Fragile Sand Star, Astropecten fragilis

Fragile Sand Star, Astropecten fragilis. Sea star collected off the Southwest coast if Baja California Sur, November 2012. Pictured stars diameter: 19 cm (7.5 inches).

Phylogeny:  The Fragile Sand Star, Astropecten fragilis (Verrill, 1867), is a member of the     Astropectinidae Family of Sea Stars. The genus Astropecten is one twenty-six genera in this family, and the are one hundred four species in this genus. They are known in Mexico as estrella frágil.

Morphology:  Fragile Sand Stars are somewhat flattened and have only a moderately wide central disc. The five arms are narrow, tapering, and about 6.5 times longer than the radius of the disc. The plates along the margin of the arms and disc are very obvious. The aboral surface of these stars is brown to gray-brown in color, and the marginal plates are lighter in color. Fragile Sand Stars reach 25 cm (10 inches) in diameter.

Habitat and Distribution: Fragile Sand Stars are found on sand. They live subtidally to depths up to 203 M (666 feet). They are an eastern Pacific species and in Mexican waters they range from the Central Sea of Cortez south to Guatemala.

Diet: Fragile Sand Stars are a poorly studied and understood species. There is limited documentation regarding the diet of this species. Other species in this family feed on bivalves, carrion, crustaceans, detritus, gastropods, sea urchins, and other sea stars. All prey is swallowed whole as they do not have the ability to extrude their stomachs.

Predators:  Fragile Sand Stars are a poorly studied and understood species. There is little documentation regarding predation of this species. Other species in this family are prey for small crabs and small fish.

Reproduction: Fragile Sea Stars are gonochoric (male or female for life). Reproduction may be asexual, by both regeneration and clonal, or sexual.  Sexual reproduction involves broadcast spawning with external fertilization.  The fertilized eggs hatch into planktonic larvae and later metamorphose into pentamerous juveniles which develop into young sea stars with stubby arms.

Ecosystem Interactions: Fragile Sand Stars are a poorly studied and understood species. The ecosystem interactions of this species have not been documented. Some species in this genus have commensal relationships with polychaetes. Also, endoparasitic crustaceans of the genus Dendrogaster parasitize species in Astropecten genus.

Human Interactions:  Fragile Sand Stars are seldom seen by humans and they have little 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:  None