Ciona savignyi Herdman, 1882

Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, Zootaxa 4657 (3), pp. 401-436 : 420

Ciona savignyi Herdman, 1882

Figure 10D

IHAK 18 BHAK 0637, 0638 UF 2488, 2489. Underside of lab dock. Two small, 4 cm long in tunic.

IHAK 23 BHAK 1684 UF 2514. Kelpie Point Scuba, 15 m. In shell of dead Balanus nubilus Darwin 1854 .

IHAK 55 BHAK 1734 UF 2545. Kwakshua Petroglyph Cliff, Scuba, 17–20 m. Vertical rock wall, high current .

XHAK 1 BHAK 0635, 0648 UF 2486, 2498. Maey Channel ARMS 7.3 m. Two specimens on plate, longest 6.2 cm long.

Like all Ciona Fleming, 1822 species, C. savignyi is distinguished by several wide longitudinal muscle bands on each side of the body wall; five are visible through the transparent tunic in Fig. 10D . There is no red spot at the end of the sperm duct as in Ciona robusta Hoshino & Tokioka, 1967 . Numerous whitish, yellow or orange spots are always visible in the body wall. The species may attain a length of up to 10 cm or more. A detailed morphological description is given by Hoshino & Nishikawa (1985).

The species is native to Japan but there is a 1903 dredging record of it from Alaska ( Ritter 1913) and a 1937 record from a floating dock in southern British Columbia (see Hoshino & Nishikawa 1985); both records had originally been misidentified as Ciona intestinalis (Linnaeus, 1787) until reexamined by Hoshino and Nishikawa. Two specimens were recently collected from Ketchikan, Alaska, the first Alaska record since 1903 ( Jurgens et al. 2018). It is considered cryptogenic in the present study.

Since the 1980’s it has become very abundant from southern British Columbia to southern California as a fouling organism on floating docks in marinas and also subtidally on natural substrates down to 20 m depth, and is considered introduced in those locations ( Lambert & Lambert 1998, 2003; Lambert 2003; Lamb & Hanby 2005).

Figures

FIGURE 10. Figure 10. Phlebobranchia. A, B: Ascidia columbiana. A: whole animal right side, anterior on the right. Arrows indicate oral siphon opening (on right) and atrial opening above. B: anterior end around oral opening showing tunic papillations. C: Ascidia paratropa 9 cm in length; D: Ciona savignyi 6.2 cm in length; E: Chelyosoma productum 1.5 cm in diameter; F: Corella inflata about 3 cm in length; G: Corella willmeriana about 3 cm in length; H: Perophora annectens. Scale bars: A, 1.5 cm; B, 2 mm; H, 4 mm. C, D, F, G photos by G. Paulay.