Ah... just the update I needed. We did have a few late surviving large
amphibians, if "Walking With Dinosaurs" is correct on that score - and I
haven't read anything on the contrary.
Whether temnospondyls are amphibians is not clear (if you use Amphibia as a
clade name). But *Koolasuchus* is indeed the youngest known temnospondyl by
something like 50 million years.