MAJOR PATTERNS OF VISUAL BRAIN ORGANIZATION IN TELEOSTS AND THEIR RELATION TO PREHISTORIC EVENTS AND THE PALEONTOLOGICAL RECORD

A cladistic analysis of the three recognized patterns of central nervo us visual organization among teleosts reveals that there is a pattern of intermediate complexity representing the plesiomorphic condition fo r teleosts, and that there is a simple visual pattern in two unrelated teleost groups which can be concluded to be a secondarily reduced der ived condition, as well as an elaborate pattern which is present only in acanthomorph teleosts, thus likely representing a synapomorphy for this taxon. The elaborate central nervous visual pattern, therefore, i s one of many functional-anatomical advanced features characterizing t he acanthomorphs. Furthermore, when neontological and paleontological data is compared with the paleoecological record of early acanthomorph history during the Late Cretaceous, it is consistent with a hypothesi s that this acanthomorph synapomorphic functional-anatomical complex a rose likely in ctenothrissiforms as an adaptation to the life in the r eorganizing reefs of that geologic period.