actinian -- sea anemone, from the scientific term for sea anemones, Actiniaria

Amphiprion -- fish genus containing 27 species, all of which are symbiotic with sea anemones

cnidarian -- member of phylum Cnidaria (also called Coelenterata), the group to which sea anemones, corals, jellyfish, and hydras belong

coelenterate -- member of phylum Coelenterata (also called Cnidaria); see cnidarian

Cryptodendrum -- sea anemones genus containing only one species, which may host anemonefish

Dascyllus -- genus of damselfishes, some species of which are facultative symbionts of actinians, particularly when young

Entacmaea -- genus containing at least two species, one of which is E. quadricolor, the most abundant host sea anemone, which harbours the greatest number of species of clownfishes

facultative symbiosis -- a relationship in which one partner may, but need not, live with another in order to survive; the relationship of most species of host sea anemones with anemonefishes is facultative

Heteractis -- genus containing four species of sea anemones, all of which may host anemonefish

host -- one of the partners in a symbiosis, generally the larger one (thus, the sea anemones that are the subject of this book are hosts to both fish and algal symbionts)

larva (plural larvae) -- a developmental stage that hatches from an egg and that typically lives in a different environment, looks entirely different, and eats different food from the adult of the species; oceanic larvae are generally very small, and are planktonic

Macrodactyla -- sea anemone genus containing only one species, which may host anemonefish

metamorphosis -- the change from larva to adult

melanism -- a tendency to develop black pigmentation, common in many species of anemonefish

mutualism -- a symbiosis in which both partners benefit

nematocyst -- microscopic, harpoon-like stinging capsule manufactured by all cnidarians (= coelenterates)

obligate symbiosis -- a relationship in which one partner must live with another in order to survive; except for a brief planktonic larval stage, anemonefishes are obligate symbionts of sea anemones

parasitism -- a symbiosis in which one partner benefits, to the detriment of the other

plankton -- oceanic plants and animals that drift with the currents; although most planktonic species are small, some, such as jellyfishes, are not

Premnas -- genus containing only one species, which is an anemonefish

Stichodactyla -- genus containing five species of sea anemones, three of which may host anemonefish

symbiont -- one of the partners in a symbiosis

symbiosis -- literally "living together", used by scientists to describe the relationship between unrelated species of plants and/or animals that live in intimate association

taxonomy -- the naming of living beings based on their evolutionary relationships to one another

zoophyte -- literally "animal plant," an archaic term for a sea anemone

zooxanthellae -- single-cell, dinoflagellate (golden-brown) algae that live symbiotically within the cells of some marine animals such as most reef-forming corals, many tropical and a few temperate sea anemones, some hydroids, and all giant clams

Return to Table of Contents