[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.
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On the Pacific coast, Henricia sanguinolenta is nearly always white to pale orange. The Atlantic form is red, as the species name suggests. It has five arms up to 13 cm long, and an arm-to-disc ratio of 5 to 7. The aboral surface consists of smalt close-set pseudopaxillae with few (3 to 6) to many (25 to 30) spinelets. The papular areas are smalt with 1 to 4 papulae. The marginals are also small and do not form an obvious series. A row of intermarginals varies from a short series to the full length of the arm. Oral intermediates form one or two series, with the longest row reaching to the distal third of the arm. The adambulacrals usually have 10 to 15 (5 to 25) spinelets on each plate, 2 or 3 of these on the edge of the furrow. A short curved spinelet sits on the furrow face.
Taxonomic Note: The taxonomy of this species in the North Pacific is in need of revision. There is disagreement in the literature that remains unresolved. According to Madsen (1987), H. sanguinolenta does not occur in the North Pacific but its close relative, H. tumida Verrill, 1909, does. H. tumida has short stubby arms and its arm-to-disc ratio is from 2 to 2.7. Fisher (1911) examined over 1000 specimens of Henricia from the west coast and determined that many fit the description of H. sanguinolenta. I have also examined specimens with an arm-to-disc ratio of 4.5 to 6.9, which is well out of the range of H. tumida and closer to that of H. sanguinolenta. Madsen did not consider North Pacific specimens in his study, so I am more inclined to agree with Fisher for the purposes of this book . Obviously, more taxonomic work on this species is needed.
In contrast to other Henricia species, this one has small marginals that do not form an obvious series. The arms are generally fat at the base and often there is a crease where the arm joins the disc. Within diving depth this is the only white
The biology of the Pacific form of Henricia sanguinolenta has not been studied. In the Atlantic form, a complex series of grooves, called Tiedemann's diverticula, connect the stomach to five pairs of digestive glands. The cilia lining these grooves create a current that allows the sea star to feed on plankton or suspended particles. H. sanguinolenta is frequently found on the sponges Mycale, Ficulina and Hymeniacidon and was thought to eat them, but Anderson (1960) suspected that they were tapping into the feeding current of the sponge. The sponge seldom seems to be damaged much by the sea star. This habit may explain why we see it here associated with Boot Sponges.
H. sanguinolenta breeds from February to April on the Atlantic coast. In the White Sea, breeding begins at the end of June. Males cast sperm into water, females arch up and retain fertilized eggs around the mouth. Twenty days after postembryonic development begins, the larva transforms into a juvenile sea star. This species shows a negative response to light. The parasitic copepod Asterocheres lilljeborgi lives on its skin.
Circumpolar. To Cape Hatteras in the Atlantic and Washington in the Pacific. Found on solid rock or mud at depths of 15 to 518 metres in the Pacific and 200 metres in the Atlantic. I have often seen it draped over boot sponges in fiords. More common in mainland inlets of British Columbia.
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 5:18:20 AM]
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