Solen Sicarius Class: Bivalvia, Heterodonta Order: Veneroida the Sickle Razor Clam, Or Blunt Jacknife Clam Family: Solenidae

Home , Solenidae, Solen (bivalve), Solen marginatus

Phylum: Mollusca Solen sicarius Class: Bivalvia, Heterodonta Order: Veneroida The sickle razor clam, or blunt jacknife clam Family: Solenidae

Description elongate, while the posterior is oblong Size: Individuals up to 125 mm in length (Oldroyd 1924). The pallial sinus is shallow (Haderlie and Abbott 1980; Kozloff 1993). (Coan and Valentich-Scott 2007) and the The illustrated specimen (from Coos Bay) is pallial line extends beyond the anterior 90 mm in length, which is the same size as adductor scar. In the illustrated specimen, reported type specimens (Oldroyd 1924; the line is a strong rib (Fig. 2), however there Ricketts and Calvin 1952). is no strong radial rib as in some Solenidae. Color: Shell very white in color, but covered Exterior: Shell shape is cylindrical with yellow green, and glossy periostracum (solen = channel pipe, Quayle 1970). Length (Ricketts and Calvin 1952). The foot can be about four times the width and gapes at both darkly pigmented (Kozloff 1993). ends (Coan and Valentich-Scott 2007). The General Morphology: Bivalve mollusks are shell is thin, the valves are moderately bilaterally symmetrical with two lateral valves inflated, beaks are at near anterior end, and or shells that are hinged dorsally and very weak (Figs. 1, 4). The dorsal margin is surround a mantle, head, foot and viscera straight or slightly concave, but not arched (see Plate 393B, Coan and Valentich-Scott (Solen, Keen and Coan 1974) (Fig. 1). The 2007). Solenid and pharid bivalves are ventral margin is arched (Oldroyd 1924) and burrowers and some species are quite fast the anterior edge is truncate while the (e.g. Siliqua patula, see description in this posterior is rounded. guide). They have shells that are longer than Hinge: The hinge is close to anterior wide and often razor-like at the opening edge end (Kozloff 1993). Beaks are terminal and (see Plate 397G, Coan and Valentich-Scott situated at anterior end (Solen, Keen 1971) 2007). (Figs. 1, 2, 4). One cardinal tooth is present Body: Long, dark and finger-like body. The in each valve and teeth are erect, recurved, posterior end swells to form an anchor (see and triangular (Oldroyd 1924). Fig. 306 Kozloff 1993). Eyes: Color: Foot: The foot is with dark pigment (Kozloff Interior: The mantle is fused along 1993) (Fig. 4). the entire ventral margin and restricts foot Siphons: Inhalant and exhalant siphons are movement along anterior-posterior axis joined (Fig. 4a). Siphons of both Solen (Pohlo 1963), but serves as a barrier to rostiformis and S. sicarius can be readily outside foreign material. The ligament is autotomized at annular constrictions on the long, entirely external, and not seated on siphon (Ricketts and Calvin 1952; Pohlo nymph (Figs. 2, 4). 1963; Haderlie and Abbott 1980; Rudy and Exterior: Rudy, personal observation). The siphon of Byssus: the former species are even too large to be Gills: retracted completely into the shell (Ricketts Shell: Shell is slightly bent, elongate, and and Calvin 1952). gapes at both ends. The dorsal margin is Burrow: The burrow of S. sicarius is slightly concave and has beaks near the permanent, vertical, and reaches depths of anterior end. The anterior margin is blunt 30–35 cm (Haderlie and Abbott 1980). while the posterior is rounded (Ricketts and Individuals dig rapidly and are very active, Calvin 1952; Haderlie and Abbott 1980). burying themselves completely within 30 Interior: Adductor scars at opposite seconds with four to five thrusts of the ends of shell and the anterior scar is muscular foot (Ricketts and Calvin 1952; Haderlie and Abbott 1980).

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.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12921 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Possible Misidentifications Siliqua patula. It lacks an interior vertical rib Solenidae and Pharidae are two razor clam and multiple hinge teeth, and is four times as families represented locally and pharid long as wide, not 2.5 times, as in S. patula genera were recently placed in the former (Keen and Coan 1974). Furthermore, the family (see previous editions of this guide). profile in S. patula is much more oval, and not They are both characterized by cylindrical as cylindrical as in Solen sicarius. shells that are about 2.5 times as long as Four species are reported locally in high and gape at both ends. They have no the Pharidae. Siliqua patula has an internal dorsal margin ears (compare to Pectinidae, rib that slopes anteriorly, a wide and tapering see Plate 394E, Coan and Valentich-Scott posterior end. Siliqua lucida is smaller than 2007), a hinge with ligament that is entirely S. patula (< 55 mm in length) and has an external and dorsal, equally shaped adductor internal rib that is vertical and narrow and a muscle scars (compare to Mytilus trossulus, posterior end that is truncate. It has been this guide), and shells that do not have suggested that S. lucida are simply young S. prominent radial sculpturing (Coan and patula individuals (Hertlein 1961), but this is Valentich-Scott 2007). The difference not yet known. Siliqua lucida lives in between the two families is that members of protected bay sands and has concentric the Pharidae have one shell valve with two brown bands on its exterior. Although cardinal teeth and the other with four, while variations in S. patula have been the Solenidae have a single cardinal tooth on synonymized, occasionally readers will find each shell valve (Coan and Valentich-Scott references to S. patula var. nuttallii, which is 2007). Other local razor-shaped clams more oval shape, with purple beaks and four besides the Solenidae such as the Mytiiidae hinge teeth in the left valve, not two (Oldroyd include some genera (e.g., Adula) which are 1924). Ensis myrae and Siliqua altra are also long and cylindrical. Adula (see A. offshore species and E. myrae is has a shell californiensis, this guide) are usually a boring that is long and thin. species, however, having hairy posterodorsal slopes, a very small anterior adductor scar, Ecological Information and no hinge teeth (Coan and Valentich- Range: Type locality is the Straits of Juan de Scott 2007). Hiatellidae, including the Fuca. Known range extends from Vancouver geoduck, Panopea generosa have large, Island, BC, Canada to San Quintin Bay, Baja quadrate, gaping bivalves, without hinge California. teeth, and with nearly equal adductor muscle Local Distribution: Locally occurs in scars (Keen and Coan 1974). mudflats of both Coos Bay and Charleston. Only two species, in the genus Solen, Habitat: Individuals found in permanent are reported locally in the Solenidae, they vertical burrows of protected parts of bays, have an almost straight dorsal margin, a within mud or muddy sand (Coan and terminal beak, and one cardinal tooth in each Valentich-Scott 2007). Solen sicarius is more valve (Keen 1971). Solen rostiformis (= S. common among eelgrass (e.g., Zostera rosaceus, but see Pohlo 1963; von Cosel marina) roots, in firm sediments than other 1992) has a thin shell that tapers and a mudflats. periostracum that is lighter than S. sicarius; it Salinity: Collected at salinities of 30 in Coos is light olive green to brown in color. Solen Bay. rostiformis is a pink shelled clam and its Temperature: Cold to warmer temperate siphons are annulated (and it can regenerate waters. them when disturbed, Pohlo 1963). It lives in Tidal Level: Low intertidal to shallow subtidal sandier situations than does S. sicarius (Coan (Haderlie and Abbott 1980). In Coos Bay, and Carlton 1975). Solen sicarius, on the individuals are primarily collected intertidally. other hand, has a thick shell, a blunt posterior Associates: Known associates include the (‘the blunt razor shell’) and a dark brown commensal pea crabs (e.g. Pinnixa, Quayle periostracum. Solen sicarius is found 1970). occasionally in permanent burrows in mud or Abundance: Not common, but becoming muddy sand (Kozloff 1974) and is the more abundant in Coos Bay (Rudy and Rudy, species most likely to be confused with personal observation). In Inchon, Korea, a 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. population of the congeneric species, S. usually just before metamorphosis and loss of scrictus, reached mean densities of 126 the velum, it is called a pediveliger (see Fig. individuals/m2 (Hong and Park 1994). 1, Kabat and O’Foighil 1987; Brink 2001). (For generalized life cycle see Fig. 1, Brink Life-History Information 2001.) In Solen grandis, D-shaped larvae Reproduction: Although little is known about hatched after 20 hours and were 125 µm. the reproduction and development in Solen After 5–6 days, larvae were early umbo stage sicarius, reproductive aspects of biology have and approximately 250 µm (Guo-qiang et al. been studied for several congeners. Solen 2009). Settlement occurred after nine days in marginatus, a species that occurs on Spanish Solen marginatus when larvae were coasts, is reproductive from May to July approximately 300 µm (da Costa and (Spain, Remacha-Trivino and Anadon 2006) Martinex-Patino 2009). and in Solen grandis, spawning occurred from Juvenile: April to May. Several spawning events were Longevity: observed for S. dactylus, in the northern Growth Rate: In the congener, Solen Persian Gulf, from August to February marginatus, seed were 19 mm at four months (Saeedi et al. 2009). The sperm morphology and one year old juveniles were 38.5 mm. of the congeners S. cylindraceus and S. After three years, individuals were 80 mm (da capensis was studied by Hodgson et al. Costa and Martinez-Patino 2009). (1987). In both species, sperm were of Food: A suspension and filter feeder. “primitive type” (i.e., typical triangular shape Predators: Known predators include birds that is not elongated in any way), with head (e.g., white-winged scoter, Grosz and Yocom pieces approximately 1.5µm in length, but 1972) and sea stars (e.g., Pisaster acrosome morphology was species specific. brevispinus, Sloan and Robinson 1983). In fact, sperm morphology appears to Behavior: A very good digger, it can bury characterize many veneroid taxa (see Fig. 2, itself in 30 seconds. However, S. sicarius is Healy 1995). Fertilized oocytes of S. not as fast a burrower as S. patula: an marginatus were approximately 156 µm in individual 7 cm in length requires 45 seconds diameter and surrounded by a chorion (da to 11 min to bury itself (compare to 7–27 Costa and Martinez-Patino 2009) and mature seconds for S. patula, see description in this oocytes of S. gordonis and S. strictus from guide) (Pohlo 1963). Interestingly, Solen Dadaepo, Pusan, Korea were 80–90 µm sicarius can also both swim and jump (Chung et al. 1986). (MacGinities 1935). They do so by either Larva: Bivalve development, including expelling water from their siphons rapidly or members of the Pholadidae, generally through the opening surrounding the siphon. proceeds from external fertilization via With these techniques they are able to move broadcast spawning through a ciliated up to two feet through the water or use the trochophore stage to a veliger larva. Bivalve blast of water to soften sediments for rapid veligers are characterized by a ciliated velum burrowing (Ricketts and Calvin 1952; Haderlie that is used for swimming, feeding and and Abbott 1980). respiration. The veliger larva is also found in many gastropod larvae, but the larvae in the Bibliography two groups can be recognized by shell morphology (i.e. snail-like versus clam-like). 1. BRINK, L. A. 2001. Mollusca: Bivalvia, In bivalves, the initial shelled-larva is called a p. 129-149. In: Identification guide to D-stage or straight-hinge veliger due to the larval marine invertebrates of the “D” shaped shell. This initial shell is called a Pacific Northwest. A. Shanks (ed.). prodissoconch I and is followed by a Oregon State University Press, prodissoconch II, or shell that is subsequently Corvallis, OR. added to the initial shell zone. Finally, shell 2. CHUNG, E. Y., H. B. KIM, and T. Y. secreted following metamorphosis is simply LEE. 1986. Annual reproductive cycle referred to as the dissoconch (see Fig. 2, of the jackknife clams, Solen strictus Brink 2001). Once the larva develops a foot,