Cryptomya Californica Phylum: Mollusca Class: Bivalvia; Heterodonta Order: Myoida False Mya Family: Myidae

Cryptomya californica Phylum: Mollusca Class: Bivalvia; Heterodonta Order: Myoida False Mya Family: Myidae

Taxonomy: Sphenia californica is the (see Plate 395H, Coan and Valentich-Scott original name given to Cryptomya californica 2007). (Keen 1966; Coan 1999; Coan and Valentich- Body: (see Fig. 319, Kozloff 1993). Scott 2012). Although C. californica is almost Color: exclusively used currently, the taxonomy of Interior: Ligament is internal and this species includes many synonyms (e.g., seated in a shallow resilifer (a pit or groove). Cryptomya kamtschatica, C. magna, C. In right valve, the ligament is orange, oregonensis, C. quadrata, C. washingtoniana, leathery, and corresponds with the Macoma kerica, Mya inopia, M. mindorensis, chondrophore on the left valve (Figs. 3, 4). M. tenuis). Sphenia species tend to live Esophagus and stomach are surrounded by attached to shells or stone, while Cryptomya extensive intestinal diverticula, which extend species are found within the burrows of other from the right side of the stomach to the invertebrates (Zhang et al. 2012, see also posterior portion of the foot, passing through Coan 1999 for Sphenia characteristics). The the heart dorsally. The rectum is positioned name of the genus reflects individual’s ability dorsally and posterior to the adductor muscle. to be buried deep within the sediment despite The anus is situated inside the excurrent short siphons (kryptos = hidden, myax = siphon (Lawry 1987; Yonge 1951). A shellfish) as they utilize the burrows of other crystalline style (consisting of a gelatinous burrowers (Coan and Valentich-Scott 2012). cortex and liquid core, Lawry 1987) resides in a sac lined with cilia, which allow it to rotate Description and press agains the gastric shield of the Size: Individuals average 20 mm in length, stomach to aid in digestion (Lawry 1987). but are found up to 30 mm (Haderlie and The crystalline style contains starch- Abbott 1980; Lawry 1987). The illustrated hydrolyzing enzyme amylase and rotation specimen (from Coos Bay) is 21 mm in length rates range from 7 to 30 rpm (at 10–21˚C). (Fig. 1). Within the crystalline style are mutualistic Color: Exterior chalky and white and bacteria of the genus Cristispira. These yellowish, with dull reddish brown spirochetes benefit from food particles periostracum (Lawry 1987). Interior glossy concentrated by C. californica and the clam white with spoon-shaped tooth on the right presumably benefits from an aid in digestion valve orange in color. (Lawry et al. 1981; Lawry 1987). (For further General Morphology: Bivalve mollusks are information on digestion in C. californica, see bilaterally symmetrical with two lateral valves Lawry 1987). or shells that are hinged dorsally and Exterior: surround a mantle, head, foot and viscera Byssus: (see Plate 393B, Coan and Valentich-Scott Gills: Gills pump water through the 2007). Myoid bivalves are burrowers and mantle cavity. They are large and covered in borers, with long siphons and hinges with few cilia that concentrate and transport food teeth (Coan and Valentich-Scott 2007), particles. Undigestable material is sorted by although C. californica has relatively short the labial palps and egested as pseudofeces, siphons (Fig. 6). A distinctive feature of the which are expelled through the incurrent Myidae is the presence of a strongly siphon (Lawry 1987; Yonge 1951). projecting chondrophore that is spoon or peg- Shell: Shell is thin, fragile with external thin shaped and is present on the left valve only and brown periostracum and light concentric sculpture (Quayle 1970). The overall shape

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12746 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] is oblong and gapes posteriorly (Haderlie and morphology and fossil evidence and one of Abbott 1980). those is the diverse Heterodonta. Recent Interior: Adductor muscle scars equal molecular evidence (18S and 28S rRNA) (family Myidae). Pallial line is entire and suggests that the heterodont order Myoida is forms a right angle posteriorly (Fig. 3). The non monophyletic (Taylor et al. 2007). The pallial sinus is absent (or inconspicuous) in family Myidae includes 25–40 species members of the genus Cryptomya (Fig. 3). worldwide, which can be divided into groups The chondrophore is broad, horizontal, and such as those that are burrowing (Mya), those projecting (left valve only). The right valve is that are attached to shells or stone (Sphenia) with resilifer to receive the chondrophore. or those utilizing the burrows of other species Exterior: The right valve is more (Cryptomya, Paramya) (Zhang et al. 2012). convex than the left (McLean 1969). The Characters of the Myidae include a shell that shell sculpturing is similar to M. arenaria, but is not cemented to the substratum, valves that smaller (Haderlie and Abbott 1980). The are (relatively) morphologically similar, a beak is central and fairly prominent (Fig. 1). dorsal margin without ears, a hinge with an Hinge: No true teeth or hinge plate, internal ligament in a distinct resilifer or except for chondrophore and resilifer (Myidae, chondrophore that is spoon shaped and McLean 1969). present on the left valve (Coan and Valentich- Eyes: Scott 2007). Cryptomya species are Foot: Foot extends through pedal gape and characterized by hinge without tooth-like facilitates digging (Fig. 1). Individuals dig with process anteriorly on the right valve. Mya, on muscular contractions of the foot coupled the other hand, have thick shells, gaping (making the foot appear alternatively knife anteriorly and posteriorly and commarginal and spade-shaped) with its epidermal ciliary growth lines (Zhang et al. 2012). action. Individuals are anchored by the foot There are only three local myid and pull themselves onto the anteroventral species including Platyodon cancellatus, Mya portion of the shell. They then rock back and arenaria (see description in this guide) and forth in a dorsoventral plane, working Cryptomya californica. Platyodon cancellatus themselves into the substrate to completely can be distinguished from the latter two bury themselves (except the siphons) in 5 species because its shells are heavy and with minutes (Lawry 1987). wavy commarginal sculpture and a round Siphons: Siphons are short (less than 1 mm anterior. It has a truncate, gaping posterior in length), oval, and white (Coan and end covered with periostracum. It also bores Valentich-Scott 2007). The excurrent siphon into rock and hard clay while M. arenaria and opening is controlled by a membrane, and C. californica burrow into sand or mud. The both siphons possess an outer tentacular ring shells of the two latter species are relatively (Lawry 1987). The incurrent siphon is thin. In M. arenaria, the pallial sinus is deep surrounded by additional tentacles and the and individuals reach sizes of 120 mm, while excurrent siphon is short and vase-like (Fig. in C. californica the pallial sinus is shallow, 6). inconspicuous and individuals tend to be Burrow: Individuals found in burrows up to smaller (30 mm) (Coan and Valentich-Scott 50 cm deep (Haderlie and Abbott 1980; Lawry 2007). Mya arenaria is found as deep as 30 1987). For digging behavior see Foot. cm and is not necessarily near Callianassa Inhabits the burrows of other invertebrates burrows, where one might find C. californica. (e.g., Callianassa californiensis, Upogebia The siphons are M. arenaria are also longer pugettensis, Urechis caupo) and extends than those of C. californica (Figs. 1, 6). short siphons into burrow. Cryptomya Additionally, Sphenia luticola is a myid californiensis receives oxygen, food, and can species that may occur in our area, but is remove waste by utilizing these burrows found offshore in rocks and within kelp (Lawry 1987). holdfasts (Coan and Valentich-Scott 2007). Juvenile Mya are not easily distinguished Possible Misidentifications from Sphenia species, but Mya can be There are five bivalve subclasses based on

Hiebert, T.C. 2015. Cryptomya californica. 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. recognized by a large continuous pallial sinus different pinnotherid (pea) crabs (e.g., Fabia (Coan 1999). concharum, Haderlie and Abbott 1980), and Cryptomya californica can be the goby, Clevelandia ios. This Callianassa- distinguished from other small white clams Cryptomya complex of organisms often co- (Macoma spp., for instance) by its lack of any occurs with Sanguinolaria nuttallii (Peterson external ligament, the fragility of its shell, and 1984). Cristispira populations are constantly internally, by its lack of hinge teeth, and replenished by ingestion of bacteria from the presence of the chondrophore in the left environment (populations decrease when valve. The Mactridae, including the gaper individuals are maintained in the laboratory clam, have a chondrophore in both valves. with filtered seawater, Lawry 1987). However, mactrid adults are large, gape Cryptomya californica individuals also have a widely, and have small hinge teeth (which commensal association with the mud shrimp, Myidae lack). Their posterior edges are also Upogebia pugettensis, and the spoon worm, truncate, not rounded, and their siphons are Urechis caupo (McLean 1969; Lawry 1987; leather-like at the tips. Coan and Valentich-Scott 2007). An average of eight C. californica were observed per U. Ecological Information pugettensis burrow (Griffin et al. 2004). Range: Type locality is Santa Barbara, Finally, amebocytes, spirochetes (Cristispira), California (Keen 1966). Gulf of Alaska to and gram negative bacteria (Vibro spp.) are northern Peru (Chicagot Island) (Keen 1971; often observed near or concentrated within Haderlie and Abbott 1980). the crystalline style and stomach (Lawry Local Distribution: In bays and estuarine 1987). mudflats and sand flats where Callianassa or Abundance: Individuals can be very Upogebia beds are found. In Coos Bay, sites common and, in some parts of Coos Bay, it is include the airport extension site, Pigeon the most abundant bivalve (e.g., airport Point, and South Slough, among others. mudflat, North Bend) (Gonor et al. 1979). Other Oregon estuaries where C. californica This common estuarine species is, thus, often occurs include Tillamook, Netarts, Nestucca used in toxicity and biomarker tests (e.g., (Hancock et al. 1979), Yaquina, and also DDT, Ferraro and Cole 1997). offshore (Lawry 1987). Habitat: Sand and sandy mud, nearly always Life-History Information with siphons extending into the burrow of Reproduction: Sperm acrosome is 5 µm in Callianassa californiensis, the ghost shrimp length and is tapered and slightly curved; the (which, in turn, often inhabits oyster beds). total sperm length (including flagellum) is 45 Individuals also occurs in muddy gravel and µm. Oocytes are oblong and 65 µm x 53 µm, rocks on the open coast (Haderlie and Abbott with nucleus that is 30 µm, and nucleolus that 1980; Coan and Valentich-Scott 2007). is 13 µm (see Fig. 4c, d, Lawry 1987). The Salinity: Collected at salinities of 30. development of C. californica has not been Temperature: Occurs over a wide range of described (Brink 2001). water temperatures geographically (see Larva: Bivalve development generally Range). proceeds from external fertilization via Tidal Level: Individuals can be found to 6 broadcast spawning through a ciliated meters below the surface (Quayle 1970) as trochophore stage to a veliger larva. Bivalve well as the upper to mid-intertidal zones. veligers are characterized by a ciliated velum Individuals also found in the low intertidal and that is used for swimming, feeding and subtidal on the open coast (Haderlie and respiration. The veliger larva is also found in Abbott 1980) and are common in lower many gastropod larvae, but the larvae in the estuarine mudflats, up to +0.3 meters (Lawry two groups can be recognized by shell 1987). morphology (i.e. snail-like versus clam-like). Associates: The burrows of Callianassa In bivalves, the initial shelled-larva is called a californiensis can include a community of D-stage or straight-hinge veliger due to the marine invertebrates including the polynoid “D” shaped shell. This initial shell is called a polychaete Hesperonoe complanata, three prodissoconch I and is followed by a

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12746 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] prodissoconch II, or shell that is subsequently 2. COAN, E. V. 1999. The eastern added to the initial shell zone. Finally, shell Pacific species of Sphenia (Bivalvia: secreted following metamorphosis is simply Myidae). Nautilus. 113:103-120. referred to as the dissoconch (see Fig. 2, 3. COAN, E. V., and P. VALENTICH- Brink 2001). Once the larva develops a foot, SCOTT. 2007. Bivalvia, p. 807-859. In: usually just before metamorphosis and loss of The Light and Smith manual: intertidal the velum, it is called a pediveliger (see Fig. invertebrates from central California to 1, Kabat and O’Foighil 1987; Brink 2001). Oregon. J. T. Carlton (ed.). University (For generalized life cycle see Fig. 1, Brink of California Press, Berkeley, CA. 2001.) 4. —. 2012. Bivalve seashells of tropical Juvenile: West America: marine bivalve Longevity: mollusks from Baja California to Growth Rate: northern Peru. Part 1. Santa Barbara Food: Filters material from water pumped Museum of Natural History, Santa into the burrows of commensal species. Barbara. Upogebia pugettensis and Urechis caupo are 5. FERRARO, S. P., and F. A. COLE. more effective detritus filterers than 1997. Effects of DDT sediment- Callianassa californiensis, and Cryptomya contamination on macrofaunal californica ingests more in the burrow of the community structure and composition latter species (MacGinitie and MacGinitie in San Francisco Bay. Marine Biology. 1949). Individual compete for suspended 130:323-334. particles with extra large gills providing a 6. GONOR, J. J., D. R. STREHLOW, and larger surface area for filtering (Haderlie and G. E. JOHNSON. 1979. Ecological Abbott 1980; Kozloff 1993). Ingested items assessments at the North Bend airport include detritus, diatoms, bacteria, extension site. School of dinoflagellates, crustaceans and annelids. Oceanography, Oregon State The Upogebia-Cryptomya complex is capable University, Salem, OR. of filtering 100% of carbon from overlying 7. GRIFFEN, B. D., T. H. DEWITT, and water in one day (4.66 x 105 to 1.86 x 106 g C. LANGDON. 2004. Particle removal Cd-1, Griffen et al. 2004). The portion of rates by the mud shrimp Upogebia suspended material removed by C. californica pugettensis, its burrow, and a increases with increasing phytoplankton commensal clam: effects on estuarine concentrations (Griffen et al. 2004). phytoplankton abundance. Marine Predators: Individuals remain relatively Ecology Progress Series. 269:223- protected within their burrow. The invasive 236. green crab, Carcinus maenas, has been 8. HADERLIE, E. C., and D. P. ABBOTT. known to eat C. californica (Palacios and 1980. Bivalvia: the clams and allies, p. Ferraro 2003) 355-410. In: Intertidal invertebrates of Behavior: Interestingly, individuals remain California. R. H. Morris, D. P. Abbott, just below the surface as a short-siphoned and E. C. Haderlie (eds.). Stanford clam of its size normally would, however, they University Press, California. can live deep within the substrate, by utilizing 9. HANCOCK, D. R., T. F. GAUMER, G. the burrows of other species (see Foot, B. WILLEKE, G. P. ROBART, and J. Associates, and Burrow). FLYNN. 1979. Subtidal clam populations: distribution, abundance, Bibliography and ecology. Oregon State University, Sea Grant College Program, Corvallis. 1. BRINK, L. A. 2001. Mollusca: Bivalvia, 10. KABAT, A. R., and D. O'FOIGHIL. p. 129-149. In: Identification guide to 1987. Phylum Mollusca, Class larval marine invertebrates of the Bivalvia, p. 309-353. In: Reproduction Pacific Northwest. A. Shanks (ed.). and development of marine Oregon State University Press, invertebrates of the northern Pacific Corvallis, OR. Coast. M. F. Strathmann (ed.).