Solen Sicarius Class: Bivalvia, Heterodonta, Euheterodonta

Home , Adapedonta, Siliqua (bivalve), Solenidae, Solen (bivalve), Solen marginatus

Solen sicarius Class: Bivalvia, Heterodonta, Euheterodonta

Order: Imparidentia, Adapedonta The sickle razor clam, Family: Solenoidea, Solenidae or blunt jackknife clam

Description gapes at both ends. The dorsal margin is Size: Individuals up to 125 mm in length slightly concave and has beaks near the ante- (Haderlie and Abbott 1980; Kozloff 1993). rior end. The anterior margin is blunt while The illustrated specimen (from Coos Bay) is the posterior is rounded (Ricketts and Calvin 90 mm in length, which is the same size as 1952; Haderlie and Abbott 1980). reported type specimens (Oldroyd 1924; Interior: Adductor scars at opposite Ricketts and Calvin 1952). ends of shell and the anterior scar is elongate, Color: Shell very white in color, but covered while the posterior is oblong (Oldroyd 1924). with yellow green, and glossy periostracum The pallial sinus is shallow (Coan and Valen- (Ricketts and Calvin 1952). The foot can be tich-Scott 2007) and the pallial line extends darkly pigmented (Kozloff 1993). beyond the anterior adductor scar. In the il- General Morphology: Bivalve mollusks are lustrated specimen, the line is a strong rib bilaterally symmetrical with two lateral valves (Fig. 2), however there is no strong radial rib or shells that are hinged dorsally and sur- as in some Solenidae. round a mantle, head, foot and viscera (see Exterior: Shell shape is cylindrical Plate 393B, Coan and Valentich-Scott (solen = channel pipe, Quayle 1970). Length 2007). Solenid and pharid bivalves are bur- about four times the width and gapes at both rowers and some species are quite fast (e.g. ends (Coan and Valentich-Scott 2007). The Siliqua patula, see description in this guide). shell is thin, the valves are moderately They have shells that are longer than wide inflated, beaks are at near anterior end, and and often razor-like at the opening edge very weak (Figs. 1, 4). The dorsal margin is (see Plate 397G, Coan and Valentich-Scott straight or slightly concave, but not arched 2007). (Solen, Keen and Coan 1974) (Fig. 1). The Body: Long, dark and finger-like body. The ventral margin is arched (Oldroyd 1924) and posterior end swells to form an anchor (see the anterior edge is truncate while the poste- Fig. 306 Kozloff 1993). rior is rounded. Color: Hinge: The hinge is close to anterior Interior: The mantle is fused along end (Kozloff 1993). Beaks are terminal and the entire ventral margin and restricts foot situated at anterior end (Solen, Keen 1971) movement along anterior-posterior axis (Figs. 1, 2, 4). One cardinal tooth is present (Pohlo 1963), but serves as a barrier to out- in each valve and teeth are erect, recurved, side foreign material. The ligament is long, and triangular (Oldroyd 1924). entirely external, and not seated on nymph Eyes: (Figs. 2, 4). Foot: The foot is with dark pigment (Kozloff Exterior: 1993) (Fig. 4). Byssus: Siphons: Inhalant and exhalant siphons are Gills: joined (Fig. 4a). Siphons of both Solen rosti- Shell: Shell is slightly bent, elongate, and formis and S. sicarius can be readily autoto-

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]

Hiebert, T.C. 2015. Solen sicarius. 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.

mized at annular constrictions on the siphon teeth (Coan and Valentich-Scott 2007). Hia- (Ricketts and Calvin 1952; Pohlo 1963; Ha- tellidae, including the geoduck, Panopea ge- derlie and Abbott 1980; Rudy and Rudy, nerosa have large, quadrate, gaping bival- personal observation). The siphon of the ves, without hinge teeth, and with nearly former species are even too large to be re- equal adductor muscle scars (Keen and tracted completely into the shell (Ricketts Coan 1974). and Calvin 1952). Only two species, in the genus Solen, Burrow: The burrow of S. sicarius is perma- are reported locally in the Solenidae, they nent, vertical, and reaches depths of 30–35 have an almost straight dorsal margin, a ter- cm (Haderlie and Abbott 1980). Individuals minal beak, and one cardinal tooth in each dig rapidly and are very active, burying valve (Keen 1971). Solen rostiformis (= S. themselves completely within 30 seconds rosaceus, but see Pohlo 1963; von Cosel with four to five thrusts of the muscular foot 1992) has a thin shell that tapers and a peri- (Ricketts and Calvin 1952; Haderlie and Ab- ostracum that is lighter than S. sicarius; it is bott 1980). light olive green to brown in color. Solen rostiformis is a pink shelled clam and its siphons Possible Misidentifications are annulated (and it can regenerate them Solenidae and Pharidae are two ra- when disturbed, Pohlo 1963). It lives in san- zor clam families represented locally and dier situations than does S. sicarius (Coan pharid genera were recently placed in the and Carlton 1975). Solen sicarius, on the former family (see previous editions of this other hand, has a thick shell, a blunt guide). They are both characterized by cy- posterior (‘the blunt razor shell’) and a dark lindrical shells that are about 2.5 times as brown periostracum. Solen sicarius is found long as high and gape at both ends. They occasionally in permanent burrows in mud or have no dorsal margin ears (compare to muddy sand (Kozloff 1974) and is the spe- Pectinidae, see Plate 394E, Coan and Va- cies most likely to be confused with Siliqua lentich-Scott 2007), a hinge with ligament patula. It lacks an interior vertical rib and that is entirely external and dorsal, equally multiple hinge teeth, and is four times as long shaped adductor muscle scars (compare to as wide, not 2.5 times, as in S. patula (Keen Mytilus trossulus, this guide), and shells and Coan 1974). Furthermore, the profile in that do not have prominent radial sculptu- S. patula is much more oval, and not as cy- ring (Coan and Valentich-Scott 2007). The lindrical as in Solen sicarius. difference between the two families is that Four species are reported locally in members of the Pharidae have one shell the Pharidae. Siliqua patula has an internal valve with two cardinal teeth and the other rib that slopes anteriorly, a wide and tapering with four, while the Solenidae have a single posterior end. Siliqua lucida is smaller than cardinal tooth on each shell valve (Coan S. patula (< 55 mm in length) and has an in- and Valentich-Scott 2007). Other local ra- ternal rib that is vertical and narrow and a zor-shaped clams besides the Solenidae posterior end that is truncate. It has been such as the Mytiiidae include some genera suggested that S. lucida are simply young S. (e.g., Adula) which are also long and cylin- patula individuals (Hertlein 1961), but this is drical. Adula (see A. californiensis, this gui- not yet known. Siliqua lucida lives in pro- de) are usually a boring species, however, tected bay sands and has concentric brown having hairy posterodorsal slopes, a very bands on its exterior. Although variations in small anterior adductor scar, and no hinge S. patula have been synonymized, occasio-

nally readers will find references to S. patu- curs on Spanish coasts, is reproductive from la var. nuttallii, which is more oval shape, May to July (Spain, Remacha-Trivino and with purple beaks and four hinge teeth in Anadon 2006) and in Solen grandis, spawning the left valve, not two (Oldroyd 1924). En- occurred from April to May. Several spawning sis myrae and Siliqua altra are offshore events were observed for S. dactylus, in the species and E. myrae is has a shell that is northern Persian Gulf, from August to Febru- long and thin. ary (Saeedi et al. 2009). The sperm morphology of the congeners S. cylindraceus and S. Ecological Information capensis was studied by Hodgson et al. Range: Type locality is the Straits of Juan (1987). In both species, sperm were of de Fuca. Known range extends from Van- “primitive type” (i.e., typical triangular shape couver Island, BC, Canada to San Quintin that is not elongated in any way), with head Bay, Baja California. pieces approximately 1.5µm in length, but Local Distribution: Locally occurs in mud- acrosome morphology was species specific. flats of both Coos Bay and Charleston. In fact, sperm morphology appears to charac- Habitat: Individuals found in permanent ver- terize many veneroid taxa (see Fig. 2, Healy tical burrows of protected parts of bays, 1995). Fertilized oocytes of S. marginatus within mud or muddy sand (Coan and Valen- were approximately 156 µm in diameter and tich-Scott 2007). Solen sicarius is more surrounded by a chorion (da Costa and Mar- common among eelgrass (e.g., Zostera ma- tinez-Patino 2009) and mature oocytes of S. rina) roots, in firm sediments than other gordonis and S. strictus from Dadaepo, Pu- mudflats. san, Korea were 80–90 µm (Chung et al. Salinity: Collected at salinities of 30 in Coos 1986). Bay. Larva: Bivalve development, including mem- Temperature: Cold to warmer temperate bers of the Pholadidae, generally proceeds waters. from external fertilization via broadcast Tidal Level: Low intertidal to shallow sub- spawning through a ciliated trochophore stage tidal (Haderlie and Abbott 1980). In Coos to a veliger larva. Bivalve veligers are charac- Bay, individuals are primarily collected inter- terized by a ciliated velum that is used for tidally. swimming, feeding and respiration. The veli- Associates: Known associates include the ger larva is also found in many gastropod lar- commensal pea crabs (e.g. Pinnixa, Quayle vae, but the larvae in the two groups can be 1970). recognized by shell morphology (i.e. snail-like Abundance: Not common, but becoming versus clam-like). In bivalves, the initial more abundant in Coos Bay (Rudy and shelled-larva is called a D-stage or straight- Rudy, personal observation). In Inchon, hinge veliger due to the “D” shaped shell. Korea, a population of the congeneric spe- This initial shell is called a prodissoconch I cies, S. scrictus, reached mean densities of and is followed by a prodissoconch II, or shell 126 individuals/m2 (Hong and Park 1994). that is subsequently added to the initial shell Life-History Information zone. Finally, shell secreted following meta- Reproduction: Although little is known morphosis is simply referred to as the disso- about the reproduction and development in conch (see Fig. 2, Brink 2001). Once the lar- Solen sicarius, reproductive aspects of biol- va develops a foot, usually just before meta- ogy have been studied for several conge- morphosis and loss of the velum, it is called a ners. Solen marginatus, a species that oc- pediveliger (see Fig. 1, Kabat and O’Foighil

1987; Brink 2001). (For generalized life cy- 1986. Annual reproductive cycle of the cle see Fig. 1, Brink 2001.) In Solen gran- jackknife clams, Solen strictus and Solen dis, D-shaped larvae hatched after 20 hours gordonis. Bulletin of the Korean Fisheries and were 125 µm. After 5–6 days, larvae Society. 19:563-574. were early umbo stage and approximately 3. COAN, E. V., and P. VALENTICH-SCOTT. 250 µm (Guo-qiang et al. 2009). Settlement 2007. Bivalvia, p. 807-859. In: The Light occurred after nine days in Solen margina- and Smith manual: intertidal invertebrates tus when larvae were approximately 300 µm from central California to Oregon. J. T. (da Costa and Martinex-Patino 2009). Carlton (ed.). University of California Juvenile: Press, Berkeley, CA. Longevity: 4. DA COSTA, F., and D. MARTINEZ- Growth Rate: In the congener, Solen mar- PATINO. 2009. Culture potential of the ra- ginatus, seed were 19 mm at four months zor clam Solen marginatus (Pennant, and one year old juveniles were 38.5 mm. 1777). Aquaculture. 288:57-64. After three years, individuals were 80 mm 5. GROSZ, T., and C. F. YOCOM. 1972. (da Costa and Martinez-Patino 2009). Food habits of white winged scoter in Food: A suspension and filter feeder. northwestern California. Journal of Wildlife Predators: Known predators include birds Management. 36:1279-1282. (e.g., white-winged scoter, Grosz and Yo- 6. HADERLIE, E. C., and D. P. ABBOTT. com 1972) and sea stars (e.g., Pisaster 1980. Bivalvia: the clams and allies, p. 355 brevispinus, Sloan and Robinson 1983). -410. In: Intertidal invertebrates of Califor- Behavior: A very good digger, it can bury nia. R. H. Morris, D. P. Abbott, and E. C. itself in 30 seconds. However, S. sicarius is Haderlie (eds.). Stanford University Press, not as fast a burrower as S. patula: an indi- California. vidual 7 cm in length requires 45 seconds to 7. HEALY, J. M. 1995. Comparative sperma- 11 min to bury itself (compare to 7–27 sec- tozoal ultrastructure and its taxonomic and onds for S. patula, see description in this phylogenetic significance in the bivalve guide) (Pohlo 1963). Interestingly, Solen order Veneroida. Memoires du Museum sicarius can also both swim and jump National d'Histoire Naturelle. 166:155-166. (MacGinities 1935). They do so by either 8. HODGSON, A. N., C. J. DEVILLIERS, and expelling water from their siphons rapidly or R. T. F. BERNARD. 1987. Comparative through the opening surrounding the siphon. spermatology of two morphologically simi- With these techniques they are able to move lar species of Solen (Mollusca, Bivalvia). up to two feet through the water or use the South African Journal of Zoology. 22:264- blast of water to soften sediments for rapid 268. burrowing (Ricketts and Calvin 1952; Hader- 9. HONG, J., and H. PARK. 1994. Growth lie and Abbott 1980). and production of macrobenthic fauna on a macrotidal flat, Inchon, Korea I. Growth Bibliography of the razor clam, Solen strictus (Bivalvia, 1. BRINK, L. A. 2001. Mollusca: Bivalvia, p. Solenidae) from Chokchon tidal flat. Bulle- 129-149. In: Identification guide to larval tin of the Korean Fisheries Society. 27:549 marine invertebrates of the Pacific North- -559. west. A. Shanks (ed.). Oregon State Uni- 10. KABAT, A. R., and D. O'FOIGHIL. 1987. versity Press, Corvallis, OR. Phylum Mollusca, Class Bivalvia, p. 309- 2. CHUNG, E. Y., H. B. KIM, and T. Y. LEE. 353. In: Reproduction and development of

marine invertebrates of the northern Pa- ern coast of the Persian Gulf (Iran). Jour- cific Coast. M. F. Strathmann (ed.). Uni- nal of the Marine Biological Association of versity of Washington Press, Seattle, the United Kingdom. 89:1635-1642. WA. 20. SLOAN, N. A., and S. M. C. ROBINSON. 11. KEEN, A. M. 1971. Sea shells of tropical 1983. Winter feeding by asteroids on a west America: marine mollusks from Ba- subtidal sandbed in British Columbia. ja California to Peru. Stanford University Ophelia. 22:125-141. Press, Stanford, CA. 21. VON COSEL, R. 1992. Solen rosaceus: 12. KEEN, A. M., and E. COAN. 1974. Ma- three species. Veliger. 35:366-3 rine molluscan genera of western North Updated 2016 America: an illustrated key. Stanford Uni- T.C. Hiebert versity Press, Stanford, CA. 13. MACGINITIE, G. E. 1935. Ecological aspects of a California marine esturary. American Midland Naturalist. 16:629- 765. 14. OLDROYD, I. S. 1924. Marine shells of Puget Sound and vicinity. University of Washington Press, Seattle. 15. POHLO, R. H. 1963. Morphology and mode of burrowing in Siliqua patula and Solen rosaceus (Mollusca: Bivalvia). Vel- iger. 6:98-104. 16. QUAYLE, D. B. 1970. The intertidal bivalves of British Columbia. British Co- lumbia Provincial Museum, Victoria, BC, Canada. 17. REMACHA-TRIVINO, A., and N. ANADON. 2006. Reproductive cycle of the razor clam Solen marginatus (Pulteney 1799) in Spain: A comparative study in three different locations. Journal of Shellfish Research. 25:869-876. 18. RICKETTS, E. F., and J. CALVIN. 1952. Between Pacific tides : an account of the habits and habitats of some five hundred of the common, conspicuous seashore invertebrates of the Pacific Coast between Sitka, Alaska, and Northern Mexi- co. Stanford : Stanford University Press, Stanford. 19. SAEEDI, H., S. P. RAAD, A. A. ARDA- LAN, E. KAMRANI, and B. H. KIABI. 2009. Growth and reproduction of Solen dactylus (Bivalvia: Solenidae) on north-