Phylum Cnidaria (lit. “nettle-bearing” G.), referring to the nematocysts possessed by all members of the phylum; includes sea anemones, corals, sea pens, gorgonians, jellyfishes, hydroids
Class (or subphylum) Anthozoa (lit. “flower animal” G.), including sea anemones, sea pens, soft corals, and cup corals
Subclass Hexacorallia (=Zoantharia) (lit. “six coral” G.), referring to six sets of mesenteries
Order Actiniaria (lit. “beach/seashore” G.), including sea anemones such as Anthopleura, Urticina, Epiactus, Metridium¹, Cribrinopsis², and others
Order Ceriantharia, including tube-inhabiting, burrowing anemones such as Pachyceriathus imbricata
Order Corallimorpharia (lit. “coral form” G.), including Corynactis californica
Order Scleractinia (lit. “hard” G.), including cup corals Balanophyllia spp.
Order Zoanthidea (=Zoanthiniaria), including epizoanthids Epizoanthus scotinus
NOTE¹ references to Metridium senile in the scientific literature on west-coast sea anemones most likely included two related types, now separated into a larger (up to 1m in height), subtidal species known as Metridium farcimen (= M. giganteum) and two smaller, intertidal/subtidal species designated M. exilis and M. senile. When it is clear that the larger species is being referred to in a research paper, the name M. farcimen is substituted. For a morphological, biochemical, and genetical analyses of the Metridium spp. complex see Bucklin & Hedgecock 1982 Mar Biol 66: 1. In a later study on the same research topic of the Metridium complex, another set of authors asks, “how did an organism as conspicuous as M. giganteum escape formal description until now?”. The question is not really a fair one, as the authors of the 1982 paper do describe its presence, but just fail to provide a name for it. Fautin et al. 1989 The Wasmann J Biol 47: 77.
NOTE² in a recent paper a consortium of Russian and Canadian scientists splits the commonly designated snakelock anemone Cribrinopsis fernaldi into two species based upon morphological and molecular data. The first, the one we usually consider as C. fernaldi, is larger with longer tentacles, has a conspicuous ring of marginal projections (verrucae) around the top of the column, has a white column with pinkish tentacles, and usually inhabits muddy bottoms. The other, now designated as C. rubens n. sp. is smaller with shorter tentacles, unformly red or white in colour, and inhabits rocky habitats. The two species also differ in their complements of cnidae (nematocysts). Sanamyan et al. 2019 Mar Biodiv https://doi.org/10.1007/s12526-019-00956-w
Fig. 1. Snakelock anemone Cribrinopsis fernaldi with inset photo showing close view of verrucae on the upper column rim
Fig. 2. Sea anemone Cribrinopsis rubens n. sp. on rock wall showing red and white colour morphs 0
Courtesy Neil McDaniel, British Columbia