[In this family,] the disc is small in relation to the arms, which are long, narrow and cylindrical. The aboral plates are arranged as a fine or coarse mesh, usually bearing short spines, alone or in groups. No pedicellariae. The tube feet have single ampullae.
Henricia leviuscula leviuscula is the most common red thin-armed sea star in the intertidal and shallow waters of British Columbia. The colour may vary from orange to brick-red, to brown, and some specimens may have a grey patch around the base of the arms or covering the disc. The aboral surface is variable, but the three rows of plates along the lower side of each arm are a constant feature. H.l. leviuscula has five arms (rarely six) up to 16 cm long, and an arm-to-disc ratio of 3 to 7. The aboral plates, covered with 30 to 60 small, close-set spinelets, are close together and normally larger than the papular spaces. The supero- and inferomarginals form a regular series. At the base of each arm, the two marginal series split to form a triangular group of intermarginals. The oral intermediates form a regular series to the arm tip, or nearly so. The adambulacrals bear 5 to 12 stubby spine lets in two transverse rows, increasing in size proximally, and a short, curved spine let deep in the furrow.
Small, yellowish sea stars that live under rocks in the intertidal zone and brood their eggs are probably an undescribed species of Henricia. Meg Strathmann of Friday Harbor Laboratories is working on the description and naming of this new animal.
Henricia leviuscula Ieviuscula feeds on plankton, dissolved organic matter, bryozoans and the encrusting sponges Sigmadocia sp. and Isodictya quatsinoensis (N. McDaniel personal comment).
I have seen large males releasing sperm from gonopores between the arms in April and May. Small yellowish females with brown mottling, that brood bright red-orange eggs (500 micrometres in diameter) from January through March are probably an undescribed species of Henricia (M. Strathmann, personal communication). The scale worm Arctonöe vittata and the caprellid Caprella greenleyi are commensal on H.l. Ieviuscula. Juveniles, less than 10 mm, live on tubes of the polychaete worm Phyllochaetopterus. H.l. Ieviuscula rights itself by somersaulting: it raises its central disc as it presses its arms onto the substrate, then two of the arms "walk" underneath the disc and the opposing arms fold over, so that the animal lands on it oral surface.
The Bering Sea to Oregon and to Okhotsk and the Sea of Japan; 9 to 680 metres.
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:
2022-01-23 8:31:33 PM]
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