Eudistoma ritteri Van Name, 1945

Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, Zootaxa 4657 (3), pp. 401-436 : 407

Eudistoma ritteri Van Name, 1945

Figure 3 D–F

IHAK 50 BHAK 1721, 1722, 1723. UF 2533, 2534, 2535. Hakai Passage, Port Reef vertical rock wall, fast current, Scuba, 21 m. Probably all three samples are from same colony. RHAK 6 Seventh Beach, north wall, low intertidal tide pool. With Aplidium kottae and Euherdmania claviformis ( Ritter, 1903 ). RHAK 6 BHAK 0633 UF 2484. Seventh Beach, north wall, low intertidal tide pool, single colony. RHAK 6 BHAK 0656 UF 2505. With parasitic copepods ZHAK 35 BHAK 3251 UF 2569. Sasquatch Commode tidepool.

Colonies with thick short stalks rising from a common base; the heads are smooth, tan or yellowish in color, translucent with the zooids visible through the tunic. There is no sand on the protruding heads, but the bases of the stalked columnar lobes are completely covered and embedded densely with sand grains. As with Cystodytes lobatus , zooids form roughly circular systems though their siphons open independently at the tunic surface. One intertidal colony had parasitic copepods in the tunic. For complete description of the species see Van Name (1945) and Levine (1962). Distribution: common from Alaska to southern California, in exposed wave-swept tidepools and subtidally in regions with good current ( Van Name 1945; Levine 1962; Abbott & Newberry 1980; Lambert et al. 1996; O’Clair & O’Clair 1998; Abbott et al. 2007).

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.