Hierarchical (mm- to km-scale) environmental variation affecting skeletal phenotype of a marine invertebrate ( Electra pilosa , Bryozoa): Implications for fossil species concepts

A comparative record of morphological change of fossil specimens through geologic time can provide insights into the rates and patterns of microevolution and speciation. However, questions concerning the extent to which environmental conditions influence skeletal morphology, and potentially confound recognition of genetic change, can be most meaningfully addressed with living taxa. The marine encrusting bryozoan, Electra pilosa (L.), was used to assess the magnitude of environmental effects on zooecium-level skeletal morphology at different spatial scales. The latter included environmental effects or factors ranging in level from (1) micro-environmental (variation within and among immediately adjacent colonies), (2) meso-environmental (small-scale colony positional effects among colonies within a common habitat), and (3) macro-environmental (morphological variation among colonies from recognizably different environmental settings).