origins & biogeography of high level taxa

[John Grehan]

Response to comments by Kenneth E. Kinman

>      Discovery of a Jurassic angiosperm was no surprise to me, since
>the early angiosperms were undoubtedly restricted to habitats that
>aren't conducive to leaving a fossil record.

Or current concepts of angiospermy prevent botanists from recocognizing
early angiosperms or their immediate ancestors


>     With such a scarcity of fossil material, I doubt that
>panbiogeography would be as helpful here as it has been for some
>vertebrate groups, etc.

Panbiogeography is a biogeographic method that compares spatial
patterns of taxa, so it can't work with what is not available.

The point of my letter was that the analysis of extant angiosperms led
to the prediction of a pre-Jurassic origin for angiosperms. Croizat went
so far as to suggest that the incipient origins of angiospermy lie
in the Carboniferous.


>   For me the main question of angiosperm origins remains the same: were
>they "woody" or "paleoherbs"????  With a poor fossil record, I believe
>biogeographical have less potential to answer this question than do
>molecular data (by which I mean extensive data sets that are properly
>analyzed and interpreted).

Such phylogenetic subjects are of course not immediately biogeoraphical
questions so there is no implication by me that panbiogeographic or other
biogeographic analysis is the issue.

>I could be surprised by some unexpected
>fossil data, but I don't presently believe that angiosperm origins is a
>good candidate for demonstrating the potential of panbiogeographical
>analysis.

That was not my point. My point was simply that the fossil record
provided another corrobrating instance of a panbigoeographic
prediction, although in this case the prediction was not novel (at
least at the general level of predicting a pre-Crectaceous origin).
However, it is worth noting that the question of angiosperm origins
was a major subject addressed by Croizat, including his "Principia
Botanica", and living angiosperms have provided good enough
material to have (in my opinion) demonstrated the potential of
panbiogeographic analysis.

Coevolution of flowering plants and pollenators is a very
>important subject, but I just don't think it can help with angiosperm
>origins at this juncture (although speculations could point the way to
>fruitful avenues of inquiry).

If one were interested in flowring plant and pollenator co-evolution for
extant groups then biogeography could be very helpful in helping to
elucidate the space and time context of such evolution. I did this for
Lepidoptera where I suggested that this group also has its origins well
into the Mesozoic (i.e. modern families and even genera may have existed
in the Cretaceous or earlier). So biogeography may be more useful than
some might think.



>                   from a non-botanist,
>                           Kenneth E. Kinman

I don't specialise in botany either. Croizat did, and since his ideas on plant
evolution were ignored by botanists of his day (and continue to be ignored
by most botanists, noteable exceptions being Rolf Sattler and Michael
Heads) it does not bother me to stick my neck out.

Thank your for your comments Ken. At least you are thinking and not
reacting (which
is more than can be said for all the conventional biogeographers and botanists
who have found it more convenient to ignore Croizat's contributions to
biology - not
that I don't think that they have a right to take such a course).

Sincerely, John Grehan