Ophiocanops
A primitive, disputed brittle star genus with one described living species.
Ophiocanops is a genus of brittle stars that includes the living species *Ophiocanops fugiens*. For a long time, this was thought to be the only living species in the family Ophiocanopidae, but recent work has uncovered three additional specimens that are clearly different from *O. fugiens*. Where this genus fits in the classification system is a matter of strong debate. It is often placed in the order Oegophiurida (suborder Zeugophiurina), sometimes treated as a genus *incertae sedis*, or even given its own subclass, Oegophiuridea. Some newer evidence points to a link with the living family Ophiomyxidae (order Phrynophiurida). It has been called the most primitive brittle star, similar to Paleozoic forms, though not all researchers agree.
The central body of *O. fugiens* is a small, armored disc, clearly separated from the arms, and measures about 3 mm across. The arms are long and flexible, reaching 35–40 mm in length and about 1 mm wide. They are supported by an internal skeleton made of calcium carbonate plates that look like vertebrae—these are called vertebral ossicles and are moved by the animal’s muscles. Both the body and arms are covered in calcium carbonate plates, likely for defense, and the arms have delicate spines. The arms lack dorsal and ventral shields, and the madreporite sits on the edge of the central disc. Digestive glands extend into the base of the arms. There are no bursae for gonads or gas exchange. The mouth is small, triangular, and plated, with six conical teeth arranged in a circle. Reported colors include dark brown or purple, sometimes with spots.
*O. fugiens* was once thought to be extinct but is found in South Asian seas, with studied specimens collected off the shores of the Philippines. It lives from the seashore floor down to depths of 200 meters. It has a mutualistic relationship with black corals, feeding on harmful microorganisms and microparticles on the reefs. It may also scavenge the benthic floor for detritus and plankton, or use its arms to propel itself and capture particles. The arms also contain photoreceptive tissues that allow the animal to sense and respond to light, even though it has no eyes. No sexual dimorphism has been reported. Its evolutionary history is largely considered an enigma, and little is known about it.
Quick Facts
- Regnum
- Animalia
- Phylum
- Echinodermata
- Classis
- Ophiuroidea
- Ordo
- incertae sedis
- Familia
- Ophiocanopidae
- Genus
- Ophiocanops
- Species
- O. fugiens
- Binomial
- Ophiocanops fugiens
- Binomial Authority
- Koehler, 1922
Facts from the source article.
Lore & Background
Ophiocanops fugiens displays a central, armored, disk-shaped body that is clearly demarcated from the arms and is 3 mm in diameter. The arms reach lengths of 35–40 mm and are roughly 1 mm across, supported by an internal skeleton of calcium carbonate plates that resemble vertebrae, called vertebral ossicles, controlled by the muscular system. The arms lack dorsal and ventral shields; the madreporite is on the edge of the central disc. The digestive glands extend into the proximal portions of the arms. It has no bursae for gonads or gas exchange/excretion. The mouth is small, triangular, and plated, featuring a set of six conically arranged teeth. The body and arms bear calcium carbonate plates, presumably for defense, and the arms have delicate spines. O. fugiens has been reported to be dark brown or purple in color, sometimes exhibiting spotted coloration.
Reader's Guide
Ophiocanops fugiens is significant as a living species once thought to be extinct, found in South Asian seas, with studied specimens from the shores of the Philippines. It inhabits waters from the seashore floor to depths of 200 meters. Ecologically, it has a mutualistic symbiotic relationship with Black Corals, feeding on potentially harmful microorganisms and micro-particles that inhabit coral reefs, and may also scavenge benthic floors for detritus and plankton, or use the propellant motion of its arms to capture surrounding particles. The arms also serve as photoreceptive tissues, as O. fugiens lacks eyes but responds to changes in light. Its evolutionary development is largely classified as an enigma, with little known about it. The small, compact central disc is proposed to have developed to lessen predation pressure, and the species is capable of regenerating arms. Reproductive tendencies are not well known; highly developed gonads extend into the arms, and it is presumed that females carry fertilized eggs in the arms and release them through a distinguishable genital slit on the arms. Juvenile development is lecithotrophic, meaning larvae feed on yolk to develop to metamorphosis; as larvae develop, the anus is lost and intestines are not apparent.
Did You Know?
- Ophiocanops fugiens was once thought to be extinct before being found alive in South Asian seas.
- Juvenile O. fugiens are lecithotrophic, feeding on yolk, and lose the anus and intestines during development.
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