Titanosaur axis from Upper Cretaceous of Brazil + theropod running strategies from footprint morphology (free pdfs)
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Ben Creisler
Jan 7, 2026, 10:59:13 AM (3 days ago) Jan 7
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Ben Creisler
The Upper Cretaceous São José do Rio Preto Formation (Bauru Group, southeastern Brazil) has yielded a fragmentary but taxonomically diverse record of titanosaur sauropods, although elements from cervical series remain scarce. Here, we describe a nearly complete sauropod axis from the Vila Ventura Paleontological Area, representing an uncommon occurrence within this unit and the Bauru Group as a whole. The Vila Ventura axis exhibits a broad axial intercentrum with paired ventral fossae, an elongated, goblet-shaped axial pleurocentrum that is longer than high, and a tall neural arch. Microcomputed tomography imaging reveals extensive camellate-type internal pneumaticity, including radial and circumferential camellae in the pleurocentrum with incipient development of internal bony plates—traits that are previously found in highly nested titanosaurs, such as saltasaurines. Comparative osteological analysis, however, indicates closer affinities with colossosaurians (e.g., Bonitasaura, Futalognkosaurus, Pitekunsaurus), particularly in centrum proportions and laminar configuration, including an enlarged odontoid, a V-shaped ventral median keel with ventrolateral excavations in the pleurocentrum, a stout prespinal lamina terminating in an anterior spinal projection, and well-developed pneumatopores in the spinodiapophyseal fossae. Additionally, the specimen exhibits unique features, such as a stranded and laterally expanded spinoprezygapophyseal lamina and a transversely broad anterior spinal projection. An evaluation of axis morphology highlights the underrepresentation of phylogenetic characters from this element in current datasets, despite its potential diagnostic value for assessing lower-level relationships within Titanosauria. This discovery increases the diversity of Brazilian titanosaur records and emphasizes the importance of axial elements in understanding sauropod functional morphology and phylogeny.
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Free pdf:
Ignacio Díaz-Martínez, Pablo Navarro-Lorbés, Erik Isasmendi, Adrián Páramo, Francesc Gascó-Lluna, Angélica Torices, Javier Ruiz, Luis Ignacio Viera, Patxi Sáez-Benito, James Farlow, Giuseppe Leonardi, Xabier Pereda-Suberbiola & Paolo Citton (2026)
Footprint morphology sheds light on running strategies in non-avian theropods
Scientific Reports 15: 44217
doi: https://doi.org/10.1038/s41598-025-31361-y
https://www.nature.com/articles/s41598-025-31361-y
This study analyzes two trackways of the fastest running theropods in the fossil record, offering a rare opportunity to examine dinosaur biomechanics during high-speed locomotion. We focus on the distinct three-dimensional morphologies of footprints—La Torre 6B-01 and La Torre 6A-14 (Early Cretaceous, La Rioja, Spain)—produced by similar theropod trackmakers on the same surface. The La Torre 6B-01 footprints range from digitigrade to subdigitigrade, whereas the La Torre 6A-14 tracks vary from fully digitigrade to digitigrade with an elongated metatarsophalangeal area. These differences are interpreted as reflecting distinct phases of running locomotion, likely linked to changes in trackmaker behavior. Comparable morphologies occurred in other trackways that have been interpreted as produced by running trackmakers, from the Early Jurassic to the Late Cretaceous. These examples emphasize how different phases of a run—combined with variations in force exertion and autopodium positioning—can strongly influence footprint morphology. Our findings reveal that theropod dinosaurs employed running strategies more complex and dynamic than previously recognized. Subtle footprint features, such as the presence or absence of metatarsophalangeal impressions, can be directly tied to changes in posture, weight distribution, and muscular activity. This approach provides new perspectives on biomechanical evolution, showing that locomotor diversity and limb morphology shaped dinosaur adaptation and diversification.
New papers:
Free pdf:
Bruno A. Navarro, Jeffrey A. Wilson Mantilla, Jhonata H. A. Martins, Fabiano V. Iori, Leonardo S. Paschoa, Alberto B. Carvalho, Joseli M. Piranha & Hussam Zaher (2026)
An unusual titanosaur axis from the Upper Cretaceous of Brazil and its significance for sauropod anatomy and systematics
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70118
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70118
Bruno A. Navarro, Jeffrey A. Wilson Mantilla, Jhonata H. A. Martins, Fabiano V. Iori, Leonardo S. Paschoa, Alberto B. Carvalho, Joseli M. Piranha & Hussam Zaher (2026)
An unusual titanosaur axis from the Upper Cretaceous of Brazil and its significance for sauropod anatomy and systematics
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70118
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70118
The Upper Cretaceous São José do Rio Preto Formation (Bauru Group, southeastern Brazil) has yielded a fragmentary but taxonomically diverse record of titanosaur sauropods, although elements from cervical series remain scarce. Here, we describe a nearly complete sauropod axis from the Vila Ventura Paleontological Area, representing an uncommon occurrence within this unit and the Bauru Group as a whole. The Vila Ventura axis exhibits a broad axial intercentrum with paired ventral fossae, an elongated, goblet-shaped axial pleurocentrum that is longer than high, and a tall neural arch. Microcomputed tomography imaging reveals extensive camellate-type internal pneumaticity, including radial and circumferential camellae in the pleurocentrum with incipient development of internal bony plates—traits that are previously found in highly nested titanosaurs, such as saltasaurines. Comparative osteological analysis, however, indicates closer affinities with colossosaurians (e.g., Bonitasaura, Futalognkosaurus, Pitekunsaurus), particularly in centrum proportions and laminar configuration, including an enlarged odontoid, a V-shaped ventral median keel with ventrolateral excavations in the pleurocentrum, a stout prespinal lamina terminating in an anterior spinal projection, and well-developed pneumatopores in the spinodiapophyseal fossae. Additionally, the specimen exhibits unique features, such as a stranded and laterally expanded spinoprezygapophyseal lamina and a transversely broad anterior spinal projection. An evaluation of axis morphology highlights the underrepresentation of phylogenetic characters from this element in current datasets, despite its potential diagnostic value for assessing lower-level relationships within Titanosauria. This discovery increases the diversity of Brazilian titanosaur records and emphasizes the importance of axial elements in understanding sauropod functional morphology and phylogeny.
====
Free pdf:
Ignacio Díaz-Martínez, Pablo Navarro-Lorbés, Erik Isasmendi, Adrián Páramo, Francesc Gascó-Lluna, Angélica Torices, Javier Ruiz, Luis Ignacio Viera, Patxi Sáez-Benito, James Farlow, Giuseppe Leonardi, Xabier Pereda-Suberbiola & Paolo Citton (2026)
Footprint morphology sheds light on running strategies in non-avian theropods
Scientific Reports 15: 44217
doi: https://doi.org/10.1038/s41598-025-31361-y
https://www.nature.com/articles/s41598-025-31361-y
This study analyzes two trackways of the fastest running theropods in the fossil record, offering a rare opportunity to examine dinosaur biomechanics during high-speed locomotion. We focus on the distinct three-dimensional morphologies of footprints—La Torre 6B-01 and La Torre 6A-14 (Early Cretaceous, La Rioja, Spain)—produced by similar theropod trackmakers on the same surface. The La Torre 6B-01 footprints range from digitigrade to subdigitigrade, whereas the La Torre 6A-14 tracks vary from fully digitigrade to digitigrade with an elongated metatarsophalangeal area. These differences are interpreted as reflecting distinct phases of running locomotion, likely linked to changes in trackmaker behavior. Comparable morphologies occurred in other trackways that have been interpreted as produced by running trackmakers, from the Early Jurassic to the Late Cretaceous. These examples emphasize how different phases of a run—combined with variations in force exertion and autopodium positioning—can strongly influence footprint morphology. Our findings reveal that theropod dinosaurs employed running strategies more complex and dynamic than previously recognized. Subtle footprint features, such as the presence or absence of metatarsophalangeal impressions, can be directly tied to changes in posture, weight distribution, and muscular activity. This approach provides new perspectives on biomechanical evolution, showing that locomotor diversity and limb morphology shaped dinosaur adaptation and diversification.
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