Viviparity and K-Selected Life History in a Mesozoic Marine Plesiosaur (Reptilia, Sauropterygia)

@article{OKeefe2011ViviparityAK,
  title={Viviparity and K-Selected Life History in a Mesozoic Marine Plesiosaur (Reptilia, Sauropterygia)},
  author={F. Robin O'Keefe and Luis Mar{\'i}a Chiappe},
  journal={Science},
  year={2011},
  volume={333},
  pages={870 - 873}
}
Plesiosaurs gave birth to a single, live large offspring and may have engaged in maternal care. Viviparity is known in several clades of Mesozoic aquatic reptiles, but evidence for it is lacking in the Plesiosauria. Here, we report a Late Cretaceous plesiosaur fossil consisting of a fetus preserved within an adult of the same taxon. We interpret this occurrence as a gravid female and unborn young and hence as definitive evidence for plesiosaur viviparity. Quantitative analysis indicates that… 
Viviparity in a Triassic marine archosauromorph reptile
Eggs or embryos have been reported in various groups of fossil reptiles, where viviparity is a common mode of reproduction in aquatic taxa such as the ichthyopterygians, some groups of
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Ontogenetic State of a Juvenile Polycotylid Plesiosaur (Sauropterygia: Plesiosauria) and its Implications for Plesiosaur Growth
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Quantitative histological models suggest endothermy in plesiosaurs
TLDR
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The oldest known amniotic embryos suggest viviparity in mesosaurs
TLDR
The finds of exceptional, well-preserved amniotic mesosaur embryos from the Early Permian of Uruguay and Brazil provide the earliest direct evidence of reproductive biology in Paleozoic amniotes and the earliest known case of viviparity.
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