E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Asterina miniata (Brandt, 1835)
Bat Star
Family: Asterinidae

© Neil McDaniel  Email the photographer   (Photo ID #15864)

E-Fauna BC Static Map
Distribution of Asterina miniata in British Columbia
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Introduction


Family Description

Flat body with short arms. The edge of body is sharp; the marginals are minute. The aboral surface is covered with overlapping plates bearing granules or short spinelets. The oral interradial area is also covered with overlapping plates bearing spinelets.


Species Information


Click on the image below to view an expanded illustration for this taxon. If more than one illustration is available for a species (e.g., two subspecies may be illustrated) then links to the separate images will be provided below.



Asterina miniata is a broad-armed sea star found in large numbers in shallow, sheltered waters on the west coast of Vancouver Island, the north coast of British Columbia, and the Queen Charlotte Islands. Its colour is extremely variable, and can be mottled or uniform red, yellow, brown, green and blue. The five arms (occasionally six) are up to 9 em long, and it has an arm-to-disc ratio of 1.6 to 2. The aboral plates along the radii of each arm are low and crescent-shaped with their concave side towards the centre. Smaller irregular plates are topped with a circle of granules. A row of tiny inferomarginals form the sharp edge between the aboral and oral sides. Immediately above them is a row of even smaller, round superomarginals. The oral interradial area is relatively flat from the mouth to the edge of the disc. Oral intermediates form a V-shaped pattern with the apex towards the mouth. Each plate has a webbed comb of 3 to 5 flat spines pointing away from the mouth that get smaller distally. The adambulacral plates have 2 to 4 furrow spines and an oblique row of 2 or 3 similar-sized spines on the oral surface. The mouth plates have 5 marginal spines and 2 or 3 heavier scoop-shaped suborals.

Similar Species

A. miniata has a similar shape to Dermasterias imbricata, but it feels like sandpaper rather than smooth and slippery.

Biology


The diet of Asterina miniata includes dead animals, seaweed, sponges, sea urchins and squid eggs. In southern California it feeds on the bryozoan Tubulipora, one of the first species to colonize a surface. Removing that bryozoan allows successional species to colonize sooner. A. miniata has an extremely large cardiac stomach with elaborate retractor muscles, but it is not able to open bivalves. Most of the digestive enzymes are produced by the pyloric caeca rather than the stomach as in other species. There is some evidence that it feeds on suspended particles with the aid of mucus. Bat Stars reach an arm length of 4 cm in about three years.

Populations of A. miniata may breed at any time of year, but individuals are not synchronized with each other. Each has an annual reproductive cycle requiring two months to rebuild the gonad after spawning. In California, the majority spawn in late spring or early summer and there may be another spawning in August. In Barkley Sound, recruitment originated mainly from the local population rather than from larvae migrating in from other regions. The final pattern of settlement was controlled by events just before settling or just after. For example, juvenile A. miniata were attacked by Pycnopodia helianthoides. Ophiodromus (formerly Podarke) pugettensis, a commensal scale worm, is often found on A. miniata. The structure of the eye spot is described by Eakin and Brandenburger (1979).

Distribution

Distribution

Sitka, Alaska, to the Gulf of California; intertidal to 302 metres. Asterina miniata is abundant intertidally on rocks, broken shells, gravel and sand on the exposed coast of British Columbia, but not in areas under the direct influence of the surf. It is found on the protected side of Vancouver Island only as far as the Gulf Islands in the south and the Port Hardy region in the north.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
UnlistedUnlistedUnlistedUnlisted
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Asterias miniata Brandt
Patiria miniata (Brandt, 1835)

Additional Range and Status Information Links

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 10/12/2019 6:11:27 AM]
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