Dynamic climate and ecological expansion drive body morphology evolution in fossil and extant neocoleoid cephalopods

Cephalopods originated in the Cambrian approximately 500 million years ago, evolving from externally shelled ancestors to forms with diverse morphologies. Despite their morphological diversity, the macroevolutionary patterns and drivers of their diversification remain incompletely understood. Here, we construct a time-calibrated phylogenetic framework for fossil and extant neocoleoid cephalopods and quantify evolutionary rates and morphological disparity over ~490 million years. We identify five peaks in morphological diversification, indicating rapid evolutionary phases during historical periods. Morphological disparity exhibits a time-lagged response to evolutionary rate shifts. Sea surface temperature and ecological factors are macroevolutionary drivers shaping evolutionary rates and morphological disparity. Major environmental perturbations, including the end–Permian and end–Triassic mass extinctions and Early Triassic and Toarcian hyperthermal events, are associated with reduced evolutionary rates, whereas post–Cretaceous conditions correspond to elevated rates driven by ecological release and adaptive radiation. Our results show that cephalopod morphological evolution is governed by coupled environmental and ecological processes that structure evolutionary dynamics over deep time.