The Forcipulatida are an

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

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 (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

Description

Forcipulatids share with the brisingid sea stars distinctive

pedicellaria A pedicellaria (: 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 Echinoidea). ...

e, consisting of a short stalk with three skeletal

ossicles The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. Although the term "ossicle" literally means "tiny bone" (from Latin ''ossi ...

. Unlike that group, however, the forcipulatids tend to have more robust bodies. The order includes some well-known species, such as the common starfish, ''Asterias rubens''. This order can be commonly found from North 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. The oldest unambiguous fossils of the family date to the Late Cretaceous. Genera The World Regi ...

— 39 genera * Family

Heliasteridae The Heliasteridae are a family of Asteroidea (sea stars) in the order Forcipulatida. It includes two genera: ''Heliaster'' from the East Pacific (California to Chile, including offshore islands), and ''Labidiaster'' from southernmost South Americ ...

— two genera * Family

Zoroasteridae The Zoroasteridae are one of three families of Asteroidea (sea stars) in the order Forcipulatida. It contains seven living genera and one extinct genus. Genera The living genera described are: * '' Bythiolophus'' Fisher, 1916 (monotypic) ** ''B. ...

— 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 catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

gives another taxonomy, with 7 families and 64 genera: * Family

Gray, 1840 * Family

Viguier, 1878 * Family

Pedicellasteridae Pedicellasteridae is a family of echinoderms belonging to the order Forcipulatida The Forcipulatida are an order (biology), order of sea stars, containing three families and 49 genera. Description Forcipulatids share with the Brisingida, bris ...

Perrier, 1884 * Family

Pycnopodiidae Pycnopodiidae is a family of echinoderms belonging to the order Forcipulatida The Forcipulatida are an order (biology), order of sea stars, containing three families and 49 genera. Description Forcipulatids share with the Brisingida, brisingi ...

Fisher, 1928 * Family

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

Perrier, 1885 * Family

Sladen, 1889 A 2020 study involving

phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

and

scanning electron microscopy A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that ...

of the skeleton and ossicles of taxa from the superorder

Forcipulatacea The Forcipulatacea are a superorder of sea stars. Subdivision * Order Forcipulatida * Order Brisingida * ''Incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefi ...

recovered

, and

Brisingida The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 and 16 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a ...

as monophyletic. The extinct family

Terminasteridae Terminasteridae is a family of fossil starfish which lived from the Jurassic to Cretaceous periods. It was erected in 2011 as a monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordina ...

has also been placed in this order.

Description

Phylogeny

See also

References

Further reading