Scientific Name and Authority

Ciona savignyi   Herdman, 1882


Description:

Ciona savignyi is a solitary tunicate with a smooth, elongated, cylindrical or vase-shaped body which can reach a length of 150 mm long. It is widest near the permanently attached posterior end and tapers toward the anterior end, compressed laterally. The tunic is transparent, translucent, and white or yellowish-green in color. Much of the tunic is soft, flexible and gelatinous. The muscle bands and organs are often visible beneath the tunic surface. Its siphons are on short, forwardly directed (not divergent) and the oral siphon is larger than the atrial siphon. The oral siphon has 8 lobes, each with a yellow margin containing 8 reddish-orange spots. The atrial siphon has 6 lobes, each with a yellow margin containing 6 reddish-orange spots. There are 5-7 conspicuous longitudinal muscle bands on each side of the body that extend nearly the entire length of the body (Van Name 1945; Kott 1985; Lambert and Lambert 1998).

Ciona savignyi is very similar in appearance to C. intestinalis, but there are a few notable morphological differences. Ciona savignyi always has white pigmented flecks, or spots, in its body wall while C. intestinalis lacks these. Additionally, C. savignyi has orange pigmentation around the siphon while C. intestinalis has yellow pigmentation (Smith et al. 2010). The number of tentacles around the oral siphon is variable in both species, but generally C. savignyi have fewer (n<50) tentacles than C. intestinalis (Hoshino and Nishikawa 1985). Ciona savignyi does not have an endostylar appendage while C. intestinalis has endostyles. Additionally, the pharyngeo-epicardiac openings in C. savignyi are located close to the oesophageal opening while in C. intestinalis these openings are usually very small and located near its base (Hoshino and Nishikawa 1985). Lastly, the color of the enlarged end of the vas deferens is always white in C. savignyi and red in the West Coast C. intestinalis (Lambert and Lambert 1998).

Taxonomic Classification:


Kingdom: Animalia
Phylum: Chordata
Subphylum: Tunicata
Class: Ascidiacea
Order: Phlebobranchia
Family: Cionidae
Genus: Ciona
Species: savignyi

Synonyms:

Ciona aspera (Herdman, 1886)

Potentially Misidentified Species:

Ciona intestinalis

Ritter 1913, mis-identification of specimen from Loring, Alaska (Lambert 2003)


Ciona robusta