Sentences with word «nonavian»
The word "nonavian" means anything that is not related to or connected with birds. Full definition
The strange new species is the first known nonavian dinosaur that could both run and swim, researchers say.
sciencenews.org
The Jehol birds faced competition with pterosaurs, and occupied sympatric habitats with nonavian theropods, some of which consumed birds.
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.
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.
Cretaceous 65 million years ago; decimated nonavian dinosaurs as well as marine reptiles and numerous species of marine organisms.
Feathered animals abound and extend deep into nonavian history — even, perhaps, to the base of dinosaurs themselves.
But when nonavian dinosaurs went extinct, mammals continued to diversify and take over niche environments that dinosaurs once filled.
2.4 billion years ago, many obligate anaerobes, in the oxygen catastrophe; 252 million years ago, the trilobites, in the Permian — Triassic extinction event; 66 million years ago, the pterosaurs and nonavian dinosaurs, in the Cretaceous — Paleogene extinction event.»
«That would include both nonavian dinosaurs and, yes, birds,» Gramling says.
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).
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.
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.
Whereas the last of the nonavian dinosaurs certainly perished 64.5 million years ago, many other animals survived — crocodiles, for example, along with almost all the mammals, which at the time were small, some with skulls the size of a thimble.
Some nonavian theropod dinosaurs were at least partially covered in feathers or filamentous protofeathers.
This report of secondaries in a larger - bodied, derived, and clearly flightless member of a nonavian theropod clade represented by feathered relatives is a substantial contribution to our knowledge of the evolution of feathers.
At the same time, Brown documented the sequence of rock layers at the site that reveal how the nonavian dinosaurs dramatically died off 65 million years ago.
How things have changed — now it would take a warehouse to store all the feathered Mesozoic stem birds and nonavian dinosaurs that have been collected from global deposits.
«The closest ancestors to birds are the nonavian dinosaurs,» Horner says.
That overturns the previously held idea that birds stayed small until the nonavian dinosaurs died out.
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.