Amphiuridae

Amphiuridae Temporal range: Jurassic - present [1]
Amphipholis squamata
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Subphylum:	Eleutherozoa
Class:	Ophiuroidea
Order:	Ophiurida
Suborder:	Gnathophiurina
Family:	Amphiuridae Ljungman, 1867
Genera
See text.

Amphiuridae (commonly called long-armed burrowing brittle stars^[2] or burrowing brittle stars) are a large family of brittle stars of the suborder Gnathophiurina. Some species are used to study echinoderm development (e.g. Amphipholis kochii^[3] and Amphioplus abditus^[4]) and bioluminescence (the dwarf brittle star, Amphipholis squamata^[5][6]).

Characteristics

Amphiuridae are generally small brittlestars. Their jaws are always with two apical papillae at the tip, and one or more papillae on each side.^[7]

Systematics and phylogeny

Amphiuridae are the most diverse family of Ophiurida with over 200 species. The family contains the following genera:^[8]

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 Verrill, 1899 Amphiomya H.L. Clark, 1939 Amphioncus Clark, 1939 Amphioplus Verrill, 1899 Amphipholis Ljungman, 1966 Amphistigma H.L. Clark, 1938 Amphiura Forbes, 1842 Ctenamphiura Verrill, 1899 Diamphiodia Fell, 1962 Dougalopus A. M. Clark, 1970 Gymnodia Fell, 1962

Icalia Fell, 1962 Microphiopholis Turner, 1985[9] Monamphiura Fell 1962 Monopholis 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:^[10]

• † 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.^[11] They live mostly by burrowing in the seafloor or hiding under rocks. Most of them are herbivores feeding directly on algae, or detritus 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).^[12]

References

1. J. Roman, G. Breton, and C. Vadon. 1993. Ophiurides et Astéride (Echinodermata) du Tithonien de Canjuers (Var, France). Annales de Paléontologie 79(1):1-18
2. P.Lambert, Checklist of the Echinoderms of British Columbia (April 2007), Royal British Columbia Museum
3. Yamashita,M., Embryonic Development of the Brittle-Star Amphipholis kochii in Laboratory Culture, Biol. Bull. 169: 131-142(Aug., 1985)
4. Hendler,G, Development of Amphioplus abditus (Verrill) (Echinodermata: Ophiuroidea): I. Larval Biology,Biol.Bull., Vol.152, No.1 (Feb., 1977)
5. P.Brehm, J.G. Morin. Localization and Characterization of Luminescent Cells in Ophiopsila californica and Amphipholis squamata (Echinodermata: Ophiuroidea) Biological Bulletin, Vol. 152, No. 1 (Feb., 1977)
6. Dewael Y, Mallefet J., Luminescence in ophiuroids (Echinodermata) does not share a common nervous control in all species, J Exp Biol. 2002 Mar;205
7. Hendler,G. Ophiuroid Skeleton Ontogeny Reveals Homologies Among Skeletal Plates of Adults: A Study of Amphiura filiformis, Amphiura stimpsonii and Ophiophragmus filograneus (Echinodermata), Biol.Bull. 174:20-29.(Feb.1988)
8. MarineSpecies.org - Amphiuridae Ljungman, 1867
9. Formerly Micropholis Thomas, 1966 (non Huxley 1859: preoccupied)
10. The Paleobiology Database
11. R.L.Turner, Effects of Long-Term Exposure to Low Salinity on the Brackish-water Amphiurid Brittlestar Ophiophragmus filograneus (Lyman, 1875) From the Indian River Lagoon, Florida.Florida Scientist, Vol 70, 4 (Sept.2007)
12. 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