A gravid lizard from the Cretaceous of China and the early history of squamate viviparity

@article{Wang2011AGL,
  title={A gravid lizard from the Cretaceous of China and the early history of squamate viviparity},
  author={Yuan Wang and Susan E. Evans},
  journal={Naturwissenschaften},
  year={2011},
  volume={98},
  pages={739-743}
}
Although viviparity is most often associated with mammals, roughly one fifth of extant squamate reptiles give birth to live young. Phylogenetic analyses indicate that the trait evolved more than 100 times within Squamata, a frequency greater than that of all other vertebrate clades combined. However, there is debate as to the antiquity of the trait and, until now, the only direct fossil evidence of squamate viviparity was in Late Cretaceous mosasauroids, specialised marine lizards without… 

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