Teuthidodrilus - AbsoluteAstronomy.com

Teuthidodrilus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

of 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...

polychaete

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...

worms discovered by marine biologists

Marine biology

Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather...

from the Scripps Institution of Oceanography

Scripps Institution of Oceanography

Scripps Institution of Oceanography in La Jolla, California, is one of the oldest and largest centers for ocean and earth science research, graduate training, and public service in the world...

in November 2010. This unique animal is currently believed to represent a transitional organism, with physical and behavioral characteristics of both the benthos

Benthos

Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...

(seabed

Seabed

The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...

-dwelling) and the 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) organisms. Teuthidodrilus samae is currently the only described species

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 this genus. Teuthidodrilus is closely related to the recently discovered 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...

genus, another pelagic cirratuliform worm of the deep ocean

Bathyal zone

The bathyal zone or bathypelagic – from Greek βαθύς , deep – is that part of the pelagic zone that extends from a depth of 1000 to 4000 metres below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The average temperature hovers at about 39°F...

Discovery

Teuthidodrilus is one of seven recently discovered deep-sea

Bathyal zone

, pelagic cirratuliforms. The first specimen was observed in the Celebes Sea

Celebes Sea

The Celebes Sea of the western Pacific Ocean is bordered on the north by the Sulu Archipelago and Sulu Sea and Mindanao Island of the Philippines, on the east by the Sangihe Islands chain, on the south by Sulawesi, and on the west by Kalimantan in Indonesia...

in October 2007. A second specimen was discovered in a nearby area by a group of marine biologists from the Scripps Institution of Oceanography in November 2010. Using a remotely operated underwater vehicle during exploration of the deep water column of the western Celebes Sea, the team found the animals at a depth of 2.8 kilometres (1.7 mi). The Celebes Sea is a deep oceanic basin

Oceanic basin

Hydrologically, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically ocean basins are large geologic basins that are below sea level...

with a maximum depth of 20,300 feet (6,200 metres). It is part of the Coral Triangle

Coral Triangle

The Coral Triangle is a geographical term so named as it refers to a roughly triangular area of the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste that contain at least 500 species of reef-building corals in each ecoregion...

, an area known for its high biodiversity

Biodiversity

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

Classification and phylogeny

Teuthidodrilus is thought to be a previously unobserved genus which may represent a transition between the benthos and the pelagic organisms. Teuthidodrilus is one of seven newly discovered species of swimming cirratuliforms. These seven species have been assigned to four new genera, forming a new phylogenetic 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. Following is a brief description of the cladistics

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...

and taxonomic classification

Taxonomic rank

In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...

of Teuthidodrilus:

Phylogenetic analysis of five of its genes has revealed that the Teuthidodrilus genus belongs to the Acrocirridae family
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...

.
the Acrocirridae family is a member of the Terebellida
Terebellida
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 , they make up the order Canalipalpata, one of the three main clades of polychaetes...

suborder of the 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...

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...

, also known as bristle-footed annelids or fan-head worms.
the Canalipalpata order belongs to 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...

, also known as bristle worms. There are more than 10,000 described species of polychaetes; they can be found in nearly every marine environment. Some species live in the coldest ocean waters of the abyssal plain
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 metres. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest...

, while others can be found in the extremely hot waters adjacent to 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. Polychaetes occur throughout the World Ocean
World Ocean
The World Ocean, world ocean, or global ocean, is the interconnected system of the Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering almost 71% of the Earth's surface, with a total volume of 1.332 billion cubic kilometres.The unity and continuity of the World Ocean, with...

at all depths, from forms that live as plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

near the surface, to a 2–3 cm specimen (still unclassified) observed by the robotic ocean probe Nereus
Nereus (underwater vehicle)
Nereus is a hybrid autonomous underwater vehicle built by the Woods Hole Oceanographic Institution . Constructed as a research vehicle to operate at depths of up to , it was designed to explore Challenger Deep, the deepest surveyed point in the global ocean...

at the bottom of the Challenger Deep
Challenger Deep
The Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...

, the deepest spot in the Earth's oceans.
the Polychaete class belongs to the Annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...

phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....

, also known as also called ringed worms. There are over 17,000 living annelid species, ranging in size from microscopic to the Australian giant Gippsland earthworm
Giant Gippsland earthworm
The giant Gippsland earthworm, Megascolides australis, is one of Australia's 1,000 native earthworm species. These Giant earthworms average 1 meter long and 2 cm in diameter and can reach 3 m in length...

, which can grow up to 3 metres (9.8 ft) long.

Anatomy and physiology

Teuthidodrilus specimens observed and collected as of 2010 have measured up to 9.4 centimetres (3.7 inches) in length. These animals are notable for the unusual tentacular

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...

appendages (referred to as "notochaetae") that protrude from its prostomium

Prostomium

Prostomium is the first body segment in annelid worms. It is in front of the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth. It sometimes bears antennae and eyes. It often functions like a kind of overlip when the animal is feeding...

(anterior segment, or head). Ten of these tentacles as long or longer than its body protrude from the head, along with six pairs of free-standing, oppositely branched nuchal organ

Nuchal organ

The nuchal organ is a ciliated pit or groove present at the posterior end of the prostomium of annelid worms, some cephalopods, and other invertebrates....

s that allow the animal to taste and smell underwater. It is the notochaetae and the nuchal organs which primarily distinguish Teuthidodrilus from other polychaetes.

Behavior

Teuthidodrilus does not appear to be a predator

Predation

In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

, feeding instead on bits of so-called "marine snow

Marine snow

In the deep ocean, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below. The term was first coined by the explorer William Beebe as he...

," a mix of sinking microscopic plants

Phytoplankton

Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...

and animals

Zooplankton

Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...

, fecal material and cast-off mucus

Mucus

In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...

. Swimming upright, it navigates by moving two body-length rows of thin, paddle-shaped protrusions that cascade like dominoes.

Geographic distribution and habitat

Squidworms live about 100 to 200 metres above the ocean floor.

Significance

Teuthidodrilus worms belong to a morphologically diverse pelagic clade within the Acrocirridae family of polychaetes. The acrocirrids are primarily benthic

Benthic zone

The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such...

. Pelagic animals within primarily benthic families are of particular interest in evolutionary biology, because their adaptations to life in the water column inform us of the evolutionary possibilities and constraints within the clade and indirectly of the selective pressures

Evolutionary pressure

Any cause that reduces reproductive success in a proportion of a population, potentially exerts evolutionary pressure or selection pressure. With sufficient pressure, inherited traits that mitigate its effects - even if they would be deleterious in other circumstances - can become widely spread...

at work in this unfamiliar habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

External links

Squidworm - New Excitement for Biologists

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.