Dynamosuchus (Triassic ornithosuchid) osteohistology + Xenodontolacerta, new lizard from Upper Cretaceous of China (free pdfs)
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Ben Creisler
Feb 3, 2026, 11:14:10 PM (8 days ago) Feb 3
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Ben Creisler
New papers:
Free pdf:
Brodsky Dantas Macedo Farias, Rodrigo Temp Müller, Fabiula Prestes de Bem, M. Belén von Baczko, Julia Brenda Desojo & Marina Bento Soares (2026)
Filling a key gap in growth patterns of Pseudosuchia through the osteohistology of Dynamosuchus collisensis (Ornithosuchidae: Archosauria)
Royal Society Open Science 13(2): 252042
doi: https://doi.org/10.1098/rsos.252042
https://royalsocietypublishing.org/rsos/article/13/2/252042/480032/Filling-a-key-gap-in-growth-patterns-of
Ornithosuchidae are among the least studied pseudosuchians from a histological perspective. We present the first long-bone osteohistological data for the ornithosuchid Dynamosuchus collisensis, based on mid-diaphyseal thin sections of the humerus and femur, supplemented by a rib. The long bones show cortices dominated by highly vascularized woven–parallel complex and parallel-fibred bone, with three well-defined annuli and a fourth incipient one near the periosteal margin. Medullary expansion occurs through endosteal resorption, and secondary osteons in formation are present. The rib displays lower vascularization, suggesting reduced growth rates in axial elements. Open neurocentral sutures, the absence of an EFS and the lack of peripheral slowdown in cortical deposition indicate that the holotype was skeletally immature, and probably sexually immature, at the time of death. This suggests that the individual had not yet reached its maximum body size and would probably have attained a larger size, consistent with a role as a top-tier predator in Carnian ecosystems. These features support sustained rapid growth, contrasting with the predominantly slow growth of late-diverging crocodylomorphs and more closely resembling early loricatans and poposauroids. Because Ornithosuchidae occupy an early-diverging position within Pseudosuchia, these data support the hypothesis that fast growth may represent a plesiomorphic condition within the clade.
Brodsky Dantas Macedo Farias, Rodrigo Temp Müller, Fabiula Prestes de Bem, M. Belén von Baczko, Julia Brenda Desojo & Marina Bento Soares (2026)
Filling a key gap in growth patterns of Pseudosuchia through the osteohistology of Dynamosuchus collisensis (Ornithosuchidae: Archosauria)
Royal Society Open Science 13(2): 252042
doi: https://doi.org/10.1098/rsos.252042
https://royalsocietypublishing.org/rsos/article/13/2/252042/480032/Filling-a-key-gap-in-growth-patterns-of
Ornithosuchidae are among the least studied pseudosuchians from a histological perspective. We present the first long-bone osteohistological data for the ornithosuchid Dynamosuchus collisensis, based on mid-diaphyseal thin sections of the humerus and femur, supplemented by a rib. The long bones show cortices dominated by highly vascularized woven–parallel complex and parallel-fibred bone, with three well-defined annuli and a fourth incipient one near the periosteal margin. Medullary expansion occurs through endosteal resorption, and secondary osteons in formation are present. The rib displays lower vascularization, suggesting reduced growth rates in axial elements. Open neurocentral sutures, the absence of an EFS and the lack of peripheral slowdown in cortical deposition indicate that the holotype was skeletally immature, and probably sexually immature, at the time of death. This suggests that the individual had not yet reached its maximum body size and would probably have attained a larger size, consistent with a role as a top-tier predator in Carnian ecosystems. These features support sustained rapid growth, contrasting with the predominantly slow growth of late-diverging crocodylomorphs and more closely resembling early loricatans and poposauroids. Because Ornithosuchidae occupy an early-diverging position within Pseudosuchia, these data support the hypothesis that fast growth may represent a plesiomorphic condition within the clade.
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Free pdf:
Xenodontolacerta fangi gen. et sp. nov.
Juan Jiang, Li-Ping Dong, Xing Xu, Alexander Bi & Susan Evans (2026)
A new polyglyphanodontian lizard from the Upper Cretaceous of southern China implies a complex evolutionary history of the clade
Royal Society Open Science 13(2): 252253
doi: https://doi.org/10.1098/rsos.252253
https://royalsocietypublishing.org/rsos/article/13/2/252253/480039/A-new-polyglyphanodontian-lizard-from-the-Upper
Polyglyphanodontian lizards were one of the dominant groups among squamates during the Late Cretaceous. They were widely distributed and exhibited a great range of body sizes and high morphological variation. The Asian taxa are preserved mostly as complete or nearly complete skulls or skeletons, therefore providing substantial anatomical information for the clade. Here, we describe a new polyglyphanodontian genus and species from the Upper Cretaceous of Ganzhou Basin, Jiangxi Province, China. The new taxon is diagnosed by its unique dentition, with complex posterior teeth having mesial, distal and lingual expansions, connected by crests and with depressions between. The phylogenetic analyses support an assignment of the new taxon to Polyglyphanodontia, forming an unresolved clade with Polyglyphanodon, Gilmoreteius, Adamisaurus, Tianyusaurus and Yechilacerta, or being a sister taxon to either Adamisaurus or a small clade of Tianyusaurus and Yechilacerta. The cranial and dental morphology suggests the new lizard was omnivorous, contrasting with the specialized herbivory of Tianyusaurus and Yechilacerta from the same region. Moreover, the new lizard is the first polyglyphanodontian taxon from Asia with a complex dentition, which shows similarities to that of some North American taxa, and this may suggest the evolutionary history of Polyglyphanodontia is more complicated than previously thought.
Juan Jiang, Li-Ping Dong, Xing Xu, Alexander Bi & Susan Evans (2026)
A new polyglyphanodontian lizard from the Upper Cretaceous of southern China implies a complex evolutionary history of the clade
Royal Society Open Science 13(2): 252253
doi: https://doi.org/10.1098/rsos.252253
https://royalsocietypublishing.org/rsos/article/13/2/252253/480039/A-new-polyglyphanodontian-lizard-from-the-Upper
Polyglyphanodontian lizards were one of the dominant groups among squamates during the Late Cretaceous. They were widely distributed and exhibited a great range of body sizes and high morphological variation. The Asian taxa are preserved mostly as complete or nearly complete skulls or skeletons, therefore providing substantial anatomical information for the clade. Here, we describe a new polyglyphanodontian genus and species from the Upper Cretaceous of Ganzhou Basin, Jiangxi Province, China. The new taxon is diagnosed by its unique dentition, with complex posterior teeth having mesial, distal and lingual expansions, connected by crests and with depressions between. The phylogenetic analyses support an assignment of the new taxon to Polyglyphanodontia, forming an unresolved clade with Polyglyphanodon, Gilmoreteius, Adamisaurus, Tianyusaurus and Yechilacerta, or being a sister taxon to either Adamisaurus or a small clade of Tianyusaurus and Yechilacerta. The cranial and dental morphology suggests the new lizard was omnivorous, contrasting with the specialized herbivory of Tianyusaurus and Yechilacerta from the same region. Moreover, the new lizard is the first polyglyphanodontian taxon from Asia with a complex dentition, which shows similarities to that of some North American taxa, and this may suggest the evolutionary history of Polyglyphanodontia is more complicated than previously thought.
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