Macoma nasuta

Taxobox
name = "Macoma nasuta"


image_caption =
image_width = 250px
status = NE
Domain = Eukarya
regnum = Animalia
phylum = Mollusca
classis = Bivalvia
subclassis =
ordo =
subordo =
superfamilia =
familia = Tellinidae
subfamilia =
genus = "Macoma"
subgenus =
species = "M. nasuta"
binomial = "Macoma nasuta"
binomial_authority = Conrad, 1837
range_

range_map_width = 250px
synonyms =

"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. [ [http://www.nwmarinelife.com/htmlswimmers/m_nasuta.html "Macoma nasuta profile] ] This rounded clam has no radial ribs and is commonly called the Bent-nosed clam. [ [http://www.google.com/search?q=macoma+nasuta&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a 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. [http://www.megalithic.co.uk/article.php?sid=18353 C. Michael Hogan, "Los Osos Back Bay", The Megalithic Portal, ed. Andy Burnham (January, 2008)] ]

Names

"Macoma nasuta" is commonly known as the "Bent-nosed clam" or "Bent-nose Macoma".HTTP://WWW.WALLAWALLA.EDU/ACADEMICS/DEPARTMENTS/BIOLOGY/ROSARIO/INVERTS/MOLLUSCA/BIVALVIA/VENEROIDA/TELLINIDAE/MACOMA_NASUTA.HTML] It is commonly misidentified as both "Macoma tersa" and "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 siphons 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. [KOZLOFF, E. 1996. Marine invertebrates of the Pacific Northwest, Univ. Wash. Press ISBN: 0295975628]

Distinguishing characteristic(s)

Valves bent rather sharply to the right at the posterior end, orange coloration of its siphons and periostracum is usually very prominent.

ize

About 5 cm at widest point from the anterior end to the posterior end. [KOZLOFF, E. 2001. Seashore life of the northern Pacific coast, Univ. of Wash. Press ISBN: 0295960841]

Habitat

Common in intertidal and subtidal (50 m) zones; Prefers mud 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. [SEPT, J. DUANE 1999. The beachcombers guide to seashore life in the Pacific Northwest, Harbor Publishing ISBN: 1-55017-204-2]

Range

Found in the neritic provinces of the eastern Pacific Ocean from Kodiak Island, Alaska, to Cabo San Lucas, Baja California. [RAE III, J.G. 1978. Reproduction in two sympatric species of "Macoma" (Bivalvia). Biol. Bull. 155: 207-219.] ]

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". [HUGHES, R.H 1969. A study of feeding in Scrobicularia plana. Journal of Marine Biology Assn. U.K. 49: 805-823.] 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. HYLLEBERG, J. AND V.F. GALLUCCI 1975. Selectivity in feeding by the deposit-feeding Bivalve "Macoma nasuta". Journal of Marine Biology, 32: 167-178.]

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.

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 PCB’s. [BOESE, B.L., LEE II, H. AND S. ECHOLS 1997. Evaluation of a first-order model for the prediction of the bioaccumulation of PCB’s and DDT from sediment into the marine deposit-feeding clam Macoma nasuta. Setac Journal of Environmental Toxicology and Chemistry. 16:1545-1553.]

Reproduction

"M. nasuta" is a dioecious (probably gonochoristic) species that spawns in early summer. [ [HTTP://ACADEMIC.EVERGREEN.EDU/T/THUESENE/BIVALVES/MAIN.HTM Bivalves of The Evergreen State College Campus ] ]

Notes/Natural History

There is archaeological data to support the use of this species by Native Americans such as the Chumash peoples of central California.

Predators

Shore birds, Lewis' Moon Snail: "Polinices lewisii", Starfish: "Pisaster spp"., Crabs: "Cancer productus","Cancer gracilis", "Cancer magister". [ KOZLOFF, E. 2001. Seashore life of the northern Pacific coast, Univ. of Wash. Press ISBN: 0295960841. ]

Known Parasites

"Graffilla Pugetensi" [ SCHELL, S.C. 1986. "Graffilla pugetensis" n. sp. (order Neorhabdocoela: Graffillidae), A parasite in the pericardial cavity of the bent-nose clam, "Macoma nasuta" (Conrad, 1837). Journal of Parasitology, 72: 748-754.] is a known parasite of the pericardial cavity and "Telolecithus pugetensi" [ DEMARTINI, J.D AND PRATT, I. 1964. The life cycle of "Telolecithus pugetensis" Lloyd and Guberlet, 1932 (Trematoda: Monorchidae). Journal of Parasitology, 50: 101-105.] is known to use "M.nasuta" as a second intermediate host in "T.pugetensi"’s life cycle.

ee also

*Macoma

References