Cystodytes lobatus ( Ritter, 1900 )

Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, Zootaxa 4657 (3), pp. 401-436 : 405-406

Cystodytes lobatus ( Ritter, 1900)

Figure 3A, B

IHAK 50 BHAK 1726 UF 2538. Hakai Passage , Port Reef, about 21 m depth, Scuba .

IHAK 60 BHAK 3245 UF 2563. Rattenbury Pinnacle 17–20 m depth, Scuba .

XHAK 10 BHAK 2951 UF 2530. On settlement plate, 5 m depth. Very thin, colorless tunic, overgrowing barnacles and bryo- zoans. Spicules sparse.

This species occurs in two color morphs, either pink with reddish pink pigment granules in the tunic or white with no pigment granules. The colonies are thick, encrusting and irregular in shape, corresponding to the rocky substrates they overgrow, and may attain a size up to 10 cm or more across. The tunic spicules are flat, disc-like, and form an overlapping layer in the tunic that covers the abdominal region of every zooid ( Fig. 3B ). The zooids are arranged in more or less circular systems, though both siphons of each zooid open independently on the tunic surface. Strong longitudinal muscles extending from the thorax to the abdomen make it very difficult to relax these zooids. See Lambert (1979) for a complete description. Distribution: British Columbia to southern California ( Van Name 1945; Abbott & Newberry 1980; Lamb & Hanby 2005).

Figures

FIGURE 3. Aplousobranchia, Polycitoridae. A, B: Cystodytes lobatus. A: whole colony, photo G. Paulay; B: small part of tunic showing disc–shaped spicules. C: Eudistoma purpuropunctatum 10 cm in width. D–F: Eudistoma ritteri. D: separated lobes of a colony; E: part of a different colony; F: thorax of single zooid showing the siphons and the three rows of stigmata. Scale bars: A, 1 cm; B, 0.5 mm; D, 1.3 cm; E, 0.5 cm; F, 1 mm.