Bat Star, Patiria miniata
Bat Star, Patiria miniata. Underwater photograph taken in coastal waters off Anacapa Island, California, February 2021. Wingspan: 10 cm (3.9 inches). Photograph and identification courtesy of Bob Hillis, Ivins, Utah.
Bat Star, Patiria miniata. Underwater photograph taken in coastal waters off Anacapa Island, California, February 2021. Wingspan: 11 cm (4.3 inches). Photograph and identification courtesy of Bob Hillis, Ivins, Utah.
Phylogeny: The Bat Star, Patiria miniata (Brandt, 1835), is a member of the Asterinidae Family of Sea Starfish, that are known in Mexico as Estrella Murcielago. There are three global members of the Patiria Genus, with this species being the only one found in Mexican waters of the Pacific Ocean.
Morphology: Bat Stars have relatively flat bodies with short, webbed arms. Most specimens have five arms, but the number can range from four to nine. Bat Stars reach a maximum of 20 cm (7.9 inches) in diameter. The aboral surface may be brown, gray, lavender, orange, red, white or yellow with either solid coloration or blotched or speckled. The aboral surface has a scale-like texture with cilia, no pedicellariae or spines. These cilia facilitate water movement across the surface of the organism to help with cleaning. Breathing occurs through gill-like respirators on the aboral surface. Each arm has visual sensors that detect light in order to locate the movement of prey. The Bat Star has two stomachs, one of which is used to digest food outside of the body: the cardiac stomach. This stomach covers the prey in digestive enzymes before pulling it back into the body. When there is no prey, the stomachs can be extended into the water and act as a net to catch microorganisms.
Distribution: Bat Stars reside on rocky reefs, and occasionally on sand bottoms. They range from the lower intertidal zone to depths up to 300 m (984 feet). Bat Stars are a temperate to subtropical Eastern Pacific species. The Bat Star has a limited distribution in Mexican waters of the Pacific Ocean being found from Cedros Island, Baja California, northward along the central and northwest coasts of the Baja Peninsula.
Diet: Bat Stars are ominous predators and scavengers of both plant and animal material. They consune algae, bryozans, carrion, sea grasses, tunicates, sea stars and sea urchins.
Predators: Bat Stars are preyed upon by shore birds, crabs, mollusks and other sea stars.
Reproduction: Bat Stars are gonochoric (male or female for life) and can reproduce both sexually and asexually. Asexual reproduction occurs through fragmentation. Sexual reproduction occurs through broadcast spawning, with external fertilization.
Ecosystem Interactions: Bat Stars often have a commensal relationship with the Annelid Worm Oxydromus pugettensis, which lives in the ambulacral grooves of the star. Bat Stars are know to fight by pushing if they encounter one another, appearing to be “arm wrestling.”
Human Interactions: Bat Stars have very limited impact on human activities. From a conservation perspective they have not been evaluated. Some populations have been severely impacted by Sea Star Wasting Disease.
Synonyms: Asterias miniata, Asterina coccinea, Asterina granulosa, Asterina miniata, Asteriscus coccineus, Asteriscus miniatus, Patiria coccinea, and Patiria granulosa.