Phylum Cnidaria
Class Anthozoa
Subclass Zoantharia
Order Actiniaria (anemones)
Family Actiniidae

Genus/species: Anthopleura xanthogrammica

GENERAL CHARACTERISTICS: A  solitary species and one of the largest species of anemone in the world. Column to 30 cm (12 in) tall and 30 cm (12 in) tentacular crown with 25 cm (10 in ) diameter mid base. The base bottom is only slightly larger than column diameter and adheres to rocks.  Tentacles are green, blue, or white without pink on the tips.  No marks or bands.  The oral disk is flat and usually green, but can be grayish-blue to greenish-blue.  Contracted animals form a green to dark greenish-brown, occasionally white hemispherical mound.

DISTRIBUTION/HABITAT: Alaska to Panama in prefers rocky areas and deeper tide pools of the low to middle intertidal zones to 9 m (30 ft), and wharf pilings. Usually solitary; in favorable locations can occur in numbers to 14 per square m.

DIET IN THE WILD: Detached mussels and sea urchins, also take crabs and small fishes. Zoochlorellae endosymbionts supplement host’s diet.

PREDATORS: Nudibranchs, snails, sea spiders and some sea stars, especially leather stars.

REPRODUCTION: A. xanthogrammica have separate sexes releasing sperm and eggs in late spring to summer. The larvae swim or float freely. They do not use asexual reproduction.


REMARKS: Some fishes and the hermit crab Pagurus samuelis develop protection from the anemone’s toxins by covering themselves with mucus that prevents them from being stung.

The bright green can be attributed to green pigment in the anemone epidermis and to symbiotic algae that live in the tissues that line the gut. Inside there may be zoochorellae (green algae) or zooxanthellae, which are dinoflagellates. The symbiotic algae are reduced in numbers or even absent (aposymbiotic) when in shady areas.

LOCATION: Tidepool and California coast.


Walla Walla University…



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