Leukoma staminea

Last updated

Littleneck clam
FMIB 44241 Paphia staminea, ripped-carpet shell, hard-shelled clam.jpeg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Venerida
Superfamily: Veneroidea
Family: Veneridae
Genus: Leukoma
Species:
L. staminea
Binomial name
Leukoma staminea
(Conrad, 1837) [1]
Synonyms [1]
  • Chione ruderata Deshayes, 1853
  • Paphia staminea (Conrad, 1837)
  • Paphia staminea orbellaCarpenter, 1864
  • Paphia staminea var. sulculosa Dall, 1902
  • Protothaca grewingkii Dall, 1904
  • Protothaca staminea (Conrad, 1837)
  • Tapes diversa G. B. Sowerby II, 1852
  • Tapes tumida G. B. Sowerby II, 1852
  • Tapes tumida Carpenter, 1857
  • Venerupis petiti Deshayes, 1839
  • Venus ampliata Carpenter, 1857
  • Venus conradi Römer, 1867
  • Venus mundulus Reeve, 1863
  • Venus pectunculoides Valenciennes, 1846
  • Venus rigida Gould, 1850
  • Venus staminea Conrad, 1837

Leukoma staminea, commonly known as the Pacific littleneck clam, the littleneck clam, the rock cockle, the hardshell clam, the Tomales Bay cockle, the rock clam or the ribbed carpet shell, [2] is a species of bivalve mollusc in the family Veneridae. [3] This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago, [4] and the distinctive shells form middens near their settlements. [5]

Contents

Description

Like other members of Veneridae, this species has a chalky shell, the umbo being anterior to the midline of the shell, but closer to the midline than to the anterior end of the shell. The two equal-sized valves are oval or heart-shaped. The width of the shell is greater than a quarter of its length, and the shell seldom exceeds 6 cm (2.4 in) in length. The umbones point towards the anterior end of the shell. The hinge has three cardinal teeth in each valve, and a row of small teeth along the ventral margins of the valves. There are numerous concentric ridges, more clearly demarcked at the anterior end, but the radial ridges are often more clearly sculpted. The foot is large and there is a clearcut pallial sinus. [2]


Right and left valve of the same specimen:

Distribution and habitat

Leukoma staminea is native to the eastern Pacific Ocean. Its range extends along the coasts of North America from the Aleutian Islands and Alaska in the north to Baja California in the south. It usually occurs in protected areas on sand, hard mud and clayey-gravel substrates from the mid and lower shore down to depths of about 10 m (33 ft), usually buried less than 8 cm (3 in) beneath the surface of the sediment. Occasionally it is in more exposed locations, in gravel-filled cracks in rocks or in empty burrows of other clams. [2]

Ecology

This clam is a filter feeder and consumes microscopic algae such as dinoflagellates, diatoms, and cyanobacteria. [2] [6] Some dinoflagellates produce neurotoxins, such as saxitoxin and its derivates, that bioaccumulate in the clams and other bivalve mollusks and can cause paralytic shellfish poisoning (PSP) when the clams are eaten. [2] [6] Despite this fact, the clam was eaten by Native Americans and is still used as a food for humans. [2] According to a 1996 report from the Marine Advisory Program at the University of Alaska, the United States Food and Drug Administration (FDA) considers seafood unsafe if it contains more than 80  μg of PSP-causing toxins per 100 g of tissue of the seafood. [7] [8] PSP is caused by a mixture of at least 21 different chemical species, some of which undergo chemical transformations within the dinoflagellates or within the animals that acquire the saxitoxins, and which are retained by different animals for different lengths of time. [7] It is clear that PSP-causing toxin levels are typically much higher in the summer months [9] though this does not mean the seafood is necessarily safe at other times. [10] Risks also vary based on species [7] [8] but seafood available for retail sale is required to meet the FDA standards. [10]

In PSP poisonings that occurred in the summer of 1993 in Kodiak, Alaska, saxitoxin levels as high as 19,600 μg / 100 g were measured in the Alaska blue mussel Mytilus edulis – sufficient to provide a lethal dose in a single 2.5 g mussel. [7] By contrast, the highest measured level of saxitoxin in the Pacific littleneck clam was 580 μg / 100 g according to this 1996 report. [8] Littleneck clams are "typically less toxic and retain their toxins for a shorter amount of time than the other species"   such as "butter clams and blue mussels [that] tend to accumulate the highest levels of PSP toxins ... [and] geoducks and scallops [that] tend to be toxic for longer periods of time"   but this does not mean that these clams "are always safe to eat [as] you can get PSP from littleneck clams." [11] The reason for the difference is likely that the littleneck clam has an enzyme that converts saxitoxin into decarbamoylsaxitoxin, a capability not shared by the blue mussel nor by the butter clam Saxidomus gigantea (in which levels of saxitoxin as high as 7,750 μg / 100 g have been reported [8] ). [12] This transformation to decarbomyl derivative has been reported in some other clam species and significantly reduces the toxicity of saxitoxins present. [13]

Predators include such molluscs as the leafy hornmouth snail (Ceratostoma foliatum) and Lewis's moon snail (Neverita lewisii), the crabs Metacarcinus magister and Cancer productus , the giant Pacific octopus (Enteroctopus dofleini) and the sea otter. [2] Fish such as the Pacific staghorn sculpin sometimes nips off the siphons when they are extended to feed. This clam spawns during the summer in the north of its range. It is a slow-growing species and may live for up to sixteen years. [2]

Related Research Articles

<span class="mw-page-title-main">Shellfish</span> Culinary and fisheries term for exoskeleton-bearing aquatic invertebrates

Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some are found in freshwater. In addition, a few species of land crabs are eaten, for example Cardisoma guanhumi in the Caribbean. Shellfish are among the most common food allergens.

<span class="mw-page-title-main">Mussel</span> Type of bivalve mollusc

Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.

<span class="mw-page-title-main">Saxitoxin</span> Paralytic shellfish toxin

Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin (PST). Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic shellfish poisoning (PSP).

<span class="mw-page-title-main">Paralytic shellfish poisoning</span> Syndrome of shellfish poisoning

Paralytic shellfish poisoning (PSP) is one of the four recognized syndromes of shellfish poisoning, which share some common features and are primarily associated with bivalve mollusks. These shellfish are filter feeders and accumulate neurotoxins, chiefly saxitoxin, produced by microscopic algae, such as dinoflagellates, diatoms, and cyanobacteria. Dinoflagellates of the genus Alexandrium are the most numerous and widespread saxitoxin producers and are responsible for PSP blooms in subarctic, temperate, and tropical locations. The majority of toxic blooms have been caused by the morphospecies Alexandrium catenella, Alexandrium tamarense, Gonyaulax catenella and Alexandrium fundyense, which together comprise the A. tamarense species complex. In Asia, PSP is mostly associated with the occurrence of the species Pyrodinium bahamense.

<span class="mw-page-title-main">Hard clam</span> Species of bivalve mollusc native to the east coast of North and Central America

The hard clam, also known as the round clam, hard-shellclam, or the quahog, is an edible marine bivalve mollusk that is native to the eastern shores of North America and Central America from Prince Edward Island to the Yucatán Peninsula. It is one of many unrelated edible bivalves that in the United States are frequently referred to simply as clams. Older literature sources may use the systematic name Venus mercenaria; this species is in the family Veneridae, the venus clams.

<i>Callista chione</i> Species of bivalve

Callista chione, the smooth clam, is a rather large, temperate, marine, bivalve mollusc that inhabits sandy bottoms or with small pebbles in clean waters down to about 200 m from the British Isles to the Mediterranean. The shell can reach up to about 110 mm Ø, its outer side is smooth and ranges from light greenish creamy colour to medium brown, probably varies to match the background; the interior is white to soft pink. The concentric and radial growth lines are easily seen. Callista chione is edible, different dishes are prepared throughout the Mediterranean in Spain, Italy, France, the Balkan and the Maghreb countries.

Shellfish poisoning includes four syndromes that share some common features and are primarily associated with bivalve molluscs As filter feeders, these shellfish may accumulate toxins produced by microscopic algae, such as cyanobacteria, diatoms and dinoflagellates.

<span class="mw-page-title-main">Neurotoxic shellfish poisoning</span> Syndrome of shellfish poisoning

Neurotoxic shellfish poisoning (NSP) is caused by the consumption of brevetoxins, which are marine toxins produced by the dinoflagellate Karenia brevis. These toxins can produce a series of gastrointestinal and neurological effects. Outbreaks of NSP commonly take place following harmful algal bloom (HAB) events, commonly referred to as "Florida red tide". Algal blooms are a naturally-occurring phenomenon, however their frequency has been increasing in recent decades at least in-part due to human activities, climate changes, and the eutrophication of marine waters. HABs have been occurring for all of documented history, evidenced by the Native Americans' understanding of the dangers of shellfish consumption during periods of marine bioluminescence. Blooms have been noted to occur as far north as North Carolina and are commonly seen alongside the widespread death of fish and sea birds. In addition to the effects on human health, the economic impact of HAB-associated shellfish toxin outbreaks can have significant economic implications as well due to not only the associated healthcare costs, but the adverse impact on the commercial shellfish industry.

Alexandrium tamarense is a species of dinoflagellates known to produce saxitoxin, a neurotoxin which causes the human illness clinically known as paralytic shellfish poisoning (PSP). Multiple species of phytoplankton are known to produce saxitoxin, including at least 10 other species from the genus Alexandrium.

Saxidomus, common name the "Washington clams", is a genus of large edible saltwater clams, marine bivalve mollusks in the family Veneridae, the Venus clams.

<i>Gonyaulax</i> Genus of single-celled organisms

Gonyaulax is a genus of dinoflagellates with the type species Gonyaulax spinifera Diesing. Gonyaulax belongs to red dinoflagellates and commonly causes red tides. It secretes a poisonous toxin known as "saxitoxin" which causes paralysis in humans.

<i>Zosimus aeneus</i> Species of crab

Zosimus aeneus, also known as the devil crab, toxic reef crab, and devil reef crab is a species of crab that lives on coral reefs in the Indo-Pacific from East Africa to Hawaii. It grows to a size of 60 mm × 90 mm and has distinctive patterns of brownish blotches on a paler background. It is potentially lethal due to the presence of the neurotoxins tetrodotoxin and saxitoxin in its flesh and shell.

<span class="mw-page-title-main">Neosaxitoxin</span> Chemical compound

Neosaxitoxin (NSTX) is included, as other saxitoxin-analogs, in a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs). The parent compound of PSTs, saxitoxin (STX), is a tricyclic perhydropurine alkaloid, which can be substituted at various positions, leading to more than 30 naturally occurring STX analogues. All of them are related imidazoline guanidinium derivatives.

<i>Saxidomus gigantea</i> Species of bivalve

Saxidomus gigantea is a large, edible saltwater clam, a marine bivalve mollusk in the family Veneridae, the venus clams. It can be found along the western coast of North America, ranging from the Aleutian Islands to San Francisco Bay. Common names for this clam include butter clam, Washington clam, smooth Washington clam and money shell.

<i>Pyrodinium bahamense</i> Species of protist

Pyrodinium was first discovered in 1906 in the waters around New Providence Island in the Bahamas. Pyrodinium is a monospecific species with two varieties, Pyrodinium bahamense var. compressum and Pyrodinium bahamanse var. bahamense. Pyrodinium is well known for producing Paralytic Shellfish Toxins (PSTs), e.g. saxitoxin, and the bioluminescence that lights up the bioluminescent bays in Puerto Rico and the Bahamas.

Alexandrium catenella is a species of dinoflagellates. It is among the group of Alexandrium species that produce toxins that cause paralytic shellfish poisoning, and is a cause of red tide. ‘’Alexandrium catenella’’ is observed in cold, coastal waters, generally at temperate latitudes. These organisms have been found in the west coast of North America, Japan, Australia, and parts of South Africa.

Dinotoxins are a group of toxins which are produced by flagellate, aquatic, unicellular protists called dinoflagellates. Dinotoxin was coined by Hardy and Wallace in 2012 as a general term for the variety of toxins produced by dinoflagellates. Dinoflagellates are an enormous group of marine life, with much diversity. With great diversity comes many different toxins, however, there are a few toxins that multiple species have in common.

<span class="mw-page-title-main">Gonyautoxin</span> Chemical compound

Gonyautoxins (GTX) are a few similar toxic molecules that are naturally produced by algae. They are part of the group of saxitoxins, a large group of neurotoxins along with a molecule that is also referred to as saxitoxin (STX), neosaxitoxin (NSTX) and decarbamoylsaxitoxin (dcSTX). Currently eight molecules are assigned to the group of gonyautoxins, known as gonyautoxin 1 (GTX-1) to gonyautoxin 8 (GTX-8). Ingestion of gonyautoxins through consumption of mollusks contaminated by toxic algae can cause a human illness called paralytic shellfish poisoning (PSP).

<span class="mw-page-title-main">Decarbamoylsaxitoxin</span> Chemical compound

Decarbamoylsaxitoxin, abbreviated as dcSTX, is a neurotoxin which is naturally produced in dinoflagellate. DcSTX is one of the many analogues of saxitoxin (STX).

<i>Megapitaria squalida</i> Species of bivalve

Megapitaria squalida, the chocolate clam, is a species of bivalve mollusc in the family Veneridae. It was first described to science by George Brettingham Sowerby, a British conchologist, in 1835. The type specimen was collected by Hugh Cuming.

References

  1. 1 2 Huber, Markus (2018). Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O (eds.). "Leukoma staminea (Conrad, 1837)". MolluscaBase. World Register of Marine Species . Retrieved 29 December 2018.
  2. 1 2 3 4 5 6 7 8 Cowles, Dave (2007). "Leukoma staminea (Conrad, 1857)". Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory (a campus of Walla Walla University, Washington). Retrieved 29 December 2018.
  3. ↑ "Family: Veneridae (Venus Clams)". Gladys Archerd Shell Collection. Washington State University Tri-Cities Natural History Museum. Retrieved 29 December 2018.
  4. ↑ Burnham, C. Michael (2008). "Los Osos Back Bay". The Megalithic Portal. Retrieved 29 December 2018.
  5. ↑ Lightfoot, Kent; Parrish, Otis (2009). California Indians and Their Environment: An Introduction. University of California Press. p. 271. ISBN   978-0-520-94228-8.
  6. 1 2 Clark, R. F.; Williams, S. R.; Nordt, S. P.; Manoguerra, A. S. (1999). "A review of selected seafood poisonings" (PDF). Undersea & Hyperbaric Medicine . 26 (3): 175–184. PMID   10485519. Archived from the original on June 17, 2012.{{cite journal}}: CS1 maint: unfit URL (link)
  7. 1 2 3 4 RaLonde, Raymond (October 1996). "Paralytic Shellfish Poisoning: The Alaska Problem" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. pp. 1–7.
  8. 1 2 3 4 "How Toxic Are Alaska's Most Common Shellfish?" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. October 1996. pp. 10–11.
  9. ↑ Gessner, Brad (October 1996). "Epidemiology of Paralytic Shellfish Poisoning Outbreaks in Alaska" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. pp. 16–17, 19.
  10. 1 2 "Truths and Myths about PSP" (PDF). Alaska's Maritime Resources. Marine Advisory Board, the University of Alaska. October 1996. pp. 14–15.
  11. ↑ Alaska Sea Grant Program (13 August 2015). "Paralytic Shellfish Poisoning in Alaska Facts and Discussion". College of Fisheries and Ocean Sciences at the University of Alaska Fairbanks . Retrieved 22 January 2019.
  12. ↑ Sullivan, John J.; Iwaoka, Wayne T.; Liston, John (1983). "Enzymatic transformation of PSP toxins in the littleneck clam (Protothaca staminea)". Biochemical and Biophysical Research Communications . 114 (2): 465–472. doi:10.1016/0006-291X(83)90803-3. PMID   6882435.
  13. ↑ Deeds, Jonathan R.; Landsberg, Jan H.; Etheridge, Stacey M.; Pitcher, Grant C.; Longan, Sara Watt (2008). "Non-Traditional Vectors for Paralytic Shellfish Poisoning". Marine Drugs . 6 (2): 308–348. doi: 10.3390/md6020308 . PMC   2525492 . PMID   18728730.
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