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Re: Sauropod necks????
On 29/5/05 6:34 am, "don ohmes" <email@example.com> wrote:
> However, current research indicates an earlier origin
> for angiosperms (as early as ~340 mys BP, in my
> readings), and there is literature discussing an
> aquatic origin of same. So as an old farm boy who has
> spent many hot days acquiring biomass, I am willing to
> reconsider a retro hypothesis, even though it might be
> a stretch.
340 Ma refers to the _stem_ lineage of angiosperms, if crown gymnosperms
form a monophyletic sister group to angiosperms as suggested by molecular
phylogenies. _Archaefructus_, the aquatic plant suggested to be the
immediate outgroup to crown angiosperms, dates from the Early Cretaceous -
whether earlier angiosperm stem lineages were aquatic is currently unknown.
I should note that it has also been suggested that _Archaefructus_ may
represent a secondarily simplified crown angiosperm, like many other aquatic
angiosperms - Nymphaeales, Podostemales, _Ceratophyllum_, etc. If so, it
would be uninformative as to the nature of the angiosperm ancestor.