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

Leptasterias polaris katherinae (Grey, 1840)
Six-armed Star
Family: Asteriidae

© Aaron Baldwin  Email the photographer   (Photo ID #4110)

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Distribution of Leptasterias polaris katherinae 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

Leptasterias polaris katherinae is a large six-armed sea star with an arm length of up to 14.8 cm and an arm-to-disc ratio of 4.5 to 5.3 It's well-spaced, subcapitate aboral spines do not form a clear carinal row. L.p. katherinae has a single row of superomarginal spines, one row of inferomarginals and two rows of oral intermediates. The adambulacral spines normally alternate one and two, with the furrow spine of the pair more slender than the distal one. The superomarginals have a complete wreath of pedicellaria; the inferomarginals and oral intermediates have a half wreath on the distal side. Each mouth plate bears three spines, a small spine guarding the entrance to the furrow, an intermediate flat spine pointing over the mouth, and a much longer tapered suboral spine.

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.

Biology


Unknown, but the gonopore opens to the ventral side, like other Leptasterias, suggesting a brooding behaviour.

Distribution

Distribution

The species Leptasterias polaris ranges across the Arctic Ocean from the intertidal zone to 137 metres deep. There are four subspecies: L.p. borealis in the waters off eastern North America; L.p. polaris in the high Arctic of eastern North America; L.p. acervata from the Arctic to the Shumagin Islands and just south of the Alaska Peninsula to Kodiak Island; and L.p. katherinae, first described from the mouth of the Columbia River and in the Strait of Georgia, but it has not been documented from this region (the area from Glacier Bay to Puget Sound to a depth to 200 metres) since. I have tentatively identified some specimens of L.p. katherinae from Glacier Bay and near Juneau at depths of 5 to 10 metres, but more records are needed to clarify its correct depth distribution.

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 6:22:54 AM]
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