R: Segnosaurs ejected from AVES

["calzola" <calzola@iol.it>]

is it more likely, for everyone of the 20 characters shared by two groups,
to have evolved indipendently  from one another or to be the indication of a
common ancestry?
You may not accept most parsimonious explanations in all cases, but in this
case you won't ever be able to discriminate between characters resulted from
direct pathways and others, because of the lack of a universal criterion .
The overal scenario represented by the character states for a taxon may give
you clues as to what character is likely to have evolved indipendently from
the same character present in another animal, but this a completely
different thing.

Ken has just decided not to consider some 15(?) characters and look just at
the carpal configuration; as Jaime said this is not exactly a scientific
process...

Filippo Calzolari

> In a message dated 1/29/02 11:02:59 PM EST, qilongia@yahoo.com writes:
>
> << There are about 20 different features that unite segnosaurs and
> oviraptorosaurs. >>
>
> In two runs of 100 flips of a coin, there will be about 50% matches. Does
> this mean that the two runs are not independent? Likewise, if two theropod
> lineages extend far enough, they will acquire a number of the same bistate
> characters independently (carpals fused into a "semilunate" being one
such).
> Does this mean they're related?