Torquaratoridae (Latin for "neck plow") is a family of

acorn worm The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in th ...

s (

Hemichordata Hemichordata ( ) is a phylum which consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and incl ...

) that lives in deep waters between 350 and 4000 meters. They can grow up to 1 m (3 ft) in length and have semitransparent gelatinous bodies, often brightly colored.

Cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

on their underside are used to glide over the ocean floor at about 8 cm (3 in) per hour, while detritus is sucked into their gut, leaving behind a constant trail of feces. When deciding to move to new feeding locations, they empty their gut and drift over the bottom, aided by an excreted balloon of

mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...

. One species (''Coleodesmium karaensis'') has been shown to care for the offspring by bearing about a dozen embryos surrounded by a thin membrane in shallow depressions on the surface of the mother's pharyngeal region. The

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...

skeleton is reduced to a small medial plate in one genus, while it is absent in the remaining species, and the

stomochord The stomochord is a flexible, hollow tube found in hemichordates. Stomochords arise in embryonic development as an outpocketing from the roof of the embryonic gut anterior to the pharynx. In adults, they extend dorsally from the pharynx into the p ...

reduced in adults. '' Terminstomo'' ''arcticus'' have lost the heart, blood sinus and proboscis skeleton, and has a stomochord that extends from the posterior end of the proboscis through the entire length of the collar. Their large eggs, which measure almost 2 mm across, suggest that there is direct development without larvae. Their genitals are unusual by being located outside the body. On each side of the worm, a flap of the skin runs the entire length of the trunk. Located on the inner surfaces of these flaps, the numerous ovaries and testicles bulge outwards in an epidermal pouch attached to the rest of the body by a slender stalk. The ovaries' eggs are protected by just a single layer of cells. One species, ''

Yoda purpurata ''Yoda purpurata'' is a species of acorn worm discovered 2.5 km (about 1.5 miles) below the surface of the Atlantic ocean, and was the first of the genus ''Yoda'' found. Ranging from in length, it was named after the fictional character Yoda fro ...

'', is also the first known

hermaphroditic A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

hemichordate. It is assumed that these modifications are an adaptation to life in their deep sea habitats. Only one known species (''

Allapasus aurantiacus ''Allapasus'' is a genus of acorn worms belonging to the family Torquaratoridae Torquaratoridae (Latin for "neck plow") is a family of acorn worms (Hemichordata) that lives in deep waters between 350 and 4000 meters. They can grow up to 1 m (3 ...

'') is muscular and robust enough to burrow into substrates. The other species have a very reduced body musculature and are too gelatinous and fragile to do so. Instead they live directly on the seafloor. The extra-wide-lipped species shows the most obvious adaptations to the free living lifestyle, and they are found almost exclusively on rocks of deep-sea lava formations. Some Antarctic species have been found to make tubes in sediments that can last for days, resembling some Cambrian species as Spartobranchus tenuis. At depths between 1500 and 3700 m, these animals are often the most numerous, along with echinoderms, molluscs, crustaceans and fish.

Genera

* ''

Allapasus ''Allapasus'' is a genus of acorn worms belonging to the family Torquaratoridae Torquaratoridae (Latin for "neck plow") is a family of acorn worms (Hemichordata) that lives in deep waters between 350 and 4000 meters. They can grow up to 1 m (3 ...

'' Holland, Kuhnz & Osborn, 2012 * '' Coleodesmium'' Osborn, Gebruk, Rogacheva & Holland, 2013 * '' Tergivelum'' Holland, Jones, Ellena, Ruhl & Smith, 2009 * '' Torquarator'' Holland, Clague, Gordon, Gebruk, Pawson & Vecchione, 2005 * ''

Yoda Yoda () is a fictional character in the ''Star Wars'' franchise. He is a small, green humanoid alien who is powerful with the Force. He first appeared in the 1980 film '' The Empire Strikes Back'', in which he is voiced and puppeteered by F ...

'' Priede, Osborn, Gebruk, Jones, Shale, Rogacheva & Holland, 2012

References

Enteropneusta Torquaratoridae {{Hemichordate-stub