Clinocardium Nuttallii Phylum: Mollusca Class: Bivalvia, Heterodonta Basket of Heart Cockle Order: Veneroida Family: Cardiidae
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Clinocardium nuttallii Phylum: Mollusca Class: Bivalvia, Heterodonta Basket of heart cockle Order: Veneroida Family: Cardiidae Taxonomy: This species was originally diagram of internal anatomy see Schneider described as Cardium nuttallii (named after 1994. the zoologist, Thomas Nuttall) by Conrad in Exterior: 1837. Cardium was later split into several Byssus: groups and C. nuttallii was moved to the Gills: Gills are filibranch type, and are genus Clinocardium, which was designated strongly plicated and fused to a siphonal by Keen in 1936 (Kafanov 1980; Schneider septum posteriorly (Bernard and Noakes 2002). Other known synonyms include 1990; Schneider 1994). The outer Cardium californianum and Cardium corbis demibranch bears 53–120 plicae (each plica (e.g. Fraser 1931; Weymouth and Thompson comprises 40 filaments), while the inner has 1931). The distinctive shell morphology of 75–110 (Schneider 1994). The gills in many Clinocardium (with some associated suspension feeding bivalves are elongated subgenera, see Kafanov 1980) is distinct and folded to increase filtering surface area within the subfamily Clinocardiinae (Karanov (Barnard and Noakes 1990). 1980). Taxonomy of the group is based Shell: When viewed from the side (left or largely on stomach and shell morphology right valve), the shell is triangular, but when (Schneider 1994, 1995). viewed from either end it is heart-shaped (Fig. 3) (hence “heart cockle”, Kozloff 1993). Description Usually approximately 34 ribs radiate outward Size: Individuals up to 72 mm (Packard from the shell umbo (fig. 1) and are crossed 1918), but often grows to greater size, with concentric growth lines (Haderlie and particularly on northern beaches (Fraser Abbott 1980). 1931), where they can be up to 100 mm Interior: White, but not pearly. The (Kozloff 1993). anterior and posterior muscle scars equal in Color: Warm brown when young and area (compare to Adula californiensis, this mottled. Adults are light brown (Kozloff guide) and pallial line is simple. Known for its 1993). large foot and short siphon. Shell of C. General Morphology: Bivalve mollusks are californiense is composed of three layers bilaterally symmetrical with two lateral valves including an inner layer that is cross-laminar, or shells that are hinged dorsally and middle complex cross laminar, and outer that surround a mantle, head, foot and viscera is prismatic in structure (Zhang et al. 2014). (see Plate 393B, Coan and Valentich-Scott Exterior: Shell as high as long 2007). Cariids have distinctly inflated shells (Kozloff 1974), or higher with individuals and central beaks, which is not seen in any generally longer than wide during first year other bivalve family (Kozloff 1993; Coan and (Length: anterior to posterior) (Fraser 1931). Valentich-Scott 2007). Valves are alike, and shell is inflated, Body: (see Fig. 298, Kozloff 1993) triangular, and with rounded corners (Kozloff Color: 1974). Shell thick, but rather brittle (Keep and Interior: Ligament is entirely dorsal, Longstreth 1935). The posterior end is evenly and not internal. Labial palps are triangular rounded and smooth. The umbones are and consist of 30 ridges. The complex prominent (Abbott 1968), beaks nearly central intestine is with 11 loops and the total length and directed anteriorly (Keen and Coan 1974) (from crystalline style to exit from visceral (Fig. 2). mass) is 300 mm (Schneider 1994). For Hiebert, T.C. 2015. Clinocardium nuttallii. 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/1794/12739 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Hinge: Hinge is central, with one strong have shells that are generally not cemented cardinal tooth, and an anterior and posterior to the substratum and a dorsal margin that is lateral tooth in each valve (Fig. 2). without ears (Coan and Valentich-Scott Eyes: Bears numerous, tiny eyes on optical 2007). No other bivalve family has such an tentacles on mantle margin (Haderlie and inflated shell and central beaks. Abbott 1980). Clinocardium blandum is an offshore Foot: Foot enables excellent digging species, with distribution from Sonoma (Ricketts and Calvin 1952; Coan and county, California northward, Nemocardium Valentich-Scott 2007). The large and strong centifilosum is also an offshore species and foot can be used to push and flip the entire Trachycardium quadragenarium is a southern body (e.g., to escape predation from species, known from southern California to Pycnopodia helianthoides, Kozloff 1993; Monterey, California (Coan and Valentich- Pisaster brevispinus, Haderlie and Abbott Scott 2007). Nemocardium, with few extant 1980). species, has a prominent shell sculpture, with Siphons: No siphon tubes. Instead, siphons posterior ribs only and an otherwise smooth are simply holes in the mantle margin that surface (see Fig. 5, ter Poorten 2013). allow for only a shallow burrow (Ricketts and Calvin 1952). Clinocardium nuttallii has 60 Ecological Information mantle tentacles, which are largely present Range: Type locality is the Columbia River dorsal to the excurrent siphon opening and estuary in Oregon. Japan, Alaska and south extend to top of posterior adductor muscles along Pacific coast to San Diego (Weymouth (Schneider 1994). and Thompson 1931; Haderlie and Abbott Burrow: Shallow burrow is within 1 mm of 1980). Fossils from the family Cardiidae are surface (Ricketts and Calvin 1952; Chang and found along the north Pacific and European Levings 1989), so that the posterior end of the subarctic, and date to the Cenozoic (Kafanov individual is situated just below the sediment 1980). (Kozloff 1993). Burrowing time is slowed (up Local Distribution: Local distribution near to two-fold) in sediments bearing seagrass bay mouths on tideflats in most Oregon roots and/or invertebrate tubes (Brenchley estuaries as well as on exposed beaches 1982), however, a greater density of C. south of Oregon (Weymouth and Thompson nuttallii was observed in mudflats that had 1931). eelgrass (Zostera marina) than those that did Habitat: Beaches of uniform, but not very not (Galleher et al. 2012). If buried less than coarse sand (Fraser 1931; ”corn meal sand”, 50 mm (e.g., by dredging), C. nuttallii can Packard 1918; Ricketts and Calvin 1952). open its siphon to filter feed after 24 hrs Often found in exposed beaches. (Chang and Levings 1989). Clinocardium nuttallii occur in diverse habitats from exposed sandy beaches to fine bay sand Possible Misidentifications (Fraser 1931), and large populations can be The taxonomy (especially among higher-level found in eelgrass/mud areas (Kozloff 1993). taxa) of family Cardiidae, or cockles, has Salinity: Not found in upper bays where been thoroughly studied due to the diverse salinities vary greatly. morphology and good fossil record (see Temperature: Schneider 1992, 1994, 1995, 2002). It Tidal Level: High and mid intertidal to deep contains one to four species locally and C. waters, up to 200 m offshore in sandy areas nuttallii is the only species included in most or bays (Haderlie and Abbott 1980; Coan and recent keys (Coan and Valentich-Scott 2007). Valentich-Scott 2007). The family is within the Hederodonta and, as Associates: Small specimens are often host such, possesses few hinge teeth and is to young Pinnixa faba or P. littoralis (pea characterized by ovate and inflated shells with crabs) (Ricketts and Calvin 1971; Haderlie central beaks, hinges with lateral teeth, shell and Abbott 1980). Mantle, siphon, and foot sculpture that is with radial ribs, a hinge tissue of individuals older than two years, ligament that is entirely external (see Plate found to house the green endosymbiotic alga, 397B, Coan and Valentich-Scott 2007). They zoochlorellae (e.g. Chlorella), with a Hiebert, T.C. 2015. Clinocardium nuttallii. 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. commensal or parasitic relationship secreted following metamorphosis is simply suggested (Cooke 1975; Hartman and Pratt referred to as the dissoconch (see Fig. 2, 1976; Jones and Jacobs 1992; Soo and Todd Brink 2001). Once the larva develops a foot, 2014). usually just before metamorphosis and loss of Abundance: Not as abundant as other the velum, it is called a pediveliger (see Fig. mollusks (e.g., Saxidomus, Protothaca, British 1, Kabat and O’Foighil 1987; Brink 2001). Columbia, Canada, Fraser 1931). This (For generalized life cycle see Fig. 1, Brink species is the most abundant of its family on 2001). At 15˚C in the laboratory, the west coast (Keep and Longstreth 1935). development proceeds as follows: first Abundant at Garrison Bay, Washington from - cleavage after 1 hour, ciliated blastula at 10 0.61 to +0.92 meters, with approximately 5– hours, and early free-swimming veliger larvae 13 cockles per square meter (Gallucci and after 18 hours (Kabat and O’Foighil 1987; Galluci 1982). In a comparison of abundance Brink 2001). Early embryonic development relative to other bay clams in two Oregon stops at temperatures below 2.8˚C (Liu et al. estuaries, C. nuttallii was found to be twice as 2008). Larval growth increases