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Re: What is Saltopus?
In a message dated 9/4/00 5:50:06 PM EST, firstname.lastname@example.org
<< George Olshevsky wrote-
> How is this a synapomorphy of Ornithodira when any >flying< bird blows
> 50% ratio away?
The same way it can be a synapomorphy if sauropods, stegosaurs, ankylosaurs,
etc. all have higher than a 50% ratio. It's most parsimonious to think it
reversed several times, but is still usefull for determining relationships
among basal members. >>
In BCF, the forelimb to hindlimb ratio is close to 1 plesiomorphically for
Archosauria, and it becomes smaller convergently within various lineages. It
remains close to 1 throughout the lineage that leads to birds, even
increasing beyond 1 as forelimbs develop into wings. Same with pterosaur
lineage, if that is considered an ornithodiran group. Ratite birds typically
have a small forelimb to hindlimb ratio, but I don't think anyone would argue
(although I believe Percy Lowe might have, in the 1930s) that this feature is
synapomorphic with the small forelimb to hindlimb ratios seen in various
theropod lineages. There is, therefore, also no good reason to argue that the
small forelimb to hindlimb ratios of the various theropod lineages are
synapomorphic with one another.