endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) This common cold-water North Pacific marine gastropod has a southernmost limit in North America in Humboldt Bay, California; but occurs from there north to the Gulf of Alaska and from there westward throughout the Aleutian Island chain, the Pribilof and Commander (Komandor) Islands, over to the east coast of Kamchatka, and in Russia south to the Kurile Islands (Reid, 1996). In the U.S. it is currently known only from Humboldt Bay, California; Coos Bay, Oregon; and Gray's Harbor, Washington (Jones, 1977; Taylor, 1981); but more localities undoubtedly exist and it was initially incorrectly thought to be a different species.

Length: 1 cm

Syntype for Paludinella newcombiana Hemphill, 1877
Catalog Number: USNM 32725
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Preparation: Dry
Collector(s): H. Hemphill
Locality: Humboldt Bay, California, United States, North Pacific Ocean

Syntype for Paludinella newcombiana Hemphill, 1877
Catalog Number: USNM 127340
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Preparation: Dry
Collector(s): H. Hemphill
Locality: Humboldt Bay, California, United States, North Pacific Ocean
Microhabitat: abundant in salt marshes

Habitat Type: Marine

Comments: Occurs in areas of cold, clear, well-oxygenated water on a mixed sand or sand/gravel bottom with rooted aquatic macrophytes (T. Frest, pers. com.), or on lower stems of Salicornia (Keen, 1970). Newcomb's littorine snail is found within coastal environments, clinging to the rocky shores in the upper intertidal zone. This snail inhabits the narrow strip of land where glasswort (Salicornia virginica) occurs in coastal estuarine wetlands (Larsen et al., 1995), living on the stems of Salicornia and possibly some other marsh plants. It also lives on the substrate beneath vegetation.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Typical snail-like crawl; subject to passive dispersal by occasional floods, inadvertant transport by birds or animals, or human activities in their aquatic habitat.

Comments: Presumably feeds on Salicornia vegetation by rasping the surfaces to remove small particles for digestion. Other vegetation may also be acceptable.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: In Oregon, it only occurs in Coos Bay and Siletz Bay, Coos Co. (OR NHP, 2001). In Washington, Newcomb's littorine snail has been reported in Neah Bay, Mukkaw Bay, Grays Harbor, and Willapa Bay with its current known distribution limited to Grays Harbor and Willapa Bay (Larsen et al., 1995; Kozloff, 1983); and Humboldt Bay, California. Considering its wide range across the Pacific, however (Reid, 1996), there are likely thousands of occurrences worldwide.

>1,000,000 individuals

Its optimal distribution within its ecosystem is at, or slightly above, mean high tide so that its is submerged in sea water only a few hours per year. In the past, sawmill waste has had a devastating effect on its habitat and, consequently, on the species itself (Keen 1970 and Jones 1977).

Comments: Present year round with possible decreased activity in winter.

Egg masses of 15-40 eggs per mass are laid in
June and July in moist locations where they will be
submerged during most high tides. The early egg masses
are light in color and tough in texture and become
darker and softer as they age. The larvae emerge from
these egg masses and crawl away as fully formed
juvenile snails (pers. obs.). Hatchlings occur in midJuly with increasing abundance through late July and
early August.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G5 - Secure

Reasons: This common cold-water North Pacific marine gastropod has a southernmost limit in North America in Humboldt Bay, California; but occurs from there north to the Gulf of Alaska and from there westward throughout the Aleutian Island chain, the Pribilof and Commander (Komandor) Islands, over to the east coast of Kamchatka, and in Russia south to the Kurile Islands (Reid, 1996).

Intrinsic Vulnerability: Highly to moderately vulnerable.

Comments: It congregates in vulnerable aggregations that are susceptible to significant population decline.

Environmental Specificity: Unknown

Global Short Term Trend: Unknown

Comments: The current population status of Newcomb's littorine snail is uncertain and trends are not known. In additioni, this species may be confused during biological resource surveys with the similar species Littorina scutulata, adding to the inaccuracy of current population estimates.

Global Long Term Trend: Decline of 30-50%

Comments: Historically, this species has always been rare in California; or, more the habitat is rare and threatened in Calfornia. In the 1930's, it was distributed over a stretch of about 10 miles along the bay margins, present wherever there was Salicornia but tending to be in uneven clusters of dense populations thinning out laterally, but during the 1940's and 1950's several sawmills were actively operating in the area and by 1961 most of the snails were gone, and only a mass of half -burned sawdust could be found blanketing their habitat. Small isolated colonies survived in parts of the bay where the sawdust was less pervasive (Keen, 1970). A revisit in February 1968 found a few colonies doing well in both the south and the north ends of the bay with habitat recovery taking place (some sawdust layer broken up, and mud again evident in places) as several of the sawmills had been abandoned or converted to a type of work not producing sawdust (Keen, 1970).

Comments: Its greatest threats are habitat loss and introduced species such as the green crab (Yamada, 2001) and pulmonate snail from Europe Ovatella myosotis (Berman, 1989). Thought to live on pickleweed (Salicornia virginica) in Willapa Bay's native saltmarsh (Washington Department of Fish and Wildlife 1995), Newcomb's littorine snail may already be experiencing habitat loss as a result of Spartina alterniflora crowding out native vegetation such as pickleweed. Larsen et al. (1995) stated that estuarine habitat loss and pollution are the greatest threats to the Newcomb's littorine snail. In addition to population and habitat infringement associated with salt marsh development, the species could be significantly impacted by habitat loss from destruction or modification of tidelands and tidal wetlands. Populations and habitats may be destroyed as salt marsh habitat is used as dumps for fill, spoils, or waste.

Global Protection: Unknown whether any occurrences are appropriately protected and managed

Comments: Different morphological forms from wave-exposed rocky shores differ consistently in shell and radular morphology than those found in wave-protected salt marshes. Kyle and Boulding's (1998) genetic sequence results indicate each ecotype has evolved independently in each habitat and the morphological similarities are the result of parallel evolution. Recently, two distinctive clades in mitochondrial DNA sequences throughout British Columbia and Washington have been attributed to dispersal from separate glacial refuges (Kyle and Boulding, 2000). Algamorda subrotundata, as listed by Turgeon et al. (1988), is a synonym of Littorina subrotundata (fide Reid and Golikov, 1991) (Turgeon et al., 1998).