Amphiuridae
A large, diverse family of burrowing brittle stars found worldwide.
Amphiuridae, also known as long-armed burrowing brittle stars, form a large family within the suborder Gnathophiurina. This group is the most diverse in the order Ophiurida, containing over 200 species. Some members, such as *Amphipholis kochii* and *Amphioplus abditus*, are used to study how echinoderms develop, while the dwarf brittle star *Amphipholis squamata* is a model for research on bioluminescence.
These brittle stars are generally small. Their jaws always have two apical papillae at the tip, with one or more additional papillae on each side.
Amphiurids live in oceans worldwide, from the tropics to the Arctic and Antarctic, and a few species tolerate brackish water. They mostly burrow into the seafloor or hide beneath rocks. Most feed on algae or detritus, using their long arms to move organic matter toward their mouths.
While many amphiurids release eggs and sperm into the water, numerous species in this family brood their young inside bursae. For instance, one adult of *Amphiodia akosmos* from California’s Monterey Peninsula was found carrying up to 11 embryos (Hendler and Bundrick, 2001). Two extinct genera are also known: †*Deckersamphiura* (Jagt, 2000) and †*Xanthamphiura* (Hess, 1970).
Quick Facts
- Taxon
- Amphiuridae
Facts from the source article.
Lore & Background
Amphiuridae are generally small brittle stars. Their jaws always have two apical papillae at the tip and one or more papillae on each side. The family contains numerous genera, as well as two extinct genera: Deckersamphiura and Xanthamphiura.
Ecologically, Amphiuridae are found in oceans worldwide from the tropics to Arctic and Antarctic regions, with some species living in brackish water. They mostly burrow in the seafloor or hide under rocks. Most are herbivores feeding directly on algae or detritus feeders, using their long arms to direct organic materials toward their mouths.
Reproduction varies: though most amphiurid brittle stars broadcast eggs and sperm into the sea, many species are brooders that 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.
Reader's Guide
Amphiuridae hold significance in scientific research, particularly in the study of echinoderm development and bioluminescence. Species such as Amphipholis kochii and Amphioplus abditus are used to study echinoderm development, while the dwarf brittle star Amphipholis squamata is used to study bioluminescence. As the most diverse family of Ophiurida, with over 200 species, they represent a major component of brittle star biodiversity. Their global distribution from tropics to polar regions and ability to live in brackish water demonstrate ecological adaptability. The family's reproductive diversity—including both broadcast spawning and brooding—provides insight into life-history strategies among echinoderms. The specific observation of Amphiodia akosmos brooding up to 11 embryos highlights the variation within the family. Their burrowing and hiding behaviors, along with herbivorous and detritus-feeding habits, define their ecological role in marine benthic communities.
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