Rebbachisaurid caudal muscles + dinosaur bone water transportation
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Ben Creisler
Jan 12, 2026, 3:22:52 PM (6 days ago) Jan 12
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Ben Creisler
New papers:
Lucas N. Lerzo (2026)
Revision of the specimen MMCH-PV 47 (Rebbachisauridae, Sauropoda) from the Candeleros Formation (Lower Cenomanian) with comments about the musculature of the caudal region
Cretaceous Research 106307
doi: https://doi.org/10.1016/j.cretres.2025.106307
https://www.sciencedirect.com/science/article/abs/pii/S0195667125002307
Highlights
The specimen MMCh-PV 47 is recognized as a rebbachisaurid sauropod.
The specimen MMCh-PV 47 is recovered in a basal clade within Rebbachisauridae, characterized by middle haemal arches with a stellate morphology.
In rebbachisaurids, the M. caudofemoralis longus extends further posteriorly along the caudal series than in other sauropods.
Abstract
The sauropod fauna of the Upper Cretaceous of Patagonia is dominated by large titanosaurs and medium to large-sized rebbachisaurids. Particularly, rebbachisaurid sauropods dominated the Cenomanian-Turonian of Patagonia. Specimen MMCh-PV 47, which includes 10 middle to posterior caudal vertebrae and haemal arches, was recovered from the Candeleros Formation of Villa El Chocón, Neuquén, Argentina, and was formerly described as a titanosaur sauropod. On the base of the amphicoelous centra with the posterior articular surface more concave than the anterior one, the placement of the neural arch close to the anterior margin of the centrum, the ventral longitudinal hollow, and middle haemal arches with a stellated morphology, the specimen MMCh-PV 47 is instead considered within Rebbachisauridae. A phylogenetic analysis recovered it in a basal clade with Sidersaura, Campananeyen, Zapalasaurus, Astigmasaura and specimen MACN-Pv-N-35. This basal clade is characterized by the presence of middle haemal arches exhibiting two set of anterior and posterior projections, one on the proximal rami and another on the distal blade. In lateral view, the first six caudal vertebrae of the specimen MMCh-PV 47 exhibits rugose surfaces on the dorsal end of the centrum, indicating that the M. caudofemoralis longus extends much further posterior than in other sauropods. Laterodorsally projected ventral bar of the transverse processes, and the development of the haemal arches would increase the surface of attachment for the M. caudofemoralis longus, being a muscle of greater functional significance compared to other sauropod clades.
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Michael Chiappone, Michele Guala, Raymond Rogers, Peter Makovicky (2026)
When the levee breaks: experimentally testing dinosaur and mammal bone transport in unsteady flows
Paleobiology (advance online publication)
DOI: https://doi.org/10.1017/pab.2025.10087
https://www.cambridge.org/core/journals/paleobiology/article/when-the-levee-breaks-experimentally-testing-dinosaur-and-mammal-bone-transport-in-unsteady-flows/7EABD0EB713023FA7F9B2194F58E89D6
Bones preserved in fluvial sediments make up the majority of the terrestrial vertebrate fossil record, and unsteady flows (overbank floods, levee breaches, debris flows, etc.) are often invoked as agents of bone transport and burial. Experiments exploring transport of mammal bones under steady-state flow led to the development of Voorhies Groups, which are used as indicators of winnowing and transport at fossil sites. Some studies have raised concerns about the use of transport groups beyond the scope of the original experiments, especially regarding untested taxa and flow conditions. Here we investigate transport of hadrosauroid dinosaur bone models and modern sheep bones in experimental sheet floods. We find that evolving flow dynamics in unsteady flows can influence bone mobility behaviors. Factors such as bedforms and interactions with other bones caused shorter transport distances than might be expected in some elements, which would be heightened in real flooding situations where trapping mechanisms are common. Our hadrosauroid bones sorted into two statistically significant groups and one overlapping intermediate group based on transport distance. However, those groups could not be identified among sheep bones. Distributions of transport distances in both taxa do not fully match predictions based on Voorhies Groups. Our results indicate that Voorhies Groups do not quantitatively apply to all potential fluvial settings and taxa, and we thus advise caution in interpretations of fossil site taphonomic history based on Voorhies Groups. Further exploration of variables underlying bone transport and burial may allow for more broadly comparative examinations of fluvial biostratinomy.
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Lucas N. Lerzo (2026)
Revision of the specimen MMCH-PV 47 (Rebbachisauridae, Sauropoda) from the Candeleros Formation (Lower Cenomanian) with comments about the musculature of the caudal region
Cretaceous Research 106307
doi: https://doi.org/10.1016/j.cretres.2025.106307
https://www.sciencedirect.com/science/article/abs/pii/S0195667125002307
Highlights
The specimen MMCh-PV 47 is recognized as a rebbachisaurid sauropod.
The specimen MMCh-PV 47 is recovered in a basal clade within Rebbachisauridae, characterized by middle haemal arches with a stellate morphology.
In rebbachisaurids, the M. caudofemoralis longus extends further posteriorly along the caudal series than in other sauropods.
Abstract
The sauropod fauna of the Upper Cretaceous of Patagonia is dominated by large titanosaurs and medium to large-sized rebbachisaurids. Particularly, rebbachisaurid sauropods dominated the Cenomanian-Turonian of Patagonia. Specimen MMCh-PV 47, which includes 10 middle to posterior caudal vertebrae and haemal arches, was recovered from the Candeleros Formation of Villa El Chocón, Neuquén, Argentina, and was formerly described as a titanosaur sauropod. On the base of the amphicoelous centra with the posterior articular surface more concave than the anterior one, the placement of the neural arch close to the anterior margin of the centrum, the ventral longitudinal hollow, and middle haemal arches with a stellated morphology, the specimen MMCh-PV 47 is instead considered within Rebbachisauridae. A phylogenetic analysis recovered it in a basal clade with Sidersaura, Campananeyen, Zapalasaurus, Astigmasaura and specimen MACN-Pv-N-35. This basal clade is characterized by the presence of middle haemal arches exhibiting two set of anterior and posterior projections, one on the proximal rami and another on the distal blade. In lateral view, the first six caudal vertebrae of the specimen MMCh-PV 47 exhibits rugose surfaces on the dorsal end of the centrum, indicating that the M. caudofemoralis longus extends much further posterior than in other sauropods. Laterodorsally projected ventral bar of the transverse processes, and the development of the haemal arches would increase the surface of attachment for the M. caudofemoralis longus, being a muscle of greater functional significance compared to other sauropod clades.
======
Free pdf:
Michael Chiappone, Michele Guala, Raymond Rogers, Peter Makovicky (2026)
When the levee breaks: experimentally testing dinosaur and mammal bone transport in unsteady flows
Paleobiology (advance online publication)
DOI: https://doi.org/10.1017/pab.2025.10087
https://www.cambridge.org/core/journals/paleobiology/article/when-the-levee-breaks-experimentally-testing-dinosaur-and-mammal-bone-transport-in-unsteady-flows/7EABD0EB713023FA7F9B2194F58E89D6
Bones preserved in fluvial sediments make up the majority of the terrestrial vertebrate fossil record, and unsteady flows (overbank floods, levee breaches, debris flows, etc.) are often invoked as agents of bone transport and burial. Experiments exploring transport of mammal bones under steady-state flow led to the development of Voorhies Groups, which are used as indicators of winnowing and transport at fossil sites. Some studies have raised concerns about the use of transport groups beyond the scope of the original experiments, especially regarding untested taxa and flow conditions. Here we investigate transport of hadrosauroid dinosaur bone models and modern sheep bones in experimental sheet floods. We find that evolving flow dynamics in unsteady flows can influence bone mobility behaviors. Factors such as bedforms and interactions with other bones caused shorter transport distances than might be expected in some elements, which would be heightened in real flooding situations where trapping mechanisms are common. Our hadrosauroid bones sorted into two statistically significant groups and one overlapping intermediate group based on transport distance. However, those groups could not be identified among sheep bones. Distributions of transport distances in both taxa do not fully match predictions based on Voorhies Groups. Our results indicate that Voorhies Groups do not quantitatively apply to all potential fluvial settings and taxa, and we thus advise caution in interpretations of fossil site taphonomic history based on Voorhies Groups. Further exploration of variables underlying bone transport and burial may allow for more broadly comparative examinations of fluvial biostratinomy.
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