Protein Variation and Systematics in the Czdex @@ens Group of Species

Electrophoretically-detected variation at 18 enzyme protein structural loci in members of the CuZex pQ&ns group of species is summa- rised using Rogers' genetic distance algorithm and presented as a simila- rity dendrogram. The two native Australian species C. austrazicus Dobr. & Drum. and C. globocotitus Dobr. are more similar to each other than either is to C- quinquefasciatus Say, C. moZestus Forsk., C. pallens Coq. and Euro- pean C. pipiens L. Within this latter group of species C. quinquefasciatus separates from the other three. The two basic clusters represent those spe- cies with rickettsial endosymbiotes, and those without these organisms. It is argued that the symbiote-free condition is the ancestral one, and that the two clusters of species represent separate evolutionary lines that di- verged during the Cretaceous.