Fig. 3: Best-fitting relationships between continuous variables inferred as significant by XGBoost and speciation rate, as estimated by QuaSSE.

Variables are in order of ranked importance according to the full XGBoost model. It is important to consider that QuaSSE does not provide the exact relationship between variables and speciation rates, only the general trend²⁹. The reported model fits are those best-supported by the data. The cases with narrow modes are likely shaped by the inability of QuaSSE to account for hidden states and confounding correlations between variables. We present these as hypotheses to inform future research.