Hiatella arctica Phylum: Class: Order: Veneroida The nestling or Arctic saxicave, little gaper, red nose Family:

Taxonomy: There are many synonyms for H. moving to the middle of the shell arctica due to the potentially cosmopolitan (Flyachinskaya and Lezin 2008). distribution of this . Research by Exterior: Strauch (1968) and Beu (1969) synonymized : These attachment threads all species worldwide (except H. are present in nestling specimens, but not in australis from southern Australia) as H. boring ones (e.g., H. pholadis). Adult attach arctica (Beu 1969). Commonly seen with byssal threads and can also bore into synonyms include Saxicava arctica, H. rock (Coan and Valentich-Scott 2007). A pholaids, and H. solida. Due to the extensive single, long byssal thread produced by post- synonymizations, it is possible that there are larval clams allows them to be moved by actually two species currently under the name weak water currents (see Juvenile) (Haderlie H. arctica, locally (Coan and Valentich-Scott 1980), in a process called thread drifting (see 2007). Macoma balthica, Nutricola tantilla, descriptions in this guide). Description Gills: Size: Individuals to 50–76 mm in length Shell: (For amino acid shell composition see (Kozloff 1993). The illustrated specimen Brigham 1983.) Right slightly larger (from Coos Bay) is 38 mm in length (Quayle than the left (Khalaman 2005) (Fig. 2). 1970). Interior: Pallial line is faint and Color: Exterior is white, chalky, granular, and broken into discontinuous scars (Fig. 3) with tan, thin, and ragged (Hiatellidae, Coan and Valentich-Scott 2007), (Hiateila, Keen and Coan 1974). The interior unlike Entodesma navicula (see description in is porcelain-like and white (Hiatellidae, Hunter this guide). Adductor muscle scars are 1949). Periostracum is light brown or tan. approximately equal in size, but not shape. General Morphology: Bivalve mollusks are There is no (Kozloff 1974). bilaterally symmetrical with two lateral valves Exterior: The shape is highly variable or shells that are hinged dorsally and due to their nestling habit. Right and left surround a , head, foot and viscera valves are equal, oblong, and gaping. The (see Plate 393B, Coan and Valentich-Scott posterior is broader and more square than the 2007). The Veneroida is a large and diverse anterior end, which is broadly truncated (Fig. bivalve heterodont order that is characterized 1). Elongate, boring specimens have been by well-developed . There are 22 reported as H. pholadis (Coan and Carlton local families, and members of the Hiatellidae 1975) (Fig. 1a). Shell is concentric are characterized by a pallial line that is only and the periostracum is light tan and thin divided into patches (see Plate 395D, Coan (Figs. 1, 2) (Hiatella, Keen and Coan 1974). and Valentich-Scott 2007) (Fig. 3). Hinge: Adult specimens are without Body: A nestling species with a thin shell (or very worn) hinge teeth (Fig. 3). However, (see Fig. 257, Kozloff 1993). young clams have 1–2 weak, peg-like Color: cardinal teeth. Umbones are depressed, Interior: is external (Figs. nearer anterior end than middle and do not 2–3) in members of the family Hiatellidae touch one other (Fig. 2). (Coan and Carlton 1975). This primary Eyes: ligament initially forms at the shell posterior in Foot: newly metamorphosed juveniles before

Hiebert, T.C. 2015. . 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/1794/12900 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Siphons: Siphons are fused and with is very pink and pearly. Entodesma navicula crimson tips (Fig. 1) (Kozloff 1993). has no hinge teeth, but does have a large Burrow: internal ligament and its pallial line is continuous. Possible Misidentifications Other bivalves that can be easily Three bivalve families including the confused with H. arctica include Protothaca Lyonisiidae, Hiatellidae, and Thraciidae are staminea, Petricola carditoides, Platyodon characterized by their lack of dorsal margin cancellatus, and Cryptomya californica. The ears or projecting teeth or chondrophores, venerid clam Protothaca staminea, like H. and two adductor muscles. In thraciids, the arctica, is white with an external ligament, and ligament can be both internal and external can be found nestling in old pholad burrows. and the pallial line is continuous; in hiatellids It has radial as well as concentric striations, the ligament is always external and the however, and interiorly has three cardinal pallial line is broken into patches (see hinge teeth and a strong pallial line and sinus. below). On the other hand, in the lyonisiids Petricola carditoides is a nestling clam which (e.g., see Entodesma navicula in this guide) has an external ligament and a chalky white the pallial line is continuous, as in thraciids, shell, as in H. arctica. It has 2–3 hinge teeth but the ligament is always internal, unlike in the adult, not just in the juveniles. Petricola thraciid species (Coan and Valentich-Scott carditoides also has purple-tipped siphons, 2007). not crimson, and its shell has some radial Burrowing and nestling clams, of sculpture. The myid clam Platyodon which there are many genera, can be difficult cancellatus is a white borer with a heavy shell to separate by shell shape as their nestling with fine, almost lamellar concentric exterior habits tend to produce a varied shell shape. sculpture. Inside it has a chondrophore and Useful characteristics for differentiating tooth in its hinges, and a well-developed, species include the hinge teeth, pallial line, deep pallial sinus. Cryptomya californica, also and siphons. Most Pholadidae can be a myid clam, can nestle among rocks, distinguished by their two distinct shell although its usual habitat is sand or mud. It is sections (see Penitella penita, Zirfaea small (to 30 mm), thin-shelled and has a pilsbryi in this guide). All pholads have file- chondrophore. Interiorly it has an entire like denticulations and (except for pallial line, and an inconspicuous pallial sinus Netastoma) an internal myophore. (Coan and Carlton 1975). There are only two local species reported in the family Hiatellidae: Ecological Information abrupta and Hiatella arctica. Panopea Range: Type region is the Arcitc coast of abrupta tends to be larger (up to 200 mm in Norway (Keen 1971) A circumpolar species length) than H. arctica and have a continuous with known range from Arctic Ocean to pallial line, not broken into patches like in H. Panama (Oldroyd 1924). Range is certainly arctica. , also known as the influenced by many human introductions (Beu , is a very deep burrower with long 1971; Narchi 1973; Russell-Hunter 1949; siphons (up to several feet) in soft sediments. Yonge 197), and potentially includes two It has one cardinal tooth in either hinge and is species as a result (Coan and Valentich-Scott rarely found in Oregon. Also, Saxicavella 2007) (see ). In Cow Head, pacifica, a small offshore species in soft Newfoundland, radiocarbon age of H. arctica sediments is reported (Coan and Valentich- fossils embedded in rock were approximately Scott 2007). 8,250 years BP (Brookes and Stevens 1984). Entodesma navicula is probably most The genus Hiatella is widespread in polar likely to be confused with H. arctica, as it is of latitudes dating to 150 million years ago a comparable size, shape, and habitat. (Laakkonen et al. 2015). A recent molecular Entodesma navicula has a dark, rough analysis of over 350 specimens using three periostracum, not a pale, thin one, an external gene regions suggests cryptic speciation ligament (like H. arctica), and short, fused rather than widespread distribution, including siphons, but without red tips. Inside the shell at least 13 different putative species, several

Hiebert, T.C. 2015. Hiatella arctica. 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. of them living sympatrically (Laakkonen et al. Abundance: Not common locally, however, 2015). These authors found several distinct H. arctica is the dominant byssal bivalve in lineages within the northeast Pacific (see the arctic and boreal regions (Coan and Laakkonen et al. 2015). Valentich-Scott 2007). Along with Local Distribution: Local distribution in edulis, H. arctica was the most abundant Coos Bay including Pigeon Point. bivalves in Eyjafordur, North Iceland, with Habitat: Individuals nestle in old pholad newly metamorphosed spat observed on burrows or bore into smooth, soft, settlement plates throughout the year (Garcia homogenous rocks. They are also found in et al. 2008). Density reached approximately mussel (e.g., Mytilus) clumps, on pilings, and 815 individuals per meter in the White Sea on open coasts within algal holdfasts. On (Khalaman 2005). hard surfaces and within crevices, individuals attach byssally (Hunter 1949). Prefers Life-History Information sheltered locations or being covered by other Reproduction: Spawning occurs from mid organisms (Khalaman 2005). June through September and larvae Salinity: Occurs in Coos Bay as well as are present through November (White Sea, more saline parts of estuary, and individuals Russia, Flyachinskaya and Lesin 2006). The have been collected at salinities of 30. Heart early development is apparently very similar rates 10 to 16 beats per minute at normal to Mytilus edulis (see description in this salinities but drops dramatically in response guide), which was described by Malakhov and to a change in salinity, returning to normal Medvedeva (1985). after 2–7 days (Bakhmet et al. 2012). Larva: Bivalve development generally Temperature: Temperature may affect shell proceeds from external fertilization via growth and structure (see Larva) leading broadcast spawning through a ciliated Lezin et al. (2015) to question the relevance stage to a veliger larva. Bivalve of shell structure as taxonomic characters and are characterized by a ciliated velum for estimation of sea surface temperature (but that is used for swimming, feeding and see Strauch 1968, 1971). Shell shape is also respiration. The veliger larva is also found in certainly affected by the nestling habits of many gastropod larvae, but the larvae in the individuals (see Rowland and Hopkins 1971). two groups can be recognized by shell Tidal Level: Intertidal to 120 m deep, but morphology (i.e. snail-like versus clam-like). also low or subtidal when attached (with In bivalves, the initial shelled-larva is called a byssus) under rocks, on floats or pilings D-stage or straight-hinge veliger due to the (Morgan and Allen 1976; Morton 1987; Yonge “D” shaped shell. This initial shell is called a 1952, 1976; Coan and Valentich-Scott 2007). I and is followed by a The highest abundance of individuals (57 per prodissoconch II, or shell that is subsequently square meter) was observed at 20-meter added to the initial shell zone (see Fig. 1, depths in the Young Sound, northeast Caddy 1969). Finally, shell secreted following Greenland (Sejr et al. 2002). metamorphosis is simply referred to as the Associates: Associates include other dissoconch (see Fig. 2, Brink 2001). Once nestling and boring molluscs (e.g., the larva develops a foot, usually just before Entodesma navicula, Penitella penita, Zirfaea metamorphosis and loss of the velum, it is pilsbryi). A potential competitor affecting called a pediveliger (see Fig. 1, Caddy 1969; settlement of Pecten maximus, the great Kabat and O’Foighil 1987; Brink 2001). (For scallop in the Bay of Brest in France generalized life cycle see Fig. 1, Brink 2001). (Chauvard et al. 1996). Hiatella arctica is a Larval development was described by facultative epibionts of the crab Hemigrapsus Flyachinskaya and Lesin (2006) where sanguineus in Japan (Isaeva et al. 2001). straight hinge larvae were 120 µm, Competes with and often associated with were 160 µm, early pediveligers were 220 Mytilus edulis fouling communities (Khalaman µm, pediveligers were 310 µm and grew to 2005). Also co-occurs with the solitary 400 µm pre-metamorphosis and were 750 µm ascidian Styela rustica, in the White Sea post-metamorphosis (see Fig. 3, (Khalaman 2007). Flyachinskaya and Lesin 2006). The shell is

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12900 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] yellowish pink when early in development and Table 1, Petersen et al. 2003) and averages changes to a darker (dirtier) yellow with pink being approximately 23.4 and 27.4 ml per margins. Veliger larvae of H. arctica have a minute per gram body weight those from the distinctly triangular shell and there are two Arctic and Sweden, respectively (Petersen et distinct posterior dorsal spines on the al. 2003). Clearance rates and assimilation dissoconch in newly metamorphosed H. efficiency (how much food is metabolized) of arctica (see Fig. 3F, Flyachinskaya and Lezin Rhodomonas baltica decreases with 2006). These spines are lost in adulthood increasing food concentration (Sejr et al. Flyachinskaya and Lezin 2008). Settlement 2004). Sejr et al. (2004) found that was observed throughout the year in individuals grow to annual observed growth in Eyjafjordur, Iceland with peaks in abundance the wild in three weeks at optimal feeding of primary (<1mm) settlers in September. conditions in the laboratory and suggest that Lezin et al. (2015) found that larvae and food is limiting in wild populations. juveniles raised at 12˚C formed ridges and Predators: Toothed snails (e.g., Nucella spines on the shell posterior. However, they spp.) can prey on small nestling clams like H. developed fewer or inconspicous spines at arctica. lower temperatures (e.g., 5˚C) (Lezin et al. Behavior: Individuals bore mechanically and 2015). Wild-caught planktonic larvae without the aid of chemical compounds measured up to 380 µm in the North Sea and (Hunter 1949). had a tough shell, a conspicuous pallial line, and concentric ridges that become more pronounced and widely spaced with distance Bibliography from the umbo (Rees 1950). Juvenile: Like other bivalve species (e.g. 1. ALI, R. M. 1970. Influence of Mytilus edulis, Macoma balthica), post-larval suspension density and temperature (i.e., juvenile) H. arctica may exploit two on filtration rate of Hiatella arctica. dispersal periods. The initial larval dispersal Marine Biology. 6:291-302. and settlement into the benthos, is followed 2. BAKHMET, I. N., A. J. by potential dispersal from the benthos by KOMENDANTOV, and A. O. thread drifting on water currents via mucous SMUROV. 2012. Effect of salinity threads by juveniles (i.e., “thread drifting”, change on cardiac activity in Hiatella Martel and Chia 1991). arctica and modiolus, in the Longevity: Age was estimated for individuals White Sea. Polar Biology. 35:143-148. in the Young Sound, northeast Greenland by 3. BEU, A. G. 1971. New light on counting growth rings (a method validated by variation and taxonomy of bivalve Sejr et al. 200b); the oldest individuals were Hiatella. New Zealand Journal of estimated to be 126 years old (Sejr et al. Geology and Geophysics. 14:64-66. 2002a). 4. BRIGHAM, J. K. 1983. Intrashell Growth Rate: Mean growth rate was variations in amino acid estimated to be 0.14 mm per year in concentrations and isoleucine northeast Greenland (Sejr et al. 2002a). epimerization ratios in fossil Hiatella Food: A suspension feeder. Filtration rates arctica. Geology. 11:509-513. were 1.4 x 10-2 liters per hour per gram wet 5. BRINK, L. A. 2001. Mollusca: Bivalvia, weight (Phaeodactylum tricornutum, 15˚C) p. 129-149. In: Identification guide to and increases up to temperatures of 17˚C larval marine invertebrates of the before decreasing above 25˚C (Ali 1970), at Pacific Northwest. A. Shanks (ed.). high temperatures H. arctica close their Oregon State University Press, valves completely (Petersen et al. 2003). Corvallis, OR. Clearance rates for individuals at varying 6. BROOKES, I. A., and R. K. temperatures were recorded by Petersen et STEVENS. 1985. Radiocarbon age of al. (2003) for individuals collected in the Arctic rock boring Hiatella arctica (Linne) and (Young Sound, northeast Greenland) and postglacial sea level change at Cow- temperate waters (Tjarno, Sweden) (see Head, Newfoundland. Canadian

Hiebert, T.C. 2015. Hiatella arctica. 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. Journal of Earth Sciences. 22:136- 15. ISAEVA, V., V. KULIKOVA, and I. 140. KASYANOV. 2001. Bivalve molluscs, 7. CHAUVAUD, L., G. THOUZEAU, and and Hiatella arctica, J. GRALL. 1996. Experimental as facultative epibionts of the crab, collection of great scallop postlarvae Hemigrapsus sanguineus, infested by and other benthic species in the Bay the rhizocephalan, Sacculina of Brest: Settlement patterns in polygenea. Journal of the Marine relation to spatio-temporal variability of Biological Association of the United environmental factors. Aquaculture Kingdom. 81:891-892. International. 4:263-288. 16. KABAT, A. R., and D. O'FOIGHIL. 8. COAN, E. V., and J. T. CARLTON. 1987. Phylum Mollusca, Class 1975. Phylum Mollusca: Bivalvia, p. Bivalvia, p. 309-353. In: Reproduction 543-578. In: Light's manual; intertidal and development of marine invertebrates of the central California invertebrates of the northern Pacific coast. S. F. Light, R. I. Smith, and J. T. Coast. M. F. Strathmann (ed.). Carlton (eds.). University of California University of Washington Press, Press, Berkeley. Seattle, WA. 9. COAN, E. V., and P. VALENTICH- 17. KEEN, A. M. 1971. Sea shells of SCOTT. 2007. Bivalvia, p. 807-859. In: tropical west America: marine The Light and Smith manual: intertidal mollusks from Baja California to Peru. invertebrates from central California to Stanford University Press, Stanford, Oregon. J. T. Carlton (ed.). University CA. of California Press, Berkeley, CA. 18. KEEN, A. M., and E. COAN. 1974. 10. FLYACHINSKAYA, L. P., and P. A. Marine molluscan genera of western LESIN. 2006. Using 3D reconstruction North America: an illustrated key. method in the investigations of bivalvia Stanford University Press, Stanford, larval development (by the example of CA. Hiatella arctica L.). Trudy 19. KHALAMAN, V. V. 2005. Testing the Zoologicheskogo Instituta. 310:45-50. hypothesis of tolerance strategies in 11. FLYACHINSKAYA, L. P., and P. A. Hiatella arctica L. (Mollusca: Bivalvia). LEZIN. 2008. Larval and juvenile shell Helgoland Marine Research. 59:187- development in the White Sea bivalve 195. Hiatella arctica (Linnaeus, 1767). 20. KHALAMAN, V. V., and A. Y. Zoologiya Bespozvonochnykh. 5:39- KOMENDANTOV. 2007. Mutual 46. influence on survival and growth rate 12. GARCIA, E. G., G. G. in fouling organisms Mytilus edulis, THORARINSDOTTIR, and S. A. Styela rustica and Hiatella arctica from RAGNARSSON. 2003. Settlement of the White Sea. Biologiya Morya. bivalve spat on artificial collectors in 33:176-181. Eyjafjordur, North Iceland. 21. KOZLOFF, E. N. 1974. Keys to the Hydrobiologia. 503:131-141. marine invertebrates of Puget Sound, 13. HADERLIE, E. C., and D. P. ABBOTT. the San Juan Archipelago, and 1980. Bivalvia: the clams and allies, p. adjacent regions. University of 355-410. In: Intertidal invertebrates of Washington Press, Seattle. California. R. H. Morris, D. P. Abbott, 22. —. 1993. Seashore life of the northern and E. C. Haderlie (eds.). Stanford Pacific coast: an illustrated guide to University Press, California. northern California, Oregon, 14. HUNTER, W. R. 1949. The structure Washington, and British Columbia. and behavior of Hiatella gallicana University of Washington Press, (Lamarck) and H. artica (L.) with Seattle. special reference to the boring point. 23. LAAKKONEN, H. M., P. STRELKOV, Proceedings of the Royal Society of and R. VAINOLA. 2015. Molecular Edinburgh, Series B. 63:271-289. lineage diversity and inter-oceanic

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Hiebert, T.C. 2015. Hiatella arctica. 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.