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

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

found along the

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

coast of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. 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, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

.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 (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically 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 a ...

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 and ...

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

mud A MUD (; originally multi-user dungeon, with later variants multi-user dimension and multi-user domain) is a Multiplayer video game, multiplayer Time-keeping systems in games#Real-time, real-time virtual world, usually Text-based game, text-bas ...

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 Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...

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

and both are the characteristic species of ''Macoma'' on the

west coast West Coast or west coast may refer to: Geography Australia * Western Australia *Regions of South Australia#Weather forecasting, West Coast of South Australia * West Coast, Tasmania **West Coast Range, mountain range in the region Canada * Britis ...

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,

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

, to

Cabo San Lucas Cabo San Lucas (, "Saint Luke Cape"), or simply just Cabo, is a resort city at the southern tip of the Baja California Peninsula, in the Mexican state of Baja California Sur. As at the 2020 Census, the population of the city was 202,694 inhabitan ...

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

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 ''Scrobicularia plana'', the peppery furrow shell, is a bivalve mollusc belonging to the family Semelidae. Taxonomy Although ''Scrobicularia plana'' is the only species currently recognized by ITIS in the genus ''Scrobicularia''; World Regist ...

''. 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 ( or faeces), known colloquially and in slang as poo and poop, 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 large intestine. Feces contain a relati ...

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

) 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 (New Latin, Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group com ...

believed to remain longer than other particles

ingested Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in a substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms inges ...

due to their disproportionably high presence in the stomach during

dissections Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause of ...

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

PCB PCB may refer to: Science and technology * Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant * Printed circuit board, a board used in electronics * ...

Reproduction

''M. nasuta'' is a

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

(probably

gonochoristic In biology, gonochorism is a sexual system where there are only two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism c ...

) 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 peoples of central

Predators

Shore birds, Lewis' Moon Snail: '' Polinices lewisii'', Starfish: ''

Pisaster ''Pisaster'' (from Greek ', "pea", and ', "star"Cleveland P. Hickman et al., ''Integrated Principles of Zoology'' (St. Louis: Times Mirror / Mosby College Pub., 1984),p. 469) is a genus of Pacific sea stars that includes three species, ''P. b ...

spp''., Crabs: ''

Cancer productus ''Cancer productus'', one of several species known as red rock crabs, is a crab of the genus ''Cancer'' found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest. Description ''Cancer p ...

'', ''

Metacarcinus gracilis The graceful rock crab or slender crab, ''Metacarcinus gracilis'' (the naming convention recognized by WoRMS) or ''Cancer gracilis'' (the naming convention recognized by ITIS), is one of only two members of the genus ''Metacarcinus,'' recognized ...

'', ''

Metacarcinus magister The Dungeness crab (''Metacarcinus magister'') is a species of crab inhabiting eelgrass beds and water bottoms along the west coast of North America. It typically grows to across the carapace and is a popular seafood. Its common name comes from ...

''.

Known parasites

*'' Graffilla pugetensi'': a

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

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 a ...

References

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