Amphiuridae (commonly called long-armed burrowing brittle stars or burrowing brittle stars) are a large
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
of
brittle star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomo ...
s of the suborder
Gnathophiurina
The Gnathophiurina are a group of Ophiuroidea mostly treated as suborder (but at first as an order Gnathophiurida, and sometimes as infraorder of OphiurinaSmith, A.B.; Paterson, G.L.J. . Ophiuroid phylogeny and higher taxonomy: morphological, mo ...
. Some species are used to study echinoderm development (e.g. ''
Amphipholis kochii'' and ''
Amphioplus abditus'') and
bioluminescence
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some b ...
(the
dwarf brittle star, ''Amphipholis squamata'').
Characteristics
Amphiuridae are generally small brittlestars. Their jaws are always with two
apical
Apical means "pertaining to an apex". It may refer to:
*Apical ancestor, refers to the last common ancestor of an entire group, such as a species (biology) or a clan (anthropology)
*Apical (anatomy), an anatomical term of location for features loc ...
papilla
Papilla (Latin, 'nipple') or papillae may refer to:
In animals
* Papilla (fish anatomy), in the mouth of fish
* Basilar papilla, a sensory organ of lizards, amphibians and fish
* Dental papilla, in a developing tooth
* Dermal papillae, part of ...
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:
In addition, two extinct genera are known:
* † ''
Deckersamphiura''
Jagt, 2000
* † ''
Xanthamphiura''
Hess 1970
Image:Amphiodia pulchella.jpg, '' Amphiodia pulchella''
Image:Amphioplus thrombodes.jpg, '' Amphioplus thrombodes''
Image:Ophiocentrus aspera.jpg, '' Ophiocentrus aspera''
Image:Amphipholis squamata Réunion.jpg, '' Amphipholis squamata''
Ecology
Amphiuridae are found in oceans worldwide from tropics to Arctic and Antarctic regions, with some species living in
brackish
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
water. They live mostly by burrowing in the seafloor or hiding under rocks. Most of them are
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s feeding directly on algae, or
detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
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).
[Hendler, G. & Bundrick, C. 2001. A new brooding brittle star from California (Echinodermata: Ophiuroidea: Amphiuridae). ''Contributions in Science from the Natural History Museum of Los Angeles County, 486'', pp 1-11]
References
Gnathophiurina
Echinoderm families
Extant Jurassic first appearances
{{ophiuroidea-stub