Somphospondylan sauropods from Cedar Mountain Formation (Lower Cretaceous) of Utah
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Ben Creisler
Apr 9, 2026, 12:12:02 PMApr 9
to DinosaurMa...@googlegroups.com
Ben Creisler
A new paper:
Junki Yoshida, Kenneth Carpenter & Yoshitsugu Kobayashi (2026)
First record of somphospondylan sauropods from the Cedar Mountain Formation (Lower Cretaceous) of Utah, USA, and spatiotemporal implications for the Cretaceous sauropods in North America
Cretaceous Research 106395
doi: https://doi.org/10.1016/j.cretres.2026.106395
https://www.sciencedirect.com/science/article/abs/pii/S0195667126000844
Early Cretaceous dinosaur records from North America have been increased, but the records of sauropod dinosaurs remain discontinuous spatiotemporally. At least six sauropod individuals were discovered from a multi-taxic dinosaur bonebed in the Ruby Ranch Member of the Cedar Mountain Formation (Aptian, Lower Cretaceous) in Utah, USA. Taxonomic identification in this study reveals the presence of at least three somphospondylan individuals (e.g., cf. Sauroposeidon), represented by cervical vertebrae, dorsal vertebrae, scapulae, and fibulae, along with brachiosaurid teeth and humeri from the site. This study provides the first record of somphospondylans from the Cedar Mountain Formation in Utah and the oldest record in North America. Osteohistological analysis of the co-occurring somphospondylan and brachiosaurid humeri from the same site demonstrates co-occurrence of different ontogenetic stages among similarly sized sauropods weighing around 11-13 tons. These findings indicate that somphospondylans appeared and co-existed with brachiosaurids in North America during the Aptian, likely reflecting differences in their ontogenetic strategies.
First record of somphospondylan sauropods from the Cedar Mountain Formation (Lower Cretaceous) of Utah, USA, and spatiotemporal implications for the Cretaceous sauropods in North America
Cretaceous Research 106395
doi: https://doi.org/10.1016/j.cretres.2026.106395
https://www.sciencedirect.com/science/article/abs/pii/S0195667126000844
Early Cretaceous dinosaur records from North America have been increased, but the records of sauropod dinosaurs remain discontinuous spatiotemporally. At least six sauropod individuals were discovered from a multi-taxic dinosaur bonebed in the Ruby Ranch Member of the Cedar Mountain Formation (Aptian, Lower Cretaceous) in Utah, USA. Taxonomic identification in this study reveals the presence of at least three somphospondylan individuals (e.g., cf. Sauroposeidon), represented by cervical vertebrae, dorsal vertebrae, scapulae, and fibulae, along with brachiosaurid teeth and humeri from the site. This study provides the first record of somphospondylans from the Cedar Mountain Formation in Utah and the oldest record in North America. Osteohistological analysis of the co-occurring somphospondylan and brachiosaurid humeri from the same site demonstrates co-occurrence of different ontogenetic stages among similarly sized sauropods weighing around 11-13 tons. These findings indicate that somphospondylans appeared and co-existed with brachiosaurids in North America during the Aptian, likely reflecting differences in their ontogenetic strategies.
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