Terebellida
Encyclopedia
Terebellida make up a suborder
of the Polychaeta
class
, commonly referred to as "bristle worms". Together with the Sabellida
, the Spionida
and some enigmatic families
of unclear taxonomic
relationship (e.g. the Saccocirridae
), they make up the order
Canalipalpata
, one of the three main clade
s of polychaetes. Like most polychaetes, almost all members of the Terebellida suborder are marine
organisms. Most are small, sessile
detritivore
s (deposit feeders) which live in small tubes they build from mud or similar substrate, or burrow in the sand. Their central nervous system
displays characteristic apomorphies
.
There is little consensus on the number of families
. Some treatments accept as little as five, while other authors list over a dozen. Here, the more inclusive view of the Terebellida is followed, based on a major review of polychaete systematics. Cladistic
studies have hitherto only analyzed a rather small proportion of polychaetes; hence it may be that some of the families today included in Terebellida by most authors will eventually be again recognized to belong elsewhere.
(Alvinella pompejana), an alvinellid
. It is the most heat-tolerant
complex organism known on Earth. Found near hydrothermal vent
s deep in the Pacific Ocean
, it thrives at a temperature of 50°C (122°F). This is near the theoretical limit for eukaryote
s, whose mitochondria
disintegrate at about 55°C (131°F).
Seven species of pelagic
(free-swimming) terebellids have recently been discovered, including Swima
in 2009 and Teuthidodrilus
in 2010. These seven species have been assigned to four new genera, forming a phylogenetic
clade
within the Acrocirridae
family.
, so they do not fossil
ize well. For this reason, only a small number of prehistoric bristle worms have been described. Several of these have been placed in the Terebellida suborder, though often only tentatively so, owing to the ongoing uncertainties about polychaete phylogeny
. However, as the terebellid habit of constructing characteristic tubes in which to live seems quite ancient, such structures are occasionally found in conservation Lagerstätten
. Polychaete remains associated with such ichnofossils
can therefore be quite certainly be allocated to the Terebellida. Prehistoric polychaete genera presumed to be Terebellida include:
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of the 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...
class
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
, commonly referred to as "bristle worms". Together with the Sabellida
Sabellida
Sabellida is a suborder 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...
, the Spionida
Spionida
Spionida is a suborder of marine polychaete worms in the order Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zones.-Characteristics:...
and some enigmatic families
Incertae sedis
, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
of unclear taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
relationship (e.g. the Saccocirridae
Saccocirridae
The Saccocirridae are small interstitial polychaetes common in coarse sand, reflective, surf beaches, usually within the zone of retention. The Saccociridae are members of the clade Protodrilida, which is in turn part of the clade Canalipalpata. Saccocirridae have a world wide distribution and it...
), they make up the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Canalipalpata
Canalipalpata
Canalipalpata, also known as bristle-footed annelids or fan-head worms, is an order of polychaete worms, with 31 families in it including the Sabellida and the Alvinellidae, a family of deep-sea worms associated with hydrothermal vents.The Canalipalpata have no teeth or jaws. Most are filter feeders...
, one of the three main clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s of polychaetes. Like most polychaetes, almost all members of the Terebellida suborder are marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
organisms. Most are small, sessile
Sessility (zoology)
In zoology, sessility is a characteristic of animals which are not able to move about. They are usually permanently attached to a solid substrate of some kind, such as a part of a plant or dead tree trunk, a rock, or the hull of a ship in the case of barnacles. Corals lay down their own...
detritivore
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...
s (deposit feeders) which live in small tubes they build from mud or similar substrate, or burrow in the sand. Their central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
displays characteristic apomorphies
Synapomorphy
In cladistics, a synapomorphy or synapomorphic character is a trait that is shared by two or more taxa and their most recent common ancestor, whose ancestor in turn does not possess the trait. A synapomorphy is thus an apomorphy visible in multiple taxa, where the trait in question originates in...
.
Systematics
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
. Some treatments accept as little as five, while other authors list over a dozen. Here, the more inclusive view of the Terebellida is followed, based on a major review of polychaete systematics. Cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
studies have hitherto only analyzed a rather small proportion of polychaetes; hence it may be that some of the families today included in Terebellida by most authors will eventually be again recognized to belong elsewhere.
- AcrocirridaeAcrocirridaeAcrocirridae is a family of polychaete worms. Acrocirrids are detritivores , catching falling particles with numerous long prostomial tentacles. There are eight known genera, and at least 21 described species and subspecies within the Acrocirridae family...
(acrocirrids, sometimes placed in SpionidaSpionidaSpionida is a suborder of marine polychaete worms in the order Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zones.-Characteristics:...
suborder) - AlvinellidaeAlvinellidaeThe Alvinellidae are a family of small, deep-sea polychaete worms endemic to hydrothermal vents in the Pacific Ocean. Belonging to the order Terebellida, the family contains two genera, Alvinella and Paralvinella; the former genus contains two valid species and the latter eight...
(alvinellids) - AmpharetidaeAmpharetidaeAmpharetidae are a family of terebellid "bristle worm" . As such, they belong to the order Canalipalpata, one of the three main clades of polychaetes. They appear to be most closely related to the peculiar alvinellids which inhabit the deep sea, and somewhat less closely to the well-known trumpet...
(ampharetids)- AmpharetinaeAmpharetinaeAmpharetinae are a subfamily of terebellid "bristle worm" . As such, they belong to the order Canalipalpata, one of the three main clades of polychaetes. They are the largest subfamily of the Ampharetidae, of which they contain far more than half of the described genera.The majority of ampharetines...
(ampharetines, a subfamily)
- Ampharetinae
- CirratulidaeCirratulidaeCirratulidae is a family of marine polychaete worms. Members of the family are found worldwide, mostly living in mud or rock crevices. Most are deposit feeders, but some graze on algae or are suspension feeders.-Description:...
(cirratulids, sometimes placed in Spionida suborder) - Ctenodrilidae (ctenodrilids, sometimes own suborder Ctenodrilida)
- Fauveliopsidae (fauveliopsids, sometimes own suborder Fauveliopsida)
- Flabelligeridae (flabelligerids, sometimes Flabelligerida suborder)
- Flotidae (flotids, sometimes included in Flabelligeridae)
- PectinariidaePectinariidaePectinariidae, or the trumpet worms or ice cream cone worms, are a family of marine polychaete worms that build sand tubes roughly resembling ice cream cones up to two inches long.-Genera:...
(pectinariids, commonly referred to as trumpet worms or ice cream cone worms) - Poeobiidae (poeobiids, sometimes own suborder Poeobiida or included in Flabelligerida suborder)
- Sternaspidae (sternaspids, sometimes own suborder Sternaspida)
- TerebellidaeTerebellidaeTerebellidae 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,...
(terebellids, commonly referred to as spaghetti worms) - Trichobranchidae (trichobranchids)
Notable species
A notable terebellid is the Pompeii wormPompeii worm
Alvinella pompejana, , is a species of deep-sea polychaete worm...
(Alvinella pompejana), an alvinellid
Alvinellidae
The Alvinellidae are a family of small, deep-sea polychaete worms endemic to hydrothermal vents in the Pacific Ocean. Belonging to the order Terebellida, the family contains two genera, Alvinella and Paralvinella; the former genus contains two valid species and the latter eight...
. It is the most heat-tolerant
Thermophile
A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122 °C . Many thermophiles are archaea...
complex organism known on Earth. Found near hydrothermal vent
Hydrothermal vent
A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...
s deep in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, it thrives at a temperature of 50°C (122°F). This is near the theoretical limit for eukaryote
Eukaryote
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...
s, whose mitochondria
Mitochondrion
In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...
disintegrate at about 55°C (131°F).
Seven species of pelagic
Pelagic fish
Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or the lake. They can be contrasted with demersal fish, which do live on or near the bottom, and reef fish which are associated with coral reefs.The marine pelagic...
(free-swimming) terebellids have recently been discovered, including Swima
Swima
Swima is a genus of polychaete worm that lives in the deep ocean. This deep ocean pelagic annelid has modified bioluminescent gills that can be cast off from an individual. These discarded gills somewhat resemble green "bombs" that remain illuminated for several seconds after they have been...
in 2009 and Teuthidodrilus
Teuthidodrilus
Teuthidodrilus , is a genus of marine polychaete worms discovered by marine biologists from the Scripps Institution of Oceanography in November 2010...
in 2010. These seven species have been assigned to four new genera, forming a phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
within the Acrocirridae
Acrocirridae
Acrocirridae is a family of polychaete worms. Acrocirrids are detritivores , catching falling particles with numerous long prostomial tentacles. There are eight known genera, and at least 21 described species and subspecies within the Acrocirridae family...
family.
Fossil record
Polychaetes lack a firm skeletonSkeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, so they do not fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ize well. For this reason, only a small number of prehistoric bristle worms have been described. Several of these have been placed in the Terebellida suborder, though often only tentatively so, owing to the ongoing uncertainties about polychaete phylogeny
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
. However, as the terebellid habit of constructing characteristic tubes in which to live seems quite ancient, such structures are occasionally found in conservation Lagerstätten
Lagerstätte
A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossil richness or completeness.Palaeontologists distinguish two kinds....
. Polychaete remains associated with such ichnofossils
Trace fossil
Trace fossils, also called ichnofossils , are geological records of biological activity. Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings , urolites , footprints and feeding marks, and root cavities...
can therefore be quite certainly be allocated to the Terebellida. Prehistoric polychaete genera presumed to be Terebellida include:
- Arthrophycus Hall, 1852
- Cryptosiphon Prantl, 1948
- Granularia Pomel, 1849
- Harlania Goppert, 1852
- Lepidenteron Fritsch, 1878
- Paraterebella Howell, 1955 (= Terebellopsis Howell, 1953)
- Proterebella Howell, 1953
- Psammosiphon Vine, 1882
- Scalarituba Weller, 1899
- Scolecoderma Salter, 1855
- Terebellites Howell, 1943
- Terebelloides Desio, 1940
- Terebellolites Desio, 1940
- Terebellopsis Leymerie, 1844 (see also Paraterebella)
See also
- Alvinella pompejana
- Amphitrite ornataAmphitrite ornataAmphitrite 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 and parapodia . Some species live freely, either swimming, crawling or burrowing,...
- Cirratulus cirratusCirratulus cirratusCirratulus cirratus is a species of marine polycheate worm in the family Cirratulidae. It occurs in the littoral and sub-littoral zones of the Atlantic Ocean....
- Eupolymnia crasscornisEupolymnia crasscornisEupolymnia crasscornis is a tropical species of annelid. The worms are commonly known as spaghetti worms and can be found mainly in the Bermudan waters near the Florida Keys and Puerto Rico. They can be found at bottoms of oceans near to the rocks and sand...
- Eupolymnia nebulosaEupolymnia nebulosaEupolymnia nebulosa is a species of sedentary marine polychaete worm in the Terebellidae family. It builds a tube of slime under stones or large shells on soft substrates on the lower shore and down to depths of about 500 metres.-Description:...
- Paralvinella sulfincolaParalvinella sulfincolaParalvinella sulfincola is a species of worm of the Alvinellidae family that thrives on undersea hot-water vents. It dwells in the hottest of waters, thriving in temperatures that would kill most other animals...
- Pectinaria australisPectinaria australisPectinaria australis, , is one of at least ten species of polychaete worms of the family Pectinariidae. It is the only pectinariid species endemic to New Zealand.-References:*...