Figure 1 in Phylogeny of sex-determining mechanisms in squamate reptiles: are sex chromosomes an evolutionary trap?

Figure 1. Parsimony analysis of sex-determining mechanisms in squamate reptiles based on the 'morphological' tree. Circles indicate maximum-likelihood reconstructions of ancestral states, only nodes with significant reconstruction are shown (tested by likelihood-ratio test). Numbers in parentheses indicate the counts of species within a genus that share