Taxacom: "Early Permian" angiosperms... real or not real taxa/names?

[John Grehan]

Hi Tony, More comment below:

With respect to your quotes of  Magallón

"We think that their true age is older than but closer to the fossil date
than to the molecular clock estimates. The pattern of their earliest
appearance in the fossil record, with increasing distribution,
local abundance, and morphological diversity of angiosperm pollen and
leaf types in Early Cretaceous sediments; and the generally coinciding
order of appearance of lineages in stratigraphic sequences and in molecular
phylogenies, are formidable objections to the possibility of a long
portion of early angiosperm history missing in the fossil record."

Well, they may 'think' so, but the data is neither here nor there. There is
nothing empirical in the earliest appearance in the fossil record,
increasing distribution (whatever that is), local abundance (in the fossil
record presumably), morphological diversity in early Cretac ous, and
'generally coinciding' (so not always, which means that there is no
complete coincidence, so some coincidence is neither here nor there), and
in molecular phylogenies (how ever a phylogeny denotes proof of age is
beyond me), that constitute 'formidable' objections of a large gap in the
fossil record (the authors may believe so, but that is just their personal
conclusion).

"So, the authors themselves (in this study) commenting that the "estimated
age" based on molecular models, far from being empirical proof of age,
is seeming less likely to be correct than one more closely approaching that
based on the known fossil evidence."

Yeah - molecular [age?] models are fine when they fit preconceptions (such
as a young age), but not when they don't.

Cheers, John

On Fri, Jun 3, 2022 at 4:06 AM Tony Rees via Taxacom <taxacom at lists.ku.edu>
wrote:

> Terribly sorry, Michael; indeed they were from John Grehan, my apologies...
>
> Meanwhile in the light of John's (not Michael's!) comment "These
> 'hypothetical dates" are widely accepted as more than that - even as
> empirical proof of age - by many, many, many people, including a number of
> individuals on Taxacom. ... The suggestions do not come from 'molecular
> evidence' but from fossils that
> are used to calibrate divergence."
>
> A further relevant paper is perhaps: S Magallón et al., 2013: "Land plant
> evolutionary timeline: gene effects are secondary to fossil constraints in
> relaxed clock estimation of age and substitution rates", Am J Bot . 2013
> Mar;100(3):556-73. doi: 10.3732/ajb.1200416. In this the authors state: "
> Among the nodes constrained in this study, the angiosperm crown node is
> unique in that its estimated age is substantially older than the oldest
> fossils that can be reliably assigned to the clade. ...  The age of the
> angiosperm crown node has proved to be a particularly difficult estimation
> problem. We think that their true age is older than but closer to the
> fossil date than to the molecular clock estimates. The pattern of their
> earliest appearance in the fossil record, with increasing distribution,
> local abundance, and morphological diversity of angiosperm pollen and leaf
> types in Early Cretaceous sediments; and the generally coinciding order of
> appearance of lineages in stratigraphic sequences and in molecular
> phylogenies, are formidable objections to the possibility of a long portion
> of early angiosperm history missing in the fossil record."
>
> So, the authors themselves (in this study) commenting that the "estimated
> age" based on molecular models, far from being empirical proof of age, is
> seeming less likely to be correct than one more closely approaching that
> based on the known fossil evidence.
>
> Regards - Tony
>
>
> On Fri, 3 Jun 2022 at 17:54, Michael Heads <m.j.heads at gmail.com> wrote:
>
> > Just a clarification - these comments were from John Grehan, not from me.
> >
> >
> >
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