Amphiuridae are a large family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of brittle star

Brittle star

Brittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the seafloor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to in length on the largest specimens...

s of the suborder Gnathophiurina

Gnathophiurina

The Gnathophiurina are a group of Ophiuroidea mostly treated as suborder .-Families:* Amphilepididae Matsumoto, 1915...

. Some species are used to study echinoderm development (e.g. Amphipholis kochii and Amphioplus abditus) and bioluminescence

Bioluminescence

Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...

 (the dwarf brittle star, Amphipholis squamata).

Characteristics

Amphiuridae are generally small brittlestars. Their jaws are always with two apical

Apical

Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical , an anatomical term of location for features associated with the base of an organism or structure...

 papilla

Papilla (fish mouth structure)

The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...

e at the tip, and one or more papillae on each side.

Systematics and phylogeny

Amphiuridae are the most diverse family of Ophiurida with over 200 species. The family contains the following genera:

Acrocnida Gislén, 1926 Ailsaria Fell, 1962 Amphiacantha Matsumoto, 1917 Amphichilus Matsumoto, 1917 Amphichondrius Nielsen, 1932 Amphicontus Hill, 1940 Amphigyptis Nielsen, 1932 Amphilimna Verrill, 1899 Amphilycus Mortensen, 1933 Amphinephthys Fell,1962 Amphiocnida Amphiodia Amphiodia Amphiodia is a genus of brittle stars belonging to the family Amphiuridae.-Species:-References:*... Verrill, 1899 Amphiomya H.L. Clark, 1939 Amphioncus Clark, 1939 Amphioplus Verrill, 1899 Amphipholis Amphipholis Amphipholis is a large genus of brittle stars found in oceans worldwide from tropics to Arctic and Antarctic regions. Some species have been used to study echinoderm development and bioluminescence .-Systematics:Amphipholis is a large genus with potentially many cryptic species... Ljungman, 1966 Amphistigma H.L. Clark, 1938 Amphiura Amphiura Amphiura is a large genus of brittle stars found in oceans worldwide from tropics to Arctic and Antarctic regions.-Systematics and phylogeny:... Forbes, 1842 Ctenamphiura Verrill, 1899 Diamphiodia Fell, 1962 Dougalopus A. M. Clark, 1970 Gymnodia Fell, 1962

Icalia Fell, 1962 Microphiopholis Turner, 1985 Monamphiura Monamphiura Monamphiura is a genus of brittle star echinoderms of the family Amphiuridae.-Species:* Monamphiura sundevalli* Monamphiura apicula * Monamphiura proposita* Monamphiura algida Fell, 1962... Fell 1962 Monopholis Monopholis Monopholis is a genus of flowering plants in the daisy family.... Fell, 1962 Nannophiura Mortensen, 1933 Nudamphiura Tommasi, 1965 Nullamphiura Fell, 1962 Nullopholis Fell, 1962 Ophiocnida Lyman, 1865 Ophiomonas Djakonov, 1952 Ophionema Lütken, 1869 Ophionephthys Lütken, 1869 Ophiophragmus Lyman, 1865 Ophiostigma Lütken, 1856 Pandellia Fell, 1962 Paracrocnida Mortensen, 1940 Paramphichondrius Guille & Wolff, 1984 Paramphiura Koehler, 1895 Silax Fell, 1962 Triodia A.M. Clark, 1970 Unioplus Fell, 1962

In addition, two extinct genera are known:

• † Deckersamphiura Jagt, 2000
• † Xanthamphiura Hess 1970

Ecology

Amphiuridae are found in oceans worldwide from tropics to Arctic and Antarctic regions, with some species living in brackish water. They live mostly by burrowing in the seafloor or hiding under rocks. Most of them are herbivore

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

s feeding directly on algae, or detritus

Detritus

Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...

feeders, using their long arms to direct organic materials towards their mouths.

Though most amphiurid brittlestars broadcast their eggs and sperm into the sea, many species in this family are "brooders" and carry their young in bursae. One species, Amphiodia akosmos from the Monterey Peninsula of California, was found with up to 11 brooding embryos in one adult (Hendler and Bundrick, 2001).