Boltenia villosa (Stimpson, 1864)
Common name(s): Spiny-headed tunicate, hairy sea squirt, stalked hairy sea squirt, bristly tunicate
|Boltenia villosa from subtidal near Rosario. Marks in background are mm, with cm noted.|
|(Photo by: Dave Cowles, July 2006)|
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.
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Morris et al., 1980
O'Clair and O'Clair, 1998
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
This closeup of the individual above shows the siphons partly open.