Triassic marine reptiles gave birth to live young

@article{Cheng2004TriassicMR,
  title={Triassic marine reptiles gave birth to live young},
  author={Yen-nien Cheng and Xiao-Chun Wu and Qiang Ji},
  journal={Nature},
  year={2004},
  volume={432},
  pages={383-386}
}
Sauropterygians form the largest and most diverse group of ancient marine reptiles that lived throughout nearly the entire Mesozoic era (from 250 to 65 million years ago). Although thousands of specimens of this group have been collected around the world since the description of the first plesiosaur in 1821 (ref. 3), no direct evidence has been found to determine whether any sauropterygians came on shore to lay eggs (oviparity) like sea turtles, or gave birth in the water to live young… 
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