The Concept of Ecospecies in Tertiary Paleobotany

Abstract

The Tertiary distribution of the fossil equivalents of modern endemic trees and shrubs brought them into contact with diverse types of climate, habitat and vegetation. Available evidence suggests that when fossil species related to these endemics are recorded in habitats which are widely different from those now occupied by their nearest descendants, we may be dealing with ecotypes having no close counterparts in the modern flora. Late Cenozoic elimination of biotypes apparently has left the modern endemics surviving in habitats which may be considerably different from those occupied by certain of their fossil relatives; a similar interpretation may be applied also to certain other trees and shrubs. Since paleoecological interpretations are based on plant communities, and not solely on individual species, the recognition of ecotypes in the fossil record has no effect on the general procedure for reconstruction of past environments. On the contrary, their recognition makes it possible to explain certain inconsistencies of association which otherwise defy interpretation.