By the way, a interesting article by Philip Donoghue about the stem group utility: http://palaeo.gly.bris.ac.uk/donoghue/PDFs/2005/Donoghue_2005b.pdf
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Roberto Takata
But trying to let the vernacular usage of a term direct the scientific/phylogenetic usage is letting the tail wag the dog. Birds are dinosaurs, and the rest are non-avian dinosaurs. The bats-are-mammals analogy is perfectly suited to the phylogenetic concept of birds-are-dinosaurs. There is no distinction between "evolved from" and "evolved within" (contra Jura/Jason). Phylogeny only recognizes relationships by descent.