Amphitrite ornata
Encyclopedia
Amphitrite ornata or ornate worm, is a species
of marine polycheate worm in the family Terebellidae
.
Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment
may bear setae (bristles) and parapodia
(paddle-like appendages). Some species live freely, either swimming, crawling or burrowing, and these are known as "errant". Others live permanently in tubes, either calcareous or parchment-like, and these are known as "sedentary".
, the Gulf of Maine
and the north west Atlantic Ocean
at a depth of up to 200 metres.
s and a spread of long, peach-coloured tentacle
s above them. The tentacles can extend to forty centimetres and are constantly in motion, searching for food particles. The rest of the worm's segmented, tapering body remains concealed in the tube.
. The sexes are separate and the females can be distinguished by their darker abdominal segments. Spawning takes place in June to August, peaking in July, especially around the periods of new and full moon and the subsequent increase in tidal
flows. The eggs and sperm develop and float freely in the body cavity of the worm but by some little understood process, only the ripe products are released. The eggs are fertilised externally and the rate of development of the larva
e is rapid. Swimming forms are present four to five hours after fertilisation, and well-formed trochophore
s within 20 hours. Larval segmentation begins at 36 hours and metamorphosis
starts at about the fifth day, when five trunk segments are already present. At this stage, the larvae cease to swim about freely and sink to the sea floor. Metamorphosis is complete by the eleventh day.
and sublittoral zones
, in soft mud and under stones. The tiny pea crab Pinnixa chaetopterana
is sometimes found living as a commensal
inside the tube behind the worm.
The ornate worm is often found in marine environments also inhabited by Notomastus lobatus (Polychaeta
) and Saccoglossus kowalewskyi (Hemichordata
), which produce and contaminate sediments with bromophenols
and bromopyrroles
. These organic halogen metabolites are toxic and it has been found that A. ornata produces a novel dehaloperoxidase
that detoxifies haloaromatic compounds. The gene
s responsible have been identified.
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 marine polycheate worm in the family Terebellidae
Terebellidae
Terebellidae is a family of polychaete worms. They are surface deposit feeders, catching falling particles with numerous elongate prostomial tentacles splayed out on the sea floor. These tentacles, which are the most or only normally visible portion of the animal and are reminiscent of spaghetti,...
.
Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment
Segmentation (biology)
Segmentation in biology refers to either a type of gastrointestinal motility or the division of some animal and plant body plans into a series of repetitive segments. This article will focus on the segmentation of animal body plans, specifically using the examples of the phyla Arthropoda,...
may bear setae (bristles) and parapodia
Parapodium
Parapodia , singular parapodium, are paired, un-jointed lateral outgrowths from the bodies of two different invertebrate groups, which are primarily marine in habitat...
(paddle-like appendages). Some species live freely, either swimming, crawling or burrowing, and these are known as "errant". Others live permanently in tubes, either calcareous or parchment-like, and these are known as "sedentary".
Distribution
This species is found in Cobscook BayCobscook Bay
Cobscook Bay is located in Washington County in the state of Maine. It opens into the Bay of Fundy immediately south of the city of Eastport and adjacent to Passamaquoddy Bay...
, the Gulf of Maine
Gulf of Maine
The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America.It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. It includes the entire coastlines of the U.S...
and the north west Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
at a depth of up to 200 metres.
Description
The ornate worm can grow to up to forty centimetres long and lives in a firm, sand-encrusted tube. All that is visible are the three bright red bushy gillGill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s and a spread of long, peach-coloured tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s above them. The tentacles can extend to forty centimetres and are constantly in motion, searching for food particles. The rest of the worm's segmented, tapering body remains concealed in the tube.
Biology
This worm lives in a tough U-shaped tube in the mud substrateSubstrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
. The sexes are separate and the females can be distinguished by their darker abdominal segments. Spawning takes place in June to August, peaking in July, especially around the periods of new and full moon and the subsequent increase in tidal
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
flows. The eggs and sperm develop and float freely in the body cavity of the worm but by some little understood process, only the ripe products are released. The eggs are fertilised externally and the rate of development of the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e is rapid. Swimming forms are present four to five hours after fertilisation, and well-formed trochophore
Trochophore
A trochophore is a type of free-swimming planktonic marine larva with several bands of cilia.By moving their cilia rapidly, a water eddy is created. In this way they control the direction of their movement...
s within 20 hours. Larval segmentation begins at 36 hours and metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
starts at about the fifth day, when five trunk segments are already present. At this stage, the larvae cease to swim about freely and sink to the sea floor. Metamorphosis is complete by the eleventh day.
Ecology
This worm is often found associated with the fringe worm, Cirratulus cirriformia, in the littoralLittoral
The littoral zone is that part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to...
and sublittoral zones
Neritic zone
The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters...
, in soft mud and under stones. The tiny pea crab Pinnixa chaetopterana
Pinnixa chaetopterana
Pinnixa chaetopterana, the tube pea crab, is a small decapod crustacean that lives harmlessly within the tube of the polychaete worm, Chaetopterus variopedatus.-Description:...
is sometimes found living as a commensal
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...
inside the tube behind the worm.
The ornate worm is often found in marine environments also inhabited by Notomastus lobatus (Polychaeta
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
) and Saccoglossus kowalewskyi (Hemichordata
Hemichordata
Hemichordata is a phylum of marine deuterostome animals, generally considered the sister group of the echinoderms. They date back to the Lower or Middle Cambrian and include two main classes: Enteropneusta , and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a...
), which produce and contaminate sediments with bromophenols
Organobromine compound
Organobromine compounds are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application is the use of polybrominated diphenyl ethers as fire-retardants. A variety of minor organobromine compounds are found in...
and bromopyrroles
Organobromine compound
Organobromine compounds are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application is the use of polybrominated diphenyl ethers as fire-retardants. A variety of minor organobromine compounds are found in...
. These organic halogen metabolites are toxic and it has been found that A. ornata produces a novel dehaloperoxidase
Bromoperoxidase
Bromoperoxidases are enzymes that catalyse the bromination of hydrocarbons. The enzymes accomplish this reaction via the following reaction:Related chloroperoxidase enzymes effect chlorination....
that detoxifies haloaromatic compounds. The gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s responsible have been identified.