Sorberacea are benthic animals and a subgroup of the Tunicata

Tunicate

Tunicates, also known as urochordates, are members of the subphylum Tunicata, previously known as Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others such...

. They superficially resemble sea squirts but prey

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...

 on invertebrates such as crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s. They also have some unique physical features that distinguish them from the ascidiacea

Ascidiacea

Ascidiacea is a class in the Tunicata subphylum of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of the polysaccharide tunicin, as compared to other tunicates which are less rigid.Ascidians are found all over the world, usually in shallow...

ns, including a severely reduced pharynx

Pharynx

The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

, the retention of the dorsal nerve cord

Dorsal nerve cord

The dorsal nerve cord is one of the embryonic features unique to chordates, along with a notochord, a post-anal tail and pharyngeal slits. The dorsal nerve cord is a hollow cord dorsal to the notochord.It is formed from a part of the ectoderm that rolls, forming the hollow tube, compared to other...

 as adults, the superficial position of their ganglion

Ganglion

In anatomy, a ganglion is a biological tissue mass, most commonly a mass of nerve cell bodies. Cells found in a ganglion are called ganglion cells, though this term is also sometimes used to refer specifically to retinal ganglion cells....

 and the unique histology

Histology

Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...

 of the cells of their digestive tracts. The branchial syphon is large and surrounded by six large lobes; the cloacal syphon is small. They live exclusively in deep water and range in size from less than one inch (3 cm) to 2.4 inches (6 cm).

See also

• Sorbera unigonas
• Hexacrobylidae
  Hexacrobylidae
  Hexacrobylidae are a family of benthic predatory tunicates. The taxon has two genera with a total of six species. Hexacrobylidae are in the order Pleurogona and in the class Ascidiacea.-Taxonomy:*Asajirus**Asajirus arcticus...
  
  
• Aspiraculata
  Aspiraculata
  Aspiraculata is an order of sea squirts in the class Sorberacea. It is the only order in the class, and includes only one family, the Hexacrobylidae....
  
  
• Ascidiaceae
  Ascidiacea
  Ascidiacea is a class in the Tunicata subphylum of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of the polysaccharide tunicin, as compared to other tunicates which are less rigid.Ascidians are found all over the world, usually in shallow...
  
  
• Thaliacea
  Thaliacea
  The Thaliacea comprise a class of marine animals within the subphylum Tunicata. Unlike their bottom-dwelling relatives the ascidians, thaliaceans are free-floating for their entire lifespan. The group includes both solitary and colonial species.-Anatomy:...
  
  
• Larvacea
  Larvacea
  Larvaceans are solitary, free-swimming tunicates found throughout the world's oceans. Like most tunicates, appendicularians are filter feeders. Unlike other tunicates, appendicularians live in the pelagic zone, specifically in the upper sunlit portion of the ocean or sometimes deeper...
  
  (Appendicularia)
• http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Urochordata/Urochordata.htm#Sorberacea