The Forcipulatida are an order of

sea star Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

s, containing three families and 49

genera 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 nomenclat ...

Description

Forcipulatids share with the brisingid sea stars distinctive

pedicellaria A pedicellaria (plural: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echi ...

e, consisting of a short stalk with three skeletal

ossicles The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ...

. Unlike that group, however, the forcipulatids tend to have more robust bodies. The order includes some well-known species, such as the

common starfish The common starfish, common sea star or sugar starfish (''Asterias rubens'') is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30 c ...

, ''Asterias rubens''. This order can be commonly found from Nor Carolina in the United States all the way to Santos in Brazil.

Phylogeny

The order is divided into three families: * Family

Asteriidae The Asteriidae are a diverse family of Asteroidea (sea stars) in the order Forcipulatida. It is one of three families in the order Forcipulatida. Genera The World Register of Marine Species lists these genera within the family Asteriidae (in a ...

— 39 genera * Family Heliasteridae — two genera * Family Zoroasteridae — eight genera

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

gives another taxonomy, with 7 families and 64 genera: * Family Asteriidae Gray, 1840 * Family Heliasteridae Viguier, 1878 * Family Pedicellasteridae Perrier, 1884 * Family Pycnopodiidae Fisher, 1928 * Family

Stichasteridae The Stichasteridae are a small family of Asteroidea (sea stars) in the order Forcipulatida. Genera were formerly unassigned, or in the family Asteriidae. Genera The World Register of Marine Species lists these genera Genus ( plural genera ) ...

* Family Zoroasteridae Sladen, 1889 A 2020 study involving

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

and scanning electron microscopy of the skeleton and ossicles of taxa from the superorder

Forcipulatacea The Forcipulatacea are a superorder of sea stars. Subdivision * order Forcipulatida * order Brisingida The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 to 18 long, attenuated ...

recovered

, Zoroasteridae, and

Brisingida The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a fu ...

as monophyletic.

Description

Phylogeny

See also

References

Further reading