View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Oregon Scholars' Bank Hiatella arctica (=Saxicava arctica) Phylum: Mollusca Class: Bivalvia Order: Myoida The nestling saxicave (Linnaeus, 1767) Family: Hiatellidae Description Size—to 50 mm (2"); this specimen (Coos The venerid clam Protothaca staminea var. Bay) 38 mm long (Quayle 1970). orbella, like Hiatella, is white with an external Color—exterior white, chalky, granular, with ligament, and can be found nestling in old tan, thin, ragged periostracum: genus Hiateila pholad burrows. It has radial as well as (Keen and Coan 1974); interior porcelain-like, concentric striations, however, and interiorly white: family Hiatellidae (Hunter 1949). has 3 cardinal hinge teeth and a strong pallial Shell Shape—variable: distorted by nestling line and sinus. habit. Valves equal, oblong, gaping: posterior Petricola carditoides is a nestling clam and broader, more square than anterior end, which (like Hiatella) has an external ligament broadly truncated (fig. 1). Elongate, boring and a chalky white shell. It has hinge teeth in specimens have been reported as H. pholadis the adult (2-3), not just in the young. P. (Coan and Carlton 1975) (fig. 1a). carditoides has purple-tipped siphons, not red Sculpture—concentric only ones, and its shell has some radial sculpture. Interior—pallial line faint, broken into Two myid clams could be confused with discontinuous scars (fig. 3): family Hiatellidae Hiatella: Platyodon cancellatus is a white (Coan and Carlton 1975). Adductor muscle borer with a heavy shell with fine, almost scars approximately equal in size (not shape). lamellar concentric exterior sculpture. Inside it No pallial sinus (Kozloff 1974a). has a chondrophore and tooth in its hinges, Hinge Area—adult without hinge teeth (or and a well-developed, deep pallial sinus. worn) (fig. 3); young clams have 1-2 weak, Cryptomya californica can nestle among peg-like cardinal teeth. rocks, although its usual habitat is sand or Umbones—depressed, nearer anterior end mud. It is small (to 30 mm), thin-shelled and than middle; do not touch each other (fig. 2). has a chondrophore. Interiorly it has an entire Ligament—external (figs. 2, 3): family pallial line, and an inconspicuous pallial sinus Hiatellidae (Coan and Carlton 1975). (Coan and Carlton 1975). Byssus—(attachment threads), present in Entodesma saxicola is probably most likely nestling specimens, not in boring ones (H. to be confused with Hiatella: it is of a pholadis); not figured. Long, single byssal comparable size, shape and habitat. thread spun by post-larval clams allows them Entodesma has a dark, rough periostracum, to be moved by weak water currents (Morris not a pale, thin one, an external ligament like et al 1980). Hiatella's, and short, fused siphons, but Siphons—fused; red tipped: genus Hiatella without red tips. Inside the shell is very pink (fig. 1) (Kozloff 1974a). and pearly. Entodesma has no hinge teeth, Periostracum—light tan, thin: genus Hiatella but does have a large internal ligament and (figs. 1, 2) (Keen and Coan 1974). lithodesma; its pallial line is entire and there is a small pallial sinus. Possible Misidentifications The nomenclature of Hiatella sp. is rather Burrowing and nestling clams, of which confused: Hiatella pholadis is a large (to 50 there are many genera, can be difficult to mm), often very elongate, boring species separate by shell shape; they tend to be strictly resident in pholad burrows and without variable and often quite distorted from the hinge teeth or red-tipped siphons (Kozloff "norm." Useful characteristics are the hinge 1974a). It has a prominent ridge from the teeth, pallial line and siphons. Most beaks to the lower posterior angle (Oldroyd Pholadidae can be distinguished by their two 1924). Coan and Carlton believe this name to distinct shell sections (see Penitella, Zirfaea); be a probably synonym for a form of H. all pholads have file-like denticulations and arctica (Coan and Carlton 1975). (except for Netastoma) an internal myophore. Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] Hiatella gallicana is a small (to 25 mm) (Lamarck) and H. artica (L.) with species which may be the same as H. arctica special reference to the boring point. (Ricketts and Calvin 1971; Quayle 1970). Proceedings of the Royal Society of Other northwest Hiatellidae include Edinburgh, series B. 63:271-289. Panopea generosa, the geoduck, which is 3. KEEN, A. M., and E. COAN. 1974. large, quadrate and not distorted. It has one Marine Molluscan Genera of Western cardinal tooth in either hinge. P. generosa is a North America: An Illustrated Key. very deep bur-rower with very long siphons; it Stanford University Press, Stanford, is rarely found in Oregon. California. 4. KOZLOFF, E. N. 1974a. Keys to the Ecological Information marine invertebrates of Puget Sound, Range—Arctic Ocean to Panama (Oldroyd the San Juan Archipelago, and 1924); circumpolar. adjacent regions. University of Local Distribution—Coos Bay: Pigeon Point. Washington Press, Seattle & London. Habitat—nestles in old pholad burrows, or 5. MORRIS, R. H., D. P. ABBOTT, and bores into smooth soft homogenous rocks; E. C. HADERLIE. 1980. Intertidal also found in Mytilus beds, on pilings, and on invertebrates of California. Stanford open coasts in algal holdfasts. On hard, University Press, Stanford, California. crevice, surfaces it will attach byssally (Hunter 6. OLDROYD, I. S. 1924. Marine shells 1949). of Puget Sound and vicinity. University Salinity—found in Coos Bay in lower, more of Washington Press, Seattle. saline parts of estuary: collected at 30 ‰. 7. QUAYLE, D. B. 1970. The intertidal Temperature— bivalves of British Columbia. British Tidal Level—intertidal to 120 m deep; Columbia Provincial Museum, Victoria, collected at 0.0 ft. Canada. Associates—other nestling and boring 8. RICKETTS, E. F., and J. CALVIN. molluscs: Entodesma, Penitella, Zirfaea. 1971. Between Pacific tides. Stanford University Press, Stanford, California. Quantitative Information Weigth— Abundance—not common. Life History Information Reproduction— Growth Rate— Longevity— Food—suspension feeder. Predators—tooth snails (Nucella, etc.) can prey on small nestling clams. Behavior—boring is mechanical, not chemical (Hunter 1949). Bibliography 1. COAN, E. V., and J. T. CARLTON. 1975. Phylum Mollusca: Bivalvia, p. 543-578. In: Light's manual; intertidal invertebrates of the central California coast. S. F. Light, R. I. Smith, and J. T. Carlton (eds.). University of California Press, Berkeley. 2. HUNTER, W. R. 1949. The structure and behavior of Hiatella gallicana Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] .