When an argument is fallacious : depends how the argument is inteneded, a formally fallacious argument is acceptable in a scientific contex; while an invalid argument is not working well in particular environment. Begging the question : arguing in a circle. Sometimes is true, even the formal fallacy. It"s formal fallacy, hence not compel someone to come to the conclusion. This is not valid( can"t come to the conclusion from the premises given) , But a quite reasonable piece of evidence. So if don"t take it as deductive argument, not to prove something. But as a piece of scientific evidence, then quite reasonable. You can say at least it fits into" the category that dinosaurs are warm-blooded. Only reasonable to believe, but not proofs: reasonably regarded as evidence, the way the animal show pain is plausible coherent as what we expected how a creature behaves when in pain. But for ants , the behavior is hard to interpret for human.