nospam@nospam.com (Paul Ciszek) wrote:
> So, there have been claims for some time now that ctenophora are a
> sister-group to all other metazoans, and recent genetic studies
> have re-inforced this. Clade-wise, some node splits into ctenophra
> and porifera, and eumetazoa branch out of one of the types of
> porifera. Or probably one node branched out into the porifera we
> know about and some other porifera that we don't, and the ctenophora
> branched out of a type of porifera that isn't around anymore.
>
> Elsewhere, Wiki claims that extant ctenophores probably descend from
> a common ancestor as recently as the KT extinction event.
>
> Putting this two together, I read that to mean that there used to be
> an entire sub-kingdom of metazoa, more different from us than we are
> from sponges, that was reduced to a single species by the KT event.
> Am I interpreting this stuff correctly?
>
> What other subkingdoms might we have lost completely in, say, the
> Permian extinction and aren't even aware that they ever existed?
>
Numerous subkingdoms could have been lost, the chance of an organism
fossilizing is next to nothing, you have to be in the right area for
fossilization, such as a floodplain, and there are other factors to,
such as if any scavengers get to the remains, does the dead organism
have hard parts or is just a blob of soft tissues, etc.

--
--- Lord Creodont, FRCS