Dirona aurantia Hurst, 1966

Common name(s): Gold dirona

Synonyms: Dirona aurantia
Phylum Mollusca
Class Gastropoda
Subclass Opisthobranchia
Order Nudibranchia
Suborder Arminacea
Family Dironidae
Dirona aurantia from Coffin Rocks, about 12 m depth.  This individual is eating a bryozoan, which is the species' diet.
(Photo by: Kirt Onthank summer 2007
Description:   As with other members of suborder Arminacea, the anus is not on the midline of the dorsum but instead is on a conspicuous papilla on the posterior third of the right side of the dorsum.  The rhinophores have no sheath and cannot be completely retracted.  This species is orange to reddish orange with scattered white spots.  Each of the flattened, leaflike cerata has a white line on it which becomes wider as it approaches the tip.  It has an oral (frontal) veil but there is no white line around the front of the frontal veil.  The rhinophores are lamellate and orange to reddish.  Adults are from 3 to 12 cm long.

How to Distinguish from Similar Species:  The cerata on Arminaceans such as this species often make them look a lot like Eolid nudibranchs, but they can be distinguished from Eolids because Arminaceans have the anus on a papilla on the rear third of the body (right side) while Eolids have it on the anterior third of the body (right side). Dirona albolineata has grayish white, salmon, or purple cerata with white lines and a white line around the foot and frontal veil and between the cerata but has no white splotches.

Geographical Range:  King Island, Alaska to Puget Sound.

Depth Range:  Shallow subtidal

Habitat:  Rocks, kelp, and mud, sometimes around floating docks.

Biology/Natural History:  This species feeds on bryozoans



 

References:

Dichotomous Keys:
  Kozloff 1987, 1996
 

General References:
  Behrens,1991
  Harbo,1999
  Kozloff,1993

Scientific Articles:

Web sites:


General Notes and Observations:  Locations, abundances, unusual behaviors:



Authors and Editors of Page:
Dave Cowles (2007):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)