Type material. Monashka Bay, Kodiak Island, Alaska, leg. GJ. Vermeij, 24 June 1987, rocky intertidal zone, holotype LACM 3488, 29.8 mm, lv.
Distribution. Southern Alaska east of the Aleutian Islands.
Description. Shell of moderate size for genus, maximum length 31.9 mm, ovate, slightly constricted abapically; spire low, comprising 23 to 29% of total shell length. Teleoconch whorls rounded, not angulated at shoulder. Suture deeply impressed but not channeled. Axial sculpture absent except for squamose growth lines in uneroded specimens. Spiral sculpture consisting of high rounded primary cords, one smaller secondary cord between adjacent primary cords. First whorl with IP, PI1 sl, P2, s2, second whorl with IP, P1, sl, P2, s2, starting adis, abis, P3, final whorl with adis, IP, abis, P1, t, sl, t, P2, t, s2, t, P3, s3, P4, s4, P5, s5, P6, t, s6, ADP, ads, MP, ABP. Aperture relatively narrow, ovate. Columellar lip narrow, adherent throughout length, smooth. Outer lip planar, very slightly produced abapically, thin, crenulated at edge, without sculpture on inner side. Siphonal canal short, widely open.
Remarks. Nucella angustior was long confused with N lima (Gmelin, 1791), but molecular data (Cox et al 2014) demonstrate that the two species are phylogenetically distinct while showing partial geographic overlap between the Aleutian Islands and northern Vancouver Island, and displaying overlapping morphological ranges. Compared to TV. lima, N. angustior tends to have a higher spire, narrower aperture, and smaller maximum size. In N. lima, the spire comprises 9-25 % of total shell length, as compared with 23—29% in N. angustior. Nucella angustior occurs in southern Alaska east of the Aleutian Islands, and may extend as far south as northern Vancouver Island. Nucella lima is distributed from the eastern Aleutian Islands westward to Kamchatka (Cox et al. 2014). In short, subtle, partially overlapping differences in shell morphology together with molecular differences and partially overlapping geographical ranges distinguish N. angustior and N. lima.