The evolutionary history of Rhinocerotidae: phylogenetic insights, climate influences and conservation implications

Family Rhinoceroidae exhibits a complex and debated phylogeny, with fossil records spanning over 50 million years. This study presents a comprehensive phylogenetic total-evidence analysis of Rhinocerotidae to date, integrating morphological, molecular, fossil and paleoclimatic data within maximum parsimony, maximum likelihood, Bayesian and time-calibrated frameworks. A matrix of 106 taxa and 534 morphological characters, including 11 newly defined ones, was assembled through systematic revision of previously ambiguous characters. In contrast to earlier studies, a fossil-based outgroup was selected in place of extant Tapirus to improve character polarity and reduce topological artefacts associated with distant outgroup choice. The resulting cladograms resolve longstanding conflicts in rhinocerotid systematics and identify many supported clades. Analyses of the studied clades revealed an association between lineage diversification and climatic thresholds, which appear to have mediated ecological turnover and the differential persistence of traits. The application of an integrative total-evidence approach illustrates the role of climatic and ecological filters in shaping the evolutionary trajectories of megafaunal lineages and contributes to broader methodological discussions in phylogenetics. The analytical framework developed provides a comparative model applicable to both extinct and extant taxa, reaffirming the value of rigorous cladistic methods in paleobiology and systematics.