Mesozoic climates were warmer in many places that are now cold. A land bridge connected South America across Antarctica
to Australia for much of Mesozoic time. The end-Cretaeous extinctions were likely the result of an asteroid impact.
Birds (Aves) were derived from lightly-built theropod dinosaurs and retain many archosaur traits.
Early birds showed varying adaptations and a mosaic diversity of both advanced and conserved traits.
Most Mesozoic birds had teeth, but a few, including the ancestors of modern birds, lost their teeth and relied instead on a horny beak.
Modern birds have diversified, but the requirements of flying have resulted in many adaptations for reduced weight and often for small size as well.
- Mesozoic faunas:
- Mesozoic continents
- Triassic
- Jurassic
- Cretaceous
- End of the Cretaceous-- Dinosaur extinction, etc.
- Was it really sudden?
- Boundary clay at Gubbio, Italy
- Iridium anomaly (Luis Alvarez: asteroid impact theory)
- Chicxulub crater
- Birds:
- Dromaeosauridae: small, feathered, predatory dinosaurs with strong claws
- Bird origins
- Jurassic birds— Archaeopteryx and "mosaic evolution"
- Cretaceous birds
New early bird with short pygostyle
- Cenozoic and modern birds
Illustrations
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