Ecological Niche Conservatism and Evolutionary Dynamics in Octopodidae: A Phylogenetic Comparative Approach

ABSTRACT Aim Understanding how ecological niches evolve is crucial for predicting species' responses to environmental change. Cephalopods, particularly those in the Octopodidae family, offer a compelling model system due to their short life spans, phenotypic plasticity and divergent developmental modes. We examined the evolutionary dynamics of the fundamental niche (FN) in Octopodidae by assessing niche overlap among closely related species pairs, quantifying phylogenetic niche conservatism (PNC) for temperature and dissolved oxygen, and evaluating phylogenetic signal and best‐fitting evolutionary models across the family. Location Temperate, tropical and subtropical oceanic waters. Time Period Occurrence records span from 1858 to 2024, with more than 80% of the records from 2000 to 2024. Environmental variables were obtained from monthly data available for 2000–2020, with the subset from 2010 to 2020 used in the analyses. Major Taxa Studies Octopodidae (d'Orbigny, 1839). Methods We conducted pairwise niche overlap analyses, incorporating both occurrence data and multiple definitions of the accessible area. Phylogenetic signal was estimated using Pagel's λ and Blomberg's K, and evolutionary models (Brownian Motion, BM; Ornstein‐Uhlenbeck, OU; and Early Burst, EB) were fitted for each niche trait. Results Sister‐species comparisons revealed no statistically significant niche overlap ( p > 0.05), suggesting niche lability at shallow phylogenetic levels, while evolutionary model selection supported the Ornstein–Uhlenbeck model for all traits ( α : 0.018–12.399), which is also consistent with the influence of stabilizing selection. Our analyses indicated stronger environmental constraints on temperature‐related traits, suggesting greater limitations under thermal stress, whereas oxygen‐related traits exhibited more variable patterns of phylogenetic constraints across niche dimensions. Main Conclusions Collectively, these findings support a mosaic pattern of niche evolution, challenging traditional assumptions of strong PNC in marine organisms. Taken together, stronger constraints under thermal stress suggest that cephalopods may have a limited capacity for rapid evolutionary adaptation to ongoing climate warming. This study provides the first comprehensive assessment of FN evolution in cephalopods, highlighting ecological constraints that may influence their adaptive capacity under future climate change scenarios.