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Christmas tree worm | |
---|---|
S. giganteus on Porites | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Annelida |
Clade: | Pleistoannelida |
Subclass: | Sedentaria |
Order: | Sabellida |
Family: | Serpulidae |
Genus: | Spirobranchus |
Species: | S. giganteus |
Binomial name | |
Spirobranchus giganteus | |
Spirobranchus giganteus, commonly known as the Christmas tree worm, is a tube-building polychaete worm belonging to the family Serpulidae.
Both its common and Latin names refer to the two chromatically hued spiral structures, the most common feature seen by divers. The multicolored spirals are highly derived structures for feeding and respiration.
Spirobranchus giganteus is similar to most tube-building polychaetes. It has a tubular, segmented body of an approximate length of 3.8 cm (1.5 in) covered with chaetae, small appendages that aid the worm's mobility. Because it does not move outside its tube, this worm does not have any specialized appendages for movement or swimming.
The worms' most distinct features are two "crowns" shaped like Christmas trees. These are highly modified prostomial palps, which are specialized mouth appendages. Each spiral is composed of feather-like tentacles called radioles, which are heavily ciliated and cause any prey trapped in them to be transported to the worm's mouth. While they are primarily feeding structures, S. giganteus also uses its radioles for respiration; hence, the structures commonly are called "gills".
One major difference between Christmas tree worms and other Sabellida fan worms is that the latter do not have any specialized body structures to plug their tube holes when they withdraw into them. S. giganteus, like other members of its family, possesses a modified radiole, usually called the operculum, that it uses to secure its hole when withdrawn into its tube.
As an annelid, S. giganteus possesses a complete digestive system and has a well-developed closed circulatory system. Like other annelids, these worms possess well-developed nervous systems with a central brain and many supporting ganglia, including pedal ganglia, unique to the Polychaeta. Although an annelid, the S. Giganteus has a faster mitochondrial sequence evolution than other annelids because of its nucleotide composition and divergence of protein sequences. [2] Like other polychaetes, S. giganteus excretes with fully developed nephridia. When they reproduce, they simply shed their gametes straight into the water where the eggs and spermatozoa become part of the zooplankton to be carried by the currents.
Christmas tree worms are widely distributed throughout the world's tropical oceans. They have been known to occur from the Caribbean to the Indo-Pacific. [1]
S. giganteus is commonly found embedded entirely in heads of massive corals, such as stony corals Porites and brain corals. Like members of its family, it can secrete a calcareous tube around its body. This tube serves as the worm's home and protection. S. giganteus usually settles onto an existing head of living coral before secreting its tube, thereby increasing its level of protection as coral tissue overgrows the calcareous tube. When the worm retreats into its tube, the opening is shut using an operculum, which is further protected by sharp, antler-shaped spines. [3]
As sedentary inhabitants of coral reefs, Christmas tree worms feed primarily by filter feeding. They use their brightly colored radioles to filter microorganisms from the water, which are then deposited straight into the worm's digestive tract.
Few organisms are known to feed on tube-borne polychaetes and S. giganteus is no exception. The symbiotic relationship between S. giganteus and its host corals is still poorly understood, but occasionally the movement of the operculum can abrade the coral tissue, and that mortality of the coral tissue is enhanced when the worm's operculum hosts filamentous algae. [4]
While the worm itself has no commercial fishery importance, it is of interest to marine aquarists and divers. The variously colored worm crowns make extremely popular underwater photographic subjects for sport divers. Many aquarists who have miniature reef aquaria purposely include heads of coral that S. giganteus specimens inhabit. [ citation needed ] [5]
As the species is widespread and relatively common, no conservation efforts focus on this species (or polychaetes in general). This species was thought to be exclusively found in coralheads, however they have also recently been described as epibionts on the giant clam species Tridacna squamosa in the Gulf of Thailand. [6] The conservation status of the host species which it inhabits varies.
Spirobranchus essentially translates to "spiral gills", referring to the worm's unique crown. Two subspecies are recognized by the ITIS: S. gigantea corniculatus [7] and S. gigantea gigantea. [8]
Polychaeta is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.
Eunicidae is a family of marine polychaetes. The family comprises marine annelids distributed in diverse benthic habitats across Oceania, Europe, South America, North America, Asia and Africa. The Eunicid anatomy typically consists of a pair of appendages near the mouth (mandibles) and complex sets of muscular structures on the head (maxillae) in an eversible pharynx. One of the most conspicuous of the eunicids is the giant, dark-purple, iridescent "Bobbit worm", a bristle worm found at low tide under boulders on southern Australian shores. Its robust, muscular body can be as long as 2 m. Eunicidae jaws are known from as far back as Ordovician sediments. Cultural tradition surrounds Palola worm reproductive cycles in the South Pacific Islands. Eunicidae are economically valuable as bait in both recreational and commercial fishing. Commercial bait-farming of Eunicidae can have adverse ecological impacts. Bait-farming can deplete worm and associated fauna population numbers, damage local intertidal environments and introduce alien species to local aquatic ecosystems.
Sabellida is an order of annelid worms in the class Polychaeta. They are filter feeders with no buccal organ. The prostomium is fused with the peristomium and bears a ring of feathery feeding tentacles. They live in parchment-like tubes made of particles from their environment such as sand and shell fragments cemented together with mucus.
The Serpulidae are a family of sessile, tube-building annelid worms in the class Polychaeta. The members of this family differ from other sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes when they withdraw into the tubes. In addition, serpulids secrete tubes of calcium carbonate. Serpulids are the most important biomineralizers among annelids. About 300 species in the family Serpulidae are known, all but one of which live in saline waters. The earliest serpulids are known from the Permian.
Serpula is a genus of sessile, marine annelid tube worms that belongs to the family Serpulidae. Serpulid worms are very similar to tube worms of the closely related sabellid family, except that the former possess a cartilaginous operculum that occludes the entrance to their protective tube after the animal has withdrawn into it. The most distinctive feature of worms of the genus Serpula is their colorful fan-shaped "crown". The crown, used by these animals for respiration and alimentation, is the structure that is most commonly seen by scuba divers and other casual observers.
A radiole is a heavily ciliated feather-like tentacle found in highly organized clusters on the crowns of Canalipalpata. Canalipalpata is an order of sessile marine polychaete worms consisting of 31 families. These benthic annelid tube worms employ radioles primarily for alimentation. While their primary role is to function as an organ for filter feeding, radioles also serve as respiratory organs. Because of their role in gas exchange, radioles are often referred to as "gills".
Pomatoceros triqueter is a species of tube-building annelid worm in the class Polychaeta. It is common on the north eastern coasts of the Atlantic Ocean and in the Mediterranean Sea.
Spirorbis borealis is a sedentary marine polychaete worm in the Serpulidae family. It is commonly called the sinistral spiral tubeworm and is the type species of the genus Spirorbis.
Sabellastarte spectabilis is a species of benthic marine polychaete worm in the Sabellidae family. It is commonly known as the feather duster worm, feather duster or fan worm. It is native to tropical waters of the Indo-Pacific but has spread to other parts of the world. It is popular in aquariums because of its distinctive appearance and its ability to remove organic particles and improve water quality.
Serpula vermicularis, known by common names including the calcareous tubeworm, fan worm, plume worm or red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is the type species of the genus Serpula and was first described by Carl Linnaeus in his 1767 12th edition of Systema Naturae. It lives in a tube into which it can retract.
Neosabellaria cementarium is a species of marine tube worm in the family Sabellariidae, perhaps better known by its previous name, Sabellaria cementarium. It is found in the North Pacific Ocean.
Biomineralising polychaetes are polychaetes that produce minerals to harden or stiffen their own tissues (biomineralize).
Glomerula is a genus of polychaete worm in the family Sabellidae. It differs from all other Sabellidae in having a calcareous tube and spinose setae. Only one living species, G. piloseta, is known from Lizard Island, Great Barrier Reef, Australia. The oldest fossils of Glomerula are known from the Early Jurassic and their tube microstructure has remained unchanged since then.
Ficopomatus enigmaticus, commonly known as the Australian tubeworm, is a species of serpulid tubeworms. Their true native range is unknown, but they probably originated in the Southern Hemisphere, perhaps from the Indian Ocean and the coastal waters of Australia. Today they have a cosmopolitan distribution, having been introduced to shallow waters worldwide. The Australian tubeworm is an invasive species that dominates and alters habitats, reduces water quality, depletes resources, and causes biofouling.
Olev Vinn is Estonian paleobiologist and paleontologist.
Salmacina dysteri is a species of tube-forming annelid worm in the family Serpulidae. It is found on submerged rocks, reefs, piles and boats in many shallow and deeper water environments around the world.
Serpula columbiana, variously called the calcareous tubeworm, plume worm, fan worm, limy tube worm and red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is a cosmopolitan species that is found in most seas in the Northern Hemisphere including the Atlantic Ocean, the Pacific Ocean and the Indian Ocean.
Spirobranchus cariniferus, commonly known as the blue tubeworm or spiny tubeworm, or by its Māori name toke pā, is a species of tube-building polychaete worm endemic to New Zealand.
Joan Chauvin Marsden was a professor of zoology, chair of the zoology department at McGill University, president of the Canadian Society of Zoologists, and director of the Bellairs Institute in Barbados.
Hydroides ezoensis is a species of tube-forming annelid worm in the family Serpulidae. It is native to the temperate northern Pacific and the central Indo-Pacific and is found in the intertidal zone and on submerged rocks, shells, pilings, jetties and boats.