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Poraniopsis inflatus inflatus (Fisher, 1906)
Sea Star
Family: Poraniidae
Extracted from Sea Stars of British Columbia, Southeast Alaska and Puget Sound by Philip Lambert.
Introduction to the Echinoderms of BC

Photograph

© Neil McDaniel     (Photo ID #15909)

Map

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Distribution of Poraniopsis inflatus inflatus in British Columbia in British Columbia

Introduction


Family Description:

Short armed and star shaped or almost pentagonal in form; the upper side is arched, the lower side flat. The aboral plates form a compact or open reticulum, but are obscured by a thick, opaque skin. Some have carinals linked to the marginals by an open reticulum with large nodal plates (as in Poraniopsis); only Poraniopsis has spines at each node. The marginals vary from prominent to small or absent; they are covered with skin and usually have no prominent spines. The oral intermediates run parallel to the inferomarginals. The adambulacrals have a few sheathed spines. Spaced or clustered papulae; no pedicellariae.

Illustration

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Illustration Source: : Sea Stars of British Columbia, Southeast Alaska and Puget Sound by Philip Lambert

Species Information

Poraniopsis inflatus inflatus is cream to bright orange with large white aboral spines. The five fat arms are up to 10 cm long and the arm-to-disc ratio ranges from 2.2 to 3.0. The aboral plates form an open mesh of large squarish areas occupied by numerous papulae. Prominent pointed spines occur at the junctions of the plates and a few smaller spines occur on secondary plates. Marginals are not readily distinguishable, because both series resemble the aboral plates and spines. Usually a row of smaller intermarginal spines are found on transverse plates between the two marginal series. Oral intermediates bear a few smaller, scattered spines between the inferomarginals and adambulacrals. The adambulacrals have one flat furrow spine and a similar flat or scoop-shaped spine on the oral surface. The mouth plates bear four marginal spines, the apical spine being largest and similar in size and shape to the adambulacral spines.

Characteristics



Similar Species

Difficult to confuse with any other species of sea star.

Biology


Not much is known about the feeding habits of Poraniopsis inflatus inflatus. Captive animals seem to prefer sponges. A spacious cardiac stomach with large retractor muscles suggests that the stomach can be extruded to digest large prey. In Tasu Sound, Queen Charlotte Islands, I collected two specimens among expanses of the large solitary cup corals Paracyathus stearnsi, which might be a likely prey. Dendrogaster punctata, a primitive barnacle, parasitizes P.i. inflatus.

Distribution

Distribution

The Gulf of Alaska, and from the Queen Charlotte Islands to San Diego, California; also to northern Honshu and Moneron Island, USSR. This sea star lives at depths of 11 to 366 metres on a variety of substrates, from mud to rocks. Uncommon in this region (the area from Glacier Bay to Puget Sound to a depth to 200 metres); only eight specimens are recorded in collections, but Neil McDaniel saw three during one dive in Barkley Sound.

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

Ocean Biogeographic Information System Distribution Map

General References

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