Morphological disparity in elateriform beetles: patterns, trends, and implications

Morphological disparity, reflecting the breadth of phenotypic variation within clades, offers critical insights into evolutionary dynamics beyond taxonomic diversity. Using a large discrete morphological character dataset, this study investigates disparity patterns in Elateriformia, a hyperdiverse beetle clade that includes click beetles, jewel beetles and their relatives, to explore macroevolutionary drivers of disparity within the clade and methodological challenges in disparity analysis. Our results show that different superfamilies within Elateriformia exhibit distinct morphospace occupation patterns. In particular, Elateroidea display disparity concentrated along leading PCoA axes, driven by repeated transitions to soft-bodiedness and paedomorphic traits, whereas Dryopoidea exhibit more evenly distributed disparity, suggesting decoupled trait evolution. Crucially, analyses incorporating fossils align closely with extant-only reconstructions, indicating that extant data retain biological significance for inferring historical disparity. However, the anatomical region studied strongly influences disparity patterns. Our work thus validates the utility of extant-based disparity reconstructions while emphasizing the need for integrative anatomical sampling to capture macroevolutionary dynamics accurately.