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Re: Sobral and Langer 2008 (was pteros have lift-off)
Don't know about how supertrees are made, and do not fully grasp what
an "average" would mean for a group of trees. Perhaps a majority rule
consensus or something like that?
Sort of. When supertrees are made by an algorithm rather than by hand (and
the latter is quite unusual), matrix representation is used: a matrix is
made with the trees as taxa and the nodes as characters -- each node is
coded as present or absent for each tree. Then the shortest tree is
calculated from this matrix.
I mean, in that study of Langer, is the only reason for pterosaurs
being most closely related with prolacertiforms and drepanosaurids
just that this hypothesis of relationship is recovered by most
studies? I would in principle think not; as far as I know the only
previous phylogenetic analysis stating that is that by Peters (2000)
in the Rivista Italiana.
But that's probably the only one that contains any prolacertiforms except
maybe *Prolacerta*. It could thus outweigh all others in this respect,
because the others are coded as unknown (inapplicable), rather than absent,
for, say, a *Cosesaurus*-*Langobardisaurus*-Pterosauria clade.