Unveiling spatial and temporal gaps in the knowledge of marine invertebrates in Mexico

This is the authors' abstract. We don't add key points for this paper.

Biodiversity knowledge gaps undermine biogeographical analyses, leading to biased interpretations with direct consequences for research, conservation and management. In Mexico, marine invertebrate diversity remains poorly documented due to historical physical, economic and social limitations. We quantified the taxonomic, spatial and temporal coverage of digitally accessible records for Mexican marine invertebrates to identify biases, gaps and priorities for future surveys. We compiled 121,502 records representing 4642 species of sponges, cnidarians, echinoderms and molluscs from two open-access repositories (GBIF and OBIS). Taxonomic coverage was evaluated based on the historical accumulation of documented species and the annual number of records, providing a temporal perspective on taxonomic knowledge. Inventory and taxonomic completeness were estimated across 50 × 50 km grid cells to identify well-surveyed areas and temporal coverage was examined relative to 2024. Ignorance maps combining the above metrics were generated to highlight priority areas for sampling. Knowledge of marine invertebrates in Mexico has expanded since the 1930s, yet biodiversity data cover less than 35% of the study area and only a small fraction of cells qualifies as well-surveyed. Records remain strongly biased towards coastal and reef systems, while deep-sea and offshore environments are largely unsampled. Temporal gaps are also evident with many areas lacking recent records. These patterns reveal persistent and uneven knowledge shortfalls. Addressing them requires targeted surveys in poorly sampled marine-coastal and deep-sea environments, as well as re-surveys in sites not visited for decades where new discoveries and updated biodiversity baselines are most likely to be found.