Liaoningosaurus bone histology
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Ben Creisler
Oct 27, 2025, 11:07:35 AM (10 days ago) Oct 27
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Ben Creisler
Wenjie Zheng, Qi Zhao, Paul M. Barrett & Xing Xu (2025)
Bone histology of Liaoningosaurus paradoxus (Ornithischia: Ankylosauria) from the Lower Cretaceous of Liaoning Province, China
Journal of Vertebrate Paleontology e2566325
doi: https://doi.org/10.1080/02724634.2025.2566325
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2566325
The ankylosaurian dinosaur Liaoningosaurus paradoxus, from the Lower Cretaceous of Liaoning Province, China, is represented by numerous specimens identified as juvenile individuals based on their body size but without bone histological evidence. Here, we present the first osteohistological study of this species based on two referred specimens, ELDM V1121 and IVPP V 20798, the latter being the largest known L. paradoxus specimen. The femoral lengths of the two specimens are 31.5 mm and 56.5 mm, respectively, and they are about 10% and 100% longer than the holotype (28.5 mm). We sampled axial (dorsal ribs), appendicular (humerus, radius, ulna, femur, and fibula) and dermal (cervical half-ring osteoderm) bones. All thin-sections of the L. paradoxus specimens in our study lack lines of arrested growth, an external fundamental system, and secondary osteons. This indicates that both specimens were less than one year old at the time of death. Specimen ELDM V1121 exhibits highly vascularized canals, primarily arranged longitudinally and surrounded by randomly distributed osteocyte lacunae. Additionally, the presence of a hatching line indicates that ELDM V1121 was a hatchling at the time of death. Liaoningosaurus is currently the only known definitive hatchling ankylosaurian dinosaur specimen globally. Histological analysis of a cervical half-ring, the co-ossified osteoderms situated dorsolaterally on the neck, of IVPP V 20798, reveals a very thin compact cortex enclosing cancellous bone. This is similar to those of ankylosaurids and Scelidosaurus but different from the osteoderm structure typical of nodosaurids.
A new paper:
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Wenjie Zheng, Qi Zhao, Paul M. Barrett & Xing Xu (2025)
Bone histology of Liaoningosaurus paradoxus (Ornithischia: Ankylosauria) from the Lower Cretaceous of Liaoning Province, China
Journal of Vertebrate Paleontology e2566325
doi: https://doi.org/10.1080/02724634.2025.2566325
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2566325
The ankylosaurian dinosaur Liaoningosaurus paradoxus, from the Lower Cretaceous of Liaoning Province, China, is represented by numerous specimens identified as juvenile individuals based on their body size but without bone histological evidence. Here, we present the first osteohistological study of this species based on two referred specimens, ELDM V1121 and IVPP V 20798, the latter being the largest known L. paradoxus specimen. The femoral lengths of the two specimens are 31.5 mm and 56.5 mm, respectively, and they are about 10% and 100% longer than the holotype (28.5 mm). We sampled axial (dorsal ribs), appendicular (humerus, radius, ulna, femur, and fibula) and dermal (cervical half-ring osteoderm) bones. All thin-sections of the L. paradoxus specimens in our study lack lines of arrested growth, an external fundamental system, and secondary osteons. This indicates that both specimens were less than one year old at the time of death. Specimen ELDM V1121 exhibits highly vascularized canals, primarily arranged longitudinally and surrounded by randomly distributed osteocyte lacunae. Additionally, the presence of a hatching line indicates that ELDM V1121 was a hatchling at the time of death. Liaoningosaurus is currently the only known definitive hatchling ankylosaurian dinosaur specimen globally. Histological analysis of a cervical half-ring, the co-ossified osteoderms situated dorsolaterally on the neck, of IVPP V 20798, reveals a very thin compact cortex enclosing cancellous bone. This is similar to those of ankylosaurids and Scelidosaurus but different from the osteoderm structure typical of nodosaurids.
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