Avian Paternal Care Had Dinosaur Origin

@article{Varricchio2008AvianPC,
  title={Avian Paternal Care Had Dinosaur Origin},
  author={David J. Varricchio and Jason R Moore and Gregory M. Erickson and Mark A. Norell and Frankie D. Jackson and John J. Borkowski},
  journal={Science},
  year={2008},
  volume={322},
  pages={1826 - 1828}
}
The repeated discovery of adult dinosaurs in close association with egg clutches leads to speculation over the type and extent of care exhibited by these extinct animals for their eggs and young. To assess parental care in Cretaceous troodontid and oviraptorid dinosaurs, we examined clutch volume and the bone histology of brooding adults. In comparison to four archosaur care regressions, the relatively large clutch volumes of Troodon, Oviraptor, and Citipati scale most closely with a bird… 
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Reconstruction of oviraptorid clutches illuminates their unique nesting biology
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It is indicated that the oviraptorid clutch has a unique architecture unknown from extant bird clutches, implying an apomorphic nesting mode, which supports the hypothesis that the clutch-associated ovirptorid adults possibly represent females after an oviposition before a catastrophic sandstorm/flooding burial.
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