Eomamenchisaurus
From Greek eos (dawn) + Mamenchisaurus (the related sauropod genus): 'dawn Mamenchisaurus', reflecting its status as an early mamenchisaurid.
Middle Jurassic stages
Eomamenchisaurus is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic Zhanghe Formation of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lü Junchang and colleagues in 2008.
Diagnosis
- Dorsal vertebrae lacking pleurocoels
- Anterior articular surfaces of dorsal vertebrae flat to slightly convex; posterior articular surfaces moderately concave
- Neural spines of third and fourth sacral vertebrae weakly fused
- Shaft of ischium straight, cross-section of mid-shaft sub-oval, longer than pubis
- Fourth trochanter placed on posteromedial margin of femur
- Length ratio of tibia to femur approximately 0.64
Species
Eomamenchisaurus yuanmouensis Lü et al., 2008
Type species
Named for Yuanmou County in Yunnan, China, where the holotype was discovered.
- Holotype
- CXMVZA 165 , Chuxiong Prefectural Museum
- Material
- Eight dorsal vertebrae, a partial sacrum, a right ilium, a right complete pubis, two incomplete ischia, one complete right tibia, and both femora
- Horizon
- Zhanghe Formation, Aalenian–Bathonian, Middle Jurassic , 174.7–165.3 million years ago
- Locality
- Banqing Houshanliangzi, Jiangyi, Yunnan, China
References
- Lü, J.; Li, T.; Zhong, S.; Ji, Q.; Li, S. (2008). A new mamenchisaurid dinosaur from the Middle Jurassic of Yuanmou, Yunnan Province, China. Acta Geologica Sinica (English Edition) 82(1): 17-26. Wiley. doi:10.1111/j.1755-6724.2008.tb00320.x lü2008a