Phylum: Mollusca Bankia setacea Class: Bivalvia, Heterodonta, Euheterodonta Order: Imparidentia, Myida The northwest or feathery shipworm Family: Pholadoidea, Teredinidae, Bankiinae Taxonomy: The original binomen for Bankia the presence of long siphons. Members of setacea was Xylotrya setacea, described by the family Teredinidae are modified for and Tryon in 1863 (Turner 1966). William Leach distiguished by a wood-boring mode of life described several molluscan genera, includ- (Sipe et al. 2000), pallets at the siphon tips ing Xylotrya, but how his descriptions were (see Plate 394C, Coan and Valentich-Scott interpreted varied. Although Menke be- 2007) and distinct anterior shell indentation. lieved Xylotrya to be a member of the Phola- They are commonly called shipworms (though didae, Gray understood it as a member of they are not worms at all!) and bore into many the Terdinidae and synonyimized it with the wooden structures. The common name ship- genus Bankia, a genus designated by the worm is based on their vermiform morphology latter author in 1842. Most authors refer to and a shell that only covers the anterior body Bankia setacea (e.g. Kozloff 1993; Sipe et (Ricketts and Calvin 1952; see images in al. 2000; Coan and Valentich-Scott 2007; Turner 1966). Betcher et al. 2012; Borges et al. 2012; Da- Body: Bizarrely modified bivalve with re- vidson and de Rivera 2012), although one duced, sub-globular body. For internal anato- recent paper sites Xylotrya setacea (Siddall my, see Fig. 1, Canadian…; Fig. 1 Betcher et et al. 2009). Two additional known syno- al. 2012. nyms exist currently, including Bankia Color: osumiensis, B. sibirica. Interior: The auricle (chamber of the heart) is medium sized and rounded. A com- Description plex digestion system allows for digestion of Size: The largest of the shipworms, with bur- wood, which passes from a short esophagus rows that in one study were found to be up to an alimentary tract to a stomach and finally to 15mm in diameter and 1m in length a caecum where wood is broken down by en- (Haderlie and Mellor 1973). Body size can zymes (for metabolic compounds see Liu and vary greatly. The illustrated specimen (Fig. Townsley 1968, 1970). The caecum is long, 1) is small and has shell diameter of 5 mm. blind and has thin walls (Fig. 1, Liu and Color: White with brownish tinges. A long Townsley 1968). soft whitish tube connects the calcareous Exterior: shell and pallets (Fig. 1) (Haderlie and Ab- Byssus: bott 1980). Gills: Also called ctenidia. Eulamelli- General Morphology: Bivalve mollusks are branchiate or filamentous and consisting of bilaterally symmetrical with two lateral valves two layers on each side of the body. Ctenidia or shells that are hinged dorsally and sur- house symbiotic bacteria that synthesize es- round a mantle, head, foot and viscera (see sential nutrients (e.g., amino acids) for the Plate 393B, Coan and Valentich-Scott host individual (see Associates, Trylek and 2007). Among the bivalves, the Heterodon- Allen 1980). ta are characterized by ctenidia that are eu- Shell: The two valves gape widely in front of lamellibranchiate, fused mantle margins and A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Hiebert, T.C. 2015. Bankia setacea. 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. the foot and behind the body (Hill and Kofold muscles, rocking the clam and toothed valves 1927; Haderlie and Abbott 1980). Each back and forth. The burrow itself becomes small valve with three lobes including ante- cylindrical as the body of the clam slowly rior, median (composed of three separate rotates as it burrows (Fig. 3) (Haderlie and areas), and posterior, or auricle (Figs. 4a, b, Abbott 1980). Burrows can be up to a meter c). In B. setacea, the anterior lobe is fairly long, with burrowing rate from 43–74 mm per small, and has many numerous, close-set month (Haderlie and Abbott 1980). ridges. Teredinidae-specific character Interior: An internal shell projection Pallets: Two calcareous, feather-like struc- for foot attachment or apophysis is present tures, attached to the posterior end under a (Fig. 4b) as well as articulating condyles fleshy collar (Figs. 1, 2). These pallets are (pivots) on ventral margins (Haderlie and used to close the burrow when animal is dis- Abbott 1980). turbed. They are symmetrical, compound, Exterior: Both valves have a file-like elongated, blade-like structures and consist of exterior surface for rasping wood (Liu and cone-shaped segments (Fig. 2). They are Townsley 1968). paired, Y-shaped and stacked such that the Hinge: smallest and oldest pallet is most distal from Eyes: the individual’s body (Fig. 10, Quayle 1992). Foot: Rounded and “sucker-like” (Fig. 1) Pallets may be extracted from and visualized and allows clam to hold onto wood (Haderlie in dead animals (Hill and Kofold 1927). and Abbott 1980). Siphons: Elongate (Heterodonta, Myoida, Possible Misidentifications Coan and Valentich-Scott 2007) and used Bivalve classification largely is based for feeding and respiration (Haderlie and Ab- on ten characters (Myoida, Coan and Valen- bott 1980). Males differ from females in tich-Scott 2007): morphology of ctenidia, having four rows of papillae (each up to 180 shell interior and exterior, foot, byssus, adduc- µm in length, see Fig. 14, Quayle 1992) on tor muscles and stomach; mode of life (e.g., the exhalant siphon, which is sometimes in- burrowing); degree of mantle edge fusion; serted into female siphon at spawning shell mineralogy; molecular phylogenetics. (Haderlie and Abbott 1980; Kabat and Within the Heterodonta, species have ctenidia O’Foighil 1987). The tip of the inhalant si- that are eulamellibranchiate, mantle margins phon is surrounded by a crown of six short that are fused and elongated siphons. This tentacles (no tentacles are present on the group consists of the orders Veneroida, exhalant siphon) (Quayle 1992). Pholadomyoida and the Myoida. Veneroids Burrow: Sinuous and revealing pattern of have well-developed hinge teeth, the shell's external grinding surface. Pholadomyoida are burrowers with thin shells Calcareous tube that is produced when and reduced or absent hinge teeth. The My- individuals stop boring is sometimes oida, to which B. setacea belongs, are bur- apparent (see Fig. 53, Kozloff 1993). rowers and borers, with few hinge teeth. Individuals burrow deep into wooden There are four local families including Myidae, structures, not just along surface (Haderlie Corbulidae, Pholadidae and Teredinidae. and Mellor 1973) and prefer horizontal The Teredinidae can be distinguished surfaces along the mudline (Walden et al. from other myoid families as wood borers with 1967). Burrowing is accomplished by distinct pallets (Fig. 2) at siphon tips and ante- alternating contractions of adductor rior shell indentations. There are only three A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] local species and B. setacea is easily recog- but do not completely deter the shipworm. nized as the only species with pallets that (see also Behavior). have an elongate, Y-shaped blade and cone Salinity: Prefers full strength sea water -shaped segments. The remaining two spe- (particularly for spawning, Kabat and O’Foighil cies have pallets that are not segmented 1987) of open oceans and doesn't tolerate (Kozloff 1993; Coan and Valentich-Scott reduced salinity (Ricketts and Calvin 1971). 2007). Can survive in salinities up to 50 (Haderlie Teredo navalis, the common and and Abbott 1980). cosmopolitan shipworm, was introduced to Temperature: Prefers cold habitats and tends San Francisco around 1910 (Hill and Kofold to lay eggs during the coldest months. Re- 1927). Teredo navalis has simple, spade- ported temperature range (Puget Sound, shaped pallets, without the separate conical Washington) is from 7 to 12°C (Johnson and elements of B. setacea. Teredo navalis also Miller 1935; Betcher et al. 2012). causes more damage to wooden structures Tidal Level: Subtidal to 70m. Individuals oc- than B. setacea, being much more cur as deep as 200 meters (Monterey Bay, adaptable to extremes of temperature and California, Haderlie 1983b), but are most salinity. It is usually much smaller than B. dense at 0.3 meters above mudline (Haderlie setacea and its burrows are nearer the and Mellor 1973). Individuals were also colle- surface. Another introduced species, cted from wooden panels suspended at Lyrodus pedicellatus, occurs locally and depths of 1–3 meters (Betcher et al. 2012). differs from T. navalis by having more Associates: Known macro invertebrate asso- periostracum covering the distal half of the ciates include small isopods from the genus pallet, rather than a pallet that is almost Limnoria (e.g., see Limnoria tripunctata, this entirely calcareous (Coan and Valentich- guide; Kozloff 1993) as well as the isopod Scott 2007). Lyrodus pedicellatus also has Ianiropsis derjugini (see description in this narrower pallets than T. navalis (Quayle guide), which was found in Charleston harbor 1992). Other Bankia species are warm with B. setacea. Shipworms are also known water animals, and do not range north of to host a community of bacterial endosymbi- San Diego (Hill and Kofold 1927). onts that aid in the digestion of consumed wood (Trylek and Allen 1980; Siddall et al. Ecological Information 2009; Betcher et al. 2012). These symbionts Range: Type locality is San Francisco Bay, are cellulolytic nitrogen-fixing bacteria and re- California (Turner 1966).