which mammals and dinosaurs achieved gigantism, highlighting the importance of integrating microanatomical, biomechanical, and functional data in interpreting the paleobiology of extinct vertebrates.
===
I missed this one earlier this year. It now has a free link in Zenodo.
Free pdf:
J.A. McLarty, Z. McKenzie, W.K. Hayes, R. Clawson, H.D. Baltazar, E.F. Alves, K.E. Nick & R. Esperante (2025)
Let that sink in: track depth as a driving factor in the formation of dinosaur tail traces
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2481520
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2481520
Free pdf:
https://zenodo.org/records/17213799
To date, most reports of dinosaur tail traces have been limited to a small number per tracksite and have not included a detailed analysis of the associated trackways. Carreras Pampa comprises an Upper Maastrichtian theropod-dominated tracksite in Torotoro National Park, Bolivia. This tracksite preserves the largest number of theropod trackways associated with tail traces worldwide, allowing us to compare trackways to better understand how dinosaurs moved when producing tail traces. We applied multiple statistical analyses to 10 trackways with associated tail traces at the Carreras Pampa tracksite. Trackway measurements indicated that dinosaurs leaving tail traces were all of a similar size, with an estimated height at hip of 1.1–1.5 m. All trackways suggested that the dinosaurs were moving at a walking gait, with speed estimates of 4.1–8.8 km/h. Many of the trackways preserved deep tracks with a metatarsal mark. Statistical analyses using runs tests and generalised estimating equations (GEEs) suggested that the walking kinematics of a dinosaur’s foot sinking into the substrate was a driving factor in the formation of tail traces. The Carreras Pampa tracksite presented a unique opportunity to understand the effect of substrate consistency on theropod body posture and the formation of tail traces.
====
J.A. McLarty, Z. McKenzie, W.K. Hayes, R. Clawson, H.D. Baltazar, E.F. Alves, K.E. Nick & R. Esperante (2025)
Let that sink in: track depth as a driving factor in the formation of dinosaur tail traces
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2481520
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2481520
Free pdf:
https://zenodo.org/records/17213799
To date, most reports of dinosaur tail traces have been limited to a small number per tracksite and have not included a detailed analysis of the associated trackways. Carreras Pampa comprises an Upper Maastrichtian theropod-dominated tracksite in Torotoro National Park, Bolivia. This tracksite preserves the largest number of theropod trackways associated with tail traces worldwide, allowing us to compare trackways to better understand how dinosaurs moved when producing tail traces. We applied multiple statistical analyses to 10 trackways with associated tail traces at the Carreras Pampa tracksite. Trackway measurements indicated that dinosaurs leaving tail traces were all of a similar size, with an estimated height at hip of 1.1–1.5 m. All trackways suggested that the dinosaurs were moving at a walking gait, with speed estimates of 4.1–8.8 km/h. Many of the trackways preserved deep tracks with a metatarsal mark. Statistical analyses using runs tests and generalised estimating equations (GEEs) suggested that the walking kinematics of a dinosaur’s foot sinking into the substrate was a driving factor in the formation of tail traces. The Carreras Pampa tracksite presented a unique opportunity to understand the effect of substrate consistency on theropod body posture and the formation of tail traces.
====
Free pdf:
Ignacio Díaz-Martínez, Sofía Urzagasti-Torres, Paolo Citton, Matteo Belvedere & Silvina de Valais (2025)
The Holotypes of Patagonichornis venetiorum Casamiquela 1996 and Tridigitichnus inopinatus Casamiquela 1996 Vertebrate Ichnotaxa (Late Cretaceous, Patagonia): History and Patrimonial Significance
Geoheritage 17: 161
doi: https://doi.org/10.1007/s12371-025-01211-4
https://link.springer.com/article/10.1007/s12371-025-01211-4
The Late Cretaceous (Campanian–Maastrichtian) vertebrate ichnotaxa Patagonichornis venetiorum Casamiquela 1996 and Tridigitichnus inopinatus Casamiquela 1996 were established based on material preserved on a sandstone slab from the Angostura Colorada Formation, Montón Iló quarry, Río Negro Province, Patagonia, Argentina. This slab, along with others from the same locality, was used for constructions near Ingeniero Jacobacci town. The holotype-bearing slab is currently housed at the Museo di Storia Naturale di Venezia Giancarlo Ligabue (Venice, Italy). This study aims to reconstruct the circumstances surrounding these holotypes. Through visits to the Museo Antropológico e Histórico Jorge H. Gerhold (Ingeniero Jacobacci, Argentina), the original sidewalk from which the slab was removed, was identified. Moreover, nine track-bearing slabs with avian footprints and invertebrate traces were identified on the same sidewalk. Due to limited accessibility of the original descriptions, these ichnotaxa have received little scientific attention. Although P. venetiorum and T. inopinatus remain available names under ICZN regulations, their ichnotaxonomical validity requires further assessment. To highlight their importance as movable paleontological heritage, a detailed report —including descriptions, photographs, and 3D model— was prepared for the Ingeniero Jacobacci and Venice museums. The compiled data serve as a crucial reference for future research and conservation initiatives, promoting their patrimonial, educational, and touristic value. This work underscores the importance of interdisciplinary collaboration for the study and preservation of paleontological heritage.
=====
=====
Free pdf:
Brian J. Pickles, Caleb M. Brown, Sean Herridge-Berry, Cameron R. Martin, Melissa Dergousoff, Teri Gilmar, Phil R. Bell & Derek R. Peddle (2025)
Remote sensing of lichens with drones for detecting dinosaur bones
Current Biology 35(21): R1044-R1045
doi: https://doi.org/10.1016/j.cub.2025.09.036
https://www.sciencedirect.com/science/article/pii/S0960982225012060
Free pdf:
https://www.cell.com/action/showPdf?pii=S0960-9822%2825%2901206-0
Advances in palaeontology and evolutionary biology are often linked to the discovery of new fossils, yet these discoveries are typically serendipitous. Here, we report that lichens can serve as biological indicators of vertebrate fossils in western North America and can be identified using remote sensing. Lichens are symbioses between fungi and algae (and/or cyanobacteria) that play important ecological roles and colonise many substrates, including fossils. Preferential colonisation of dinosaur bones by lichen with vibrant orange pigmentation (Figure 1A,B) has been recognised anecdotally for decades (Darren H. Tanke, personal communication). We found that the spectral reflectance profiles of these lichen pigments and the preferential association between modern lichens and ancient bones can be used to detect dinosaur fossils by remote sensing, for which we propose new spectral indices.
====
====
Peter J. Makovicky, James M. Clark & Stephen L. Brusatte (2025)
Mark Norell (1957–2025)
Current Biology 35(21): R1033–R1034
doi: https://doi.org/10.1016/j.cub.2025.09.056
https://www.cell.com/current-biology/fulltext/S0960-9822(25)01256-4
Mark Norell (1957–2025)
Current Biology 35(21): R1033–R1034
doi: https://doi.org/10.1016/j.cub.2025.09.056
https://www.cell.com/current-biology/fulltext/S0960-9822(25)01256-4
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