Kingdom: Animalia
Phylum: Echinodermata
Class: Asteroidea (Starfish or sea stars)
Order: Forcipulatida
Family: Asteriidae

Genus/species: Asterina miniata

GENERAL CHARACTERISTICS: Colors may be colored red, orange, brown, purple or mottled. They have webbing between their short, triangular arms, which gives them a batlike look. Size is up to 20 cm (eight inches) across. Radially symmetrical they normally have five arms, but they occasionally have as many as nine arms. They have tube-feet that allow locomotion.

DISTRIBUTION/HABITAT: Sitka, Alaska to Baja California, Mexico. Found in low intertidal areas on rocks overgrown with surfgrass, large algae and sponges. Depth intertidal to 290 m (950 ft) on rocky or sandy substrates.

DIET IN THE WILD: Sensors at the end of each arm that sense light and detect prey. Typically an omnivore or scavenger: surfgrass, algae, colonial tunicates, organic films on hard surfaces, as well as other seastars.  Like most seastars, feeds by everting its stomach over prey.

See everted Bat Star stomach below.

REPRODUCTION: Usually spawns May to June. The male broadcasts sperm and the female broadcasts eggs from pores near the bases of their arms. Embryos and larvae are transparent.

PREDATORS Other sea stars, molluscs, and crustaceans. Like some other sea stars, bat stars can sometimes avoid predation by secreting chemicals that evoke flight responses in other animals.

CONSERVATION: IUCN No special status. Collecting by tidepool visitors has diminished some populations, for example around the Monterey Peninsula.

REMARKS: When two bat stars bump into each other, a gentle brawl begins. They seem to be “arm wrestling” in a slow motion skirmish where no winner is usually obvious.

Bat stars lack the pedicillariae, or pincers, common to most other sea stars and used to clear the animal of unwanted parasites and other debris. Even so, bat stars are free of debris, perhaps because small, constantly moving hairs (cilia) discourage settling

Sea stars have endoskeletons made up of plates (calcified ossicles) joined by connective tissue to protect the bat star’s vital organs.  The bat star’s ossicles are so large and defined that they look like rough shingles. 


REMARKS:  SEA STAR WASTING SYNDROME has become a major issue in both the Pacific and Atlantic Oceans. For an excellent summary check this link to the University of Santa Cruz 9-9-14.

Fitzgerald Marine Reserve.



Monterey Bay Aquarium

U. of Michigan Animal Diversity Web

Ron’s flickr

Ron’s WordPress shortlink