Pyura haustor ( Stimpson, 1864 )

Lambert, Gretchen, 2019, The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz, Zootaxa 4657 (3), pp. 401-436 : 425

Pyura haustor ( Stimpson, 1864)

Figure 12D

IHAK 12 BHAK 0610, 0611, 0612 UF 2467, 2468, 2469. Common in the low intertidal under rocks by lab, small.

IHAK 31 BHAK 1696 UF 2520. Triquet Island Macro site, Scuba, 8 m. Tiny, on Pugettia richii .

This leathery solitary stolidobranch can be very variable in shape, and so confusing to determine if all the variants are the same species that Ritter (1909) undertook a detailed internal and external examination of many specimens in southern California to determine what he called the “law and order” (!) that delimits a species, long before genetic sequencing was possible. He separated one variant as P. johnsoni ( Ritter, 1909) , but this species was later synonymized by Van Name (1945).

Specimens may attain a height of more than 5 cm not including the length of the siphons. The reddish brown tunic is very tough and irregularly rugose, the long tubular siphons at the anterior end are divergent, and there are sharply pointed siphonal spines ( Van Name 1945; Lambert 2019). The pharyngeal sac contains six folds per side. There is great variability in the number of the branched oral tentacles, with southern California specimens having up to 42 while northern Washington and British Columbia specimens averaging about half that number. See Van Name (1945) for a detailed morphological description. Distribution: Alaska to southern California ( Van Name 1945; O’Clair & O’Clair 1998; Lamb & Hanby 2005) and the Galápagos ( Lambert 2019). In the present study only small specimens were collected, mostly under rocks near the marine station.

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.