[Taxacom] Hedges /Kumar (eds) The Timetree of Life

[Richard Pyle]

> If we find evidence that the particular species WAS there, even for a short
> time, then we have to invoke # 1if the species is not there today.
> So, circling in on my own logic, if a species that was there, established, and is
> now gone (extinct), can I invoke # 1 again?
> Surely, if it was there and does not carry on indefinitely, then it has to be # 1.

I disagree.  That a species does not live somewhere, where it once lived in the past, does not mean it *cannot* live there now.  It only means that it failed (for whatever reason) when it was there before.  Perhaps it failed because conditions are such that it cannot live there; but it may also have failed as a result of anomalous circumstances  that no longer apply (e.g., unusual climate conditions, catastrophic event, predator that has also gone extinct; prey that went extinct but has since become re-established, etc.).

Aloha,
Rich