How to Distinguish from Similar Species: The only other solitary ascidians with an opaque tunic and with spinelike projections have no distinct stalk and the projections have side branches arranged in circles.
Geographical Range: Southern Alaska to San Diego, CA. Most common on outer coasts.
Depth Range: Low intertidal to 100 m
Habitat: Attached to hard substrates in water with good circulation
Biology/Natural History: This species concentrates vanadium in its body tissues (500-750 ppm by dry weight, excluding the tunic). These are some of the highest levels of vanadium concentration seen in tunicates. Diet includes crustacean nauplii, mollusc veligers, and eggs. Predators include the seastars Dermasterias imbricata and Orthasterias koehleri, and the predatory Oregon triton snail Fusitriton oregonesis . Sometimes contains the symbiotic crab Pinnotheres pugettensis or the several species of copepods. Gametes are ripe year-round, but mainly in the summer. Fertilization is external. Settle 6 hours to 5 days after hatching.
Flora and Fairbanks, 1967
Kozloff 1987, 1996
Smith and Carlton, 1975
Zeng, Liyun, Molly W. Jacobs, and Bill J. Swalla, 2006. Coloniality has evolved once on Stolidobranch ascidians. Integrative and Comparative Biology 46:3 pp 255-268
General Notes and Observations: Locations, abundances, unusual behaviors:
Authors and Editors of Page:
Dave Cowles (2006): Created original page