Cnemidocarpa finmarkiensis Kiaer, 1893
Common name(s): Broad base sea squirt, Orange sea squirt, Red sea squirt, Shiny orange sea squirt, Shiny red tunicate, Finmark's tunicate
|Synonyms: Cnemidocarpa joannae, Polycarpa finmarkiensis, Styela elsa, Styela finmarkiensis, Styela joannae, Styela stimpsoni, Tethyum finmarkiensis|
|Cnemidocarpa finmarkiensis from 15 m depth off Northwest Island. Scale is in centimeters and mm|
|(Photo by: Dave Cowles, July 2005)|
How to Distinguish from Similar Species: Other tunicates of similar shape are not usually pinkish-red, or have a wrinkled tunic. The sea peach, Halocynthia aurantia, is a similar smooth, shiny pinkish color but it has broader siphons of unequal size and is taller than it is wide. Of other common local smooth, orange tunicates, Metandrocarpa taylori is a social ascidian, with multiple individuals living near each other and connected by narrow stolons or sheets of tunic. Distaplia occidentalis is a compound ascidian with many individuals within the same tunic.
Geographical Range: Alaska to Point Conception, CA; most common from Washington north. Also northwestern Pacific, circumboreal in the Arctic
Depth Range: Very low intertidal to at least 50 m (540 m in Japan)
Habitat: Hard substrates in well-circulated waters. Sometimes found on floats. Sometimes lives in holes.
Biology/Natural History: This species
is hermaphroditic. Fertilization is external, during the summer.
The tunic is thin but tough, with 12.4% organic content. Just over
half the organic matter in the tunic is tunicin (a carbohydrate); the rest
is protein. Vanadium content of the body is low (but higher in the
tunic?) Predators include the seastar Orthasterias koehleri.
The copepod Pygodelphys aquilonarius may live symbiotically in the
branchial chamber and many invertebrates may live around the base.
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Morris etal., 1980
Ricketts et al., 1985
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
In this side view one can see the two siphons (partly retracted) and some material adhering to the tunic.
In this underwater photo of Cnemidocarpa finmarkiensis near Northwest Island by Kirt Onthank (Feb 2006), the siphons are open and partly extended. The animal above is the sea cucumber Psolus chitonoides
Another underwater photo by Kirt Onthank, July 2007