"Dinosaur ancestors" refers to the creatures who came before dinosaurs and are related to them. These ancient animals are like the grandparents or great-grandparents of dinosaurs. Full definition
That makes it less likely, he says, that the behavior was «widespread and ubiquitous» in their extinct dinosaur ancestors. (sciencemag.org)
But they can't look at every single generation and every single gene that separates a bird, for example, from its two - legged dinosaur ancestors. (discovermagazine.com)
THE DESCENT OF BIRDS Dinosaur ancestors of birds shrank steadily for more than 50 million years. (sciencenews.org)