Multi-colored Brittle Star, Ophioderma variegatum
Multi-colored Brittle Star, Ophioderma variegatum. Underwater photograph taken in Zihuantanejo Bay, Guerrero, March 2019. Photograph courtesy of Ron Woheau, Zihuantanejo.
Phylogeny: The Multi-colored Brittle Star, Ophioderma variegatum (Lütken, 1856), is a member of the Ophiodermatidae Family of Brittle Stars. The genus Ophioderma is one of eleven genera in this family, and this genus contains thirty-six species. The genus name Ophioderma comes from the Greek words meaning “snake skin”, and refers to the snake-like arms of these brittle stars. The species name variegatum comes from the Latin word for “variegated” or “marked with different colors”. This refers to the mottled coloration of this species.
Morphology: Multi-colored Brittle Stars have pentaradial symmetry. They have a flattened central disk and five arms. The arms are long, thin, and flexible. The arms have tube feet on their underside, but unlike the tube feet of sea stars, these feet lack suction cups. There is a mouth on the underside of the disk. The mouth consists of five “jaws”. Unlike sea stars, brittle stars cannot extend their stomach out though their mouth to digest prey externally. They use their arms and tube feet to pass prey into their mouth. Multi-colored Brittle Stars are highly mobile, using their arms to walk and climb. The arms are banded, in varying colors- red, orange, brown, tan, black, and white. The disk also varies in color, usually red or brown. Some individuals have white blotches at the margins of the disk, between the arms. Multi-colored Brittle Stars reach a maximum of 17.5 cm (6.9 inches) in diameter.
Habitat and Distribution: Multi-colored Brittle Stars are usually hiding under rocks on rubble, sand, or mud bottoms. They are found in the lower intertidal zone, and to depths of 110 m (360 feet). The Multi-colored Brittle Star is an Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean.
Diet: Multi-colored Brittle Stars are a poorly studied and understood species There is no documentation of their diet. Other species within this genus are either predators or opportunistic scavengers. Species within this genus consume algae, copepods, crustaceans, echinoderms, foraminifera, mollusks, and polychaetes.
Predators: There is limited documentation related to the predators of Multi-colored Brittle Stars. Other species in the Ophioderma genus are primarily preyed upon by crustaceans and fish.
Reproduction: Multi-colored Brittle Stars are gonochoric (male or female for life). They can reproduce sexually or asexually. In sexual reproduction, they engage in broadcast spawning, with external fertilization. The fertilized egg turns into planktonic larvae that drift before settling on the ocean floor; then, they mature into adult brittle stars. Asexual reproduction is accomplished through regeneration.
Ecosystem Interactions: Multi-colored Brittle Stars are a poorly studied and understood species. There is no documentation of their involvement in commensal, parasitic, or symbiotic relationships.
Human Interactions: Multi-colored Brittle Stars have no direct impact on human activities. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Ophioderma variegata and Ophiura variegata.