RESEARCH PAPER Beyond Bergmann’s rule: size–latitude relationships in marine Bivalvia world-widegeb_775 173..183

Aim Variations in body size are well established for many taxa of endotherms and ectotherms, but remain poorly documented for marine invertebrates. Here we explore how body size varies with latitude, temperature and productivity for a major marine invertebrate class, the Bivalvia. Location Continental shelves world-wide. Methods We used regression models to assess univariate relationships between size and latitude as well as multivariate relationships between size, latitude and environmental parameters (mean and seasonality in temperature and mean pro-ductivity). The dataset consisted of 4845 species in 59 families from shelf depths at all latitudes in the Pacific and Atlantic oceans. We also used Blomberg’s K to assess whether size–latitude relationships show phylogenetic signal, and test whether functional groups based on feeding mode, substrate relationships, mobility and fixation can account for observed size–latitude trends. Results Size–latitude trends are taxonomically and geographically common i