Phylum: Mollusca

Littorina sitkana Class: Gastropoda, Caenogastropoda

Order: Littorinimorpha The Sitka littorine Family: Littorinoidea, Littorinidae, Littorininae

Description confused with L. sitkana in Oregon estuaries: Size: to 15 mm (Kozloff 1974b); but usually Littorina scutulata is taller than wide, under 12.5 mm (Ricketts and Calvin 1971); with a purple interior and often with a checker- Coos Bay specimens: 4-9 mm, average board pattern on its whorls (never with a about 7 mm. strong spiral sculpture). It is found on wrack, Color: rough variety (fig 1) can be solid col- and rarely in saltmarshes, where L. sitkana ored: plain buff or gray. A smoother variety predominates. (figs 2, 3), has strong spiral sculpture ap- Littorina planaxis is stout, like L. sit- pearing as horizontal bands, especially on kana, and usually quite a bit bigger; its sur- the largest whorl-brown to yellow or orange: face is plain, without spiral sculpture; it has a these bands can be visible inside aperture white band inside the aperture, and a charac- and are usually fainter on upper whorls. Ani- teristic flat, roughened area between the colu- th mal white, with black on tentacles and snout mella and the 4 whorl. It is an outer coast, (fig 4). rocky shore species. Shell: The introduced European periwinkle, Shape: turbinate, thick, pointed, few- Littorina littorea, has been found in San Fran- whorled (3-4); aperture rounded, outer lip cisco and Trinidad Bays. It is thick shelled, acute: genus Littorina (Oldroyd 1924). This smooth, dark brown to black, with many very species stout, globose, almost as wide as fine horizontal lines. high (in contrast to L. scutulata, for in- Littorina (Algamorda) newcombiana stance). belongs to an unusual subgenus with a simple Columella: rather flattened inner lip, chink between the columella and the largest not perforated: genus Littorina; rounded, up- whorl. It is very small: to 6 mm, but averaging per columella is flush with 4th whorl (fig 2a): 3.5 mm, tall, with a smooth shiny surface cov- no gap between columella and whorl: genus ered with a brown periostracum. Its color is Littorina. tan or white, with brown or black horizontal Operculum: oval (paucispiral); a sol- stripes at times on the largest whorl. Small id, horny, trap door (fig 1). specimens of L. sitkana can look very like L. Body: white, with cephalic tentacles only (fig (A.) newcombiana; the important differences 4), no metapodial, or foot tentacles (see La- are the simple chink next to the columella, the cuna porrecta, fig 5). taller profile, small size and lighter base color of L. (A.) newcombiana. This latter, like L. sit- Possible Misidentifications kana, is a salt marsh inhabitant, although it is Littorines are turbinate, thick, pointed found very high in the tidal zone. and few-whorled, with a rounded aperture Another similar genus is Lacuna, the and an acute outer lip. The columella is ra- chink snail, quite tiny (2-4 mm) and distin- th ther flattened but flush (appressed) with 4 guished from Littorina sp. chiefly by a definite whorl, and lacks a columellar groove. There groove or gutter between the columella and are 3 other species of genus that might be 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]

Unknown. 1983. Littorina sitkana. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to 140 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.

the whorl. Two species, L. porrecta (which Growth Rate: see) and L. marmorata, have been found in Food: herbivorous; scrapes algae from sub- our area, but usually in eelgrass, not in Sali- strate with radula. cornia marshes. Predators: Behavior: Ecological Information Range: southern limit seems to be about Bibliography Cape Arago, near Coos Bay. North to Bering 1. KEEN, A. M., E. COAN, and C. L. DOTY. Sea (Oldroyd 1924). Not included in Califor- 1942. An annotated check list of the gas- nia keys. tropods of Cape Arago, Oregon. Studies in Local Distribution: Coos Bay: South Zoology. 13. Slough. 2. KOZLOFF, E. N. 1974b. Seashore life of Salicornia Habitat: quiet areas of marshes Puget Sound, the Strait of Georgia, and under debris and marsh weed. Seems to the San Juan Archipelago. University of need less protection than other thinner Washington Press, Seattle & London. snails (Matthews 1979). In Puget Sound, 3. MATTHEWS, R. 1979. A comparative found with barnacle/mussel association on study of preferred salinities among South or under rocks, as well as in marshes Slough snails. Oregon Institute of Marine (Kozloff 1974b). Biology (University of Oregon). Salinity: Littorinidae generally can withstand 4. OLDROYD, I. S. 1924. Marine shells of salinity changes well (Keen et al 1942): con- Puget Sound and vicinity. University of ditions that can prevail in salt marshes. Pre- Washington Press, Seattle. fers salinity of 24 ‰ or saltier; found at 23- 5. RICKETTS, E. F., and J. CALVIN. 1971. 30 ‰ (Matthews 1979). Between Pacific tides. Stanford University Temperature: intertidal saltmarsh tempera- Press, Stanford, California. tures can vary greatly: L. sitkana adapts well. Updated 1983 Tidal Level: near the high-tide mark (Kozloff 1974b). Associates: sphaeromid isopods, amphipod Traskorchestia traskiana, pulmonate snail Ovatella myosotis, tiny snail Assiminea cali- fornica, other littorines, L. scutulata, L. (A.) newcombiana. On rocks (Puget Sound): Balanus, Mytilus. Abundance: often the dominant small gas- tropod in salt marshes. Life-History Information Reproduction: dioecious (separate sexes); small egg capsules can be seen about one month after copulation (Littorina sp.) (Ricketts and Calvin 1971). Larva: Juvenile: Longevity: 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]