Macoma nasuta
Encyclopedia
Macoma nasuta is a species
of bivalve found along the Pacific Ocean
coast of North America
. It is often found buried in sands of 10 to 20 centimeters in depth. This rounded clam has no radial ribs and is commonly called the bent-nosed clam. There is archaeological data to support the use of this species by Native Americans
such as the Chumash peoples of central California
.
distinctly separated (as they are in all Macoma
) and have a distinct orange
pigmentation. The periostracum
is usually very prominent and the shell has a dirty brown wrinkled look to it, especially near the margin.
to muddy sand substrates situated in quiet waters and can burrow up to 40 cm beneath the surface sediment. M. nasuta and M. secta are geographically sympatric species
and both are the characteristic
species of Macoma on the west coast
of North America.
, Alaska
, to Cabo San Lucas
, Baja California
.
motion with the tip of its siphon into the sediment or by using a rotating motion similar to Scrobicularia plana. New sediment is found by moving the siphon into virgin sediment but the clams have also been ob served to consume their pseudofeces
and feces
. It is assumed that the siphon tip is unselective in the particles it intakes.
Non-specific nematodes have been found in the stomach
in all stages of digestion from live to empty cuticles. The small (about 500 μm) Bivalve Transenella tantilla has also been found living in the stomach. The relationship with both nematodes and T. tantilla is uncertain.
The exhalant siphon is kept below the sediment surface (about 1 cm). The gut
clearance time for inert
particles of M. nasuta ranges from 1 to 9 hours with smaller particles and diatoms believed to remain longer than other particles ingested due to their disproportionably high presence in the stomach during dissections.
’s.
(probably gonochoristic) species that spawns in early summer.
such as the Chumash peoples of central California
.
spp., Crabs: Cancer productus
, Metacarcinus gracilis, Metacarcinus magister
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of bivalve found along the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coast of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. It is often found buried in sands of 10 to 20 centimeters in depth. This rounded clam has no radial ribs and is commonly called the bent-nosed clam. There is archaeological data to support the use of this species by Native Americans
Native Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...
such as the Chumash peoples of central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
Names
Macoma nasuta is commonly known as the Bent-nosed clam or Bent-nose Macoma. It is commonly misidentified as either Macoma tersa or Macoma kelseyiDescription
The hinge plate is without lateral teeth and the length of shell much less than twice the height. Posterior portions of both valves distinctly bent to the right with the siphonsSiphon (biology)
The term siphon is used for a number of biological structures, either because flowing liquids are involved, or because the object is shaped like a siphon...
distinctly separated (as they are in all Macoma
Macoma
Macoma is a large genus of saltwater clams, marine bivalve mollusks in the family Tellinidae, the tellins.- Species :According to the World Register of Marine Species , the following species are included as accepted names within the genus Macoma * Macoma balthica * Macoma biota Arruda & Domaneschi,...
) and have a distinct orange
Orange (colour)
The colour orange occurs between red and yellow in the visible spectrum at a wavelength of about 585–620 nm, and has a hue of 30° in HSV colour space. It is numerically halfway between red and yellow in a gamma-compressed RGB colour space, the expression of which is the RGB colour wheel. The...
pigmentation. The periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
is usually very prominent and the shell has a dirty brown wrinkled look to it, especially near the margin.
Distinguishing characteristics
Valves bent rather sharply to the right at the posterior end, orange coloration of its siphons and periostracum is usually very prominent.Habitat
Common in intertidal and subtidal (50 m) zones; Prefers mudMud
Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...
to muddy sand substrates situated in quiet waters and can burrow up to 40 cm beneath the surface sediment. M. nasuta and M. secta are geographically sympatric species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
and both are the characteristic
Characteristic
Characteristic may refer to:In physics and engineering, any characteristic curve that shows the relationship between certain input and output parameters, for example:...
species of Macoma on the west coast
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
of North America.
Range
Found in the neritic provinces of the eastern Pacific Ocean from Kodiak IslandKodiak Island
Kodiak Island is a large island on the south coast of the U.S. state of Alaska, separated from the Alaska mainland by the Shelikof Strait. The largest island in the Kodiak Archipelago, Kodiak Island is the second largest island in the United States and the 80th largest island in the world, with an...
, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, to Cabo San Lucas
Cabo San Lucas
Cabo San Lucas , commonly called Cabo, is a city at the southern tip of the Baja California peninsula, in the municipality of Los Cabos in the Mexican state of Baja California Sur. As of the 2010 census, the population was 68,463 people...
, Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
.
Feeding and digestion
Found to feed off the top millimeter of sediment by using a boringBoring
Boring often refers to anything that causes boredom.Boring may also refer to:Making holes*Boring , the drilling of holes or tunnels in the earth**Tunnel boring machine machine used in boring tunnels or shafts...
motion with the tip of its siphon into the sediment or by using a rotating motion similar to Scrobicularia plana. New sediment is found by moving the siphon into virgin sediment but the clams have also been ob served to consume their pseudofeces
Pseudofeces
Pseudofeces or pseudofaeces are a way that filter-feeding bivalve mollusks get rid of suspended particles which have been rejected as unsuitable for food. The rejected particles are wrapped in mucus, and are expelled without having passed through the digestive tract...
and feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
. It is assumed that the siphon tip is unselective in the particles it intakes.
Non-specific nematodes have been found in the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
in all stages of digestion from live to empty cuticles. The small (about 500 μm) Bivalve Transenella tantilla has also been found living in the stomach. The relationship with both nematodes and T. tantilla is uncertain.
The exhalant siphon is kept below the sediment surface (about 1 cm). The gut
Gut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
clearance time for inert
Inert
-Chemistry:In chemistry, the term inert is used to describe a substance that is not chemically reactive.The noble gases were previously known as inert gases because of their perceived lack of participation in any chemical reactions...
particles of M. nasuta ranges from 1 to 9 hours with smaller particles and diatoms believed to remain longer than other particles ingested due to their disproportionably high presence in the stomach during dissections.
Bioaccumulation of toxins
Due to their feeding behavior of deposit feeding M. nasuta have been found to have a high level(s) of DDT and PCBPolychlorinated biphenyl
Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...
’s.
Reproduction
M. nasuta is a dioeciousDioecious
Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...
(probably gonochoristic) species that spawns in early summer.
Natural history
There is archaeological data to support the use of this species by Native AmericansNative Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...
such as the Chumash peoples of central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
Predators
Shore birds, Lewis' Moon Snail: Polinices lewisii, Starfish: PisasterPisaster
Pisaster is a genus of Pacific sea stars that includes three species, P. brevispinus, P. giganteus, and P. ochraceus. Their range extends along the Pacific coast from Alaska to southern California in the intertidal zone. Pisasters can reach up to in width and typically have five arms...
spp., Crabs: Cancer productus
Cancer productus
Cancer productus, one of several species known as the red rock crab, is a crab of the genus Cancer found on the western coast of North America.- Description :...
, Metacarcinus gracilis, Metacarcinus magister
Dungeness crab
The Dungeness crab, Metacarcinus magister , is a species of crab that inhabits eelgrass beds and water bottoms on the west coast of North America. It typically grows to across the carapace and is a popular seafood...
.