Figure 2
From: On the historical biogeography of global Galliformes: ancestral range and diversification patterns
Clade age-richness relationships. The black fitted line indicated the result from ordinary least-squares regression analysis (OLS), while the red line is from the phylogenetical general least-squares regression analysis (PGLS). Both lines have significant slopes (p < 0.05). For OLS, the fitted equation is clade richness = 1.24 × clade age − 8.29; while for PGLS, the fitted equation is clade richness = 3.111 × clade age − 101.48.