Epizoanthus scotinus Wood, 1958

Common name(s): Zoanthid, Yellow zoanthid

Synonyms: NW Island zoanthids
Phylum Cnidaria
 Class Anthozoa
  Subclass Zoantharia
   Order Zoanthidea
    Family Epizoanthidae
Epizoanthus scotinus from about 5 m depth, Northwest Island.
(Photo by: Jim Nestler, July 2005)
Description:  This anemone-like cnidarian lives in groups, with individuals connected to one another at the base by a sheet of tissue to make a clonal colony.  The column of individuals may have embedded sand or other material.  Subtidal.  Color tan, light yellow, or brown, with light yellow or white tentacles (paler than the column).  Height to about 5 cm, diameter to about 2 cm.  Colony may be 1-2 m wide.

How to Distinguish from Similar Species:  This is the only species of zoanthid in our area.  While Anthopleura elegantissima anemones aggregate, they are not actually attached together, plus they are green and intertidal.

Geographical Range:  Western Aleutian Islands, Alaska to northern Channel Islands, CA

Depth Range:  Low intertidal to 54 m

Habitat:  Rocks in strong current

Biology/Natural History:  These individuals reproduce asexually by budding, thus adding to the colony.  They can also reproduce sexually.  These animals may take several hours to expand again if they are stimulated to contract.

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Dichotomous Keys:
  Kozloff 1987, 1996

General References:
  Gotshall, 1994
  Gotshall and Laurent, 1979
  Harbo, 1999
  Kozloff, 1993

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

I have not seen these colonies before 2005 around Rosario, but perhaps that is because they are not particularly showy and I haven't noticed them.  I was startled to see Jim Nestler's 2005 photo of zoanthids right from Northwest Island.  I will have to watch more carefully for them.

Here are some photos of zoanthids I found in a colony about 0.5m across under an overhang at Sares Head at about 10 m depth. Photos by Dave Cowles, August 2020. Individual polyps are about 0.5 cm diameter. Notice how their bases are actually joined together, which clearly distinguishes them from anemones.

Authors and Editors of Page:
Dave Cowles (2005):  Created original page