''Teuthidodrilus samae'', dubbed as the squidworm, is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

of acrocirrid marine

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

worms. It is free-swimming and can be found in the deep sea

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

at depths of . It feeds on

marine snow In the deep ocean, marine snow (also known as "ocean dandruff") 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 ...

and can grow to about in length and in width. It is named for the ten squid-like appendages emerging from its head. It was discovered in 2007 in the

benthopelagic zone The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a laye ...

of the

Celebes Sea The Celebes Sea, (; ms, Laut Sulawesi, id, Laut Sulawesi, fil, Dagat Selebes) or Sulawesi 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 b ...

, near the

Tawi-Tawi Tawi-Tawi, officially the Province of Tawi-Tawi ( tl, Lalawigan ng Tawi-Tawi; Tausug: ''Wilaya' sin Tawi-Tawi''; Sinama: ''Jawi Jawi/Jauih Jauih''), is an island province in the Philippines located in the Bangsamoro Autonomous Region in Muslim ...

islands of the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. It is the only species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Teuthidodrilus''.

Discovery

''Teuthidodrilus samae'' was discovered in the 2007 "Exploring the Inner Space of the Celebes Sea" expedition by the

remotely operated underwater vehicle A remotely operated underwater vehicle (technically ROUV or just ROV) is a tethered underwater mobile device, commonly called ''underwater robot''. Definition This meaning is different from remote control vehicles operating on land or in the ...

Global Explorer ROV Global Explorer ROV is a unique deep water remotely operated vehicle that has made numerous dives below on science and survey expeditions for National Geographic, the National Oceanographic and Atmospheric Administration (NOAA) and other resear ...

'' operated from the Philippine research vessel BRP ''Hydrographer Presbitero''. Seven specimens were observed and collected from the deep-water column of the

seafloor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

) of the

near the

islands of the

. This area is part of the

Coral Triangle The Coral Triangle (CT) is a roughly triangular area in the tropical waters around the Philippines, Indonesia, Malaysia, Papua New Guinea, the Solomon Islands and Timor-Leste. This area contains at least 500 species of reef-building corals in ea ...

, a location known for its increased biodiversity. The specimens were recovered at depths ranging from , all within the

demersal zone The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a laye ...

of around from the

Taxonomy

''Teuthidodrilus samae'' is the only species classified in the

''Teuthidodrilus.'' It belongs to the

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

Acrocirridae Acrocirridae is a family of polychaete worms. Acrocirrids are detritivores (deposit feeders), catching falling particles with numerous long prostomial tentacles. There are eight known genera, and at least 21 described species and subspecies wi ...

of the class

Polychaeta 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 ...

in the

phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclatu ...

Annelida. It is classified along with the genus '' Swima'' in the "swimming clade" within the family Acrocirridae. A similar undescribed and uncollected specimen observed from off western

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

by the ''Hercules 7'' ROV in 2004 may represent a second species in the genus. The generic name comes from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

for "squid worm", while the

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

is in honor of the Sama people of the Tawi-Tawi islands. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

is deposited in the

National Museum of the Philippines The National Museum of the Philippines ( fil, Pambansang Museo ng Pilipinas}) is an umbrella government organization that oversees a number of national museums in the Philippines including ethnographic, anthropological, archaeological, and visu ...

Physical characteristics

The collected specimens ranged in size from in body length. The

has a body width of around . Adults are light brown when alive, becoming light black in color when preserved. Juveniles are almost transparent. The body is divided into 25 segments ( chaetigers) with pairs of large flattened paddle-shaped notopodia, around in length. Each notopodium has greater than 50

chaeta A chaeta or cheta (from Greek χαίτη “crest, mane, flowing hair"; plural: chaetae) is a chitinous bristle or seta found in annelid worms, (although the term is also frequently used to describe similar structures in other invertebrates such ...

e (bristles) arranged into a fin-like shape, except the first segment which has less than 10. Alongside the notopodia are pairs of neuropodia, each with around 2 to 4 chaetae. The head segment (

prostomium The prostomium (From Ancient Greek, meaning "before the mouth"; plural: prostomia; sometimes also called the "acron") is the cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not include) th ...

) supports five pairs of long appendages. Four pairs of appendages are sensory and breathing organs (branchiae) at least in length. They are arranged along the upper and side ridges of the head, arising from the pair of feather-like

nuchal organ The nuchal organ is a ciliated pit or groove present at the posterior end of the prostomium of annelid worms, some cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, o ...

s which analyze chemical signals in the sea. The fifth pair of appendages are grooved and coiled feeding palps arising from below the mouth, which is located in the front-bottom corner of the head. Their internal anatomy is relatively visible from the outside since their outer body is semi-transparent. Two parallel

ventral nerve cord The ventral nerve cord is a major structure of the invertebrate central nervous system. It is the functional equivalent of the vertebrate spinal cord. The ventral nerve cord coordinates neural signaling from the brain to the body and vice versa, in ...

s run lengthwise throughout the body, fusing into two pairs of

ganglia A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympath ...

in each segment. The gut forms three loops in the second to sixth segments. The circulatory system consists of a heart body and large vessels leading to the gills. The pair of

nephridia The nephridium (plural ''nephridia'') is an invertebrate organ, found in pairs and performing a function similar to the vertebrate kidneys (which originated from the chordate nephridia). Nephridia remove metabolic wastes from an animal's body. Neph ...

extends from the first segment to the fifth segment. The female

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces ...

s are located in the second to fourth segments with beige-colored grape-like clusters of variously-sized ova (with a maximum diameter of ).

Behavioral characteristics

Not much is known of this creature’s behavior other than its ability to swim with proficiency using their paddle-like notopodia. It is categorized as a suspension eater since it consumes

, which consists of pieces from animals, plants, feces and other organic materials that precipitate from the higher parts of the ocean towards the abyss. In total, sixteen specimens were observed and seven were collected within just a few dives suggesting that this animal is a common member of the benthopelagic community of the Celebes Sea basin.

References

External links

* {{Taxonbar, from1=Q15303032, from2=Q1948429 Polychaetes