Batillaria attramentaria (G.B. Sowerby I)
Common name(s): Japanese false cerith, false cerith, zoned cerith, screw shell, tall-spired snail
|Synonyms: Batillaria cumingi, Batillaria zonalis, Batillaria alterima|
Family Batillariidae (one type of hornsnails)
|Batillaria attramentaria, from Padilla Bay west of March Point.|
|(Photo by: Dave Cowles )|
How to Distinguish from Similar Species: There is only one (introduced) species from this family in this area, and this is the only locally common mudflat snail with a high, turreted shell. Among other turreted snails, this species can be distinguished from Cerithidea californica, the California horn snail, which lives farther south by the fact that the siphonal notch of C. californica is barely developed and does not twist sharply toward the midline (photo photo). C. californica also has a pallial eye on the edge of the siphon, which B. attramentaria does not have. Bittium spp. (Family Cerithiidae) also have a barely evident siphonal canal. They may have both spiral ridges and axial ribs, but the most common species, Bittium eschrichtii, has no axial ribs. Members of Family Cerethiopsidae ((e.g. Cerithiopsis spp.) have a siphonal canal which angles about 45 degrees toward the midline, may have well over 12 axial ribs, and rarely grow over 1 cm high. Exilioidea rectirostris (Family Neptuneidae) has a much more prominent siphonal canal (over 1/2 the height of the aperture) and prominent axial ribs but has only faint spiral ridges which do not form beads with the axial ribs.
Geographical Range: Japan, other areas of Asia from 40 degrees N to south of the equator. Common in several bays in California and the Pacific Northwest where oysters have been grown, at least up into British Columbia.
Depth Range: Mid to high intertidal.
Habitat: Lives on mud in salt marshes, especially in brackish waters.
Biology/Natural History: This species was introduced from Asia, probably along with oysters. Since they seem to remain in areas near where oysters were planted, their larvae probably have a very short or no pelagic stage. This species is slowly replacing the native snail Cerithidea californica in California bays where they coexist. Both this species and C. californica frequently are infested with abundant cercariae larvae from flukes (Trematodes), and serve as alternate hosts to the flukes which infect seabirds.
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General Notes and Observations: Locations, abundances, unusual behaviors:These occur abundantly on the soft mud west of March Point but are much less common on the harder mud east of March Point.
|Below are 3d images made of a Batillaria attramentaria snail 24 mm long. 3d images are made of a composite of 8-10 photos each at different depths so that the entire depth of field is in focus. Photos by Dave Cowles using a Keyence VHX-100 photomicroscope.|
|These views can be contrasted with that of the California hornsnail, Cerithidea californica, which can be seen in aperture view and rear view by clicking these links.|