Theropod remains from Lower Jurassic of China + juvenile mamenchisaurid cervical ribs + titanosaurian caudal vertebra from Upper Cretaceous of Antarctica
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Ben Creisler
Jun 29, 2026, 11:06:43 AM (4 days ago) Jun 29
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Ben Creisler
Lida Xing, Jens N. Lallensack, Zhixin Yang, Donghao Wang, Qiyan Chen, Xiaodong Wang, Songling Zhuang, Sheng Hu & Qi Qi (2026)
New theropod remains from the Lower Jurassic Fengjiahe Formation of Yunnan, China
HIstorial Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2026.2676032
https://www.tandfonline.com/doi/full/10.1080/08912963.2026.2676032
The Lower Jurassic Fengjiahe Formation in the Chuxiong Basin, Yunnan Province, is characterised by abundant dinosaur tracks but a scarcity of skeletal remains compared to the coeval Lufeng Formation. Here, we report on a new fossil site at Anle Township, Mouding County, which preserves both a diverse assemblage of an isolated theropod tooth and theropod tracks. An isolated theropod tooth (LGFM 2501) was recovered from a purple calcareous mudstone layer stratigraphically located approximately 10 cm above the track-bearing horizon. This specimen is identified as a tetanuran tooth with close affinities to Allosauroidea based on a variety of analyses. This specimen is distinct from Sinosaurus, the dominant theropod in the Early Jurassic of the region, suggesting a higher predator diversity in the Fengjiahe Formation than previously recognised. The track assemblage consists of approximately 30 tracks divisible into two morphotypes: Morphotype A, medium-to-large tracks resembling Kayentapus with wide divarication angles, strongly mesaxonic digit III and V-shaped ‘heel’, and Morphotype B, small Grallator isp. tracks with narrow divarication angles and high length/width ratio. Notable extramorphological variations, including parallel digit marks and penetrative tracks preserving digit I impressions, indicate a very soft substrate at the time of track formation.
Chen-Chen Zhou, Hui Ouyang, Jing-Xin Gao, Mao-Yin Tang & Qi Zhao (2026)
Chondroid bone in the cervical ribs of a new juvenile mamenchisaurid
Journal of Vertebrate Paleontology e2655673
doi: https://doi.org/10.1080/02724634.2026.2655673
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2655673
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2655673
As a well-known sauropod dinosaur clade dominant in the Middle–Late Jurassic of Asia, Mamenchisauridae exhibits unique body size evolution and ecological adaptability, making it a key focus in dinosaur biology. However, most previous studies have focused on macro-morphological descriptions, while microscopic histological data remain largely underexplored. Here, we conducted histological analyses of cervical ribs from a new mamenchisaurid specimen recovered from Sichuan, China, to characterize the histological features of cervical rib ossification and infer its potential ossification mechanism. The cervical rib comprises an anterior process, a shaft, a tuberculum, and a capitulum. The capitulum and its surrounding regions formed through the mode of normal bone matrix formation, whereas the others developed through the metaplasia of tendons into fibrocartilage, followed by ossification via a process analogous to endochondral ossification. We identified the widespread presence of chondroid bone (CB). Microscopically, CB is characterized by distinctive CB cell lacunae, which are irregularly distributed and resemble chondrocytes, accompanied by spheritic mineralization. Chondroid bone may significantly enhance skeletal growth efficiency during rapid growth phases, potentially explaining the extreme slenderness of cervical ribs in Mamenchisauridae. This special tissue may have been an adaptation to buffer mechanical stress during neck movements.
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Paul M. Barrett, Philip D. Mannion, Samantha L. Beeston, Matthew C. Lamanna, Brett Clark, Alejandro Otero, José P. O’gorman, and Mark Evans (2026)
A titanosaurian sauropod dinosaur from the Upper Cretaceous of Antarctica
Acta Palaeontologica Polonica 71(2): 349-362
doi:10.4202/app.01315.2025
https://www.app.pan.pl/article/item/app013152025.html
Free pdf:
https://www.app.pan.pl/archive/published/app71/app013152025.pdf
Antarctica preserves a meagre Mesozoic dinosaur record, with fossils known only from the Lower Jurassic Hanson Formation of the Transantarctic Mountains and Upper Cretaceous units of the James Ross Sub-Basin of the Antarctic Peninsula. Upper Cretaceous assemblages include ankylosaurs, ornithopods, and non-avian and avian theropods, but sauropods are exceptionally rare. Here, we describe a titanosaurian caudal vertebra from a lower Campanian (Upper Cretaceous) horizon of the Santa Marta Formation of James Ross Island and discuss its implications for the evolutionary and palaeobiogeographic history of Antarctic sauropods. The specimen is a small, procoelous anterior caudal vertebra, identified as that of a non-saltasaurid eutitanosaurian. Its morphology closely corresponds to that of rinconsaurians and aeolosaurines, particularly a specimen previously assigned to the Late Cretaceous Argentinean species Muyelensaurus pecheni, and it differs from earlier-diverging titanosaurs, although its fragmentary preservation warrants a conservative taxonomic assignment of Eutitanosauria indet. Size comparisons indicate that the individual in question was small for a titanosaur, possibly reflecting immaturity or a genuinely small-bodied form. This discovery represents only the second sauropod body fossil known from Antarctica, although it was the first dinosaur bone to be collected from the continent. Coupled with the occurrence of diamantinasaurians in Patagonia and Australia during the mid-Cretaceous, its eutitanosaurian affinities imply the presence of multiple somphospondylan lineages in Antarctica, informing dispersal patterns and highlighting biogeographic links with other Gondwanan landmasses.
https://www.bbc.com/news/articles/cdep67jnn9zo
https://www.nhm.ac.uk/discover/news/2026/june/first-ever-dinosaur-fossil-discovered-on-antarctica-a-titanosaur.html
Video:
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New papers:
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Lida Xing, Jens N. Lallensack, Zhixin Yang, Donghao Wang, Qiyan Chen, Xiaodong Wang, Songling Zhuang, Sheng Hu & Qi Qi (2026)
New theropod remains from the Lower Jurassic Fengjiahe Formation of Yunnan, China
HIstorial Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2026.2676032
https://www.tandfonline.com/doi/full/10.1080/08912963.2026.2676032
The Lower Jurassic Fengjiahe Formation in the Chuxiong Basin, Yunnan Province, is characterised by abundant dinosaur tracks but a scarcity of skeletal remains compared to the coeval Lufeng Formation. Here, we report on a new fossil site at Anle Township, Mouding County, which preserves both a diverse assemblage of an isolated theropod tooth and theropod tracks. An isolated theropod tooth (LGFM 2501) was recovered from a purple calcareous mudstone layer stratigraphically located approximately 10 cm above the track-bearing horizon. This specimen is identified as a tetanuran tooth with close affinities to Allosauroidea based on a variety of analyses. This specimen is distinct from Sinosaurus, the dominant theropod in the Early Jurassic of the region, suggesting a higher predator diversity in the Fengjiahe Formation than previously recognised. The track assemblage consists of approximately 30 tracks divisible into two morphotypes: Morphotype A, medium-to-large tracks resembling Kayentapus with wide divarication angles, strongly mesaxonic digit III and V-shaped ‘heel’, and Morphotype B, small Grallator isp. tracks with narrow divarication angles and high length/width ratio. Notable extramorphological variations, including parallel digit marks and penetrative tracks preserving digit I impressions, indicate a very soft substrate at the time of track formation.
====
Free pdf:
Chen-Chen Zhou, Hui Ouyang, Jing-Xin Gao, Mao-Yin Tang & Qi Zhao (2026)
Chondroid bone in the cervical ribs of a new juvenile mamenchisaurid
Journal of Vertebrate Paleontology e2655673
doi: https://doi.org/10.1080/02724634.2026.2655673
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2655673
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2655673
As a well-known sauropod dinosaur clade dominant in the Middle–Late Jurassic of Asia, Mamenchisauridae exhibits unique body size evolution and ecological adaptability, making it a key focus in dinosaur biology. However, most previous studies have focused on macro-morphological descriptions, while microscopic histological data remain largely underexplored. Here, we conducted histological analyses of cervical ribs from a new mamenchisaurid specimen recovered from Sichuan, China, to characterize the histological features of cervical rib ossification and infer its potential ossification mechanism. The cervical rib comprises an anterior process, a shaft, a tuberculum, and a capitulum. The capitulum and its surrounding regions formed through the mode of normal bone matrix formation, whereas the others developed through the metaplasia of tendons into fibrocartilage, followed by ossification via a process analogous to endochondral ossification. We identified the widespread presence of chondroid bone (CB). Microscopically, CB is characterized by distinctive CB cell lacunae, which are irregularly distributed and resemble chondrocytes, accompanied by spheritic mineralization. Chondroid bone may significantly enhance skeletal growth efficiency during rapid growth phases, potentially explaining the extreme slenderness of cervical ribs in Mamenchisauridae. This special tissue may have been an adaptation to buffer mechanical stress during neck movements.
=====
Free pdf:
Paul M. Barrett, Philip D. Mannion, Samantha L. Beeston, Matthew C. Lamanna, Brett Clark, Alejandro Otero, José P. O’gorman, and Mark Evans (2026)
A titanosaurian sauropod dinosaur from the Upper Cretaceous of Antarctica
Acta Palaeontologica Polonica 71(2): 349-362
doi:10.4202/app.01315.2025
https://www.app.pan.pl/article/item/app013152025.html
Free pdf:
https://www.app.pan.pl/archive/published/app71/app013152025.pdf
Antarctica preserves a meagre Mesozoic dinosaur record, with fossils known only from the Lower Jurassic Hanson Formation of the Transantarctic Mountains and Upper Cretaceous units of the James Ross Sub-Basin of the Antarctic Peninsula. Upper Cretaceous assemblages include ankylosaurs, ornithopods, and non-avian and avian theropods, but sauropods are exceptionally rare. Here, we describe a titanosaurian caudal vertebra from a lower Campanian (Upper Cretaceous) horizon of the Santa Marta Formation of James Ross Island and discuss its implications for the evolutionary and palaeobiogeographic history of Antarctic sauropods. The specimen is a small, procoelous anterior caudal vertebra, identified as that of a non-saltasaurid eutitanosaurian. Its morphology closely corresponds to that of rinconsaurians and aeolosaurines, particularly a specimen previously assigned to the Late Cretaceous Argentinean species Muyelensaurus pecheni, and it differs from earlier-diverging titanosaurs, although its fragmentary preservation warrants a conservative taxonomic assignment of Eutitanosauria indet. Size comparisons indicate that the individual in question was small for a titanosaur, possibly reflecting immaturity or a genuinely small-bodied form. This discovery represents only the second sauropod body fossil known from Antarctica, although it was the first dinosaur bone to be collected from the continent. Coupled with the occurrence of diamantinasaurians in Patagonia and Australia during the mid-Cretaceous, its eutitanosaurian affinities imply the presence of multiple somphospondylan lineages in Antarctica, informing dispersal patterns and highlighting biogeographic links with other Gondwanan landmasses.
***
News:
https://www.bbc.com/news/articles/cdep67jnn9zo
https://www.nhm.ac.uk/discover/news/2026/june/first-ever-dinosaur-fossil-discovered-on-antarctica-a-titanosaur.html
Video:
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