Phylum: Mollusca Lottia pelta Class: Gastropoda, Patellogastropoda Order: The shield, or helmet limpet Family: Lottioidea, Lottiidae Taxonomy: A major systematic revision of (Sorensen and Lindberg 1991). May be fouled the northeastern Pacific limpet fauna was with a sabellid (Kuris and Culver 1999). undertaken by MacLean in 1966. Notoac- Interior: Blue gray to white, with mea was at first considered a subgenus and subapical brown spot (fig 3), and horseshoe- then later a full genus (MacLean 1969). Col- shaped muscle scar joined by a thin, faint line lisella was synonymized with Lottia, and lat- (fig. 3) (Keen and Coan 1974). Uses suction er Notoacmea was replaced with Tectura to attach to substratum, as well as a glue that (Lindberg 2007). The current practice in may be helpful in maintaining a seal around The Light and Smith Manual is to use only the edge of their feet on irregular surfaces Acmaea and Lottia to describe Pacific North- (Smith 1991). west species (Lindberg 2007). Possible Misidentifications Description Many species of limpets of the family Size: 25mm (Brusca and Brusca 1978); can Acmaeidae occur on our coast, but only about reach 40 mm farther north (Kozloff 1974b four are found in estuarine conditions. Lottia Yanes and Tyler 2009); illustrated specimen, scutum (=Notoacmaea), which, like Lottia pel- 32.5 mm. ta, have a horseshoe-shaped muscle scar on Color: Extremely variable dependent on the shell interior, joined by a thin curved line, substrata (Sorensen and Lindberg 1991); and various coloration, but not pink-rayed or called the brown and white shield limpet by white. These two genera differ in that L. pelta Ricketts (Ricketts and Calvin 1971); gray, has a pair of uncini or teeth on the radula (not slightly raised ribs with white, sometimes figured), while L. scutum does not. L. scutum green, between them; some specimens also has significantly longer cephalic tentacles without ribs, but with a checkered or striped (5.5mm) than Lottia (3.7mm) (Bros 1986) and pattern. Slightly hooked apex eroded. are usually not as heavily ribbed as Lottia Shell: species (Keen 1971). Lottia scutum is also Shape: Elevated, height usually found only occasionally in bays, is thick 1 greater than /3 length (Carlton and shelled, and rather flat with coarse lines quite Roth1975); surface with fine regular ribbing, like those of L. pelta. It has a subcentral apex anterior space straight or very slightly con- and a low elevation and is often filmed with cave; apex subcentral, very slightly directed algae. anteriorly (fig 2); posterior slope slightly con- Lottia digitalis, the common fingered vex, nearly straight (Kozloff 1974a). Margin limpet, differs from L. pelta in having an apex slightly scalloped with contour intervals 1.11 very close to or even overhanging the anterior mm on a 3 cm individual, and when oriented margin, which forms a strong hook; its anteri- anteriorly upstream exhibits 40% reduction or slope is concave. This species has strong in drag at 1.6 m/s water velocity (Denny raised ribs and a moderately scalloped edge; 1989). Exhibits several ecophenotypes or its rough ribs may show only on the posterior “morphs” based on its substrata and diet slope. It occurs higher in the tidal range than A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Knorek, Z. 2015. Lottia pelta. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. does L. pelta. cladia. Lottia strigatella, once thought to be a Abundance: Not common in bays; relatively hybrid of Lottia digitalis and L. pelta, has common on outer coast (Brusca and Brusca been found just inside Coos Bay. Like L. dig- 1978). italis, it has a hooked apex near the anterior Life-History Information margin, and a slightly concave anterior Reproduction: Separate sexes; eggs rose slope. It is a bay dwelling form of Lottia colored (Hadfield and Strathmann 1996) with limatula, L. I. moerchii, has a higher eleva- sperm shed into sea. In lab, ova developed tion than the usual form of that species. It into trochophore larvae 24 hours post-spawn, has buff and dark mottling, or greenish and after 3-4 days are capable of retracting brown with white bands; its ribs are imbricat- into their post-torsional shells; many settled ed (set like tiles); its edges are serrated. It after 8 days and metamorphosed after 28 has not been found as far north as Oregon. (Hadfield and Strathmann 1996). Estimated Lottia persona is also found in bays. It pelagic period of 6-7 days in situ with a 3+ is large, nocturnal and smooth. It has an an- week-long settlement phase following thereaf- terior hooked apex and is dark brown with ter (Hadfield and Strathmann 1996). Active white checked edges. throughout year; spawns at sea temperatures Lottia pelta young can resemble the of 48.5°-60°F (Fritchman 1962). limpet Lottia insessa which lives only on the Larva: marine alga Egregia. N. insessa adults are Juvenile: Some subadults (over 6 mm) with brown, translucent and smooth. (See Young, dark brown exterior, lustrous, smooth and with above). fine radial sculpture, living on alga Egregia. Ecological Information Interior light brown to gray, with postapical Range: Aleutian Islands to Punto Santo To- brown spot. (Lottia insessa, of which subadult mas, Baja California (Ricketts and Calvin pelta is similar, is dark brown inside.) 1971). Longevity: Local Distribution: Coos Bay, South Growth Rate: Probably grows faster than C. Slough and Cape Arago. digitalis, to 30 mm in 3 years (Abbott and Habitat: On rocks (locally), also with various Haderlie 1980). algae (e.g. Laminaria, Egregia; Abbott and Food: They consume a variety of microscopic Haderlie 1980) and in mussel beds (Carlton and large algae, but especially common erect and Roth 1975); eurytopic; South Slough: on algae (Abbott and Haderlie 1980); was shown floats, under rocks. to eat more of the red algae Mazzaella in Salinity: Collected at 30. shaded, warm conditions (Menge et al. 2002); Temperature: significantly reduce the crust thickness of cor- Tidal Level: Just below L. digitalis and N. alline algae Lithophyllum impressum (Steneck persona (Puget Sound) at 0.15 to 1.8 m et al. 1991). (Tyler et al. 2014); on rocks usually uncov- Predators: Seastars: Pisaster ochraceus, for ered by the tide. On outer coast, upper-mid which it has developed an escape mechanism to lower mid-intertidal (Brusca and Brusca (Margolin 1964); few (2.4%) drilled by Nucel- 1978). la, to which L. pelta may be resistant at a cer- Associates: Lottia digitalis; in mussel/ tain size (14mm in elevation, 25 mm in length; barnacle aggregations on pilings. With algae Yanes and Tyler, 2009); black oyster catcher Egregia, Postelsia, Laminaria, and Endo- (Haematopus bachmani), whom has difficulty A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] in visually predating L. pelta morphs that 4:134-140. match their substrate (Sorensen and Lind- 7. HADFIELD, M. G. and M. F. STRATH- berg 1991); experimental caged protection MANN. 1996. Variability, flexibility and against bird depredation did not result in in- plasticity in life histories of marine inverte- creased L. pelta abundance (Wootton, brates. Oceanologica Acta. 19: 323-334. 1992); one laboratory feeding trial reported 8. KEEN, A. M. 1971. Sea shells of tropical 57% mortality due to predation by cancrid west America; marine mollusks from Baja crabs (Tyler et al. 2014). California to Peru. Stanford University Behavior: A small percentage exhibit hom- Press, Stanford. ing behavior (Abbott and Haderlie 1980); do 9. KEEN, A. M., and E. COAN. 1974. Marine not feed at all high tides and will only move molluscan genera of Western North Ameri- and feed when submerged or wet by waves ca: An illustrated key. Stanford University (Abbott and Haderlie. 1980). Press, Stanford, California. 10. KOZLOFF, E. N. 1974a. Keys to the ma- Bibliography rine invertebrates of Puget Sound, the San 1. ABBOTT and HADERLIE. 1980. Proso- Juan Archipelago, and adjacent regions. branchia: Marine Snails. In: Intertidal in- University of Washington Press, Seattle & vertebrates of California. R. H. Morris, D. London. P. Abbott, and E. C. Haderlie. Stanford 11. ——.1974b. Seashore life of Puget Sound, University Press, Stanford, California. the Strait of Georgia, and the San Juan 2. BROS, W. E. 1986. Mortality of the lim- Archipelago. University of Washington pets, Collisella pelta (Rathke) and No- Press, Seattle & London. toacmea scutum (Rathke), as a function 12. KURIS, A. M and C. S. CULVER. 1999. of predation from the seastar, Pisaster An introduced sabellid polychaete pest in- ochraceous (Brandt). Bulletin of Marine festing cultured abalones and its potential Science. 39(1): 92-101. spread to other California gastropods. In- 3. BRUSCA, G. J., and R. C. BRUSCA. vertebrate Biology. 118: 391- 1978. A naturalist's seashore guide. Mad 403MARGOLIN, A. S. 1964. A running re- River Press, Arcata, CA. sponse of Acmaea to seastars. Ecology. 4. CARLTON, J. T., and B. ROTH. 1975. 45:191-193. Phylum Mollusca: Shelled Gastropods, p. 13. LINDBERG, D.R. 2007. Patellogastropo- 467-514. In: Light's manual; intertidal in- da, p. 753-761. In: The Light and Smith vertebrates of the central California Manual: intertidal invertebrates from cen- coast. S. F. Light, R. I. Smith, and J. T.