Meeting Abstract

120.3  Monday, Jan. 7  Small and mighty: the phylogenetic significance of mastigophore nematocysts in sea anemones REFT, AJ*; DALY, M; Ohio State University; Ohio State University ajreft@gmail.com

An account of the size, distribution, and morphotypes of microscopic stinging capsules called nematocysts is historically included in species descriptions of sea anemones (Cnidaria: Anthozoa: Actiniaria). Differences in the observed size ranges of capsules may justify the separation of species, and the occurrence of particular morphotypes justifies higher-level taxonomic distinctions. Nonetheless, the identity of some types of nematocysts remains obscure, and their phylogenetic significance remains untested. Here we use scanning and transmission electron microscopy, light microscopy, and shape analysis to evaluate the similarities among mastigophores, the most common type of nematocyst in sea anemones. We recognize several new types of mastigophores, and find that many of these occur uniquely in particular lineages or tissue types.