Broad disc with five or more long arms. The aboral skeleton is meshlike; the plates bear pseudopaxillae. The marginal pseudopaxillae are larger than the aborals. Oral intermediates are present. The adambulacral spines consist of two series at right angles to each other. The mouth plates are prominent. No pedicellariae.
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Solaster endeca has a broad disc and 7 to 13 - usually 9 to 11 - short, sharply tapering arms. It is usually red or orange aborally and yellow or beige on oral side, but it occasionally has a purple stripe down each arm, similar to S. stimpsoni. The arm length can be up to 20 cm; the average length in British Columbia is 9 cm. The ratio of arm to disc is from 2.3 to 3.3. S. endeca has numerous fine, crowded aboral pseudopaxillae and 5 to 9 spinelets with single papulae between. Its disc is thick and tapers down to the arm tips. The superomarginals are only slightly larger than the aboral pseudopaxillae, but the wide inferomarginals alternate with them and form a very obvious series. The size of oral interradial area varies with the number of arms but is larger than the other species of Solaster. The adambulacral spines do not protrude noticeably above the general oral surface. There are 1 to 4 furrow spines deep in the furrow and a curved transverse series of 6 to 8 sharp spines on the oral surface. The inner and outermost spines of the curve are farthest from the mouth. The mouth plates have 7 to 9 marginal spines (the apical spines are largest) and 6 to 15 sub orals in two series or in a triangular group.
Solaster endeca differs from S. stimpsoni in its arm-to-disc ratio and the arrangement of the adambulacral spines.
In the Atlantic, Solaster endeca is reported to be a voracious feeder on sea stars and molluscs, but on the Pacific coast it neither attacks nor evokes escape responses in other sea stars. Of 29 specimens examined, 21 were feeding on the small sea cucumber Cucumaria lubrica, 2 on C. miniata (Orange Sea Cucumber), and the remainder on bryozoans, sea squirts, and unidentified organisms. S. endeca causes the California Sea Cucumber (Parastichopus califomicus) to swim when contacted. Near Juneau, Dr. Rita O'Clair reported that S. endeca fed on the False White Sea Cucumber (Eupentacta pseudoquinquesemita) in the intertidal zone.
S. endeca breeds from March to April. Its large yolky eggs (1 mm in diameter) develop into non-feeding planktonic larvae. After about 20 days, they form small tube feet and settle to the bottom. Unlike Pycnopodia helianthoides and S. dawsoni, in British Columbia S. endeca does not elicit escape responses in the abalone Haliotis, key-hole limpet Oiodora, turban snail Tegula or the swimming scallops Chlamys spp. The scale worm Arctonoe vittata is commensal on S. endeca.
Circumboreal: Arctic Ocean; in the North Atlantic to Great Britain and Cape Cod; in the North Pacific to Puget Sound. Found from the intertidal zone to 475 metres deep. In shallow water, it is usually on rocky substrates, but in the deeper part of its range, it is often on pebbles or mud. Uncommon.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. 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:
2022-11-26 4:40:43 AM]
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