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Re: something's wrong here: Qianosuchus phylogeny
David Marjanovic writes:
> > Really? What is the reason for knowing a priori that scleromochlids
> > could not possibly be paraphyletic with respect to pterosaurs?
> There is only one known scleromochlid, *Scleromochlus* itself, and
> it has autapomorphies, so the most parsimonious assumption is that
> it's not an ancestor of anything else we know -- never mind its
> geological age, which IIRC isn't older than the oldest known
OK, but that's an accident of what we currently happen to know about
scleromochlids. I guess you were making a point about that specific
taxon; I misread your comment as meaning that no taxon ever can be
directly ancestral to any other -- which of course is what I was
> And then there's the widely acknowledged principle that only
> monophyletic taxa should be named above the species level.
Widely acknowledged, no doubt; but certainly not universally
> If there were two scleromochlids known, and the group as a whole
> turned out to be paraphyletic, that would mean one of the
> scleromochlids had turned out not to be a scleromochlid.
If a cladistic definition is in use for Scleromochlidae, yes.
/o ) \/ Mike Taylor <firstname.lastname@example.org> http://www.miketaylor.org.uk
)_v__/\ "The shell inparts commands, addresses memory for programs and
executes via the Unix pipe" -- ix MAGAZINE, April 1985