Phylogenetic Biogeography of Mayflies

The number of biogeographers who confidently drew dispersal routes on fixed continent maps ten or more years ago and now just as confidently draw dispersals of the same organisms on continental drift maps must cause us to seriously question the procedures of biogeographers. Because of its complexity, biogeography is unlikely to easily make the transition to a precise science, but certainly it is possible to greatly increase the rigor of the basic principles and procedures and avoid intuitive assessments of distribution patterns within the constraints of preconceived notions. I would like to discuss the approach to biogeography that I find most useful, and to express objections to some of the practices and viewpoints common among biogeographers. I have spent most of my academic career running against the current of prevalent biogeographic opinion and many continue to believe that my phylogenetic methods are not valid, but my results generally conform to the patterns of earth history from plate tectonics. I was trained in Neo-Matthewian biogeography, but as a mayfly worker I have not been seriously influenced by such dogma. Every worker treating the mayflies of Chile and adjacent Argentina has recognized the relationship of these mayflies to those of Australia and New Zealand. Furthermore, I was strongly influenced by C. P. Alexander of the University of Massachusetts who in numerous papers on craneflies has clearly recognized these austral affinities. For example, in 1929, he noted that the close affinities of the craneflies from Chile-Patagonia, New Zealand and Australia gave evidence "overwhelmingly in favor" of a former Antarctic land connection to explain the distribution pattern (Alexander, 1929). Early in my career I was told by a famed vertebrate zoologist that the evidence that I had of closely related mayflies in Chile, New Zealand and Australia meant little because insect studies had not reached a significant level of sophistication, and even if I was correct, the distribution of these insects could be explained by island hopping. This event increased my determination to do first hand detailed studies on these austral disjuncts. The fixed continent dogma led many investigators who found, for example, related organisms only in southern Chile-Argentina and southeast Australia to explain such distribution through tortuous rationalizations. Some drew a dispersal arrow through Asia, the Bering Sea, and North and South America. Others decided that the organisms were obviously cases of parallel evolution. Still others invoked long distance dispersal even when it was highly improbable. The fixed continent dogma was a costly lesson, but many did not learn it. After listening to papers at the XIV International Congress of Entomology at Canberra, 1971, and the First International Congress of Systematic and Evolutionary Biology in Boulder, 1973, I am convinced that many workers have dropped the dogma of fixed continents