Pseudochitinopoma occidentalis ( Bush, 1905 )

Bastida-Zavala, J. Rolando, 2008, Serpulids (Annelida: Polychaeta) from the Eastern Pacific, including a brief mention of Hawaiian serpulids, Zootaxa 1722, pp. 1-61 : 38-39

Pseudochitinopoma occidentalis ( Bush, 1905)

( Figures 9A–D)

Hyalopomatopsis occidentalis Bush, 1905: 229–230 , pl. 40, figs. 3, 22; pl. 44, figs. 2, 4, 8–9. Type locality: Virgin Bay , Prince William Sound, Canada.

Pseudochitinopoma occidentalis .— Zibrowius, 1969: 7–9, figs. 2a–g (revision of the species).

Material examined. Two hundred twenty-six specimens: Alaska ( USA), SERC s.v., 136 spec. (several bays in Alaska : approx. 53º53’N, 166º31’W, Dutch Harbor , approx. 59º36’N, 151º25’W, Kachemak Bay , approx. 61º07’N, 146º20’W, Valdez Bay , approx. 57º46’N, 152º24’W, Kodiak Bay , approx. 57º02’N, 135º20’W, Sitka , PVC fouling plates, 1999–2002). Washington ( USA), SERC s.v., 75 spec. (approx. 47º39’N, 122º22’W, Puget Sound , PVC fouling plates, 1999–2002). Oregon ( USA), SERC s.v. (approx. 43º20’N, 124º19’W, Coos Bay , PVC fouling plates, 1999–2002). California ( USA), LACM-AHF N1908 (approx. 36º36’N, 121º53’W, Monterey Shale, dredged off Del Monte, 12–16 m, June 3, 1934, coll. E.F. Ricketts, as Ditrupa sp. ); LACM-AHF N1909 , 2 spec. (approx. 37º12‘N, 122º24‘W, Moss Beach, July, 1933, as? Ditrupa ); LACM-AHF N1910 , 2 spec. (approx. 37º12‘N, 122º24‘W, Moss Beach, 1934, as? Ditrupa ); SERC s.v., 9 spec. (approx. 37º46‘N, 122º23‘W, San Francisco, PVC fouling plates, 1999–2002) .

Diagnosis. Tube white, smooth, with a longitudinal ridge, lacks crests, peristomes or alveoli. Opercular peduncle smooth, white. Operculum fleshy, white, spherical or conical in shape ( Figs 9A–B). Collar with (more or less) fin-and-blade chaetae, with proximal denticulate expansion close to distal limbate zone ( Fig. 9D). Thoracic uncini with anterior bifurcate tooth.

Habitat. Depth: intertidal to 16 m; Zibrowius (1969) recorded it from shore to 229 m. Fouling species.

Distribution. North-eastern Pacific. From Alaska to California ( USA) ( Zibrowius 1969).

Taxonomic remarks. Ten Hove (1975) noted that Pseudochitinopoma occidentalis could be confused with Pseudovermilia conchata , since both species co-occur in California waters; but both species differ in the collar chaetae, fin-and-blade in Pseudochitinopoma occidentalis ( Fig. 9D) and hooded (limbate) chaetae in Pseudovermilia conchata . Although the opercula of both species superficially are similar, the operculum of P. conchata has a fleshy bulbous part, slightly transparent, and a horny cap, sometimes with a spine on top ( Fig. 9E); while in P. occidentalis all the operculum is fleshy and opaque, without a spine ( Figs 9A–B).

Remarks. Abdomen with more or less rounded oocytes ( Fig. 9C).