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

Leptasterias aequalis
Six-Armed Star
Family: Asteriidae

© Aaron Baldwin  Email the photographer   (Photo ID #2059)

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Distribution of Leptasterias aequalis in British Columbia
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Introduction


Family Description:

Five or more arms. At least one adambulacral is fused into an adoral carina. The adambulacrals are wider than their length. Crossed and straight pedicellariae are present, the former usually in dense tufts around the spines. The aboral skeleton is meshlike. The tube feet are arranged in four rows.

Species Information

Members of the Leptasterias aequalis species complex are small to medium sized. They have six arms up to 5 cm long, and their arm-to-disc ratio is about 4. To the naked eye, the aboral and lateral surfaces seem to be compactly covered with clusters of granular spines (up to 10) with small papular areas separating them. These sea stars have a carinal series of tightly spaced clusters of spines and a dorsolateral series of one to six spinelets per cluster in well-defined longitudinal rows; their pedicellariae are usually present but inconspicuous; the aboral spines are typically subcapitate; the superomarginals each have 4 to 8 slightly bent spines in a vertical series; the inferomarginals have two longer spines; and the oral intermediates are arranged in one, occasionally two, well-developed series. The adambulacrals have one or two spines in irregular alternation. There are clusters of crossed pedicellariae on the distal sides of the adambulacrals, oral intermediates and inframarginals.

Similar Species

Small Leptasterias may be confused with juveniles of Pisaster ochraceus or Evasterias troschelii, which occasionally have six arms. P. ochraceus has a single spine on each adambulacral, with a cluster of pedicellariae at the base but not on the spine. Leptasterias has one or two spines per plate with a cluster of pedicellariae on the spine itself. E. troschelii has pedicellariae on the adambulacrals but an arm-to-disc ratio of 5.0-7.6 and six similar rows of spines between the superomarginals and the furrow, made up of two inferomarginals and four oral intermediates. Leptasterias has no more than two oral intermediates.

Distribution

Distribution

Vancouver Island and the San Juan Islands to Santa Catalina Island, California, in the intertidal zone. The small brooding forms of Leptasterias are commonly found on rocky shores under rocks, in crevices and in mussel beds; larger specimens are found subtidally.

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.

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: 18/11/2019 5:27:41 AM]
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