''Mulinia lateralis'', the dwarf surf clam or coot 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 ...

of small saltwater clam, a

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 ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Mactridae Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Venerida. Description These clams have two short siphons, each with a horny sheath. The shell is shaped like a rounded- ...

. It occurs in the western

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

and the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

Description

''Mulinia lateralis'' has a somewhat inflated triangular

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard ou ...

, with valves that are thin but not brittle. The shell reaches 15 mm in adult size. The anterior end of the shell is rounded, but the posterior end has a distinctive radial ridge giving it an angular look. The outer surface is white or yellowish and somewhat glossy, covered with fine concentric sculpturing. The beaks are prominent and are slightly angled towards the anterior end. The hinge has a small chondrophore, and the ligament joining the valves is internal. The inner surface of the valves is glossy white.

Distribution

''Mulinia lateralis'' is found on the eastern coasts of North America from the north-eastern United States (

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

) southwards to Mexico. It lives shallowly buried in sand or mud on the lower shore and in the

sublittoral zone 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 ...

. It is tolerant of low

salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

and is found in estuaries and lagoons.''Mulinia lateralis''
Smithsonian Marine Station a Fort Pierce. Retrieved 2012-01-30. It is sometimes abundant, and as many as 21,000 individuals have been found in a square metre.

Biology

''Mulinia lateralis'' is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

. The diet is mainly

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

or other

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic material. Like other bivalve molluscs, the animal raises its

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 to the surface of the sediment, draws water in though one and expels it through the other, having filtered out nutrient particles in the gills. The sexes are separate in ''Mulinia lateralis''. The female produces up to 2 million eggs at a time, and fertilisation is external. The

veliger A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod ...

larvae disperse as part of the

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and take from 1 to 3 weeks to develop into the pediveliger stage, whereupon they settle and undergo

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

. The juveniles grow fast and are sexually mature within 2 months.

Ecology

A number of different animals

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

on ''Mulinia lateralis''. These include birds such as the

sanderling The sanderling (''Calidris alba'') is a small wading bird. The name derives from Old English ''sand-yrðling'', "sand-ploughman". The genus name is from Ancient Greek ''kalidris'' or ''skalidris'', a term used by Aristotle for some grey-coloure ...

and

laughing gull The laughing gull (''Leucophaeus atricilla'') is a medium-sized gull of North and South America. Named for its laugh-like call, it is an opportunistic omnivore and scavenger. It breeds in large colonies mostly along the Atlantic coast of North Am ...

and crabs. The gray sea star (''Luidia clathrata'') selectively feeds on it and the

knobbed whelk The knobbed whelk (''Busycon carica'') is a species of very large predatory sea snail, or in the US, a whelk, a marine gastropod mollusk in the family Busyconidae, the busycon whelks. The knobbed whelk is the second largest species of busy ...

(''Busycon carica'') is also a major predator. In addition to a variety of salinities, ''Mulinia lateralis'' is able to tolerate other ecologically stressful conditions like temperature extremes and anoxia. ''Mulinia lateralis'' has been found in the European wadden sea, and has the potential to become an invasive alien species due to its high fecundity, short generation cycle of just 60 days, and broad ecological amplitudes.

References

{{Taxonbar, from=Q3016320 Mactridae Bivalves described in 1822