Phylum: lamellosa (= Thais) Class: , Prosobranchia Order: The wrinkled or frilled dogwinkle (Gmelin, 1791) Family: Thaisidae

Description no anal notch (fig. 1). Widest part of aperture Size—to 50 mm (California)(Morris et al. (generally near its middle) at least half as 1980), 100 mm Puget Sound and north wide as shell (Kozloff 1974a). (Kozloff 1974a); largest specimen figured, 54 Umbilicus—small, often closed (fig. 1). mm (fig. 1). Largest of the Nucella. Operculum—usually large enough to close Color—white to brown, some are pink, aperture; conspicuous, with strong spiral lavender or orange tan; not highly polished. lines; with nucleus on one side (fig. la). Inside whitish, sometimes with color showing Eggs—vase-shaped, yellow, about 10 mm through. long; in clusters on underside of rocks (Morris Shell Shape—shell heavy, solid, strong; et al. 1980); called "sea oats"; (fig. lb). spirally coiled, fusiform (spindle-shaped). 5-7 whorls; nuclear whorl small, in-conspicuous. Possible Misidentifications Spire usually high; siphonal canal relatively Nucella can be distinguished from other long for genus; aperture ovate, almost 1/2 predatory estuarine snails by its sculpture, shell length. which is the same on the whorls and spire, by Sculpture—extremely variable. Spire and the large last whorl and by the ovate aperture base have similar sculpture: genus Nucella (about 1/2 the shell length). Unlike Nassarius, (Smith and Carlton 1975, Keen and Coan it has no distinct revolving furrow setting off 1974). Axial ribs present (fig. 1). Three chief the body whorl from the anterior canal (Keen variations with many gradations): lamellar and Coan 1974). It has no single strong tooth variety with strong axial ribs, developed in on the anterior margin of the outer lip, as in quiet water specimens into frilly ruffles (fig. 4); Acanthina. There are no columellar folds as in (2) Nucella from rough conditions are smooth, Olivella, Buccinus, etc. The siphonal canal is with only faint axial sculpture (figs. 1, 3); and not spout-like, as in Ocenebra, and (3) strongly sculptured spirally with one to two Ceratostoma. strong horizontal ribs at top of each whorl and There are several of Nucella in the smaller ribs below; axial sculpture only northwest: between ribs. This variety has flattened and Nucella lima, the file dogwhelk, is a angled whorls (fig. 2) (Kozloff 1974a). subtidal snail with about 16 alternating large Outer Lip—thickened, smooth, without and small file-like spiral ridges on the large denticles on posterior portion of aperture 6 whorl. It is fairly rare, is whitish to brown in (near anal notch) ; no single strong tooth on color, short-spired and somewhat smaller edge near anterior canal (see Possible than N. lamellosa (to 43 mm). Misidentifications). Outer lips rounding Nucella canaliculata, the channeled smoothly to anterior end of shell. At least one dogwhelk, is white to or orange, sometimes row of denticles within lip (fig. 1). banded. It has a high spire, a prominent Columella—(central pillar): without folds shoulder below the deep suture, and rounded (Kozloff 1974a); incrusted, smooth. spiral ridges of equal size with axial lamellae Suture—(between whorls): Impressed, between them. It is small, to just over 30 mm. distinct, but not a deep groove. Usually found in mussel beds, it is rare in Anterior (Siphonal) Canal—short, but longer bays (Kozloff 1974a). than other Nucella species; narrow, slot-like, Nucella emarginata (which see) is the not spout-like (i.e. with edges touching, other Nucella most often to be found in making a closed tube: see Possible estuaries; it usually occurs in heavier surf Misidentifications). Not separated from large than N. lamellosa. Called the rock-dwelling whorl by revolving groove (fig. 1). dogwinkle, it is generally only up to 20 mm Aperture—almost 1/2 length shell; ovate to long. This snail has alternately large and quadrate in outline, with a siphonal notch, but small, often Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]

Life History Information nodulose, spiral ridges over most of the shell. Reproduction—breeding in winter and spring (These ridges are often obscure). It has no (California) by aggregations of snails; noticeable axial sculpture. Found in the individuals become sexually mature in 4th mid- and high intertidal in mussel beds, it is year, when they often return to their hatching easily confused with variation of N. lamellosa site and join a breeding group (Morris et al. (fig. 2). 1980); individuals tend to breed with same Nucella was previously called Thais. This group. Egg capsules deposited synchronously name is now re-served for subtropical and by females; development varies with tropical species. temperature: snails emerge after 140 days (at 6.8°C), after 67-91 days (9.6-11 °C). Ecological Information Capsules rarely contain "nurse eggs" (sterile Range—Bering Strait to central California eggs to be consumed by the developing snail (Morris et al 1980). larvae): nearly all eggs are fertile (Lyons and Local Distribution—Coos Bay: Pigeon Point, Spight 1973). Just over half of eggs reach Empire; Umpqua estuary: Ziolkouski Beach hatching stage; high mortality among young (1/2 mile from mouth). snails: of 1000 eggs (from one female, one Habitat—on rocks with mud, sand substrate; year), probably fewer than 10 grow to 1 year often in protected bays (Carlton and Roth of age. 1975); below mussel beds on outer shores. Growth Rate—varies greatly with food Salinity—collected at 30 ‰ salt: lower, more supply. Shell growth, type, dependent on marine parts of bays with more constant food: barnacle diet produced heavy, stout saline concentrations. shells. Temperature—cold to temperate waters: Longevity—sexually mature at four years geographic distribution would indicate a (Morris et al. 1980). preference for cool temperatures. Lower part Food—primarily barnacles: Balanus glandula of bay does not generally have high and B. cariosus, on which it is the primary temperatures. Smallest individuals have predator (Puget Sound) (Kozloff 1974a). highest thermal limits; snails active at 0-30 °C Mussels (outer shores), periwinkles and other (Bertness 1977). mollusks. Radula penetrates shell of prey with Tidal Level—found at low intertidal, below aid of secretions from boring organ on foot other species of the genus. Largest (Morris et al. 1980). lowest in tidal range (Bertness 1977). Predators—egg capsules and young snails Associates—its primary prey: barnacle heavily preyed upon by other Nucella. Balanus; the under-rock community: porcelain crab Petrolisthes, brachyuran crabs Literature Cited Hemigrapsus and Cancer oregonensis, chiton Mopalia, isopod Idotea, anemones 1. BERTNESS, M. D. 1977. Behavioral Anthopleura elegantissima and A. artemesia, and ecological aspects of shore-level nudibranch Onchidoris, gastropod Tegula; gradients in Thais lamellosa and Thais Pisaster ochraceus. Discarded N. lamellosa emarginata. Ecology. 58:86-97. shells are often inhabited by the hermit crab 2. CARLTON, J. T., and B. ROTH. 1975. Pagurus hirsuitusculus. Phylum Mollusca: Shelled Gastropods, p. 467-514. In: Light's manual; Quantitative Information intertidal invertebrates of the central Weight—largest collected (including shell) 28 California coast. S. F. Light, R. I. gr. (wet). Smith, and J. T. Carlton (eds.). Abundance—one of the most abundant University of California Press, intertidal snails of the northwest; becomes Berkeley. less abundant in California. By far the most 3. KOZLOFF, E.N. 1974a. Keys to the common Nucella species in the Coos Bay marine invertebrates of Puget Sound, estuary. the San Juan Archipelago, and adjacent regions. University of Washington Press, Seattle & London. Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] 4. LYONS, A., and T. M. SPIGHT. 1973. invertebrates of California. Stanford Diversity of feeding mechanisms University Press, Stanford, California. among embryos of Pacific Northwest Thais. The Veliger. 16:189-194. 5. MORRIS, R. H., D. P. ABBOTT, and E. C. HADERLIE. 1980. Intertidal

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]