Sentences with phrase «nonavian dinosaur»

If the genes in the chick embryo are very close to those of an ancestral, nonavian dinosaur — and if the changes, over more than 150 million years, have been almost all in regulation of the genes — then we could reactivate the old pattern of regulation.

The strange new species is the first known nonavian dinosaur that could both run and swim, researchers say.

Changes in the presence of growth factors produced the teeth, which were consistent with those of archosaurs (the group that includes birds, nonavian dinosaurs, and crocodilians).

It seemed so obvious that if fairly small changes in development, which adjusted the timing and concentrations of growth and signaling factors, could have led to the evolution of birds from nonavian dinosaurs, we could readjust those changes in development and get a dinosaur from a chick embryo.

H. escuilliei lived in the Late Cretaceous around 75 million to 71 million years ago and belonged to maniraptora, a diverse line of theropods that include both nonavian dinosaurs and birds.

But when nonavian dinosaurs went extinct, mammals continued to diversify and take over niche environments that dinosaurs once filled.

«The closest ancestors to birds are the nonavian dinosaurs,» Horner says.

The object that slammed into Earth 66 million years ago wiped out the nonavian dinosaurs and many other groups but largely spared species in freshwater ecosystems, a disparity explained by a new study.

Not exact matches

Some nonavian theropod dinosaurs were at least partially covered in feathers or filamentous protofeathers.

For the past two decades, scientists using cladistics have claimed that dromaeosaurs were nonavian ancestors of birds, representing the best examples of how ground - dwelling dinosaurs supposedly evolved into birds.

Feathered animals abound and extend deep into nonavian history — even, perhaps, to the base of dinosaurs themselves.