Halocynthia aurantium (Pallas, 1787)

Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, Zootaxa 4657 (3), pp. 401-436 : 424

Halocynthia aurantium (Pallas, 1787)

Figure 12A

IHAK 50 BHAK 1720 UF 2532. Hakai Passage , Port Reef, Scuba, 21 m. Vertical rock wall, fast current. Large: 10 cm long including siphons, 5.5 cm wide at base .

IHAK 52 BHAK 1727 UF 2539. Mouth of Kwakshua , Scuba, 22 m. One small specimen, 4 cm in length .

IHAK 55 BHAK 1737 UF 2548. Kwakshua Petroglyph Cliff, Scuba, 17–20 m, vertical rock wall, high current. One large specimen.

IHAK 67 Under the Pruth Bay dock. Two small specimens.

This is a large species, orange or reddish-orange in color, often up to 10 cm in length but 15 cm specimens have been recorded ( Ritter 1900). Although both siphons are at the anterior end, the atrial siphon is somewhat recurved ( Fig. 12A ). The tunic is thickly covered with small rounded papillae with very short spines projecting from the top of each papilla. There are longer minutely branched spines around the siphons. It is closely related to the North Atlantic H. pyriformis (Rathke, 1806) but based on an extensive comparison of the two species by Ritter (1913), there are distinct differences such as number of gonads, pattern of tunic spines, and length/width ratio. Van Name (1945) summarized these differences. In the NE Pacific this species’ native range extends from Alaska to Washington ( Huntsman 1912a, b; Van Name 1945; Lambert CC et al. 1996). It is also native in the NW Pacific and is extensively cultured for food in northern Japan, while wild specimens are collected for food in Korea and Russia ( Lambert et al. 2016).

Figures

FIGURE 12.A–D: Pyuridae; E, F: Molgulidae.A: Halocynthia aurantium 10 cm in length; B: Halocynthia igaboja; C: Boltenia villosa; D: Pyura haustor; E: Molgula pacifica whole animal left side, tunic removed; F: M. pacifica close-up of siphons. Scale bars: B, 5 mm; C, 5 mm; D, 5 mm; E, 1.6 mm.