''Macoma nasuta'', commonly known as the bent-nosed clam, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

found along the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

coast of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It is about long. It is often found buried in sands of in depth. This rounded clam has no radial ribs. Archaeological data supports the use of this species by Native Americans such as the Chumash peoples of central

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

.C. Michael Hogan, ''Los Osos Back Bay'', The Megalithic Portal, ed. Andy Burnham (January, 2008)
/ref>

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 kelseyi''.

Description

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

siphon A siphon (; also spelled syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, abo ...

s distinctly separated (as they are in all '' Macoma'') and have a distinct orange pigmentation. The

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods an ...

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 The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various sp ...

and

subtidal The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminate ...

(50 m) zones; Prefers

mud Mud (, or Middle Dutch) is loam, silt or clay mixed with water. Mud is usually formed after rainfall or near water sources. Ancient mud deposits hardened over geological time to form sedimentary rock such as shale or mudstone (generally cal ...

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 In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

and both are the characteristic species of ''Macoma'' on the west coast of North America.

Range

Found in the

neritic The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

provinces of the eastern Pacific Ocean from

Kodiak 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 Un ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

, to

Cabo San Lucas Cabo San Lucas (, "Luke the Evangelist, Saint Luke Cape (geography), Cape"), also known simply as Cabo, is a Resort town, resort city at the southern tip of the Baja California peninsula, in the Mexican Political divisions of Mexico, state of Baja ...

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Feeding and digestion

Found to feed off the top millimeter of sediment by using a boring 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 observed to consume their

pseudofeces Pseudofeces or pseudofaeces are a specialized method of expulsion that filter-feeding bivalve mollusks (and filter-feeding gastropod mollusks) use in order to get rid of suspended particles such as particles of grit which cannot be used as food ...

and

feces Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...

. It is assumed that the siphon tip is unselective in the particles it intakes. Non-specific

nematodes The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (he ...

have been found in the

stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...

in all stages of digestion from live to empty cuticles. The small (about 500

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

) 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 A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

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 high levels of

DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...

and PCBs.

Reproduction

''M. nasuta'' is a

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

(probably gonochoristic) species that spawns in early summer.

Natural history

There is archaeological data to support the use of this species by Native Americans such as the

Chumash Chumash may refer to: *Chumash (Judaism), a Hebrew word for the Pentateuch, used in Judaism *Chumash people, a Native American people of southern California *Chumashan languages, Indigenous languages of California See also

* Pentateuch (dis ...

peoples of central

Predators

Shore birds, Lewis' Moon Snail: '' Polinices lewisii'', Starfish: '' Pisaster spp''., Crabs: '' Cancer productus'', '' Metacarcinus gracilis'', '' Metacarcinus magister''.

Known parasites

*'' Graffilla pugetensi'': a

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

of the pericardial cavity. *'' Telolecithus pugetensi'': uses ''M. nasuta'' as a second

intermediate host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

References

{{Taxonbar, from=Q3014540 Tellinidae Bivalves described in 1837 Seafood in Native American cuisine