Ophionereis reticulata
A reticulated brittle star with unique tube-foot locomotion.
Ophionereis reticulata, the reticulated brittle star, belongs to the family Ophionereididae. This species lives in shallow waters of the western Atlantic, the Caribbean Sea, and the Gulf of Mexico.
Its body consists of a small, flat, five-sided disc and five long, thin arms. The disc reaches up to 15 mm across, while the arms can extend to 120 mm in length. The upper side of the disc is covered in small plates and is pale grey, marked by a fine network of reddish-brown lines—the pattern that gives the animal its common name. The arms are made up of many short segments, each fringed with short spines. They are white or pale grey, with a chocolate-brown band appearing roughly every fourth joint. This coloring helps the brittle star blend into its surroundings.
The species ranges from the West Indies and Bermuda through Mexico, Belize, Honduras, Venezuela, and Brazil, with its type location in the Florida Keys. It lives on sandy or gravelly bottoms, among boulders, and under rocks, at depths between 3 and 40 meters.
When moving, Ophionereis reticulata holds its disc above the seafloor and uses its tube feet for locomotion. These feet are long and pointed, and they are the only part of the arm that touches the ground. To move forward, the brittle star bends the base of a tube foot at a right angle, extends the tip forward, then straightens the foot while lifting itself onto the tip. Repeating this action allows it to creep at up to 50 cm per minute, with any arm or pair of arms leading the way.
This brittle star is an herbivore and filter feeder, but its stomach has also been found to contain detritus and bits of polychaete worms. It mainly eats red and green algae and diatoms, catching them by raising one or more arms into the water current while keeping its disc hidden. If a predator attacks an arm, the arm can break off through autotomy, and the brittle star later regenerates a new one. The sexes are separate, and spawning occurs once a year. The resulting ophiopluteus larvae drift as plankton, passing through several stages before settling on the seabed and metamorphosing into juveniles.
Quick Facts
- Genus
- Ophionereis
- Species
- reticulata
Facts from the source article.
Lore & Background
Ophionereis reticulata has a small flattened, pentagonal disc and five narrow, elongated arms. The aboral surface of the disc is covered with small plates and is pale grey with a network of fine reddish-brown lines, giving it its common name. The arms have many short joints and are fringed on either side with short spines; they are white or pale grey with a band of chocolate brown approximately every fourth joint. This colouration makes the brittle star inconspicuous against its typical background.
It is found on sandy or shingle bottoms, among boulders and under rocks at depths between 3 and 40 metres. Unlike many other brittle stars, it uses its tube feet in locomotion: the long, pointed tube feet are extended forward by bending at right angles at the base, then straightened as the brittle star raises itself onto the points, allowing it to creep forward at up to 50 centimetres per minute. Any arm or pair of arms can lead.
Ophionereis reticulata is an herbivore and filter feeder, but detritus and fragments of polychaete worm have also been found in its stomach. It mainly consumes red and green algae and diatoms, catching them by raising one or more arms into passing water currents while keeping its disc concealed. If an arm is attacked by a predator, it can break off through autotomy and later regenerate. The sexes are separate, and spawning occurs once a year; the ophiopluteus larvae are planktonic, passing through several larval stages before settling on the seabed and undergoing metamorphosis into juveniles.
Reader's Guide
Ophionereis reticulata is a distinctive brittle star of the western Atlantic, Caribbean Sea, and Gulf of Mexico, recognized for its reticulated pattern and unique mode of locomotion using tube feet rather than arm movement. Its coloration—pale grey with fine reddish-brown lines on the disc and chocolate-brown bands on the arms—provides effective camouflage on sandy or shingle bottoms, among boulders, and under rocks. The species is both an herbivore and filter feeder, primarily consuming red and green algae and diatoms, though it also ingests detritus and polychaete worm fragments. Its ability to raise arms into water currents to capture food while concealing its disc demonstrates a specialized feeding strategy. Autotomy allows it to shed an arm if attacked, with subsequent regeneration. The annual spawning and planktonic larval stages contribute to its dispersal across a range extending from Bermuda and the West Indies to Brazil. The type locality is the Florida Keys, and it occupies depths from 3 to 40 metres. Its locomotion speed of up to 50 centimetres per minute and the use of tube feet in movement are notable behavioral traits that distinguish it from many other brittle stars.
Did You Know?
- Ophionereis reticulata uses its tube feet for locomotion, unlike many other brittle stars.
- The species is an herbivore and filter feeder, but also consumes detritus and polychaete worm fragments.
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