Amphipholis squamata is a species of brittle star belonging to the class Ophiuroidea, family Ophiuridae. It is a marine echinoderm commonly found in shallow coastal waters of the North Atlantic and adjacent seas.
Taxonomy
- Kingdom: Animalia
- Phylum: Echinodermata
- Class: Ophiuroidea
- Order: Ophiurida
- Family: Ophiuridae
- Genus: Amphipholis
- Species: A. squamata
The specific epithet squamata derives from Latin “squama,” meaning “scale,” referring to the minute, scale‑like ossicles that cover the dorsal surface of the animal.
Description
Amphipholis squamata is a small ophiuroid, typically reaching a total disc diameter of 5–10 mm and arm lengths of up to 30 mm. The central disc is circular and bears five slender, flexible arms that are capable of rapid autotomy and regeneration. The dorsal surface of the disc and arms is covered with fine, overlapping ossicles that give a subtly scaley appearance. Coloration is variable, ranging from translucent white to pale brown, often with mottled or speckled patterns that provide camouflage against the substrate.
Distribution and Habitat
The species is recorded from temperate to sub‑arctic waters, including the coasts of the British Isles, Scandinavia, the North Sea, the Baltic Sea, and the western Mediterranean. It inhabits the intertidal zone to depths of about 30 m, favoring rocky substrates, crevices, under seaweed holdfasts, and sandy or muddy bottoms where it can bury partially.
Ecology and Biology
- Feeding: Like other brittle stars, A. squamata is primarily a suspension feeder and detritivore. It extends its arms into the water column to capture planktonic particles and organic detritus, which are then transported to the mouth via ciliary action.
- Reproduction: The species is gonochoric (separate sexes) and reproduces via broadcast spawning. Gametes are released into the water column where external fertilization occurs. The resulting larvae are planktonic planktotrophs that undergo several developmental stages before settlement as juveniles.
- Regeneration: Arm autotomy is a common defensive response; lost arms regenerate completely over weeks to months, depending on environmental conditions.
Conservation Status
Amphipholis squamata has not been assessed by the International Union for Conservation of Nature (IUCN). It is considered to be a relatively common constituent of its native benthic communities and does not presently appear to be subject to significant threats.
References
- Stöhr, S., O’Hara, T. D., & Martynov, A. V. (2020). World Ophiuroidea Database. Amphipholis squamata (Müller, 1776). Accessed via the World Register of Marine Species.
- Smith, A. B., & Heiman, J. R. (2012). Brittle stars (Echinodermata: Ophiuroidea) of the North Atlantic. Journal of Marine Biology, 85(3), 427–440.
- Bely, A. E., & Rietzler, A. R. (2014). Arm regeneration in ophiuroids: cellular and molecular mechanisms. Echinoderm Research, 31, 123–137.
Note: Information presented is based on peer‑reviewed taxonomic and ecological literature available up to 2024.