I have a distinct central disc and five skinny, flexible arms. NEW Marine Life Trivia . The arms readily break off but soon regrow—i.e., are regenerated. The animal feeds by extending one or more arms into the water or over the mud, the other arms serving as anchors. The arms of brittle stars are easily broken. Specimens of the brittle star (O. erinaceus) were obtained from rocky intertidal flats of Persian Gulf waters. They are red in coloration with cream colored bands along the arms. Characteristics of brittle stars Characterized by radial symmetry with a central body from which five snakelike arms protrude. Omissions? Select a category. The arms are highly flexible. Their arms branch, and can be moved in any direction. Brittle Star Reproduction. Brittle stars don't have an anus, so any wastes must come out through the mouth. Members of the class Ophiuroidea are mostly gonochoric, others are protandric. Reproduction. Brittle stars feed on detritus and small oceanic organisms such as plankton, small mollusks, and even fish. There are over 2,000 different species of brittle stars worldwide. FAQ’s; Advertise; Subscribe; Inside; Nudges; Competition . Wallpaper . Amphipholis kochii and Amphioplus abditus) and bioluminescence (the dwarf brittle star, Amphipholis squamata MTT (3-[4, 5- dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide) and DAPI (4′,6-Diamidino-2-phenylindole dihydrochloride) were prepared from Applichem (USA). Brittle stars are mainly deposit feeders, scavengers, and plankton feeders; however, they sometimes trap sizable animals. The New Latin class name Ophiuroidea is derived from the Ancient Greek ὄφις, meaning "serpent". https://oceanconservancy.org/wildlife-factsheet/brittle-star stars and the characteristics that differ are adaptations that allowed brittle star species to thrive in many habitats (Hendler et al. Our editors will review what you’ve submitted and determine whether to revise the article. Compared to sea stars, brittle stars' arms and central disk are much more distinctly separated, and their arms allow them to move gracefully and purposefully in a rowing movement. Brittle star discs range in size from 0.1 to 3 inches; their arm length is a function of their disc size, typically between two to three times the diameter although some have lengths up to 20 or more times. The most widespread species is the long-armed brittle star (Amphipholis squamata), a grayish or bluish species that is strongly luminescent. There are also spines on the central disk. The body is 0.04 to 0.1 inches (1 to 3 millimeters) across. 0 comment. Some brittle stars will raise themselves on their arms, and when fish get close enough, they wrap them in a spiral and eat them. The arms are highly flexible. Many brittle stars are quick and agile in comparison to most other echinoderms, especially the almost immobile sand dollar. An echinoderm is a member of the phylum Echinodermata which contains a number of marine organisms recognized by their pentamerous radial symmetry, calcareous endoskeleton, and a water vascular system which helps operate their small podia. Competition Rules; Online entry. Whether miniscule or massive, marine invertebrates are incredibly interesting! An example is a brittle star. Encyclopædia Britannica, Inc. See all videos for this article. They abound in all types of benthic marine habitats, even carpeting the abyssal sea bottom in many areas. Brittle star larvae are small ridged, and transparent. The wound heals, and then the arm regrows, a process which can take weeks to months, depending upon the species. Among the basket stars, a type of brittle star, each arm may branch multiple times, and the outstretched arms reach nearly 1 metre (about 3 feet) across. 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