Hi, Dr A.
Dr Adequate writes:
As a final bit of confusion, some people would argue that the answer should really be "no" by definition, because the common ancestor of (for example) a platypus and an echidna should not be considered to be either no matter how much it looks like a platypus. This bit of cladistic pedantry is, however, probably not something you were thinking of when you asked you question.
Within a species, there are cladistic population structures that would ensure that some populations of the parent species will, at least temporarily, be more closely related to the incipient daughter species than they are to other populations of the parent species, despite remaining members of the parent species according to the biological species concept.
So, use of the biological species concept requires us to accept that species can be paraphyletic with respect to other species.
-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.
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