Rostanga pulchra MacFarland, 1905 Common name(s): Red sponge nudibranch, Red sponge doris, Red nudibranch, Crimson doris
Synonyms:
Phylum Mollusca Class Gastropoda Subclass Opisthobranchia Order Nudibranchia Suborder Doridacea Family Rostangidae
	Rostanga pulchra, approximately 1 cm long, on a sponge at Swirl Rocks
	(Photo by: Dave Cowles July 2005)

How to Distinguish from Similar Species: Aldisa sanguinea, which lives from Oregon to Baja California and also feeds and lives on red sponges, has perfoliate rhinophores.

Geographical Range: Point Craven, Alaska to the Gulf of California; Chile, Argentina

Depth Range:  Intertidal to 102 m

Habitat:  On and around red sponges

Biology/Natural History:  This species feeds on, and is often found on, red sponges such as Acarnus,Esperiopsis,Ophlitaspongia, and Plocamia.  It lays its eggs in a tight orange circle on the sponges March to October (photo).  The larvae are planktonic for 30-45 days, then settle.  An encounter with at least one prey sponge, Ophlitaspongia pennata, can induce larvae to settle.  It is believed that its orange pigment comes from the sponge.  Adults can locate and navigate to distant Ophlitaspongia sponges by smell.  Some individuals seem to stay quite close to one area while others range for distant sponges.  Predators may include the flatworm Notoplana acticola.  The cephalaspidean predatory nudibranch Navanax inermis is repelled by secretions from Rostanga.

References:

General References:
  Behrens, 1991
  Bruscaa nd Brusca, 1978
  Harbo, 1999
  Hinton, 1987
  Johnson and Snook, 1955
  Kozloff, 1993
  Morris et al., 1980
  Niesen, 1994
  Niesen, 1997
  O'Clair and O'Clair, 1998
  Ricketts et al., 1985
  Sept, 1999

Scientific Articles:

Web sites:

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

This individual is crawling across red algae in a tidepool.  Photo by Dave Cowles, July 2005

This 1/2 cm specimen was photographed by Dave Cowles at San Simeon, CA May 2001

This species lays red coils of eggs on the red sponge on which it feeds.  Photo by Dave Cowles in a tidepool, July 2012

This pair of nudibranchs on a sponge near the one shown above with eggs are probably preparing to mate and lay eggs as well.

The closeup rhinophore views above and below show the structure of the rhinophores, with vertically oriented leaves terminating in a slender papilla.

Dorsal (above) and side views (below) of the retractable gills. The gills have a small piece of debris clinging to them. Animal is 14 mm long.

The dorsum is textured by small dorsal tubercles, as is visible in the view of the posterior dorsum behind the gills.