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either all dinosaurs are stem-group birds, or birds are derived dinosaurs, but there is no taxon Dinosauria, acceptable in cladistic taxonomy, that excludes the taxon Aves. Pseudoextinction cannot be applied to the genus or family levels as, "when a species evolves to a new form, causing the pseudoextinction of the ancestral form, the new species is normally assigned the same higher taxa as the ancestor." When a family or genus goes extinct it must be true extinction, because pseudoextinction would

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