A cloacal opening in a non-avian dinosaur

  title={A cloacal opening in a non-avian dinosaur},
  author={Jakob Vinther and Robert Nicholls and Diane A. Kelly},
  journal={Current Biology},
Oldest preserved umbilical scar reveals dinosaurs had ‘belly buttons’
Background In egg-laying amniotes, the developing embryo is tethered to a number of the extraembryonic membranes including the yolk sac and allantois that deliver oxygen and nutrients and remove
Morphology and distribution of scales, dermal ossifications, and other non‐feather integumentary structures in non‐avialan theropod dinosaurs
The morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications are reviewed.


3D Camouflage in an Ornithischian Dinosaur
Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus
The discovery of bristle-like structures in Psittacosaurus is of great evolutionary significance since it shows that the integumentary covering of at least some dinosaurs was much more complex than has ever been previously imagined.
Female cloacal protuberance of the polygynandrous Alpine Accentor Prunella collaris: histological features and possible functional significance
It is speculated that the morphological changes in the cloacal lips of the female Alpine Accentor are mediated hormonally by the brain–pituitary–gonadal axis.
Remarks on the Cloaca and on the Copulatory Organs of the Amniota. [Abstract]
Arich material of Crocodiles and Alligators has enabled me to clear up several points in the structure of their sexual apparatus, which have hitherto escaped notice, probably owing to the scarcity of
Evolution of External Genitalia: Insights from Reptilian Development
The question of the deep homology (shared common ancestry) of genital structures and of developmental mechanisms, and new areas of investigation that can be pursued by taking a comparative approach to studying development of the external genitalia are addressed.
Morphological signals of sex and status in Spotted Bowerbirds
It is found that bower owners had larger crests than non-owner males or females and that crest area provided the most accurate predictor of a bird's sex and status in a discriminant function analysis.
Analysis of gular and paracloacal gland secretions of the american alligator (Alligator mississippiensis) by thin-layer chromatography Gland, sex, and individual differences in lipid components
Gland, sex, and individual differences are suggested in the thinlayer profiles of extracts from both glands of adult male and female alligators.
Evolution: One Penis After All