Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Composition and biometry of cnidae within a small colonial sea anemone (Family: Actiniidae).       (#416)

Katrina L Kaposi 1 , Jamie E Seymour 1 , Robert L Courtney 1 , Michela Mitchell 2
  1. James Cook University, Smithfield, Queensland, Australia
  2. Museum of Tropical Queensland, Townsville, QLD, Australia

Cnidarians, including jellyfish, corals, and sea anemones, are collectively a diverse group of ancient, yet highly successful, marine organisms. A defining feature of all cnidarians is the presence of unique cellular organelles called cnidocysts (or cnidae), located within epidermal tissues. Across the phylum, there are approximately thirty types of cnidae, each distinctly designed to serve a specific ecological purpose. Divided amongst three broad categories, nematocysts, spirocysts, and ptychocysts, cnidae are generally described as tiny collagenous capsules equipped with a tightly coiled thread, that when triggered, is expelled with immense force, allowing for the adhesion to substrate, or the entanglement and penetration of tissue in opposing organisms.

The types and distribution of cnidae (cnidom), found within cnidarians vary significantly between species. While cnidae are widely recognized as an important taxonomic tool, they may also provide valuable insights into the ecology of a species. This talk will take a close look into the cnidom of a small clonal tropical sea anemone (Family: Actiniidae), exploring not only what cnidae are present within this species, but also the intraspecific differences and potential ecological roles of these cnidae.