Living fossils: On lampreys, Baronia, and the search for medicinals

Abstract

"Living fossils" are organisms that, while still resembling their extinct progenitors in fundamental ways, have escaped the fate of these ancestors by specializing in ways that gave them an edge in survival. An example is provided by the butterfly Baronia brevicornis, the lone survivor of an ancient lineage; B. brevicornis may have beaten the odds against extinction by having evolved a form of defense, namely, mimicry of distasteful butterflies. In this article we argue that defense, particularly chemical defense, is likely to have often played a role in the survival of living fossils; consequently, the screening of such organisms for medicinals may have a better than average chance of paying off.