This revision of the sea anemone subfamily Edwardsiinae (Cnidaria: Anthozoa: Actiniaria) addresses the diversity of one of the most speciose and poorly known groups of sea anemones. Edwardsines are burrowing anemones, and they inhabit some of the most threatened inshore habitats, including tidal marshes and mud flats; the pressures on these sensitive ecosystems has led to the documented decline of edwardsine populations in Australia, Ireland, the United Kingdom, and the United States. Elsewhere, edwardsines dominate macrofaunal communities, reaching densities of hundreds or thousands of individuals per square meter. Edwardsiinae is one of the few truly cosmopolitan groups of sea anemones, with all genera comprising species found in soft sediments at all depths in all oceans. The diversity and global distribution of edwardsines permits a variety of ecological, biogeographic, and evolutionary hypotheses to be examined, including: the correlations between habitat type and life history attributes, the relationship of polar and deep sea taxa, and evolution of burrowing. This project is the first such examination for any member of Actiniaria.
The described diversity of Edwardsiinae centers on the North Atlantic, with a handful of species known from tropical and polar oceans. Because edwardsines are globally distributed and may be locally abundant, edwardsines are frequently collected during biodiversity surveys, oceanographic expeditions, and in ecological monitoring projects. Most specimens of Edwardsiinae in museum collections are unidentified, either because they belong to undescribed species or because identification is difficult, relying on attributes accessible only through histological examination. This project will document and describe species collected in the Pacific and Southern Oceans and re-evaluate the status of species from the North Atlantic and Arctic oceans, providing a comprehensive assessment of the biodiversity of Edwardsiinae. The establishment of identity for samples collected during faunal surveys and monitoring projects increases the value of such studies, and allows for more nuanced comparisons between sites. By describing species from under-studied regions and by producing electronic keys to the species of Edwardsiinae that facilitate identification by non-specialists, both bottlenecks in the identification of edwardsines are addressed.
