Gondwanic or Pacific elements?

[John Grehan]

At 05:23 PM 4/8/00 +0200, Simon Peter wrote:

>I am interested to know how the Gondwanic element (eg. Myrtaceae,
>Proteaceae) reaches Southeast Asia.

This question is problematic as it depends on how one arrives at the
classification of "Gondwanic element". In the example of the Proteaceae
this is not stated. In terms of spatial baselines much of the Proteaceae
appears not to be Gondwanic but Pacific in origin. In terms of this
classification the question is how Pacific elements came to reach South
East Asia as well as Gondwana.

Hubert Turner provided several references, but as these appear to exclude,
or most probably exclude, panbiogeographic perspectives (seemingly rather
annoying to dispersalists and vicariance cladists as they mess up what
otherwise would be a nice geologically preformationist view of the world).
I would, therefore, draw attention to Croizat's (1952, 1958, 1968) books as
a beginning as a way of obtaining a global perspective on South East Asia
to provide a foundation of determining biogeographic "elements".

>It has been suggested that several
>fragments of continents that are now embedded in S.E. Asia were initially
>part of thr Gondwanaland. These continental fragments began to drift
>northwards, forming island between Gondwanaland and Laurasia before they
>actually collided with Laurasia.

Keep in mind that this is just a theoretical model - a sort of historical
cartoon. It may right, or may be wrong, no matter how confident we or the
geologists are. Simply basing the "how" on such models is to render
biogeography incompetent. This view separates panbiogeography from
dispersalist and vicariance cladistic biogeography (at least as currently
practiced).

John Grehan