Compatibility analysis and its applications

A two-state character is defined as uniquely derived if it has only evolved once in the history of a group, without subsequent reversal. Two independent characters cannot both be uniquely derived if all four possible combinations (or all three excluding that of the two ancestral forms) occur. A number of ways of choosing compatible sets of uniquely derived characters are discussed and used to derive possible unrooted and rooted trees. Results of these are related to those chosen on parsimony criteria, using data for orthopteroid groups, and the assumptions of both methods are compared. Application of compatibility analysis to the moth genera Teldenia and Argodrepana is also discussed. Compatibility and parsimony methods are complementary rather than exclusive of each other.